CN109613079A - A kind of detection method of the total lead of environment water - Google Patents
A kind of detection method of the total lead of environment water Download PDFInfo
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- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
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Abstract
A kind of detection method of the total lead of environment water belongs to a kind of detection method of heavy metal in environment water.By obtained CNTs/poly (L-Arg) electrode first in 50mL, the acetate buffer solution (ABS) of pH=5 is scanned using Differential Pulse Voltammetry, until curve is stablized, a certain amount of Pb is added afterwards2+Standard solution stands 20s in -0.7V preenrichment under stirring condition after a certain period of time.Observation oxidation peak current value from -1V ~ 0V differential pulse voltammetry volt-ampere curve, recording curve, the temperature of experiment are 25 ± 0.1 DEG C.The present invention is by CNTs/poly (L-Arg) film modified electrode in detection Pb2+When with good stability, excellent sensitivity and high selectivity, the repeatability and reproducibility also having had.Rapidly and efficiently, material is cheap and easy to get for detection.
Description
Technical field
The invention belongs to a kind of detection methods of heavy metal in environment water, particularly belong to a kind of by composite film material pair
Pb in environment water2+The method detected.
Background technique
In recent years, increasing to the exploitation processing of heavy metal, heavy metal element is not just discharged by processing, in turn
Cause the pollution of water body, soil property.It is well known that heavy metal can not be degraded, but can constantly be accumulated by food chain, finally
Then possibly into and poison human body.Therefore, heavy metal pollution be food, environment, the monitoring of hygiene the most important thing.Currently, micro
There are many mature analyzing detecting methods for the measurement of heavy metal.Such as ultraviolet-visible spectrophotometry (UV), atomic absorption method
(AAS), Raman spectroscopy, Inductively coupled plasma-mass spectrometry (ICP-MS), high performance liquid chromatography (HPLC), the chromatography of ions
Deng though they have the advantages that respective, also generally existing equipment price is expensive, and instrument maintenance expense is larger, and application surface is narrow etc.
Disadvantage.Interfacial electrochemistry is quickly grown in recent years, relative to the valuableness of other detection heavy metal ion methods such as photometry, operation
Complexity, electrochemical analysis method is not only sensitive, quick, efficient, and it is easy to operate, easy to carry, cost is relatively low, answered extensively
It uses among detection heavy metal ion, and the attention more and more by people.Accordingly it is desirable to can have one kind effective
The method for detecting total lead in water.
Summary of the invention
The purpose of the present invention is being directed to defect described above, a kind of detection method of total lead of environment water, this method are provided
Easy to operate, easy to carry and with good stability, excellent sensitivity and high selectivity also have good heavy
Renaturation and reproducibility, rapidly and efficiently.
The purpose of the present invention is what is be achieved by the following technical programs.
A kind of detection method of the total lead of environment water, it is characterised in that: in turn include the following steps:
(1) CNTs/poly (L-Arg) compound film electrode is prepared:
(1) pretreatment of glassy carbon electrode
Polishing powder (the Al of suitable 30 nm is sprinkled on chamois leather2O3), a few drop deionized waters are then added dropwise, with glass-carbon electrode side
Edge stirs evenly, and pinches glass-carbon electrode vertically afterwards, uniformly firmly, at the uniform velocity draws circle, is then cleaned with deionized water, ear washing bulb is blown
It is dry, nitric acid is dripped in glassy carbon electrode surface, is cleaned after static 10 ~ 15s with deionized water, then in ethanol water, nitric acid
20 s of ultrasound are distinguished in aqueous solution, deionized water, ear washing bulb drying is spare；
The glass-carbon electrode handled well is put into 5mM K3Fe(CN)6、0.2M KNO3In solution, with electrochemical workstation, using three
Electrode system, reference electrode select saturated calomel electrode (SCE), select carbon-point to electrode, working electrode selects glass-carbon electrode
(GCE) (3 mm of diameter), using cyclic voltammetry, the scanning in the scanning range of 0 ~ 0.5V；If redox peaks potential difference exists
Within 64mV or so, 80mV, 0.2M H is changed to2SO4It is activated in solution, the scanning in -0.2 ~ 1.4V, until cyclic voltammogram weight
It is multiple；
(2) processing of carbon nanotube
1) electronic balance weighs 5.0g hydroxylated multi-walled carbon nanotubes, takes HCL, MWCNT and the HCL of 100mL 0.4M molten with graduated cylinder
Liquid mixes, mechanical stirring 5h after ultrasonic oscillation；
2) in the H of 100mL2SO4And HNO3Ultrasonic 5 hours in mixed solution (concentration ratio is 3:1), then magnetic agitation 10 hours；
3) carbon nanotube and mixed acid solution are filtered by vacuum, and are washed with deionized water to neutrality, are placed in drying box and are dried for 24 hours；
4) take the processed carbon nanotube of 5mg that deionized water is added to be settled to 10mL, ultrasound is uniform to solution, spare；
(3) preparation of poly (L-Arg) electrode
