CA3191531A1 - Injection module - Google Patents

Abstract

An injection module having an injection valve and a restriction tubing permitting fluid flow from the injection valve to a column. The injection valve having a sample inlet port, a mobile phase inlet port, a waste port, a column port and a sample loop. The restriction tubing having a valve end coupled to the column port, and a column end configured for coupling to a column; wherein the restriction tubing is configured for reducing separation of a sample into a gas phase and a liquid phase when the injection valve permits fluid flow from the injection valve to the column. The injection module can be used for analysis of samples having multiple phases, and is attachable to a gas chromatogram (GC). Also disclosed is a method for analyzing a sample having multiple phases, a GC having the injection module and a system having the injection module.

Description

INJECTION MODULE
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of and priority to US
Provisional Patent Application No. 63/088,073 filed October 6th, 2020, under the title INJECTION SYSTEM. The content of the above patent application is hereby expressly incorporated by reference into the detailed description hereof.
FIELD

[0002] The specification relates to an injection module, a method of analyzing a sample, a device having the injection module and an analytical system having the injection module.
BACKGROUND

[0003] Gas Chromatography (GC) is a separation technique of complex mixtures based upon the chemical and physical properties of the individual components such as molecular weight, boiling point, polarity, degree of saturation etc. A sample mixture is injected into a column with either a solid adsorbent or thin film liquid phase coating on the inside of the column referred to as the stationary phase. A carrier gas, known as the mobile phase, is passed through the column.
The individual chemical components are pushed via the carrier gas and pass through the column at different rates depending on their interaction with the stationary phase. The individual chemicals can then be identified and quantitated.
Both compositional and trace analysis by GC are used in modern industry for process control, to predict physical characteristics and maintain product quality.

[0004] Sample mixtures are introduced into the GC column with various techniques depending on their phase. Permanent gases such as He, Hz, 02, Ar, Nz, CH4, CO, CO2, C2H5, C2H4, C2I-12 and H25 are already in the gas phase and can be injected directly via headspace syringe or gas sampling valve. Moving up in molecular weight are mixtures of C3s and C4s referred to as Liquified Petroleum Gases (LPGs). These are gases at Normal Temperature and Pressure (NTP) but can be condensed by application of pressure. LPGs can be introduced into a GC via high-pressure liquid sampling valves (LSVs). C5 and higher are liquids at NTP
and can be introduced into a GC via LSV or liquid syringe. Both high-pressure liquids and atmospheric liquids are vaporized prior to or within the separation column in order to flow with the carrier gas and interact with the stationary phase. All three of these types of samples may contain thousands of compounds at trace levels, but it is the majority percentage compositional compounds which determine the phase of the overall mixture.

[0005] When an LSV is used to inject a high-pressure liquid sample into a gas stream, the sample is pressurized to ensure it remains in a single phase. The pressure required to keep the sample in single phase is determined by the composition of the sample and the temperature of the liquid sampling valve.
Referencing phase diagrams of C3-C4 mixtures (Figure 1) (https://www.engineeringtoolbox.com/propane-butane-mix-d 1043. html, incorporated herein by reference) shows that a minimum working range around 10bar or 150psi at 30 C will ensure that the sample stays in the liquid phase.
It is common to increase the pressure to ensure all components are in the liquid phase, for example between 400 and 1000psi. This approach is commonly used for the compositional GC analysis of high-pressure propane, butanes, pentanes, natural gas liquids, condensates and even crude oil.

[0006] When the liquid valve is actuated, the liquid volume trapped in the sample loop at 400 psi is placed in series with the carrier gas flow. Carrier gas head pressures are generally between 5-50ps1, depending on the interior diameter and length of the column and carrier gas chosen. The LPG sample is now vaporized, either by heated zone or by pressure drop. The resultant vaporized sample is then pushed by the flowing carrier gas stream onto the column for chromatographic separation. This technique is limited to characterizing only the lighter compounds in the sample mixture due to incomplete vaporization of the heavy compounds. It is very difficult to accurately characterize sample composition beyond C30 with a traditional liquid valve injection because the heavy components fall out of phase (remain liquid) the moment the majority of the lighter components are vaporized. This is referred to as mass discrimination. Vaporization of the liquid sample does not occur until the sample is moved into the heated zone and is close to or directly on-column. Heavy compounds can be analyzed separately from light compounds by first dissolving the sample in Carbon Disulfide (CS2). This solvent is both toxic and flammable. In addition, this approach requires separating the sample in two or three fractions, each processed and analysed on different instruments.

[0007] There is a need in the art for an injection module which can be used for injecting a sample for analysis and keeping the sample in liquid phase when the valve is actuated, and to help address some of the challenges of injection of a sample or where the sample can contain compounds having a broad range of boiling points. In addition, there is a need in the art for a method for analyzing a sample containing compounds having a broad range of boiling points. Moreover, there is a need in the art for a device having the injection module or an analytical system having the injection module as disclosed herein.
SUMMARY OF THE INVENTION

[0008] In one aspect, the specification relates to an injection module having:

[0009] - an injection valve having a sample inlet port, a mobile phase inlet port, a waste port, a column port and a sample loop;

[0010] the injection valve configurable from a first position to a second position,

[0011] the first position directing fluid flow from the sample inlet port to the sample loop, and from the sample loop to the waste port, and also directing fluid flow from the mobile phase inlet port to the column port, and

[0012] the second position directing fluid flow from the sample inlet port to the waste port, and also directing fluid flow from the mobile phase inlet port to the sample loop, and from the sample loop to the column port;

[0013] - a restriction tubing having a valve end and a column end, the valve end coupled to the column port of the injection valve, and the column end configured for coupling to a column; wherein the restriction tubing is configured for reducing separation of a sample into a gas phase and a liquid phase when the injection valve is in the second position.

