WO2020091765A1 - Detection of contaminants or particles including sensing conductivity with a microinjector nozzle - Google Patents

Abstract

The present disclosure relates to a device for water quality testing. The device includes a chamber, a heater, a nozzle, and a sensor. The heater may heat the fluid in the chamber such that at least a portion of the fluid forms a droplet. The nozzle is in fluid communication with the chamber, and is at least partially defined by a nozzle material. The nozzle may be positioned for ejection of the droplet. The sensor includes at least two electrodes, at least one of which may be supported by the nozzle material and may be positioned to contact the droplet during the ejection to determine properties of the fluid.

Description

DETECTION OF CONTAMINANTS OR PARTICLES INCLUDING SENSING CONDUCTIVITY WITH A MICROINJECTOR NOZZLE

BACKGROUND

[001] The disclosure relates generally to techniques for testing fluids. More specifically, the disclosure relates to water quality testing. Water may contain a variety of trace materials which determine the water’s suitability for a variety of applications, such as drinking. Different applications may require a determination that amounts of certain materials fall inside a predetermined range. Periodic testing of a given water source may be required by certain regulatory environments.

[002] In order to test water, samples may be collected and sent to a laboratory for analysis. Other tests may be performed at or near the water source. Tests may require large sample volumes, bulky or delicate equipment, and/or expensive reagents that make it difficult to regularly test water samples.

SUMMARY

[003] Examples described herein include devices. An example device may include a chamber, a heater, a nozzle, and a sensor. The heater may heat a fluid in the chamber to form a droplet. The nozzle may be in fluid communication with the chamber, and may be at least partially defined by a nozzle material. The nozzle may be positioned for ejection of the droplet from the chamber. The sensor may include at least two electrodes supported by the nozzle material and positioned to contact the droplet during the ejection.

[004] Examples described herein include methods. An example method includes heating fluid in a chamber to form a droplet. The method also includes forcing the droplet out of the chamber through a micromjector nozzle including contacting the droplet with a sensor. The sensor may include at least a pair of electrodes wherein at least one of the pair of electrodes is supported by the microinjector nozzle. The method also includes measuring an aspect of the fluid using the sensor.

[005] Examples described herein include systems. An example system may include a fluid source, and a plurality of devices. The fluid source may contain a fluid which may include water and a contaminant. Each of the plurality of devices may include a chamber, a heater, a nozzle, a sensor, and a measurement unit. The chamber may be in selective fluid communication with the fluid source. The heater may heat the fluid in the chamber to form a droplet. The nozzle may be in fluid communication with the chamber. The nozzle may be at least partially defined by a nozzle material and may be positioned for ejection of the droplet. The sensor may include at least two electrodes wherein at least one of the at least two electrodes is supported by the nozzle material and positioned to contact the droplet during the ejection. The measurement unit may be coupled to the sensor and may be configured to determine a property of the fluid.

QQ6] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[007] The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several examples in accordance with the disclosure and are, therefore, not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through use of the accompanying drawings, in which;

[008] Figure 1 is a schematic illustration, partially in cross-section, of a water quality measurement device;

Figures 2A - 2D are schematic diagrams, partially in cross-section, depicting an example operation of a micro-dispenser;

Figure 3 is a schematic diagram, partially in cross-section, of a device with a droplet in contact with a sensor;

Figure 4 is a schematic diagram in cross-section showing a device with electrode contacts at the nozzle material and heater;

Figure 5 is a schematic diagram in cross-section of a device with contacts placed around the sidewalls of the nozzle;

Figure 6 is a schematic diagram, partially in cross-section, depicting an array of devices;

Figure 7 is a flowchart depicting a method of measuring an aspect of a fluid; and Figure 8 is a block diagram illustrating an example computing device that is arranged for determining fluid properties,

all arranged in accordance with at least some embodiments of the present disclosure.

DETAILED DESCRIPTION

[009] In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative examples described in the detailed description, drawings, and claims are not meant to be limiting. Other examples may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the Figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are implicitly contemplated herein.

[Q1Q] This disclosure is drawn, inter alia, to methods, systems, products, devices, and/or apparatus generally related to a water quality testing device. The device includes a chamber, a heater, a nozzle, and a sensor. The heater may heat a fluid in the chamber to form a droplet. The nozzle is m fluid communication with the chamber and is at least partially defined by a nozzle material. The nozzle may be positioned for ejection of the droplet. The sensor includes at least two electrodes supported on the nozzle material positioned to contact the droplet during the ejection.

[011] Figure 1 is a schematic illustration, partially m cross section, of a water quality' measurement device, arranged in accordance with at least some embodiments described herein. Figure 1 shows device 102, substrate 104, chamber 106, heater 108, nozzle material 110, nozzle 112, sensor 114, first electrode 116, second electrode 117, and droplet 1 18. Additionally shown are fluid source 120, fluid 122 with water 124 and contaminants (and/or particles, impurities, biological matter, etc.) 126, measurement unit 128, controller 130, processor 132, and storage 134, temperature sensor 136 and output 138. The various components described in Figure 1 are merely examples, and other variations, including eliminating components, combining components, and substituting components are all contemplated.

[012] The device 102 is at least partially composed of a substrate material 104. This substrate material is shaped to form a chamber 106, which may be in selective fluid communication with the fluid source 120 to allow fluid 122 into the chamber. The chamber 106 may be connected to the fluid source 120 by a channel. In some embodiments, the channel may wick the fluid 122 into the chamber 106 (e.g., with capillarj⁷ action), in order to refill the chamber 106. A heater 108 is positioned near the chamber 106 in order to heat the fluid 122. The heater 108 may be positioned on the substrate material 104. A nozzle material (or nozzle substrate) 110 with a nozzle 112 is positioned so that the nozzle fomis an exit to the chamber 106. A sensor 114 has a first electrode 1 16 and a second electrode 117, in this vie each supported by the nozzle material 110 and positioned on opposite sides of the nozzle 1 12. As described herein, as the fluid 122 is heated in the chamber 106, it may form a droplet 118, which exits the chamber 106 through the nozzle 1 12, contacting the first and second electrodes 1 16, 117. Although only two electrodes 1 16, 1 17 are shown in the example of Figure 1, it is to be understood that additional electrodes may be used the device 102. For example, a reference electrode may be provided in some embodiments. The sensor 114 may be connected to a measurement unit 128, which may include a controller 130, a processor 132, and storage 134. The measurement unit 128 may also be coupled to a temperature sensor 136 and/or an output 138.