At room temperature, the good concentration of configured in advance is 0.1M to accurate measuring, and 50 mL of phosphate buffer solution that pH value is 6 adds
Enter 0.25mM arginine, after stirring to all dissolutions ultrasound obtain within 20 minutes taking out after uniform mixed solution place it is spare；With
Electrochemical workstation, three-electrode system is identical as step (1), and using cyclic voltammetry, scanning range is -1 ~ 2V, and sweeping speed is
100mV/s；Deposition end is rinsed well rear spare with deionization, obtains poly (L-Arg) electrode；
(4) preparation of CNTs electrode
It takes the MWCNTs that 6 μ l concentration are 0.5mg/mL to drop to the surface glass-carbon electrode (GCE) with liquid-transfering gun, is placed under ultraviolet lamp, do
It is taken out after dry, ion dries up spare after rinsing, and obtains CNTs electrode；
(5) preparation of CNTs/poly (L-Arg) electrode
CNTs electrode is taken to be put into the arginine PBS mixed solution prepared (concentration is identical with step (3))；Use circulation
Voltammetric scan, scanning range are that sweep speed be that 50mV/s(three-electrode system is identical as step (1) to -1 ~ 2V)；It is spent after deposition
Ion is rinsed well rear spare, obtains CNTs/poly (L-Arg) electrode；
(2) CNTs/poly (L-Arg) electrode is to Pb2+Detection:
By obtained CNTs/poly (L-Arg) electrode first in 50 mL, difference is shown in acetate buffer solution (ABS) use of pH=5
A certain amount of Pb is added until curve is stablized in pulse voltammetry scanning afterwards2+Standard solution, in the pre- richness of -0.7 V under stirring condition
Collection stands 20 s after a certain period of time.Observe the differential pulse voltammetry volt-ampere curve from the V of -1 V ~ 0, oxidation peak current in recording curve
Value, the temperature of experiment are 25 ± 0.1 DEG C.
Arginine was found in 1886, and Schulze et al. is studied for lupin seedling, was successfully separated out smart ammonia
Sour (Arginine, Arg), and named.To 1895, in animal protein, Hedin et al. is also successfully made point
From having obtained arginine.Arginine is one of protein basic composition unit, and there are amino, carboxyl in both ends, there is guanidine radicals, ammonia on chain
Base is in alkalinity, and for carboxyl in acidity, existing hydrophobic grouping also has hydrophilic radical, and intramolecular has hydrogen bond, can be formed between molecule point
Hydrogen bond between son, is highly studied.Arginine has 2 basic groups of amino and guanidine radicals, belongs to basic amino acid, pH probably exists
10.5 ~ 12.5, most strong in 20 kinds of amino acid neutral and alkalis, scientific name is 2- smino guanidyl valeric acid, molecular formula C6H14N4O2, structural formula
As follows, can abbreviation Arg, can also abbreviation R, the arginine containing two molecular crystalline water be white diamond, the crystallization water is not in
Monocline sheet is divided to two kinds of D-Arg and L-arginine essence.The Main way of current amino acid application development is to obtain its polymerization
Object, polymer have higher activity, the preparation method of amino acid polymer have extraction and it is artificial synthesized.Artificial synthesized method
In, the method for electrochemistry is fast and convenient, and it is pollution-free, poly- L-arginine is made with cyclic voltammetry and has been used to detection adrenal gland
Element, uric acid, dopamine ascorbic acid, uric acid biphenyl 3 phenol, hydroquinone is right/o-aminophenol xanthine etc..
Carbon coming in every shape and being stored on the earth extensively, well-known only two kinds of forms of graphite and diamond, directly
The gate of carbon is opened for us to Smalley.Smalley has found fullerene in its research process, off the beaten track
Obtain C with pyrotechnics method60, since then, the world of colourful carbon expands bosom to scholars, carbon nanometer after this
Pipe, carbon dots and graphene etc. carbon structure subsequently enter our sight.Carbon nanotube (CNTs) was found in 1991,
The close attention of numerous scientific workers is obtained with its excellent performance, then takes that rapid development.CNTs tensile strength is very
It is even more that researchers is allowed to go after like a flock of ducks that height, which is electric conductivity and heat exchange among the best, excellent in the fibre, unique
Hollow structure can be used to hydrogen storage or as catalyst carrier material, and application scenarios are very broad.But since CNTs compares table
Area is bigger, and draw ratio is relatively high, and mutual Van der Waals force is bigger, so being easy to reunite, how to divide it uniformly
It dissipates, becomes crucial.Experimental study verifying, grinding ultrasound can accelerate its dispersion, can also promote its dispersion after strong acid and strong base processing,
Also someone is improved by addition surfactant or growth in situ synthesis, significant effect.Each carbon atom is through sp in CNTs2
Hydridization and other carbon atom bondings, are rolled similar to plane graphite.Single-walled carbon nanotube (SWNTs) is by mono-layer graphite plane
It is rolled into, correspondingly, multi-walled carbon nanotube (MWNTs) is rolled by Multi-layer graphite plane.CNTs has many excellent speciality, in electro-catalysis
It is widely used with electroanalysis direction, is even more by favor in the fields such as nano-probe and electrochemical sensor.In addition there are also theoretical
If calculating and test result showing to add it in high molecular material, its electric conductivity can be improved, make the electricity of high molecular polymer
Resistance reduces by three orders of magnitude or more.