[0014] In a second aspect, the specification relates to a method of analyzing a sample having multiple phases using an injection module as disclosed herein, the method containing the steps of:

[0015] - injecting the sample into the sample loop;

[0016] - transporting the sample from the sample loop to the column while maintaining a pressure and/or a temperature on the sample for reducing separation of a sample into a gas phase and a liquid phase;

[0017] - separating the sample in the column; and

[0018] - detecting constituents of the sample.

[0019] In a third aspect, the specification relates to an analytical device for analysis of a sample, the analytical device having:

[0020] - an injection module as disclosed herein;

21 [0021] - a column for separation of constituents of the sample, wherein one end of the column is in fluid communication with the injection module; and

[0022] - a detector coupled to a second end of the column for detecting the constituents of the sample.

[0023] In a fourth aspect, the specification relates to an analytical system for analysis of a sample having:

[0024] - an injection module as disclosed herein;

[0025] - a column for separation of constituents of the sample;
and

[0026] - a detector for detecting the constituents of the sample;

[0027] - a mobile phase delivery system; and

[0028] - a computer system having a program for executing a method for analysis of the sample.

[0029] Reference will now be made, by way of example, to the accompanying drawings which show example embodiments of the present application, and in which:
BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Reference will now be made, by way of example, to the accompanying drawings which show example embodiments of the present application, and in which:

[0031] Figure 1 shows a phase diagrams of C3-C4 mixtures;

[0032] Figure 2 shows a schematic of an analytical device having the injection module in accordance with the specification;

[0033] Figure 3 shows an embodiment of an injection valve in different positions;

[0034] Figure 4 shows an example of an injection system in accordance with the specification;

[0035] Figure 5 shows a High Pressure Liquid Sample Valve, flush mounted to MGCI (arrow "A") and the LSV column port is vertically oriented down into the MGCI (arrow "B");

[0036] Figure 6 shows a restriction tubing (arrow) mounted in the column oven, coupled to column and connected to detector;

[0037] Figure 7 shows a Certificate of Analysis of 1m1 of Supelco 5000ppm ASTM 2887 Quantitative Calibration Solution used to spike the butane sample;

[0038] Figure 8 shows comparative chromatograms of three samples;

[0039] Figure 9 shows a schematic of a second analytical device having the injection module in accordance with the specification;

[0040] Figure 10 shows a connection of a mobile phase restriction tubing to a mobile phase system tubing;

[0041] Figure 11 shows connection to an injection valve in accordance with a second embodiment;

[0042] Figure 12 shows setup of a restriction tubing from the injection valve in accordance a second embodiment; and

[0043] Figure 13 shows a chromatogram obtained by analysis of a sample using a second embodiment of the injection module.

[0044] Similar reference numerals may have been used in different figures to denote similar components.

DESCRIPTION OF EXAMPLE EMBODIMENTS

[0045] The specification relates to an injection module 10 that can be used for analysis of a sample having different constituents, and where some of the constituents of the sample can exist in multiple phases, such as, for example and without limitation, a gas phase and a liquid phase.

[0046] As noted above, for example and without limitation, butane exists as a gas at normal temperature and pressure (NTP), however, at high pressures, butane liquefies. Analyzing, for example and without limitation, a sample containing butane and longer hyrdocarbons can be challenging, as reduction in pressure can lead to separation of butane from the other constituents in the sample, leading to mass discrimination; and potentially, with some longer hydrocarbons going from a liquid phase to a solid phase, making their analysis even more challenging.

[0047] The injection module 10 disclosed herein can help to retain sufficient pressure on the sample to reduce separation of the sample constituents that have different vapor pressures. In one embodiment, for example and without limitation, the injection module 10 helps to retain the sample in a liquid phase, by reducing separation of the sample into a gas phase and a liquid phase. An embodiment of the injection module is shown in Figure 2, described further herein.

[0048] According to one aspect, the specification relates to an injection module 10 having:

[0049] - an injection valve 12 having a sample inlet port 14, a mobile phase inlet port 16, a waste port 18, a column port 20 and a sample loop 22;

[0050] the injection valve 12 configurable from a first position to a second position,

[0051] the first position directing fluid flow from the sample inlet port 14 to the sample loop 22, and from the sample loop 22 to the waste port 18, and also directing fluid flow from the mobile phase inlet port 16 to the column port 20, and

[0052] the second position directing fluid flow from the sample inlet port 14 to the waste port 18, and also directing fluid flow from the mobile phase inlet port 16 to the sample loop 22, and from the sample loop 22 to the column port 20;

[0053] - a restriction tubing 24 having a valve end 26 and a column end 28, the valve end 26 coupled to the column port 20 of the injection valve 12, and the column end 28 configured for coupling to a column 30; wherein the restriction tubing 24 is configured for reducing separation of a sample into a gas phase and a liquid phase when the injection valve is in the second position.

[0054] The injection valve 12 used in the injection module 10 disclosed herein is not particularly limited, and can be varied depending upon design and/or application requirement. Moreover, the injection valve 12 (sometimes also referred to as sampling valves), as used for purposes of chromatographic purification, should be known to a person of ordinary skill in the art. The injection valve selected should be able to withstand the pressure applied for purification of the sample using the method as disclosed herein. In one embodiment, for example and without limitation, the injection valve 12 is a six-port rotary valve. In a further embodiment, for example and without limitation, the six-port rotary valve is a liquid sampling valve as shown in Figure 3.

[0055] As shown in Figure 3, the injection valve 12 has a sample inlet port 14, a mobile phase inlet port 16, a waste port 18, a column port 20 and a sample loop 22. The sample inlet port 14, a mobile phase inlet port 16, a waste port 18, a column port 20 and a sample loop 22, disclosed and used in the injection valve 12, disclosed herein, can be, for example and limitation, similar to a liquid sampling valve (LSV) typically employed in high pressure liquid chromatography (H PLC).