[Q13] The device 102 may selecti vely eject small volumes of the fluid 122 m the form of droplets 118. The droplets 1 18 may be about 50pL in some examples, about 40pL in some examples, about 30pL in some examples, about 20pL in some examples, or about 12pL in other examples. Other volumes may be used in other examples. The device 102, may be, for example, a micro-dispenser (or pdispenser). The device 102 receives the fluid 122 from fluid source 120 and into chamber 106. When the heater 108 is active (e.g., in an‘on’ state), a portion of the fluid 122 in the chamber 106 may superheat and nucleate, which may eject the remainder of the fluid 122, and the chamber 106 may refill with fluid 122 from the fluid source 120 when the heater 108 is inactive (e.g., in an 'off state). After the droplet 118 has been ejected from the chamber 106, the chamber may refill with additional fluid from the fluid source 120, allowing for the ejection of further droplets

[014] The device 102 is composed, at least m part, of substrate materi al (substrate) 104.

A chamber 106 is formed at least partially from the substrate material 104. The chamber 106 may take the form of a rectangular box, with the walls and floor of the chamber 106 composed of the substrate material 104. Example materials that may be used for the substrate material 104 include silicon, pyrex, quartz, and polyimides. In some embodiments, the walls and the floor of the chamber 106 may be composed of different materials. For example the floor of the chamber 106 may be composed of a first substrate material while the walls are composed of a second substrate material. Other chamber shapes may also be used, including circular chambers. An opening in one of the walls of the chamber 106 allows a fluid such as fluid 122 to enter the chamber 106. in addition to the substrate material(s) 104, part of the boundary of the chamber 106 may be formed from the nozzle material 110. In some embodiments, the chamber 106 may include a first substrate material as the floor of the chamber, a second substrate material as the walls of the chamber 106, and a nozzle material 110 as the top of the chamber 106. The nozzle material 1 10 may be used, for example, as a top surface enclosing the chamber 106. The nozzle material may be, for example, nickel which may be electroplated. Other nozzle materials, such as electroplated metals, etched structures, and photolithographically formed structures may be used in other examples. The nozzle 112 forms an opening of the chamber 106. As shown, the nozzle 112 is positioned in a center of one of the faces of the chamber 106 opposite heater 108. Other positions are possible in other examples, such as off-center.

[015] The heater 108 may heat fluid 122 while it is in chamber 106. The heater 108 may heat the fluid 122 by directly applying energy to the fluid 122, or may heat the fluid 122 indirectly, such as by applying energy to and heating the substrate 104. The heater 108 may be a resistive (joule) heater including a resistor, where voltage is applied to the resistor to generate heat. Other types of heaters may be used in other examples. The heater 108 may be positioned on an inner surface of the chamber 106 in contact with the fluid 122 while it is in the chamber 106. The heater 108 may be cycled between an‘on' state where it is applying energy to the fluid 122, and an‘off state where it is not applying energy to the fluid 122. A portion of the fluid 122 in the chamber 106 may superheat and nucleate, which may eject the remainder of the fluid 122 when the heater 108 is in an‘on’ state, and the chamber 106 may refill with fluid 122 from the fluid source 120 when the heater 108 is in the‘off state. The heater 108 may be cycled between the two states in order to eject droplets from the device 102 in a predictable pattern. As an example, the heater 108 may be in the‘on’ state for about a few psec, and the droplets may be ejected at a rate of about 10 kHz in some examples, 5kHz in some examples, 2 kHz in some examples, 1 kHz in some examples. Other rates may be used in other examples.

[016] In some embodiments, activation of the heater 108 (e.g., by flowing a current through it) may create inadvertent coupling with the sensor 114. The heater 108 may be spatially and/or temporally uncoupled from the sensor 114 to mitigate this. In some embodiments, the heater 108 may be positioned in an area of the chamber 106 away from the sensor 114. For example, as shown in Figure 1, the heater 108 may be located along a bottom surface of chamber 106 opposite the nozzle 112, while the sensor is positioned about the nozzle material 110. Other arrangements of the relative position of the heater 108 and sensor 114 are possible in other examples. In some embodiments, the measurement unit 128 may collect measurements from the sensors 114 when the heater 108 is not activated. Other arrangements to spatially and/or temporally decouple the heater 108 and sensor 114 may be used in other examples.

[017] The nozzle 112 may be an aperture that forms a passage from an inside to an outside of the chamber 106. The nozzle may be a passage passing through nozzle material 110. The nozzle may be a passage partially defined by the nozzle material 1 10 and partially defined by the substrate 104. The same piece of nozzle material 1 10 may- have multiple nozzles 1 12 connected to different chambers, such as the chamber 106. The nozzle material 110 may take the form of a flat plate. The nozzle material 110 may be a nickel orifice plate. The nozzle 112 may take the form of a hole passing from one side of the nozzle material to the other side of the nozzle material. The nozzle 112 may taper such that an area of the nozzle 112 at an end proximate the chamber 106 is larger than an area of the nozzle 112 at an end distal to the chamber 106. The profile of the nozzle 1 12 may have straight sides or curved sides. The nozzle 112 may be shaped to prevent a backflow of fluid into the chamber 106 through the nozzle 112. Q18] The sensor 114 is positioned to measure aspects or properties of the fluid 122 when the fluid 122 is ejected through the nozzle 112. In some examples, the aspects or properties of the fluid 122 which may be measured may include directly measured properties such as conductivity, resistance, impedance, capacitance, dielectric constant, or combinations thereof. In some examples, the aspects of the fluid 122 may include indirectly measured (or calculated) properties such as pH, temperature, conductivity, total dissolved solids (TDS), dissolved gases (e.g., dissolved oxygen), bubbles of gas (e.g., air), free chlorine, fluorine, E. coh, nitrates, phosphates, various heavy metals, organics, pathogens, or combinations thereof. In some examples, the directly measured properties may be used to determine a volume of fluid in the chamber and/or a rate at which the fluid fills the chamber, which in turn may be used to determine viscosity , hydrophobicity, and/or hydrophilicity of the fluid. In some examples, the device 102 may measure a rate at which droplets are ejected from the nozzle 112 which may be used to determine, for example, heat capacity and/or thermal conductivity of the fluid.

Q19] The sensor 114 may include the electrodes 116, 117 which may be separately addressable conductive regions. Although only two electrodes are shown in this example, it is to he understood that more electrodes could be used. The sensor may have a first electrode 116 and a second electrode 117. As shown in Figure 1, the first electrode

1 16 and the second electrode 1 17 are both positioned on the top (outer) surface of the nozzle material. The electrodes 1 16,1 17 are positioned on opposite sides of the nozzle 112, with ends positioned at an edge of the nozzle 112. The ends of the electrodes 116,

117 may come into contact with the droplet 118 as it is being ejected from the chamber 106 and through the nozzle 112. The electrodes 116, 117 may be arranged such that they are parallel to, or perpendicular to the flow of fluid 122 during the ejection. In some embodiments, one or more of the electrodes 116, 117 may be an array of electrodes positioned along the flow path of the fluid 122. In some embodiments, the electrodes 116, 117 may be comb finger electrodes, which may have an increased ability to sense the capacitance of the fluid 122 between the fingers of opposing electrodes. In some embodiments, a dielectric material may be layered over all or part of the electrode 116 or 117 to protect it from direct contact with the fluid 122. The fluid 122 of the droplet

118 forms an electrical connection between the ends of the two electrodes 1 16, 117 and allows sensor 114 to make an electrical connection with the fluid, which may be used to determine aspects of the fluid 122. The electrodes may have connectors (not shown) or other attachment methods for coupling to the measurement unit 128.