The beneficial effects of the present invention are: CNTs electric conductivity used in the present invention is high, large specific surface area, poly (L-Arg)
Contain many amides and amino, easy and Pb2+Chelating, Pb when being easy to detect2+Enrichment, CNTs/poly (L-Arg) laminated film
Material has both the advantages of the two.Therefore the present invention has the glass-carbon electrode of CNTs as carrier using drop coating, electropolymerization poly (L- on it
Arg), CNTs/poly (L-Arg) composite film material is prepared.Film forming procedure is studied with cyclic voltammetric, combines time current curve
It is applied to Pb in detection water with linear scan research CNTs/poly (L-Arg) composite film material modified electrode2+。
Detailed description of the invention
Fig. 1 is that CNTs/poly (L-Arg) modified glassy carbon electrode detects Pb2+Schematic diagram.
Fig. 2 is respectively electrodeposition process (a) of the L-arginine on glass-carbon electrode, L-arginine on carbon nanotube electrode
Electrodeposition process (b) vs.SCE.
Fig. 3 is respectively glass-carbon electrode (a), poly arginine electrode (b), poly arginine electro-conductive glass (c).
Fig. 4 is respectively the SEM figure (a) of poly (L-Arg), the SEM figure (b) of CNTs, CNTs/poly (L-Arg) SEM figure
(c)。
Fig. 5 is respectively the infrared figure (a) of arginine and the infrared figure (b) of poly arginine.
Fig. 6 is respectively bare (a), CNTs(b), poly (L-Arg) (c), CNTs/poly (L-Arg) (d) modification glass
Carbon electrode is in 5 mM Fe (CN) of neutrality6 3-/4-Redox couple (includes 5 mM K4Fe(CN)6·3H2O、5 mM K3
[Fe(CN)6] and 0.1 M KCl) cyclic voltammogram vs.SCE(A) and Nyquist diagram (B).
Fig. 7 is CNTs(a), poly (L-Arg) (b), CNTs/poly (L-Arg) (c) modification glass-carbon electrode containing 1
ppm Pb2+0.1 M acetate salt buffer molten (pH=5) in differential pulse voltammetry scanning figure (- 0.7 V of preenrichment voltage, when preenrichment
Between 120 s); vs. SCE.
Fig. 8 is respectively carbon nano tube modified glass-carbon electrode in 5 mM Fe (CN) of neutrality6 3-/4-Redox couple
It (include 5 mM K4Fe(CN)6·3H2O、5 mM K3Fe(CN)6And 0.1 M KCl) in respectively with 0.02 ~ 0.18 VS-1
Sweep the obtained cyclic voltammogram vs.SCE of speed and peak current (from the inside to surface) and sweep the subduplicate linear graph of speed.
Fig. 9 is respectively the glass-carbon electrode of CNTs/poly (L-Arg) modification in 5 mM Fe (CN) of neutrality6 3-/4-Redox
Electricity (includes 5 mM K to solution4Fe(CN)6·3H2O、5 mM K3Fe(CN)6And 0.1 M KCl) in respectively with 0.02 ~
0.18 V·S-1(from the inside to surface) the cyclic voltammogram vs.SCE and peak current and sweep fast subduplicate linear that speed obtains are swept
Figure.
Figure 10 is the optimization schematic diagram of pH.
Figure 11 is the optimization schematic diagram of preenrichment voltage (vs.SCE).
Figure 12 is the optimization schematic diagram of preenrichment time.
Figure 13 is respectively that the glass-carbon electrode of CNTs/poly (L-Arg) modification is containing for 0.03 ~ 0.18 ppm Pb2+
(from the inside to surface) (pH=5) linear scan response and peak current and Pb in 0.1M acetate buffer solution2+Concentration it is linear
Figure.
Figure 14 is respectively 0 ~ 5 ppm Zn of CNTs/poly (L-Arg) electrode detection2+(a), 0 ~ 10 ppm Cu2+
(b), 0 ~ 0.18 ppm Cd2+(c) linear scan (vs.SCE) response.
Figure 15 is that the glass-carbon electrode of CNTs/poly (L-Arg) modification is including 0.2 ppm Pb2+0.1 M acetate
- 0.7 Vvs.SCE under stirring state in buffer solution (pH=6), the linear scan figure (a) and+0.5 after 120 s preenrichments
Vvs.SCE solves the linear scan figure (b) after 120 s of chelating under stirring state.
Figure 16 is CNTs/poly (L-Arg) electrode repeatability schematic diagram.