[0056] The injection valve 12 can be configured from a first position (position A' in Figure 3) to a second position (Iposition B' in Figure 3). In the first position, the sample inlet port 14 is in fluid communication with the sample loop 22, at one end of the sample loop 22, and the opposing end of the sample loop 22 is in fluid communication with the waste port 18. Hence, any sample injected in the sample inlet port 14 would travel into the sample loop 22, filling the sample loop 22, and with the excess exiting out from the waste port 18. In addition, in the first position, the mobile phase inlet port 16 is in fluid communication is in fluid communication with the column port 20; and where the column port 20 is in fluid communication with a column 30. Hence, the mobile phase flows from the mobile phase inlet port 16 and exits from the column port 20 towards the column 30.

[0057] Once the sample is filled in the sample loop 22, the injection valve 12 can be actuated to move from the first position ('position A' in Figure 3) to the second position ('position B' in Figure 3). The means for actuation of the injection valve 12 is not particularly limited, and should be known to a person of skill in the art. In the second position, the mobile phase inlet port 16 is in fluid communication with the sample loop 22, and the other end of the sample loop 22 is in fluid communication with the column port 20, which is in fluid communication with the column 30. Hence, upon actuation of the injection valve 12, the mobile phase pushes the sample from the sample loop 22 to exit from the column port 20, towards the column 30. In addition, in the second position, the sample inlet port 16 is in fluid communication to the waste port 18, and directs any flow from the sample inlet port 14 towards the waste port 18.

[0058] Positioned between the injection valve 12 and the column 30 is a restriction tubing 24, with one end ('valve end') 26 of the restriction tubing coupled to the injection valve 12 at the column port 20, permitting fluid flow from the injection valve 12 that exits from the column port 20 to fluidly flow in the restriction tubing 24 from the valve end 26 towards a column end 28 of the restriction tubing 24. The column end 28 of the restriction tubing 24 is coupled to a column 30, permitting fluid flow from the restriction tubing 24 to exit from the column end 28 of the restriction tubing 24 into the column 30.

[0059] The restriction tubing 24 used or selected for use in the injection module 10 helps to ensure that sufficient pressure is maintained on the sample to reduce or limit separation of the sample constituents into multiple phases, such as a gas phase and a liquid phase. Hence, the restriction tubing 24 has specifications that it can withstand the pressure of the fluid flowing through the restriction tubing 24. In one embodiment, the restriction tubing 24 is selected such that the pressure drop from the valve end 26 to the column end 28 of the restriction tubing 24 is sufficiently low to reduce, and preferably avoid, separation of a sample into a gas phase and a liquid phase in the restriction tubing 24. In a further embodiment, the restriction tubing 24 is selected such that the fluid pressure at the column end 28 of the restriction tubing 24 lies within the pressure limits of the column 30 being used for separation of the sample. In another further embodiment, the restriction tubing 24 is selected such that the mobile phase has a flow rate within the flow rate limits of the column 30 and detector 68 being used for analysis of the sample.

[0060] In one embodiment, for example and without limitation, the restriction tubing 24 is selected to have a dimension, such as, for example and without limitation, an internal diameter and/or length, to maintain sufficient pressure on the sample to limit or prevent separation of the sample constituents into a gas phase and a liquid phase, while the sample is in the injector valve 12. In one embodiment, for example and without limitation, the restriction tubing 24 is selected to have a dimension, such as, for example and without limitation, an internal diameter and/or length, to maintain sufficient pressure on the sample to limit or prevent separation of the sample constituents into a gas phase and a liquid phase, till the sample constituents are within a heating zone, such as, for example and without limitation, inside an oven of a gas chromatography (GC) device. As such, as the sample flows from the injector valve 12 into the restriction tubing 24, when the sample reaches a portion of the restriction tubing 24 inside a heating zone (such as a GC oven), some separation of the sample constituents can occur.
Although not ideal, once inside the heating zone, the sample constituents will encounter the heat inside the heating zone and can be vaporized, and carried by the mobile phase on to the column 30 for separation. In another embodiment, for example and without limitation, the restriction tubing 24 is selected to have a dimension, such as, for example and without limitation, an internal diameter and/or length, to maintain sufficient pressure on the sample to limit or prevent separation of the sample constituents into a gas phase and a liquid phase, prior to positioning of the sample on to the column. In a further embodiment, for example and without limitation, the restriction tubing 24 is selected to have a dimension, such as, for example and without limitation, an internal diameter and/or length, to maintain sufficient pressure on the sample to limit or prevent separation of the sample constituents into a gas phase and a liquid phase, to attain one or more conditions as described above, and wherein the sample contains constituents having a carbon length of C4 and C14, C4 and C20, C4 and C25, C4 and C30, C4 and C40, or C4 and C40+.

[0061] By selecting the appropriate restriction tubing 24 that maintains sufficient pressure on the sample, the sample can move from the injection valve 12 to the column 30, while limiting separation of the sample constituents in gas and liquid phases. This can be analogous to a cold on-column injection, where a sample is positioned on the column before separation of the constituents is initiated.
However, with the injection module 12 disclosed herein, a sample having different vapor pressures can be analyzed. In one embodiment, for example and without limitation, the injection module 12 can be used for characterization of liquid petroleum gases (LPG) containing hydrocarbons, for example and without limitation, up to C120.

[0062] Without being bound to a particular theory, as noted herein, maintaining sufficient pressure on a sample above the vapor pressure of the lowest boiling point constituent of the sample can help to maintain the constituents of the sample in a single phase, which for instance, is the liquid phase. Temperature also has an impact, and as such, the temperature should be considered and controlled, along with pressure to reduce, and limit, separation of a sample into a gas phase and a liquid phase.

[0063] When injecting a sample using the injection module 10 disclosed herein, the injection module 10 is selected to withstand the pressure required for reducing, and preferably limiting, separation of a sample into a gas phase and a liquid phase. In a further embodiment, the injection module 10 can be maintained, or positioned to limit exposure to any heat source, to limit temperature variation thereby limiting separation of the sample into gas and liquid phases.