[020] The sensor 114 may be made of electrically conductive areas (such as first and second electrodes 116, 117) and may be integral with the nozzle, added to the nozzle, or both. The sensor 114 may be made from separate pieces of a conductive material attached to the nozzle material 110 The sensor 114 may be a patterned additional layer of conductive material layered on top of the nozzle material 110. The sensor 114 may include nickel, gold, or combinations. The nozzle material 110 may be patterned to include one or more electrodes of the sensor 1 14. The patterned material may include one or more gaps (and/or other non-conductive regions) between the electrically conductive areas to prevent shorting. In some embodiments, the gap may include non- conductive material, such as a dielectric material. In some examples, the gaps may be filled with air, silica, and/or other insulators. The pattern of conductive and non- conductive regions may be chosen for specific operations of the sensor 114 or specific measurements to be made.

[021] The fluid 122 may be water 124, which may contain impurities and/or contaminants 126. Other fluids may be used in other examples, including beverages (e.g., juice, milk, beer, wine, soda), chemicals, or other fluids. The water 124 may have certain properties, measurable by the electrode 1 14, which are altered by the presence and/or amount of the contaminants 126 present in the fluid 122. As an example, the presence of ions, such as salts, in the water 124 may change the conductivity' of the water 124. The fluid 122 in fluid source 120 may be sampled from municipal wastewater, industrial wastewater, drinking water, environmental water (e.g., lakes, rivers, groundwater, and marine water), aquatic environments (e.g., agriculture, aquaculture), or combinations. The fluid 122 may be loaded into the fluid source 120 for testing with the device 102 while the device 102 is on-site, at or near the location where the fluid 122 was obtained. The fluid source 120 of the device 102 may be in-line with a system using or transporting the fluid 122, such as in-line with a pipe.

[Q22] Although the fluid 122 has been described as water 124 with a contaminant 126, it is to be understood that the present disclosure may be used with a variety of fluids 122 containing a variety of substances. As an example, the fluid may contain particles or other dissolved or suspended matter which is measured. In some embodiments, the fluid 122 may be a multi -phasic fluid, and/or may contain dissolved biological material. For example, the fluid may contain cells and/or DNA. In some embodiments, the fluid 122 may be blood, and one or more properties of the blood cells (e.g., hematocrit, white blood cell count, etc.) may be measured.

[023] The measurement unit 128 includes a controller 130, a processor 132, and a storage function 134. The processer 132 may be used to determine a property of the fluid 122 based on a signal provided from the sensor 114. The sensor 114 may directly measure properties of the fluid 122 such as capacitance, resistance, conductance, dielectric constant, impedance, or combinations. The controller 130 may apply a voltage and/or current to the sensor 114 to assist in the property measurement. The applied voltage and/or current may be static or may vary in time to allow additional measurement techniques such as differential pulse anodic stripping voltammetry (DPASV), dielectric spectroscopy, dielectric sensors (capacitance probes), electrochemical impedance spectroscopy, or combinations thereof.

[Q24] The temperature sensor 136 may monitor a temperature of the device 102, the fluid 122, or both. The controller 130 may operate the heater 108 on a set cycle, or may- use feedback from the temperature sensor 136 to operate the device 102. The processor 132 may use the temperature sensor 136 to determine a temperature of the fluid 122. In some embodiments, the temperature sensor 136 may be a part of (or may be embedded in) the substrate 104. The measured temperature of the fluid 122 over time may be used to help calculate properties of the fluid, such as, for example, conductivity, thermal conductivity or heat capacity. The processor 132 may calculate additional properties of the fluid based on the directly measured properties such as pH, temperature, conductivity, total dissolved solids (IDS), dissolved gases (e.g., dissolved oxygen), bubbles of gas (e.g., air), free chlorine, fluorine, E. coli, nitrates, phosphates, various heavy metals, organics, pathogens, or combinations thereof. Tire measurement unit may be a separate part attached to the device 102, or may be integral with the device 102.

[Q25] The measurement unit 128 may be directly coupled to the sensor 114 or the sensor may act as an RC circuit to be resonantly interrogated at a distance. The measurement unit 128 may determine the properties of the fluid 122 in real-time or close to real-time. The determined properties may be output from the measurement unit 128 to output 138, stored in the storage unit 134, or combinations thereof. [Q26] Figures 2A - 2D are schematic diagrams, partially in cross-section, depicting stages of an example operation of a micro-dispenser, arranged in accordance with at least some embodiments described herein. Figures 2A-2D show device 202, chamber 206, heater 208, nozzle 212, droplet 218, fluid 222, and bubble 240. The various components described in Figures 2A-2D are merely examples, and other variations, including eliminating components, combining components, and substituting components are all contemplated.

[Q27] The device 202 depicted in each of Figures 2A - 2D may be implemented using the device 202 of Figure 1 in some examples. Other devices (e.g., other micronozzles) may be used to perform the depicted stages in other examples. As described, the device 202 has a chamber 206 which tills with fluid 222. In some examples, the chamber 206 may completely fill with fluid. In some examples, the chamber may be partially filled with fluid. As the fluid 222 is heated by heater 208, it may be ejected from the chamber 206 and through the nozzle 212 to form droplet 218.

[Q28] Figure 2A depicts a device 202 where the chamber 206 is filled with the fluid 222 The heater 208 is applying energy to the fluid. For example, the heater 208 may receive activation energy' from an energy source (not shown). The energy' may be applied such that the fluid is heated by about 100°C per psec in some examples. Other rates of heating may be used in other examples. The energy may raise the temperature of a portion of the fluid 222 above a boiling point of the fluid 222. The energy' may superheat that portion of the fluid 222. The heated portion of the fluid 222 may nucleate and form bubbles in the chamber. The bubbles may form in less than about 3psec in some examples. Other nucleaiion times may be used in other examples. The heated portion of the fluid may undergo a superheated vapor explosion.

[029] Figure 2B depicts the device 202 after the bubble nueleation depicted in Figure 2A. Part of the heated fluid 222 may form a bubble 240 which expands to fill chamber 206. As the bubble 240 expands, it may push some of the fluid out of the chamber 206 through the nozzle 212 to form the droplet 218. The growth of the bubble may take about 3 to 10 psec in an example. Other rates of bubble growth may occur m other examples. As shown in Figure 1, the electrodes 216, 217 of the sensor 214 may contact the droplet 218 during this stage of the process. Other electrode configurations may contact the droplet 218 during the same and/or different parts of the process. [Q30] Figure 2C depicts the device 202 after the bubble expansion of Figure 2B. After expansion, the bubble 240 may collapse. This collapse may release droplet 218, ejecting it from the nozzle 212. The droplet 218 may move away from the device 202 after ejection. The collapse of the bubble 240 may also cause more of the fluid 222 (or another fluid) to be drawn into chamber 206. The bubble collapse and droplet ejection may take about 10 to 20 psec m an example. Other times may be used in other examples.