Figure 17 is CNTs/poly (L-Arg) electrode reproducibility schematic diagram.
Specific embodiment
In order to further illustrate the present invention, following serial specific embodiment is provided in conjunction with attached drawing, but the present invention is not by this
The limitation of a little specific embodiments, any understanding person skilled in art will can achieve few modifications of the invention similar
As a result, these changes are also contained among the present invention.
Embodiment 1.
One, the preparation of metal ion standard solution.
The preparation method (1 mg/mL) of copper standard solution.
Weigh copper sulphate (CuSO4·5H2O) 3.9281 g, adds moderate amount of sulfuric acid, and constant volume shakes up in 1000 mL volumetric flasks
It is spare.
The preparation method (0.1 mg/mL) of Zinc standard solution.
Weigh zinc sulfate (ZnSO4·7H2O) 44 mg, constant volume shake up spare in 1000 mL volumetric flasks.
The preparation method (1 mg/mL) of cadmium standard solution
2.0311 g of caddy is weighed, constant volume shakes up spare in 1000 mL volumetric flasks.
The preparation method (0.1 mg/mL) of lead standard solution.
Weigh plumbi nitras (Pb (NO3)2) 0.160 g, add appropriate nitric acid, constant volume shakes up spare in 1000 mL measuring bottles.
Two, the preparation of CNTs/poly (L-Arg) compound film electrode.
(1) pretreatment of glassy carbon electrode.
Polishing powder (the Al of suitable 30 nm is sprinkled on chamois leather2O3), a few drop deionized waters are then added dropwise, use glass-carbon electrode
Edge stirs evenly, and pinches glass-carbon electrode vertically afterwards, uniformly firmly, at the uniform velocity draws circle, is then cleaned with deionized water, ear washing bulb is blown
It is dry, nitric acid is dripped in glassy carbon electrode surface, is cleaned after static 10 ~ 15 s with deionized water, then in ethanol water, nitre
20 s of ultrasound are distinguished in aqueous acid, deionized water, ear washing bulb drying is spare.
The glass-carbon electrode handled well is put into 5 mM K3Fe(CN)6、0.2 M KNO3In solution, with electrochemical workstation,
Using three-electrode system, reference electrode selects saturated calomel electrode (SCE), selects carbon-point to electrode, working electrode selects glass carbon
Electrode (GCE) (3 mm of diameter), using cyclic voltammetry, the scanning in the scanning range of 0 ~ 0.5 V.If redox peaks are electric
Potential difference changes to 0.2 M H within 64 mV or so, 80 mV2SO4It is activated in solution, the scanning in -0.2 ~ 1.4V, until following
Ring voltammogram repeats.
(2) processing of carbon nanotube.
1) electronic balance weighs 5.0 g hydroxylated multi-walled carbon nanotubes, and the HCL of 100 mL, 0.4 M, MWCNT are taken with graduated cylinder
It is mixed with HCL solution, 5 h of mechanical stirring after ultrasonic oscillation.
2) in the H of 100 mL2SO4And HNO3Ultrasonic 5 hours in mixed solution (concentration ratio is 3:1), then magnetic agitation 10
Hour.
3) carbon nanotube and mixed acid solution are filtered by vacuum, and are washed with deionized water to neutrality, are placed in drying box dry 24
h。
4) take the processed carbon nanotube of 5 mg that deionized water is added to be settled to 10 mL, ultrasound is uniform to solution, spare.
(3) preparation of poly (L-Arg) electrode.
At room temperature, the good concentration of configured in advance is 0.1 M, the phosphate buffer solution 50 that pH value is 6 to accurate measuring
0.25 mM arginine is added in mL, after stirring to all dissolutions ultrasound obtain within 20 minutes taking out after uniform mixed solution place it is standby
With.With electrochemical workstation, the same step of three-electrode system (1), using cyclic voltammetry, scanning range is -1 ~ 2 V, sweeps speed
For 100 mV/s.Deposition end is rinsed well rear spare with deionization, obtains poly (L-Arg) electrode.
(4) preparation of CNTs electrode.
Taking 6 μ l concentration with liquid-transfering gun is that the MWCNTs of 0.5 mg/mL drops to the surface glass-carbon electrode (GCE), is placed in ultraviolet lamp
Under, it is taken out after dry, ion dries up spare after rinsing, obtain CNTs electrode.
(5) preparation of CNTs/poly (L-Arg) electrode.
CNTs electrode is taken to be put into the arginine PBS mixed solution prepared (the same step of concentration (3)).It is lied prostrate using circulation
Peace scanning, scanning range are that -1 ~ 2 V sweep speed as the 50 same steps of mV/s(three-electrode system (1)).Deionization is used after deposition
It rinses well rear spare, obtains CNTs/poly (L-Arg) electrode.
Three, the characterization of CNTs/poly (L-Arg) electrode.