[0064] In a further embodiment, during the injection process, as the sample is carried by the mobile phase from the injection valve 12, via the restriction tubing 24, to the column 30, the temperature of the mobile phase, injection module 10, analytical device 64 having the injection module 10 or system 70 having the analytical device 64 with the injection module 10, can be controlled to limit, and preferably avoid, separation of the sample into gas and liquid phases prior to the sample coming in contact with the column 30. In another further embodiment, the temperature can be controlled by avoiding heating of the mobile phase, injection module 10, analytical device 64 having the injection module 10 or system 70 having the analytical device 64 with the injection module 10, before the sample reaches the column 30. Once the sample reaches the column 30, the column 30 can be heated to assist with separation of the constituents of the sample.

[0065] In still another embodiment, during the injection process, as the sample is carried by the mobile phase from the injection valve 12, via the restriction tubing 24, to the column 30, the pressure of the mobile phase, injection module 10, analytical device 64 having the injection module 10 or system 70 having the analytical device 64 with the injection module 10, can be controlled to limit, and preferably avoid, separation of the sample into gas and liquid phases before the sample reaches the column.

[0066] The time the sample takes from the injection valve 12 to reach the column 30 can be determined based on the flow rate and distance between the injection valve 12 and the column 30. This time required for the sample to reach the column 30 from the injection valve 12 can be determined by a person of skill in the art.

[0067] The dimensions, such as, length and internal diameter of the restriction tubing 24 used can be determined based on the pressure required to maintain the sample in a single fluid phase till it reaches the column 30, or near the column 30 in a heated zone, where sufficient heat can be provided to mobilize the constituents of the sample to allow for analysis of the constituents. In an embodiment, the dimensions of the restriction tubing 24 take into account the pressure limits of the column 30, such that the mobile phase pressure at the column end 28 of the restriction tubing 24 is within the limits of the column 30. In a further embodiment, the dimensions of the restriction tubing 24 take into account the flow rate of the mobile phase achieved, such that the flow rate of the mobile phase in the column 30 and at the detector 68 are within the limits of the column 30 and the detector 68, to allow separation and detection of the constituents.
Such calculation of the dimensions of the restriction tubing are not particularly limited, and should be known or can be determined by a person of skill in the art. To assist with better understanding such a calculation, disclosed herein is an example.

[0068] In one embodiment, the restriction tubing is selected to having an internal diameter that is narrower than an internal diameter of the column to which the restriction tubing is configured for coupling. In another embodiment, the internal diameter and/or length of the restriction tubing is selected for maintaining sufficient pressure for reducing separation of a sample into a gas phase and a liquid phase when the injection valve in the second position.

[0069] In one embodiment, the injection valve 12 is further provided with a first waste tubing 32 having a first end 34 coupled to the waste port 18, and a second end 36 coupled to a waste valve system 38 (Figure 2). Excess sample can be directed to the waste port 18 of the injection valve 12 in both the first and second positions of the valve. The first waste tubing 32 used is not particularly limited, and standard tubing utilized in separation devices for directing waste should be known to a person of skill in the art.

[0070] The waste valve system 38 used with the injection module disclosed herein, is provided with a first waste valve 40 coupled to the second end 36 of the first waste tubing 32. Also provided in the waste valve system 38 is a second waste tubing 44 coupled at one end to the first waste valve 40, permitting fluid flow from the first waste tubing 32 to the second waste tubing 44, when the first waste valve 40 is open (or actuated). In addition, the waste valve system 38 is provided with a second waste valve 42, coupled to the second end of the second waste tubing 44. The second waste valve 42 permitting fluid flow from the second waste tubing 44 to an outlet 46 upon actuation (or opening) of the second waste valve 42.

[0071] In one embodiment, the waste valve system 38 disclosed herein can help to maintain the integrity of the sample by use of the first waste valve 40 and second waste valve 42 in series. The waste valve system 38 operates by actuation of the first waste valve 40 to permit fluid flow from the first waste tubing 32 into the second waste tubing 44, while ensuring that the second waste valve 42 remains closed, and filling the second waste tubing 44. This can help to reduce or limit separation of the sample in to gas and liquid phases, by ensuring sufficient pressure is maintained on the sample. In the absence of a second waste valve 42, the sample would be open to atmosphere leading to a sudden pressure drop, resulting in change in the constituents of the sample. Once the second waste tubing 44 is filled, the first waste valve 40 closes, and the second waste valve 42 is actuated to open, allowing fluid in the second waste tubing 44 to exit from the outlet 46.
Again, by closing the first waste valve 40 and opening the second waste valve 42, pressure can be maintained on the sample to reduce or limit separation of the sample in to gas and liquid phases in the injection module 12. In another embodiment, for example, the waste valve system 38 operates such that only one of the first waste valve 40 and the second waste valve 42 is open at any time.

[0072] In one embodiment, the injection module 10 is provided with a sample tubing 48 having a first end 50 coupled to the sample inlet port 14, and a second end 52 for coupling to a sampling system 54, the sample tubing 48 configured to permit fluid flow from the sampling system 54 to the sample inlet port 14. The sample tubing 48 disclosed herein is not particularly limited and should be known or can be determined by a person of skill in the art. The sample tubing 48 used with the injection valve 12 helps to ensure that sufficient pressure is applied on the sample to limit or avoid separation of the constituents of the sample into a gas phase and a liquid phase.

[0073] In one embodiment, the injection module 10 disclosed herein is provided with a mobile phase tubing 56 having a first end 58 coupled to the mobile phase inlet port 16 and a second end 60 configured for coupling to a mobile phase system 62, the mobile phase tubing 56 configured to permit fluid flow from the mobile phase system 62 to the mobile phase inlet port 16.