[031] Figure 2D depicts device 202 after the bubble collapse of figure 2C. After the bubble collapse, additional fluid 222 continues to flow into chamber 206. The chamber may be either completely or partially refilled with fluid 222. The fluid may form a meniscus across the nozzle 212. After refilling, the device 202 may repeat the steps shown in Figures 2A - 2D as a cycle to continue ejecting more droplets 218. The total duration of the process may take less than about 80 psec m an example. Other process times may be used in other examples.

[032] Figure 3 is a schematic diagram, partially in cross-section, of a device with a droplet in contact with a sensor, arranged in accordance with at least some embodiments described herein. Figure 3 shows device 302, chamber 306, heater 308, nozzle material 310, nozzle 312, sensor 314, electrodes 316 and 317, droplet 318, fluid 322, and bubble 340. The various components described in Figure 3 are merely examples, and other variations, including eliminating components, combining components, and substituting components are all contemplated.

[033] The device 302 of Figure 3 may be implemented using the devices 102, 202 of Figures 1 - 2D in some examples. As shown in Figure 3, the sensor 314 includes a first electrode 316 and a second electrode 317 both positioned on a surface of the nozzle material 310 outside of the chamber 306. The two electrodes 316, 317 are selectively electrically separated from each other by the nozzle 312 when the nozzle 312 does not contain a droplet 318. The electrodes 316, 317 may be formed by an additional material added to a surface of nozzle material 310. The electrodes 316, 317 may include nickel electroplated onto the nozzle material 310. The electrodes 316, 317 may include a gold flash.

[Q34] Figure 3 shows device 302 at a particular point in operation, which may be the bubble expansion stage depicted in Figure 2B. The heater 308 has caused some portion of the fluid 322 to form a bubble 340 winch has forced a portion of the fluid 322 into the nozzle 312. The fluid 322 may be in the process of forming a droplet 318 in the nozzle 312 As shown, the droplet 318 bridges the diameter of the nozzle 312 and is in contact with both electrodes 316, 317. While in this position, the droplet 312 forms an electrical connection between the first electrode 316 and the second electrode 317, which may facilitate the sensor 314 measuring a signal proportional to a property of the fluid.

[035] The sensor 314 may apply a current and/or voltage between the electrodes 316, 317 which may pass through droplet 318. The applied current/voltage may be static in tune (e.g., direct current), may vary in tune (e.g., alternating current), or may include both static and time variant components. The current/voltage may take the form of a signal with known characteristics. The signal may have a frequency which is varied in time. The sensor 314 may measure changes in the signal to determine properties of the fluid 322. In an example, a current may be passed through the droplet 318 to determine a resistance/conductivity of the fluid 122.

[036] Although the droplet 318 is shown filling an area of the nozzle 312 to electrically couple the electrodes 316, 317, the droplet 318 may in some examples occupy only a portion of the nozzle 312, Similarly, although the electrodes 316 and 317 are shown on opposite sides of a diameter of the nozzle 312, they could occupy any relative positions around the surface of the nozzle 312, such as, for example 90° apart around a circumference of the nozzle 312 Other orientations may be possible in other examples. The sensor 314 may determine properties of the fluid 122 based on the positioning of the electrodes 316, 317. The sensor 314 may be able to determine properties of the fluid 122 when the fluid 122 does not directly contact both electrodes 316, 317.

[Q37] Figure 4 is a schematic diagram in cross-section showing a device with electrode contacts at the nozzle material and heater, arranged in accordance with at least some embodiments described herein. Figure 4 show¾ device 402, substrate 404, chamber 406, heater 408, nozzle material 410, sensor 414, first electrode 416, second electrode 417, and liquid 422. The various components described in Figure 4 are merely examples, and other variations, including eliminating components, combining components, and substituting components are all contemplated.

[Q38] The device 402 may be implemented by the device 102 of Figures 1 - 2D in some examples, except that the device 402 may have a different arrangement of the sensor 414 and electrodes 416, 417. The device 402 has a chamber 406 formed at least partially from substrate 404. The chamber 406 may be selectively filled with fluid 122 which may be selectively heated by heater 408. The fluid 422 may be selectively ejected from the chamber 406 through a nozzle 412 at least partially defined by nozzle material 410. The sensor 414 includes electrodes 416, 417 which selectively electrically couple to the fluid 422 to measure a property of the fluid 422.

[039] As shown in Figure 4, the device 402 has a first electrode 416 wfiich may be positioned at the nozzle material 410. The second electrode 417 may be positioned at or near the heater 408. The first and second electrodes 416, 417 may be separate conducti ve components or integral to the nozzle material 410 and heater 408. One or both of the nozzle material 410 and heater 408 may act as the electrodes 416, 417 in some examples. For example, one or both of the nozzle material 410 and heater 408 may include conductive materials which are electrically coupled with the sensor 414. Tire electrodes 416, 417 may formed of conductive material which may be positioned on one or more of the nozzle material 410, the heater 408, the substrate 404, or combinations. The conductive material may extend from an outside of the chamber 406 to an inside of the chamber 406 to form one or more of the electrodes 416, 417.

[040] The two electrodes 416, 417 may be positioned on opposite sides of the chamber 406. As shown, they are positioned on a top and bottom surface of the chamber 406 corresponding to the nozzle material 410 and the heater 408. One or both of the electrodes may be positioned on the substrate 404 at various orientations around the chamber 406. The electrodes 416, 417 may, for example, be positioned on opposite walls of the chamber 406 between the heater 408 and the nozzle material 410.

[041] When a liquid 122 is present in device 402, it may form an electrical connection between the electrodes 416, 417 in an analogous manner as described with reference to the electrical connection formed by the droplet 118, 218, or 318 of Figures 1-3. In the device 402 as shown m Figure 4, the connection may be formed while the fluid 422 is in chamber 406. The sensor 414 may pass a current between the electrodes 416, 417 to determine a resistance and/or conductivity of the fluid 422. The electrodes 416, 417 may have a charge applied to them to form plates of a capacitor which may be used to measure a capacitance of the fluid 422,

[042] As an example, the size of a floor of the chamber 406 may be about 60pm x 60pm, the droplet 418 may have a volume of about 12pL, and the chamber 406 may therefore have about a 330mhi height of fluid in the chamber 406. Based on these example dimensions for a single device 402, water would have a capacitance of about 8 femtoFarads (fF), benzene (an example contaminant) would have a capacitance of about 0.23 fF, and air would have a capacitance of about 0.1 fF. Multiple devices 402 may have their signals pooled to increase the signal to be measured. The capacitance may also be increased by using different devices with for example, increased chamber area and/or decreased height of fluid in the chamber. The properties of the fluid 422 may also be measured at various electrical frequencies (e.g., other than DC) to determine additional diagnostic information and/or increase the sensitivity of the device.