The microstructure of material is observed using field emission scanning electron microscope (FESEM), and acceleration voltage is 15 kV.Electricity
Mirror sample preparation methods: electropolymerization obtains material on the electrode, removes electrode tip and observes directly at microscope.Material it is infrared
Infrared sample preparation methods: spectrum is obtained using measuring in Fourier Transform Infrared Spectrometer in electro-conductive glass on piece electropolymerization
Material scrapes powder, carries out tabletting with potassium bromide (KBr).
Four, electro-chemical test.
The AC impedance (EIS) of material is completed using electrochemical workstation, using the three-electrode system of standard, reference electrode
It selects saturated calomel electrode (SCE), carbon-point is selected to electrode, working electrode selects the glass-carbon electrode (GCE) of different materials modification
(3 mm of diameter), supporting electrolyte solution are containing 5 mM K3[Fe(CN)6] and 5 mM K4Fe(CN)6·3H20.1 M of O
KCl solution, frequency range are set as the kHz of 0.1 Hz ~ 100.
Five, modified electrode is to Pb2+Detection.
Different electrodes (CNTs electrode or poly (L-Arg) electrode or CNTs/poly (L-Arg) electrode) is first 50
The acetate buffer solution (ABS) of mL, pH=5 are scanned using Differential Pulse Voltammetry, until curve is stablized, it is rear to be added centainly
The Pb of amount2+Standard solution stands 20 s in -0.7 V preenrichment under stirring condition after a certain period of time.Observation is from the V's of -1 V ~ 0
Differential pulse voltammetry volt-ampere curve, oxidation peak current value in recording curve, the temperature of experiment are 25 ± 0.1 DEG C.
Six, results and discussion.
1, the manufacturing process of sample.
In order to study arginine electropolymerization on the surface that glass-carbon electrode and drop have the glass-carbon electrode of CNTs, lied prostrate using circulation
An Fa, using the PBS buffer solution of pH=6 as supporting electrolyte electropolymerization arginine, electropolymerization voltage scan range be -1 V ~
2 V(vs.SCE).Arginine in glass-carbon electrode powers on polymerization process as shown in Figure 2 a, former circles of cyclic voltammetric, with electropolymerization
It carries out, electrode surface electropolymerization substance is increasing, and redox peak is continuously increased, with the increase of electropolymerization substance, electricity
Pole surface electric conductivity is affected and reduces, and rear a few circle peak currents are not further added by, and slowly tends towards stability.Fig. 2 b is that arginine is dripping
Cyclic voltammetry curve when having electropolymerization on the glass-carbon electrode of CNTs, it is very big just to have started a few circle peak currents, because CNTs is led on electrode
Electrically very well, keep peak current very high, but as electric polymerization reaction carries out, electrode surface constantly has polymer generation, and polymer is led
It is electrically poor, cause conductivity of composite material to reduce, peak current reduces.Increase then as electropolymerization substance, peak current starts small
Amplitude reduces, and as electropolymerization substance is continuously increased, and electrode surface material thickeies, and electric conductivity reduces, and peak current no longer becomes
Change tends towards stability.It is evident that having a pair of apparent redox peaks when depositing arginine with or without CNTs
Occur, and spike potential does not almost become.There is peak current after CNTs to improve a lot, undoubtedly, this is because CNTs is mentioned
Efficient conductive channel has been supplied, conductivity of composite material is improved, has increased conduction rate.
2, the characterization and analysis of material.
(1) morphology analysis.
Fig. 3 is respectively glass-carbon electrode (a), deposited arginic glass-carbon electrode (b) and deposited arginic conductive glass
The significant change of color proves that electro-deposition is successfully realized at glass piece (c), electrode and electro-conductive glass deposition materials.In order to further right
Its pattern is characterized, using field emission scanning electron microscope to poly (L-Arg) electrode (Fig. 4 a), CNTs electrode (Fig. 4 b), CNTs/
The electrode surface of poly (L-Arg) electrode (Fig. 4 c) is observed.Fig. 4 a can be clearly seen that, on poly (L-Arg) electrode
Poly (L-Arg) material being unevenly stacked up is distributed with to be caused this is because the universal electric conductivity of high molecular polymer is bad
Caused by deposition is uneven.Fig. 4 b is CNTs electrode surface electron microscope, it may be clearly seen that hydroxylating multi wall CNTs is more equal
It is distributed on glass-carbon electrode evenly, CNTs tube wall is smooth smooth.Fig. 4 c can see, on CNTs deposit poly (L-Arg) with
Afterwards, the surface CNTs is no longer smooth, has more uniformly coated layer of material, and the surface CNTs is caused to seem very coarse.This is
Because poly (L-Arg) more uniform deposition on CNTs with good conductivity, is coated on the surface CNTs, good in conjunction with CNTs
Electric conductivity and biggish specific surface area, increase entire material specific surface area, electric conductivity also has with respect to poly (L-Arg) electrode
Large increase, this also increases preenrichment amount for after and provides possibility when preenrichment.
(2) infrared analysis.