[0074] In another embodiment, the mobile phase tubing 56 is also a tubing that restricts flow of the mobile phase through the mobile phase tubing 56.
Hence, the mobile phase tubing 56 is similar to the restriction tubing 24 disclosed herein, and is a second restriction tubing (or restricted mobile phase tubing 56). The restricted mobile phase tubing 56, similar to the restriction tubing 24, helps to ensure that sufficient pressure is maintained on the sample to limit or avoid separation of the sample constituents in gas and liquid phases.

[0075] Without being bound to a particular theory, when the sample is in the sample loop 22, and the injection valve 12 is actuated to move from the first position to the second position, the mobile phase in the mobile phase tubing should push the sample from the sample loop 22 towards the column port 20.
However, if the mobile phase pressure is below the phase separation line of the sample, the sample constituents can separate into gas and liquid phases. To limit or avoid separation of the sample constituents in to gas and liquid phases, the mobile phase should be at a higher pressure than the phase separation line of the sample constituents. This can be achieved by using a restricted mobile phase tubing 56 that maintains sufficient pressure on the sample to limit or avoid separation of the sample constituents in to gas and liquid phases.

[0076] The restricted mobile phase tubing 56 disclosed herein is similar to the restriction tubing 24 disclosed herein; and the reader is directed to the description of the restriction tubing 24 which is applicable to the restricted mobile phase tubing 56, disclosed herein. Hence, in one embodiment, the restricted mobile phase tubing 56 is configured for limiting separation of the sample constituents into a gas phase and a liquid phase when the injection valve is in the second position.
In another embodiment, for example and without limitation, the internal diameter and/or length of the restricted mobile phase tubing 56 is selected for maintaining sufficient pressure for limiting separation of a sample constituents into a gas phase and a liquid phase when the injection valve 12 in the second position.

[0077] The injection module 10 disclosed herein can be coupled to a mobile phase system 62 for supplying a mobile phase. The mobile phase system 62 used and disclosed herein is not particularly limited, and should be known to a person of skill in the art. In one embodiment, for the embodiment for example and without limitation, the mobile phase system 62 is provided with a mobile phase tank 72 having one or more regulators 74 for controlling mobile phase flow from the mobile phase tank 72. The one or more regulators 74 are coupled to a mobile phase system tubing 76 that carries the mobile phase towards the injection valve 12.
Additional valves or control meters can be used depending upon design and application requirements, and which should be known to a person of skill in the art.

[0078] In one embodiment, for example and without limitation, the restricted mobile phase tubing 56, disclosed herein, is selected to having an internal diameter narrower than an internal diameter of a mobile phase system tubing 76 to which the restricted mobile phase tubing 56 is configured for coupling.

[0079] The use of the injection module 10 disclosed herein is not particularly limited. In one embodiment, for example and without limitation, the injection module 10, disclosed herein, is for use with an analytical device 64, wherein the device is, for example and without limitation, a gas chromatography (GC) instrument. The injection module 10 can be provided as a stand alone part, or part of an analytical device 64, or a system 70 having the analytical device 64.

[0080] Gas chromatography (GC) is a known separation technique, and used in analytical chemistry for separating/or and analyzing compounds that can be vaporized. Typical GC instruments include an injection module for injection of a sample, which is carried by a carrier gas on to a column, where the column is placed in an oven. Separation of the constituents occurs in the column, which exit from the column and are detected by a detector. The detector is coupled to a display, typically, a computer system having a monitor, to record and display the analysis of the sample. Depending upon the sample, different separation methods involving column type, flow rate, and oven temperature, including heating ramp rate, is employed for separation and/or analysis of a sample. Typically, an analytical device, such as a GC, is provided with an injection module, a GC
oven and detector. However, a system having the GC device, along with a computer and software, can be provided for separation and/or analysis of a sample.

[0081] When provided with a sample having constituents that have varying vapor pressures, and can be in different phases under NTP, an injection module 10, as disclosed herein, can be used in an analytical device 64, which can be a GC

instrument. The GC instrument 64 can be provided as a stand alone unit, or provided as part of a system 70, having a computer with software installed.
The software can be programmable to control the pressure of the mobile phase, flow rate, and temperature, along with time, at which the oven should be heated. In accordance with the disclosure herein, in one embodiment, upon injection of a sample into the injection valve 12, the valve can be actuated to direct the sample towards the column 30, while maintaining the temperature of the oven to limit and/or avoid heating the column. The pressure applied and/or maintained on the sample, due to the bore width of the restriction tubing 24 being narrower than the column for limiting or avoiding separation of the sample in a gas phase and a liquid phase, moves the sample on to the column 30. Once on column 30, in one embodiment, heat can be applied to the column 30, by ramping up the temperature in the GC oven. This can lead to separation of the constituents of the sample, which are detected at the detector, and can be displayed with the help of the system 70 and software.

[0082] Disclosed herein below are different embodiments, along with a description of the figures, to assist with further understanding of the injection module 10, device 64 and method for separation and/or analysis of a sample.

[0083] In one embodiment, the technique uses the carrier gas pressure at the injection valve 12 to be above the evaporation pressure of all constituents of the sample, which can be LPG. In one embodiment, for example and without limitation, this can be achieved by placing two pressure restrictions in the system (Fig.
2).

One mobile phase restriction tubing 56 can be between the carrier gas flow controller 78 and the injection valve 12, and a second restriction tubing 24 can be between the injection valve 12 and the GC capillary column 30. In a particular embodiment, the later restriction can flow through an injector, which can be, for example and without limitation, a modified GC injector (MGCI). The first restriction 56 can help prevent the sample from vaporizing and expanding backwards towards the flow controller 78. The second restriction 24 can help to ensure the sample remains in a pressurized liquid state until it is deposited at the head of the column 30.