[043] In another example, using the same chamber geometry 406, conductivity may be measured. Very pure water has a conductivity of about 5.5c10^L-6 S/m, and drinking water has a conductivity of about 0.005 - 0.05 S/m. If the electrodes are positioned at a top and bottom of the chamber (assuming the water fills the chamber), then a conductance of about 1.8 nS would be measured for pure water, and a conductance of about 17 - 1.7 pS would be meas ured for drinking water. If the electrodes are positioned on opposite walls of the chamber 406, then a conductance of about 0.3 nS would be measured for pure water, and a conductance of about 0.3 to 3 pS would be measured for drinking water. The conductance may be used to determine total dissolved solids (TDS) of the water.

[044] Figure 5 is a schematic diagram in cross-section of a device with electrodes placed around the sidewalls of the nozzle, arranged in accordance with at least some embodiments described herein. Figure 5 shows device 502, chamber 506, nozzle material 510, nozzle 512, sensor 514, first electrode 516, second electrode 517, non- conduetive gap 542, and fluid 522. The various components described in Figure 5 are merely examples, and other variations, including eliminating components, combining components, and substituting components are all contemplated.

[045] Figure 5 depicts a device 502 that may be implemented using the device 102 of Figures 1 - 2D in some examples. The device 502 has a first electrode 516 and a second electrode 517 positioned on a sidewall of nozzle 512. A non-conductive gap 542 may be between the two electrodes 516, 517, which may reduce and/or prevent inadvertent electrical contact between them. The gap 542 may be implemented using, for example, a break in conductive material that has been patterned on a surface of the device 502. The gap may include a non-conductive material, such as, for example, a dielectric material, present between conductive regions. The electrodes 516 and 517 may extend from a surface of the nozzle material 510 into the sidewall of the nozzle 512. The electrodes 516, 517 may extend along the entire length of the nozzle sidewall or only a portion of the length of the sidewall. The electrodes 516, 517 may extend along the entire length of the sidewall and into the chamber 506. The electrodes 516, 517 may extend around all or a portion of a circumference of the sidewall of the nozzle 512. While two electrodes are shown in Figure 5, any number may be used, arid they may be positioned on any number of sidewalls.

[046] The embodiment of Figure 5 functions similarly to the device 102, 202, 302, or 402 of Figures 1-4. When the liquid 522 is ejected from the device 502 through the nozzle 512, it may form an electrical connection between the electrodes 516, 517 facilitating a sensor 514 to measure properties of the fluid 522 in a manner similar to the other devices described herein.

[Q47] Figure 6 is a schematic diagram, partially m cross-section, depicting an array of devices, arranged in accordance with at least some embodiments described herein. Figure 6 shows devices 602 and 602’, chamber 606, nozzle 612, sensor 614, array 644, test fluid source 646, test fluid 648, reference fluid source 650, and reference fluid 652. The various components described in Figure 6 are merely examples, and other variations, including eliminating components, combining components, and substituting components are all contemplated.

[Q48] Figure 6 depicts an arrangement of de vices 602 into an array 644. The devices 602 may form a grid, or may be arranged in other patterns. The devices 602 may be adjacent to each other or may be spaced apart. Groups of devices 602 may be clustered together with space between the different clusters. The devices 602 may all be directed to eject droplets in a similar direction, such as parallel to each other, or may eject droplets in different directions. The array 644 may be connected to multiple fluid sources, each of which may selectively fill one or more of the devices 602. Each of the devices may implemented using one of the devices 102, 402, or 502 from Figures 1-5 in some examples. Each of the devices 602 may be coupled to a sensor 614. Multiple devices 602 may share the same sensor 614. Each of the devices 602 of the array 644 may have the same configuration, or may have differing configurations. As an example, certain of the devices 602 may vary in area of the nozzle 612 or height of the chamber 606 compared to other of the devices 602, As another example, the channels which connect each of the devices 602 to the fluid source(s) may have different characteristics (e.g., size of channel, length of channel, hydrophobic or hydrophilic coating on the channel) which lead to refilling the chambers 606 of the devices 602 at different rates and/or different amounts of fluid. Varying the rate at which the fluid 622 fills the chambers 606 and/or the amount of the fluid 622 in the chambers 606 may be especially useful when the fluid 622 is contaminated with non-hydrophilic (e.g., organic) materials. Readings from devices 602 with different properties may be compared (such as by the measurement unit 128 of Figure 1).

[049] As shown, the array 644 may be fluidly coupled to a test fluid source 646 containing test fluid 648 and a reference fluid source 650 containing reference fluid 652. The test fluid source 646 and the reference fluid source 650 may each selectively fill different devices 602 of the array 644. Valves may be provided between the fluid sources 644, 646 and the devices 602 so that any of the devices 602 may fill, or partially fill, with different fluids at different times. Although only two fluid sources are shown, it should be understood that a variety of fluid sources and fluids may be provided. For example, multiple different test fluids could be compared to single reference fluid. Other configurations are possible in other examples.

[050] The array 644 may operate by filling multiple of the devices 602 with test fluid 648. The test fluid 648 may be similar to the fluid 122 of Figures 1-5. Properties of the test fluid 648 may be measured by multiple of the devices 602. Tire signals from the multiple devices 602 may be combined. The combining may be done physically by connecting the sensors 614, computationally by combining measurements from the sensors 614 with a processor (such as processor 132 of Figure 1), or combinations thereof. The combining may be accomplished by connecting the electrodes of multiple devices 602 together such that the sensor 614 records data from a plurality of devices 602. Tins may, for example, facilitate measurement of a signal that is too small to be detected by a sensor 614 coupled to a single device 602. The array may have a higher analytical sensitivity than a single device operated alone.

[051] The array 644 may operate by filling one device 602 with the test fluid 648 and a second device 602’ with the reference fluid 652. The second device 602 may be proximate to the first device 602. In some examples, the second device may be adjacent to the first device 602. Although only a single first device 602 and second device 602' are described, it should be understood that any number of devices may be filled with each of the test fluid 648 and reference fluid 652. For example, there may be a single device 602 filled with test fluid 648 and a plurality of devices 602’ filled with reference fluid 652 surrounding it. In another example, the devices 602, 602’ filled with test and reference fluid respectively, may repeat in a pattern across the array 644. The reference fluid 652 may be chosen so that it has known properties. The reference fluid 652 may, for example have similar properties to expected properties of the test fluid 648. The devices 602’ containing reference fluid 652 may experience similar environmental conditions (e.g., temperature, humidity) as the devices 602 containing the test fluid 648. Measurements from the devices 602 and 602’ may be compared. The devices 602’ containing reference fluid 652 may be used to calibrate measurements from the devices 602 containing the test fluid 648. The comparing may increase accuracy or raise a signal- to-noise ratio of the measurements. The array 644 may both fill multiple devices 602 with a test fluid 648 and also fill one or more devices 602’ with a reference fluid 652.