It may determine that the functional group in material by infrared test, it is pure arginine (a) and poly respectively that Fig. 5, which is shown,
(L-Arg) infrared spectrogram of (b) material.Each absorption peak can belong in Fig. 5 b are as follows: 750,870,1249 cm-1Place is N-H, C-H
Deformation vibration C -- C single bond skeletal vibration, 1544 cm-1Place is II C ≡ N stretching vibration of amide and N-H bending vibration, 1749 cm-1
Place is I C of amide=O carbonylic stretching vibration and guanidine stretching vibration C ≡ N, 3260/3300/3559/3625 cm-1Place be N-H, C-H,
O-H stretching vibration.
3, the electrochemical Characterization of modified electrode.
(1) impedance analysis.
Bare glassy carbon electrode (a), CNTs electrode (b), poly (L-Arg) electrode (c) and CNTs/poly (L-Arg) electrode (d)
In the 5 mM Fe (CN) containing 0.1 M KCl6 3-/4-Fe (CN) is used in solution6 3-/4-Oxidation-reduction pair detection, obtained circulation
Volt-ampere curve is as shown in Figure 6A (vs.SCE).Opposite bare glassy carbon electrode, it is equal to deposited arginic anodizing reduction peak current
Being reduced, this result surface electronic transfer rate is restrained by electrode material i.e. poly (L-Arg), hence it is demonstrated that
Poly (L-Arg) electric conductivity is bad.And CNTs electrode also has reduction this is because thickness effect with respect to bare glassy carbon electrode peak current
The good electric conductivity of CNTs, from the addition of CNTs so that CNT/ poly (L-Arg) electrode electroactive increases, peak current is obtained
It improves, just can prove that.Electrochemical impedance spectroscopy (EIS) is observed that the impedance variations of different modifying electrode, further to electrode
Surface interface feature is characterized.This interface can be modeled by equivalent circuit, which includes ohm of electrolyte
Resistance Rs, electronics transfer resistance Ret, double layer capacity Cd.One typical Nyquist diagram includes semicircle and low frequency under high frequency
Under oblique line, high frequency region be interfacial charge transfer mechanics control semi arch, low frequency range be diffusion control straight line, high frequency lower half
Circular portion diameter corresponds to electronics transfer resistance Ret, and radius is bigger, and resistance is bigger, is most important a part in Impedance Research.
GCE electrode resistance 62 Ω of minimum, are up to 160 Ω of poly (L-Arg) electrode, carbon nanotube electrode 135 Ω, CNTs/poly
(L-Arg) combination electrode because carbon nanotube addition, 155 Ω of resistance reduced.EIS is as shown in Figure 6B, according to circular arc half
The resistance of the available poly of the bigger conclusion of the bigger resistance of diameter (L-Arg) is maximum, and after having added CNTs, CNTs/poly
(L-Arg) combination electrode resistance is reduced because CNTs can improve the electric conductivity of composite film material, with fitting circuit data with
And cyclic voltammetric diagram data is almost the same before.
(2) Pb2+Electrochemical behavior research on modified electrode.
Glass-carbon electrode, arginine electrode and CNTs/poly (L-Arg) electrode are respectively in Pb2+Solution in one section of preenrichment
Time, then respectively with Differential Pulse Voltammetry by Pb2+The peak current size that oxidation reaction occurs when dissolution is compared in dissolution.Fig. 7 is
The CNTs electrode (a) that electropolymerization obtains before, poly (L-Arg) electrode (b) and CNTs/poly (L-Arg) (c) electrode are through pre-
After enrichment, the Differential Pulse Voltammetry figure that dissolves out respectively.As shown, all electrodes can observe Pb in dissolution2+'s
Peak, but the arginine glass-carbon electrode of CNTs will be apparently higher than CNTs electrode and arginine electrode, this is because two kinds of materials it
Between synergistic effect so that the advantages of composite material has both two kinds of materials, high chela between existing polymer film and heavy metal ion
Cooperation is used, and has the electric conductivity and specific surface area of CNTs high.
(3) the electroactive analysis of electrode surface.
According to Randles-Sevcik equation: ip=kn3/2ACD1/2ν1/2, wherein ip: peak current, n: electrode reaction electricity
Son transfer number, ν: sweeps speed, A: electrode effective area, D: reactant diffusion coefficient, C: the concentration of reactant, k=2.69 × 105,
D = 7.6E-6 cm2/s.It can be calculated the glass-carbon electrode of CNTs modification and the glass-carbon electrode of CNTs/ poly (L-Arg) modification
Active area is respectively as follows: 1.15 × 10-2 cm2With 1.16 × 10-2 cm2, it is about the same, however, CNTs/poly (L-Arg) is modified
Glass-carbon electrode peak current obviously than CNTs modification glass-carbon electrode it is big.By this result it may be speculated that dissolution peak current increases
It may be because poly (L-Arg) has ability that can well with metal ion chelating, so having although electric conductivity is bad
Help electrode surface accumulation Pb2+, this is also consistent with testing result in Fig. 7.