[0084] Once the sample reaches the head of the column, the MGCI and the GC oven can be heated simultaneously to convert the sample to gas allowing it to flow trough the column 30 for separation and analysis. The second restriction 24, MGCI, all connections and the column 30 can be heated up to 430 C in order to elute all heavy hydrocarbons present in the sample. In one embodiment, the injection valve 12 itself is not heated but insulation is placed between the injection valve 12 and the injector to prevent heat from the injector to reach the injection valve 12. In a particular embodiment, the injection valve 12 is maintained at a consistent temperature at the point of injection. This can allow calculation of the evaporation pressure required to keep the sample in single phase. In a further embodiment, sample can travel from the injection valve 12 onto a column 30, where the restriction tubing 24 is coupled directly to a column 30 using a union 80, and without having to pass through a MGCI.

[0085] In one embodiment, for example and without limitation, as per Figures 2, 4, 5 and 6, two pieces of narrow Inner-Diameter (ID) steel tubing (24, 56) were installed in series with the capillary column to raise the pressure up above the evaporation point of the sample. The first length of tubing (56) was 4' x 1/16" x 0.005" ID SS. It was installed between the 100psi flow controller 78 to the carrier gas IN 16 connection on the injection valve 12. The temperature of this piece is not particularly limited, as directly contact with sample is unlikely. This first piece 56 can help to prevent the sample from vaporizing and expanding backwards up towards the flow controller 78. The second length of tubing 24 was 12' x 1/32"
OD
x 0.005" ID. It was installed from the column port 20 on the injection valve 12 and routed vertically down through the programmable temperature valve (PTV) injector.
The lengths and diameters of the tubing 24, 56 were chosen so the total length of 16' x 0.005" ID would yield 10m1/min of Argon at 100psi. The relative lengths were chosen because they were commercially available in pre-cut lengths and would give a pressure of approximately 84psi at the injection valve 12. This was above the evaporation pressure of the butane sample which was analyzed. Argon was chosen as the carrier gas because it is inert, inexpensive and has the highest backpressure with the lowest linear velocity, but Helium or Nitrogen should also work.

[0086] The injection valve 12 was mounted so that the orientation of the column port 20 connection on the injection valve 12 was facing vertically down.
The injection valve 12 was flush mounted into the top of the PTV injector, so the steel line could be heated as close to the valve as possible to prevent a cold spot.
However, this is not necessary, and the injection valve 12 can be placed further away from the oven, to avoid heating the sample, which can lead to separation of the sample constituents in to different phases. The 12' x 1/32" tubing 24 passed through the PTV injector but was not connected with any unions or glass inserts.
The PTV was solely used as a heating/cooling zone so that the temperature of the tubing could be accurately controlled very close to the injection valve 12.
The 12' x 1/32" 24 was coiled and mounted in the column oven of the gas chromatograph and connected with a zero dead volume union 80 to the capillary column 30 which was a 10m x 0.53mm x 1.0um MXT-1 from Restek. Both the narrow bore steel tubing and the capillary column should be able to safely withstand up to 430 C
in order to elute the potential heavy hydrocarbons in the sample. The calculated head pressure at the column 80 is around 2.2p5i at 30 C and 10m1/min Argon flow.
Although not ideal because the LPG sample can vaporize somewhere upstream in the 12' of tubing, but has been utilized to show proof of concept. The injection valve 12 itself was not mounted in an isothermal oven. However, there was some insulation between the injection valve 12 and the top of the PTV to prevent some heat bleed. When utilizing the method disclosed herein, the injection valve 12 can be kept at a consistent temperature at the point of injection. This allows the calculation of the evaporation pressure required to keep the sample in single phase.

[0087] Figure 6 shows a Certificate of Analysis of lml of Supelco 5000ppm ASTM 2887 Quantitative Calibration Solution used to spike the butane sample, which were analyzed. The analysis is shown in Figure 7 which shows comparative chromatograms of three samples.

[0088] First Chromatogram at the top of Figure 7 is: Butane sample pressurized up to 400p5i and injected via LSV directly into a 10m x 0.53mm x 1.0um MXT-1 Capillary column. The injection system disclosed herein is NOT
employed in this injection.

[0089] The chromatogram in the middle, as shown in Figure 7 is:
Butane sample spiked with lml of a 5000ppm ASTM 2887 Calibration standard containing n-hydrocarbons (HC) from C5-C44. The Butane sample is approximately 200m1, giving an estimated concentration of 25ppm for each spiked hydrocarbon (HC).
The HCs should yield a similar height and area count response. However, only HCs up to C12 reached the detector. At 400psi the butane sample is in the liquid phase and acts as a solvent which solubilizes and carries the heavy hydrocarbons.
When the LSV is actuated, the butane in the sample loop is in series with the carrier gas which is only flowing at around 2.5psi. Since 2.5psi is below the vapour pressure required on the phase diagram for butane at room temperature, it evaporates and most of the heavy hydrocarbons fall out of phase and are not pushed by the carrier gas to the detector.

[0090] The chromatogram at the bottom in Figure 7 is: Same spiked butane sample, however, the embodiment of the injection system disclosed herein has now been installed into the gas chromatograph. Now when the LSV actuates, the 400p5i Butane moves into series with the carrier gas at approximately 84ps1. At this pressure, the Butane sample stays in the liquid phase and keeps the heavier hydrocarbons solubilized. The butane as a liquid droplet, is pushed by the carrier gas through the restriction and into the heated zone of the GC. As the butane moves through the restriction towards the capillary column, the pressure will be decreasing down to an estimated 2.5p5i at the top of the capillary column. The HCs are now within the heated zone of the GC which will ramp up to 430 C, vaporizing all components and selectively sending them to the detector. As illustrated in the results from the current setup, it can be possible to achieve effectively zero mass discrimination up to C34, approximately 25% mass discrimination at C36 and 50%
at C40 =

[0091] Disclosed herein below is a second embodiment where the injection valve 12 is positioned away from the GC oven, and the restriction tubing 24 connects directly to a column 30 for separation.

[0092] Flush mounting the LSV over the PTV injector can cause inconsistent heat in the LSV. As the PTV heated during the analysis, the LSV would warm up from the heat radiation. This can cause the Butane to partially evaporate inside the LSV when running the instrument multiple times leading to inconsistent analyses.