[052] One or more devices may be provided on a cartridge. The devices may, for example be implemented using the devices 102, 402, or 502, of Figures 1-5, or a combination of those devices. Each cartridge may have devices which are the same configuration or different configurations. The cartridge may include an array of micro dispensers such as the array 644 of Figure 6. The cartridge may removably attach to a system (e.g., may he inserted into a system) containing one or more fluid sources 120, a measurement unit 128, a temperature sensor 136, an output 138, and combinations thereof. The cartridge may contain connectors to attach components of the cartridge to components of the system. For example, electrical connectors may be provided to connect sensors of the devices to the measurement unit. The cartridge may‘plug-in’ to the system for rapid connection and disconnection. The cartridge may be disposable, or may be reusable.

[Q53] Figure 7 is a flowchart depicting a method of measuring an aspect of a fluid. An example method may include one or more operations, functions or actions as illustrated by one or more of blocks 710, 720, 730, 740, and/or 750. The operations described in the blocks 710 to 750 may be performed in response to execution (such as by one or more processors described herein) of computer-executable instructions stored in a computer- readable medium, such as a computer-readable medium of a computing device or some other controller similarly configured.

[054] An example process may begin with block 710, which recites“Cause fluid to flow into a chamber”. Block 710 may be followed by block 720, which recites“Heat at least a portion the fluid.” Block 720 may be followed by block 730, which recites“Force the fluid out of the chamber and into a microinjector nozzle.” Block 730 may be followed by block 740 which recites“Measure an aspect of the fluid.” Block 740 may be followed by block 750 which recites“Force the fluid out of the microinjector nozzle.”

[055] The blocks included in the described example methods are for illustration purposes. In some embodiments, the blocks may be performed in a different order. In some other embodiments, various blocks may be eliminated. In still other embodiments, various blocks may be divided into additional blocks, supplemented with other blocks, or combined together into fewer blocks. Other variations of these specific blocks are contemplated, including changes in the order of the blocks, changes in the content of the blocks being split or combined into other blocks, etc. In some examples, block 740 may precede block 730, may follow block 740, or may happen at multiple points throughout the method.

[056] Block 710 recites,“Cause fluid to flow' into a chamber” As described herein, devices (such as device 102 of Figure 1) may include chambers which may be selectively filled with fluid. The fluid may be a mix of w¾ter and contaminants. The fluid may flow from a source. The fluid may flow in response to a pressure gradient. The fluid may flow into the chamber automatically as part of a cycle of operation as described in Figures 2A - 2D. The fluid may be driven into the chamber such as by a pump, or passively flow, such as due to gravity or wicking along a channel. The flow of the fluid may be selectively controlled by valves. Multiple fluid sources containing multiple fluids may be connected to the chamber by one or more valves such that a given one, or a controlled mixture, of the multiple fluids may selectively fill the chamber.

[Q57] Block 720 recites,“Heat at least a portion of the fluid.” The device may include a heater (such as heater 108 of Figure 1), which applies energy to the fluid while it is in the chamber. The energy may be applied continuously, or in cycles. The energy may be applied directly to the fluid, indirectly, or combinations. The energy may superheat the fluid or a portion of the fluid. The heating of the fluid may be monitored by a temperature sensor. The heater may be controlled based on readings from the temperature sensor.

[058] Block 730 recites,“Force the fluid out of the chamber and into a microinjector nozzle.” The energy applied to the fluid in block 720 may cause a portion of the fluid to expand, such as by a vapor explosion. The expanding fluid may force the remainder of the fluid out of a nozzle of the device. The fluid forced out of the chamber by the expanding portion of the fluid may form a droplet as it passes through the nozzle. The entire volume of fluid m the chamber may be forced into the nozzle, or only a portion of the fluid.

[059] Block 740 recites,“Measure an aspect of the fluid.” The fluid may contact electrodes positioned about the nozzle as shown, for example, in Figure 1. As described herein, the electrodes may have various positions about the device. The electrodes may form a circuit with the fluid. A sensor coupled to the electrodes may measure an aspect of the fluid while the fluid is forming a circuit with the electrodes. The aspect may be passively determined. The aspect may be interrogated by applying a voltage and/or a current to the electrodes. The voltage and/or current may have frequency components which are varied in time. The measuring may happen at different times during the method (such as before block 730) and may be repeated multiple times throughout the method. Multiple aspects may be determined during a single measurement step. A single aspect may be determined at each measurement step. Additional properties of the fluid may be calculated based on the measured aspects.

[Q60] Block 750 recites,“Force the fluid out of the microinjector nozzle.” The fluid passes through the nozzle and leaves the device. The fluid may be directed to a specific location, such as to a waste container, or back into the water source. The devices may^¬ be used as pumps to move a volume of fluid over time. The method may repeat by- repeating block 710 and filling the chamber with more fluid. Tire method may act as a cycle by returning to block 710 each time that block 750 is completed.

[061] Figure 8 is a block diagram illustrating an example computing device 800 that is arranged for determining fluid properties in accordance with the present disclosure. The computing device 800 may serve, for example, as the measurement unit 128 of Figure 1. In a very- basic configuration 801, computing device 800 typically includes one or more processors 810 and system memory 820. A memory bus 830 may be used for communicating between the processor 810 and the system memory 820.

[062] Depending on the desired configuration, processor 810 may be of any type including but not limited to a microprocessor (mR), a microcontroller (pC), a digital signal processor (DSP), or any combination thereof. Processor 810 may include one or more levels of caching, such as a level one cache 811 and a level two cache 812, a processor core 813, and registers 814. An example processor core 813 may include an arithmetic logic unit (ALU), a floating point unit (FPU), a digital signal processing core (DSP Core), or any combination thereof. An example memory controller 815 may also be used with the processor 810, or in some implementations, the memory controller 815 may be an internal part of the processor 810.

[063] Depending on the desired configuration, the system memory 820 may be of any type including but not limited to volatile memory (such as RAM), non-volatile memory (such as ROM, flash memory, etc.) or any combination thereof. System memory 820 may include an operating system 821, one or more applications 822, and program data 824 Application 822 may include a measurement procedure 823 that is arranged to measure an aspect or property of a fluid as described herein. Program data 824 may include operation data 825 which may be information regarding mathematical constants, relationships, data regarding expected reference and/or test fluid properties, properties of known or suspected contaminants, and/or other information useful for the measurement of the fluid properties. In some embodiments, application 822 may be arranged to operate with program data 824 on an operating system 821 such that any of the procedures described herein may be performed. This described basic configuration is illustrated in FIG. 8 by those components drawn within the dashed line of the basic configuration 801.