4, modified electrode detects Pb2+Condition optimizing.
(1) pH detects Pb to modified electrode2+Influence.
Since pH value can influence the response of volt-ampere analysis, suitable pH value is extremely important.PH is studied between 4 ~ 6
When respectively to differential pulse voltammetry Stripping Voltammetry detect Pb2+The influence of peak current, the results are shown in Figure 10.When between 4 to 5, peak current
Increasing always, and peak current declines always instead after having crossed 5.Peak current may be because of Pb in high pH value decline2+Water
Solution generates the chelate of hydroxide, prevents Pb2+Enrichment, therefore it is further to select the acetate buffer solution of pH=5 to carry out
Experiment.
(2) preenrichment voltage detects Pb to modified electrode2+Influence.
As shown in figure 11, heavy metal ion Pb is detected2+It is by the first preenrichment Pb on the electrode of constant potential2+, lead to again later
Linear scan is crossed by Pb2+Peak current size is observed in dissolution, therefore the deposition voltage in preenrichment stage and sedimentation time are all inherently
The peak current of subsequent detection is impacted.Have studied -0.4 V, -0.6 V, -0.8 V, -1.0 V, -1.2 V (vs.SCE) point
Not carry out preenrichment, Pb of the detection with concentration under the same terms2+, observation peak current variation.It is observed after mapping, with reduction
The increase of voltage, after preenrichment, Pb2+Dissolution peak current increase with it, until -0.7 V reach oxidation peak current maximum, then
Increase preenrichment voltage, dissolution oxidation current reduces instead.It may be to generate H because having begun this when2, have analysis
The competition of hydrogen reaction.Therefore preenrichment voltage is selected to carry out further experiment for -0.7 V.
(3) the preenrichment time detects Pb to modified electrode2+Influence.
As shown in figure 12, for the different preenrichment times carry out dissolution oxidation peak current compare, selected 60 s, 120 s,
180 s, 240 s, 300 s compare research.The preenrichment time is more long, the Pb being reduced out on electrode2+It is more, showing poor arteries and veins
Oxidation peak current is bigger when rushing voltammetric scan, therefore, as the preenrichment time increases, detects Pb2+When peak current successively increase.But
Be by observation it was found that, enrichment time is too long, and heavy metal ion is blocked up on electrode, is unfavorable for dissolving out instead.In enrichment 120
As the preenrichment time increases before s, Pb2+Peak current successively increases, more than after 120 s with the preenrichment time increase, detection
Pb2+When peak current reduce instead, therefore select the preenrichment time for 120 s carry out further experiment.
5, modified electrode is to Pb2+Detection research.
(1) detection limit and range of linearity research.
The preenrichment in the case where all conditions are all optimal situation of CNTs/poly (L-Arg) electrode, then uses differential pulse voltammetry again
Voltammetric scan dissolution observes the variation of its oxidation peak current, detects various concentration Pb2+Electric current, and derive accordingly corresponding
Peak current and Pb2+Concentration is linear.As shown in figure 13, CNTs/poly (L-Arg) electrode detection Pb2+Occur near -0.65 V
Clear sharp peak, when concentration range is 0.03 ~ 0.18 ppm, dissolution peak current and corresponding concentration of heavy metal ion are at just
Than.Its linear equation are as follows: i (μ A)=- 2.08+58.98c (ppm), coefficient R2= 0.993.According to described above,
Detection limit can be acquired by following formula:
D = 3N/S
In formula: N-noise
S-detector sensitivity
D-detection limit
S = I/Q
In formula: I-signal response
Q-sample volume
S-sensitivity
To obtain D=3NQ/I, the current value standard deviation of blank solution METHOD FOR CONTINUOUS DETERMINATION 11 times institutes is 4.2 %, therefore CNTs/
Poly (L-Arg) electrode detection Pb2+Detection be limited to 2.1 ppb.
(2) Journal of Sex Research is selected.
When detecting heavy metal ion, selectivity is also vital.For other heavy metal ion such as Zn2+、Cu2+、Cd2 +It is detected respectively, discharge standard is respectively 2 ppm, 5 ppm, 0.1 ppm, respectively with Zn2+(0, 1, 2, 5 ppm)、
Cu2+(0, 1, 5, 10, ppm)、Cd2+(0,0.05,0.1,0.18, ppm) it detects, without apparent oxidation peak electricity
Outflow is existing.The experimental results showed that in CNTs/poly (L-Arg) electrode detection Pb2+The range of linearity in Zn2+、Cu2+、Cd2+Not
It is detected and is impacted, it is seen that CNTs/poly (L-Arg) electrode possesses relatively good selectivity.
(3) solution chelating research.