[0093] Figures 9, 10, 11 and 12 relates to an embodiment where by increasing the distance between LSV and PTV, to reduce the heat bleeding from the PTV to the LSV, was tested to improve the consistency of multiple analyses.

[0094] This allows to mount the LSV in an insulated oven for consistent temperature.

[0095] In the embodiment disclosed in Figures 9, 10, 11 and 12, a shorter but much narrower bore restrictor, and a longer and much narrower bore MXT
capillary column was utilized. This allowed utilization of much higher pressures.

[0096] The goal was to keep the pressure at the head of the column above the 40 C Butane vapour pressure estimated at 60psi. This should keep all the heavy hydrocarbons present in the sample to be solubilized in the liquid butane, until deposited on the head of the column.

[0097] The following specifications were utilized.

[0098] Argon carrier pressure at the regulator was ¨250psi.

[0099] Pressure at the LSV at the point of injection was ¨160psi.

[00100] Pressure at the head of the column was ¨75 psi

[00101] Flow through the column was approximately 6m1/min at 30 C

[00102] In the embodiment disclosed in Figures 9, 10, 11 and 12, a shorter but much narrower bore restrictor, and a longer and much narrower bore MXT
capillary column was used. The goal was to keep the pressure at the head of the column above the 40 C Butane vapour pressure estimated at 60psi.

[00103] The following specifications were utilized.

[00104] Argon carrier pressure at the regulator was ¨250p5i.

[00105] Pressure at the LSV at the point of injection was ¨160psi.

[00106] As shown by the chromatographic analysis shown in Figure 13, the embodiment disclosed in Figures 9, 10, 11 and 12, provided better mass discrimination. In the embodiment disclosed in Figures 9, 10, 11 and 12, 0%
mass discrimination was observed from C8-C4o, and 10% mass discrimination for C44 with improved consistency from multiple injections.

[00107] Described herein below is an embodiment of a calculation of the restriction tubing dimensions for use in the injection module disclosed herein. In the embodiment below helium is used as an example. However, the specification is not limited to helium, and other gases, such as, for example and without limitation, argon, can be used, depending upon design and application requirements.

[00108] Step 1:

[00109] Look at sample matrix and phase diagram to determine minimum pressure and temperature within the injection system and the head of the column.
Example 100% butane has a vapour pressure of approximately 55psi at 50 C. To keep the butane sample in single phase during injection, the pressure in the entire system should be above 55 psi including at the LSV and at the head of the capillary column. To ensure partial vaporization doesn't occur, the minimum pressure can be increased up to 70psi. Once the sample has been deposited on the capillary column, the oven can be heated up to 350 C at a linear ramp rate and selective vaporization of all the heavy hydrocarbons that were dissolved in the butane sample will occur over time. Using this technique, it is possible to analyze up to Cso hydrocarbons dissolved in butane.

[00110] Step 2

[00111] Using the Restek EZGC Flow calculator https://ez.restek.com/ezgc-mtfc, a 20m x 0.18mm ID x 0.4um MXT-1 column was chosen. The calculator disclosed herein is not particularly limiting, and other calculators and method of calculation are available and should be known to a person of skill in the art.
The column chosen is a metal column with a 100% PDMS phase and has a maximum temperature of 400 C, so it will be capable of eluting n-hydrocarbons up to C50.
According to the EZGC Flow Calculator (Table 1), the optimum carrier gas range for a 0.18mm ID column is between 1-1.4m1/min. However, 70psi head pressure leads to 5.4m1/min carrier gas at the outlet leading to the FID, which is above our optimum carrier gas range for a 0.18mmID column.
EZGC Flow Calculator -`.
_ =
Helium CW40111.1* _ ___________ Long 20.00 I noel- Diameter 0.18 win Filiii Thickner,s 0.25 pm Temperature 50.00 'C
- "
Optimum Range Column Flow r nt 1 0 In 11 5.44 mLimin Average Velocity 99.57 cm/sec Holdup Time 0.33 min Inlet Pressure psi 70.00 psi Outlet PFessuce Cabs) 14.70 psi Table 1.: Calculation of gas carrier range.

[00112] The injection system is currently isobaric (meaning, one cannot pressure program to compensate for increasing viscosity of the carrier gas as the column oven heats during analysis). Therefore as the column heats up to 350-400 C, the flow in the column will actually drop from 5.4nril/min at 50 C to 1.5m1/min at 400 C., which is very close to our optimum column flow range.
EZGC Flow Calculator _______________________________________________________ - __ -Helium Length 2000. ri Inner Diameter 0.18 ram Film Thickness 025 pm Temperature 400.00 c rti*Ifell****1_1k - -Optimum Range Column Flow !ram 1.0 !a 1.4 158 fliJniir mUrnin Average Velocity 60.30 or/see Holdup Time 0.55 min Inlet Pressure psi 70.00 psi Outlet Pressure (absS 14.70 psi vorvit Table 2: Calculation of flow in column after accounting for temperature.

[00113] Step 3:

[00114] In order to calculate the length and inner diameter of the restrictor that is coupled upstream of the capillary column, one can type the column flow rate at the FID in the Restek EZGC Flow Calculator. Keeping the temperature at 50 C

and the length at 1m (which is an easily purchased length for restrictor tubing), one can enter the various IDs that are available for restrictor tubing. Tubing IDs of 10, 15, 20, 25, 30, 40, 50, 75, 100, 125, 180 and 250um are all available "off-the-shelf". Using a 1m x 0.05mm tube gives us 230p5i head pressure in order to deliver 5.4rn1/nnin at 50 C.

EZGC Flow Calculator =i Helium U6161.011ni Length 1.00 m I niier- Diameter 0.05 In m Filin Thickness 0.25 inn Temperature 50.00 .c .
Optimum Range Column Flow Mom 0.2 to 0..z 540 rn i etL..rnirr Average Velocity 459.62 Imsec HUILILIp TIITIt 0.00 min Inlet Pressure psi 230.08 psi outlet Pressure (abs) 14.70 ps =
Table 3.: Calculating the length and inner diameter of the restriction tubing.