[064] Computing device 800 may have additional features or functionality , and additional interfaces to facilitate communications between the basic configuration 801 and any required devices and interfaces. For example, a bus/interface controller 840 may be used to facilitate communications between the basic configuration 801 and one or more storage devices 850 via a storage interface bus 841. The storage devices 850 may be removable storage devices 851, non-removable storage devices 852, or a combination thereof. Examples of removable storage and non-removable storage devices include magnetic disk devices such as flexible disk drives and hard-disk drives (HDD), optical disk drives such as compact disk (CD) drives or digital versatile disk (DVD) drives, solid stale drives (SSD), and tape drives to name a few. Example computer storage media may include volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information, such as computer readable instructions, data structures, program modules, or other data.

[065] System memory 820, removable storage 851 and non-removable storage 852 are all examples of computer storage media. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD- ROM, digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which may be used to store the desired information and which may be accessed by computing device 800. Any such computer storage media may be part of computing device 800.

[Q66] Computing device 800 may also include an interface bus 842 for facilitating communication from various interface devices (e.g., output interfaces, peripheral interfaces, and communication interfaces) to the basic configuration 801 via the bus/interface controller 840. Example output devices 860 include a graphics processing unit 861 and an audio processing unit 862, which may be configured to communicate to various external devices such as a display or speakers via one or more A^;V ports 863. Example peripheral interfaces 870 include a serial interface controller 871 or a parallel interface controller 872, which may be configured to communicate with external devices such as input devices (e.g., keyboard, mouse, pen, voice input device, touch input device, etc.) or other peripheral devices (e.g., printer, scanner, etc.) via one or more I/O ports 873. An example communication device 880 includes a network controller 881, which may be arranged to facilitate communications with one or more other computing devices 890 over a network communication link via one or more communication ports 882.

[067] The network communication link may be one example of a communication media. Communication media may typically be embodied by computer readable instructions, data structures, program modules, or other data in a modulated data signal, such as a carrier wave or other transport mechanism, and may include any information delivery media. A‘'modulated data signal” may be a signal that has one or more of its characteristics set or changed in such a manner as to encode information m the signal. By way of example, and not limitation, communication media may include wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, radio frequency (RF), microwave, infrared (IR) and other wireless media. The term computer readable media as used herein may include both storage media and communication media

[068] Computing device 800 may be implemented as a portion of a small-form factor portable (or mobile) electronic device such as a cell phone, a personal data assistant (PDA), a personal media player device, a wireless web- watch device, a personal headset device, an application specific device, or a hybrid device that include any of the above functions. Computing device 800 may also be implemented as a personal computer including both laptop computer and non-laptop computer configurations.

[069] The present disclosure is not to be limited in terms of the particular examples described in this application, which are intended as illustrations of various aspects. Many modifications and examples can be made without departing from its spirit and scope, as wall be apparent to those skilled in the art. Functionally equivalent methods and apparatuses within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing descriptions. Such modifications and examples are intended to fall within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It is to be understood that this disclosure is not limited to particular methods, reagents, compounds compositions or biological systems, which can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular examples only, and is not intended to be limiting.

[070] With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity .

[071] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally- intended as“open” terms (e.g., the term“including” should be interpreted as“including but not limited to,” the term“having” should be interpreted as“having at least,” the term “includes” should be interpreted as“includes but is not limited to,” etc ).

[072] It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited m the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases“at least one” and“one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles“a” or“an” limits any particular claim containing such introduced claim recitation to examples containing only one such recitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as“a” or“an” (e.g.,“a” and/or“an” should be interpreted to mean“at least one” or“one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (e.g., the bare recitation of“two recitations,” without other modifiers, means at least two recitations, or two or more recitations).

[073] Furthermore, in those instances where a convention analogous to“at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art wOuld understand the convention (e.g.,“a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to“at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g.,“a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase“A or B will be understood to include the possibilities of“A” or“B” or“A and B.”

[074] In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled m the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.

[075] As will be understood by one skilled in the art, for any and ail purposes, such as m terms of providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein can be readily broken down into a lower third, middle third and upper third, etc. As will also be understood by one skilled in the art all language such as‘up to,”“at least,”“greater than,”“less than,” and the like include the number recited and refer to ranges which can be subsequently broken down into subranges as discussed above. Finally, as will be understood by one skilled in the art, a range includes each individual member. Thus, for example, a group having 1-3 items refers to groups having 1, 2, or 3 items. Similarly, a group having 1-5 items refers to groups having 1 , 2, 3, 4, or 5 items, and so forth.

[076] While the foregoing detailed description has set forth various examples of the devices and/or processes via the use of block diagrams, flowcharts, and/or examples, such block diagrams, flowcharts, and/or examples contain one or more functions and/or operations, it will be understood by those within the art that each function and/or operation within such block diagrams, flowcharts, or examples can be implemented, individually and/or collectively, by a wide range of hardware, software, firmware, or virtually any combination thereof. In one example, several portions of the subject matter described herein may be implemented via Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), digital signal processors (DSPs), or other integrated formats. However, those skilled in the art will recognize that some aspects of the examples disclosed herein, in whole or in part, can be equivalently implemented in integrated circuits, as one or more computer programs running on one or more computers (e.g., as one or more programs running on one or more computer systems), as one or more programs running on one or more processors (e.g., as one or more programs running on one or more microprocessors), as firmware, or as virtually any combination thereof, and that designing the circuitry and/or writing the code for the software and/or firmware would be well within the skill of one of skill in the art in light of this disclosure. For example, if a user determines that speed and accuracy are paramount, the user may opt for a mainly hardware and/or firmware vehicl e; if flexibility is paramount, the user may opt for a mainly software implementation; or, yet again alternatively, the user may opt for some combination of hardware, software, and/or firmware.

[077] In addition, those skilled in the art will appreciate that the mechanisms of the subject matter described herein are capable of being distributed as a program product in a variety of forms, and that an illustrative example of the subject matter described herein applies regardless of the particular type of signal bearing medium used to actually cam out the distribution. Examples of a signal bearing medium include, but are not limited to, the following: a recordable type medium such as a floppy disk, a hard disk drive (HDD), a Compact Disc (CD), a Digital Versatile Disk (DVD), a digital tape, a computer memor', etc.; and a transmission type medium such as a digital and/or an analog communication medium (e.g., a fiber optic cable, a waveguide, a wired communication link, a wireless communication link, etc.).

[078] Those skilled in the art will recognize that it is common within the art to describe devices and/or processes m the fashion set forth herein, and thereafter use engineering practices to integrate such described devices and/or processes into data processing systems. That is, at least a portion of the devices and/or processes described herein can be integrated into a data processing system via a reasonable amount of experimentation. Those having skill in the art will recognize that atypical data processing system generally includes one or more of a sy stem unit housing, a video display device, a memory such as volatile and non-volatile memory, processors such as microprocessors and digital signal processors, computational entities such as operating systems, drivers, graphical user interfaces, and applications programs, one or more interaction devices, such as a touch pad or screen, and/or control systems including feedback loops and control motors (e.g., feedback for sensing position and/or velocity; control motors for moving and/or ad_justing components and/or quantities). A typical data processing system may be implemented utilizing any suitable commercially available components, such as those typically found in data computing/communication and/or network computing/communication systems

[079] The herein described subject matter sometimes illustrates different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely examples, and that in fact many other architectures can he implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively "associated" such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as "associated with" each other such that the desired functionality is achieved, irrespective of architectures or intermedia! components. Likewise, any two components so associated can also be viewed as being "operably connected", or "operably coupled", to each other to achieve the desired functionality, and any two components capable of being so associated can also be viewed as being "operably couplable", to each other to achieve the desired functionality. Specific examples of operably couplable include but are not limited to physically mateable and/or physically interacting components and/or wirelessly interactable and/or wirelessly interacting components and/or l ogically interacting and/or logically interactable components.

[080] While various aspects and examples have been disclosed herein, other aspects and examples will be apparent to those skilled in the art. The various aspects and examples disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Claims

CLAIMS What is claimed is:

1. A device comprising:

a chamber;

a heater configured to heat a fluid in the chamber such that at least a portion of the fluid forms a droplet;

a nozzle in fluid communication with the chamber, the nozzle at least partially defined by a nozzle material, the nozzle positioned for ejection of the droplet; and

a sensor comprising at least two electrodes supported by the nozzle material positioned to contact the droplet during the ejection.

2. The device of claim 1, further comprising a measurement unit coupled to the sensor, the measurement unit configured to measure an aspect of the fluid.

3. The device of claim 2, wherein the measurement unit is configured to measure the aspect of the fluid in real-time.

4. The device of claim 2, wherein the measurement unit is configured to measure the aspect of the fluid on-site at a location where the fluid was collected.

5. The device of claim 2, wherein the aspect of the fluid comprises an amount of a contaminant within the fluid, an amount of an impurity within the fluid, or a combination.

6. The device of claim 2, wherein the measurement unit is configured to measure at least one of an electrical conductivity, a dielectric constant, and an electrical resistance of the fluid.

7. The device of claim 2, wherein the measurement unit is configured to measure one or more of: a dielectric constant of the fluid to determine an amount of an inorganic material within the fluid including an oil-based pollutant, a bacteria, a gas, one or more dissolved solids, a heavy metal, or combinations thereof;

a volume of the fluid m the chamber to determine viscosit)', hydrophilicity, hydrophobicity, or combinations thereof; and

an ejection rate of the device to determine heat capacity, thermal conductivity, or combinations thereof.

8. The device of claim 1 , wherein the nozzle material is a nickel orifice plate.

9. The device of claim 1, wherein the sensor forms at least a portion of an outlet of the nozzle and wherein the nozzle material further supports a dielectric material between the at least two electrodes.

10. The device of claim 1, wherein the nozzle material defines a sidewall connecting an outlet and an inlet of the nozzle, wherein at least one of the at least†.WO electrodes of the sensor comprises at least a conductive portion of the sidewall.

1 1 The device of claim 1, wherein a surface of the nozzle material supports the sensor, and wherein the sensor comprises a plate of a capacitive sensor.

12. The device of claim 11, further comprising another plate of the capacitive sensor positioned to contact the droplet during the ejection.

13. The device of claim 1, wherein the heater is configured to superheat and nucleate a portion of the fluid in order to eject a remaining portion of the fluid to form the droplet.

14. The device of claim 1 , further comprising an electrochemical detector coupled to the sensor.

15. The device of claim 1 , further comprising a pH detector coupled to the sensor.

16. The device of claim 1, further comprising a differential pulse anodic stripping voltammeter coupled to the sensor.

17. The device of claim 1, wherein the chamber is at least partially defined by a substrate.

18. The device of claim 17, further comprising a temperature sensor configured to measure a temperature of the fluid, the substrate, or both.

19. A method comprising:

heating a fluid a chamber and forming a droplet from at least a portion of the fluid;

forcing the droplet out of the chamber through a microinjector nozzle including contacting the droplet with a sensor comprising at least a pair of electrodes wherein at least one of the pair of electrodes is supported by the microinjector nozzle; and

measuring an aspect of the fluid using the sensor.

20. The method of claim 19, wherein measuring the aspect of the fluid comprises performing an electrochemical impedance spectroscopy of the fluid.

21. The method of claim 19, wherein measuring the aspect of the fluid comprises measuring a pH of the fluid.

22. The method of claim 19, wherein the fluid comprises water and wherein measuring the aspect of the fluid includes measuring an amount of at least one contaminant within the fluid.

23. The method of claim 19, wherein measuring an aspect of the fluid comprises measuring at least one of an electrical conductivity, or a resistance of the fluid.

24. The method of claim 19, wherein measuring an aspect of the fluid comprises measuring a dielectric constant of the fluid.

25. The method of claim 24, further comprising, based on the dielectric constant of the fluid, determining an amount of an inorganic material within the fluid, a bacteria within the fluid, other organic matter within the fluid, gases within the fluid, total dissolved solids within the fluid, heavy metals within the fluid, or combinations thereof.

26. The method of claim 19, further comprising measuring a temperature of at least one of the fluid or the chamber, and determining properties of the fluid based, at least m part, on the measured temperature.

27. A system comprising:

a fluid source containing a fluid comprising water and a contaminant;

a plurality of devices, each device comprising:

a chamber in selective fluid communication with the fluid source;

a heater configured to heat the fluid in the chamber such that at least a portion of the fluid forms a droplet;

a nozzle in fluid communication with the chamber, the nozzle at least partially defined by a nozzle material, the nozzle positioned for ejection of the droplet;

a sensor comprising at least two electrodes wherein at least one of the at least two electrodes is supported by the nozzle material and positioned to contact the droplet during the ejection; and

a measurement unit coupled to the sensor and configured to determine a properly' of the fluid.

28. The system of claim 27, wherein the plurality of devices comprise an array of devices.

29. The system of claim 27, wherein each of the chambers of the plurality of devices are filled with the fluid, and the measurement unit is configured to combine outputs from the electrodes of multipl e of the plurality of chambers.

30. The system of claim 27, wherein the fluid source comprises a reference fluid source containing a reference fluid, the plurality of devices in selective fluid communication with the reference fluid source such that each of the plurality' of devices is filled with one of the fluid or the reference fluid.

31. The system of claim 30, wherein the measurement unit compares a determined property of the fluid to a determined property of the reference fluid.

32. The system of claim 27, further comprising a temperature sensor coupled to the measurement unit.

33. The system of claim 27, wherein at least some of the plurality of devices have different dimensions than others of the plurality' of devices.

34. The system of claim 33, wherein the dimensions comprise an area of an opening of the nozzle, a height of the chamber, or combinations thereof.