[00115] Using a dual stage regulator to deliver 230psi into our restrictor tubing, a person of skill in the art should recognize that it will approximately yield 70psi at the head of the capillary column and deliver 5.4m1/min carrier gas to the FID at 50 C. We can also estimate an approximate linear pressure drop along the length of the lm restrictor tube which is divided into a 1 foot and a 2 foot length.
The pressure in the LSV can be estimated at 160-180ps1, which is above the vapour pressure of butane at 50 C and will prevent the vaporization of the sample prior to depositing on the head of the column.

[00116] Certain adaptations and modifications of the described embodiments can be made. Therefore, the above discussed embodiments are considered to be illustrative and not restrictive.

Table of reference numerals No. Description No. Description Injection module 62 Mobile phase system 12 Injection valve 64 Analytical device 14 Sample inlet port 66 sample 16 Mobile phase inlet port 68 detector 18 Waste port 70 System having 64 Column port 72 Mobile phase tank 22 Sample loop 74 Regulator for 72 24 Restriction tubing 76 Mobile phase system tubing 26 Valve end of 24 78 Flow controller 28 Column end of 24 80 union Column 82 PTV injector 32 First waste tubing 84 oven 34 First end of 32 86 36 Second end of 32 88 38 Waste valve system 90 First waste valve 92 42 Second waste valve 94 44 Second waste tubing 96 46 Outlet 98 48 Sample tubing 100 First end of 48 52 Second end of 48 54 Sampling system 56 Mobile phase tubing 58 First end of 56 Second end of 56

Claims (16)

WHAT IS CLAIMED IS:

1. An injection module, comprising:
- an injection valve having a sample inlet port, a mobile phase inlet port, a waste port, a column port and a sample loop;
the injection valve configurable from a first position to a second position, the first position directing fluid flow from the sample inlet port to the sample loop, and from the sample loop to the waste port, and also directing fluid flow from the mobile phase inlet port to the column port, and the second position directing fluid flow from the sample inlet port to the waste port, and also directing fluid flow from the mobile phase inlet port to the sample loop, and from the sample loop to the column port;
- a restriction tubing having a valve end and a column end, the valve end coupled to the column port of the injection valve, and the column end configured for coupling to a column; wherein the restriction tubing is configured for reducing separation of a sample into a gas phase and a liquid phase when the injection valve is in the second position.

2. The injection module of claim 1, wherein the restriction tubing is selected to having an internal diameter narrower than an internal diameter of the column to which the restriction tubing is configured for coupling.

3. The injection module of claim 1 or 2, wherein the internal diameter and/or length of the restriction tubing is selected for maintaining sufficient pressure for reducing separation of a sample into a gas phase and a liquid phase when the injection valve in the second position.

4. The injection module of any one of claims 1 to 3, further comprising:
- a first waste tubing having a first end coupled to the waste port, and a second end coupled to a waste valve system.

5. The injection module of claim 4, the waste valve system comprising - a first waste valve coupled to the second end of the first waste tubing, - a second waste valve, and - a second waste tubing permitting fluid flow from the first waste tubing to the second waste valve upon actuation of the first waste valve.

6. The injection module of claim 5, wherein the waste valve system is configurable from a first position permitting fluid flow from the first waste tubing to the second waste tubing upon actuation of the first waste valve, to a second position permitting fluid flow from the second waste tubing to an outlet upon actuation of the second waste valve, and preventing fluid flow from the first waste tubing to the second waste tubing.

7. The injection module of any one of claims 1 to 6, further comprising:
- a sample tubing having a first end coupled to the sample inlet port, and a second end coupled to a sampling system, the sample tubing permitting fluid flow from the sampling system to the sample inlet port; and - a mobile phase tubing having a first end coupled to the mobile phase inlet port and a second end configured for coupling to a mobile phase system, the mobile phase tubing permitting fluid flow from the mobile phase system to the mobile phase inlet port.

8. The injection system of claim 7, wherein the mobile phase tubing is configured for reducing separation of the sample into a gas phase and a liquid phase when the injection valve is in the second position.

9. The injection system of claim 7 or 8, wherein the mobile phase tubing is selected to having an internal diameter narrower than an internal diameter of a mobile phase system tubing to which the mobile phase tubing is configured for coupling.

10. The injection module of any one of claims 7 to 9, wherein the internal diameter and/or length of the mobile phase tubing is selected for maintaining sufficient pressure for reducing separation of a sample into a gas phase and a liquid phase when the injection valve in the second position.

11. The injection module of any one of claims 1 to 10, wherein the injection module is for use with a gas chromatography (GC) instrument.

12. A method of analyzing a sample having multiple phases using an injection module as defined in any one of claims 1 to 11, the method comprising the steps of:
- injecting the sample into the sample loop;
- transporting the sample from the sample loop to the column while maintaining a pressure and/or a temperature on the sample for reducing separation of a sample into a gas phase and a liquid phase;
- separating the sample in the column; and - detecting constituents of the sample.

13. An analytical device for analysis of a sample, the analytical device comprising:
- an injection module as defined in any one of claims 1 to 11;
- a column for separation of constituents of the sample, wherein one end of the column is in fluid communication with the injection module; and - a detector coupled to a second end of the column for detecting the constituents of the sample.

14. The analytical device of claim 13, wherein the analytical device is a gas chromatography (GC) instrument.

15. The analytical device of claim 13 or 14, wherein the detector is a flame ionization detector (FID).

16. An analytical system for analysis of a sample comprising:
- an injection module as defined in any one of claims 1 to 11;
- a column for separation of constituents of the sample;
- a detector for detecting the constituents of the sample;
- a mobile phase delivery system; and - a computer system having a program for execution of a method for analysis of the sample.