Detect heavy metal ion Pb2+When, in the case of stirring through constant potential first, preenrichment is for a period of time afterwards with again
The Pb that electrode surface is enriched with Differential Pulse Voltammetry2+Peak current size is observed in dissolution.Because dissolution can not be electricity every time
Extremely upper all Pb2+It can dissolve out, thus will affect electrode and detect next time, therefore the research for solving chelant ability to it also has very much
Meaning.It is dissolved out again through differential pulse voltammetry voltammetric scan after preenrichment, obtains Figure 15 a curve.Condition as preenrichment:
Stirring rate, the same parameter setting (in addition to voltage) also passes through 120 s with the solution chelating voltage of 0.5 V, again with
Parameter when detection is scanned to obtain Figure 15 b with differential pulse voltammetry.It can be evident that, not observe Pb2+Oxidation peak,
Pb on electrode2+Taken off completely by solution, thus we it is concluded that, CNTs/poly (L-Arg) electrode have it is good
Solve chelant ability.
(4) repetitive research.
CNTs/poly (L-Arg) electrode of deposition is containing 0.5 ppm Pb2+ABS buffer solution in measure 5 times it is (same
Root electrode), measurement terminates all to carry out solution chelating every time, obtains no Pb2+The electroactive electrode of remaining recovery carries out next time
Measurement.As a result as shown in figure 16,5 measurement result relative standard deviations are 3.4 %, show that the modified electrode has weight well
Renaturation.
(5) Journal of Sex Research is reappeared.
Under conditions of the same, 6 CNTs/poly (L-Arg) electrodes are made respectively, are containing 0.8 ppm Pb respectively2+ABS
It is measured in buffer solution, 6 times measurement result is as shown in figure 17.It is computed, 6 measurement result relative standard deviations are 3.9 %, table
The bright modified electrode has good reproducibility.
From the present invention it can be concluded that in, CNTs/poly (L-Arg) composite film material is by quick, efficient, green electricity
What the method for deposition polymerization obtained.By Differential Pulse Voltammetry to detect heavy metal ion Pb in water2+, CNTs/poly (L-
Arg) film modified electrode is in detection Pb2+When it is with good stability, excellent sensitivity and high selectivity also have
Repeatability and reproducibility.Rapidly and efficiently, material is cheap and easy to get for detection, it is believed that can become detection Pb2+Very promising material.
Claims (4)
1. a kind of detection method of the total lead of environment water, it is characterised in that: in turn include the following steps:
(1) CNTs/poly (L-Arg) compound film electrode is prepared:
(1) pretreatment of glassy carbon electrode
Then a few drop deionized waters are added dropwise in the polishing powder that suitable 30 nm is sprinkled on chamois leather, stirred with glass-carbon electrode edge equal
It is even, it pinches glass-carbon electrode vertically afterwards, uniformly firmly, at the uniform velocity draws circle, then cleaned with deionized water, ear washing bulb drying, in glass carbon
Electrode surface drips nitric acid, is cleaned after static 10 ~ 15s with deionized water, then in ethanol water, aqueous solution of nitric acid, go
20 s of ultrasound are distinguished in ionized water, ear washing bulb drying is spare；
The glass-carbon electrode handled well is put into 5mM K3Fe(CN)6、0.2M KNO3In solution, with electrochemical workstation, using three
Electrode system, reference electrode select saturated calomel electrode, select carbon-point to electrode, working electrode selects glass-carbon electrode, using following
Ring voltammetry, the scanning in the scanning range of 0 ~ 0.5V；If redox peaks potential difference is within 64mV or so, 80mV, change
0.2M H2SO4It is activated in solution, the scanning in -0.2 ~ 1.4V, until cyclic voltammogram repeats；
(2) processing of carbon nanotube
1) electronic balance weighs 5.0g hydroxylated multi-walled carbon nanotubes, takes HCL, MWCNT and the HCL of 100mL 0.4M molten with graduated cylinder
Liquid mixes, mechanical stirring 5h after ultrasonic oscillation；
2) in the H of 100mL2SO4And HNO3Ultrasonic 5 hours in mixed solution, then magnetic agitation 10 hours；
3) carbon nanotube and mixed acid solution are filtered by vacuum, and are washed with deionized water to neutrality, are placed in drying box and are dried for 24 hours；
4) take the processed carbon nanotube of 5mg that deionized water is added to be settled to 10mL, ultrasound is uniform to solution, spare；
(3) preparation of poly (L-Arg) electrode
At room temperature, the good concentration of configured in advance is 0.1M to accurate measuring, and 50 mL of phosphate buffer solution that pH value is 6 adds
Enter 0.25mM arginine, after stirring to all dissolutions ultrasound obtain within 20 minutes taking out after uniform mixed solution place it is spare；With
Electrochemical workstation, three-electrode system is identical as step (1), and using cyclic voltammetry, scanning range is -1 ~ 2V, and sweeping speed is
100mV/s；Deposition end is rinsed well rear spare with deionization, obtains poly (L-Arg) electrode；
(4) preparation of CNTs electrode
It takes the MWCNTs that 6 μ l concentration are 0.5mg/mL to drop to glassy carbon electrode surface with liquid-transfering gun, is placed under ultraviolet lamp, taken after dry
Out, ion dries up spare after rinsing, and obtains CNTs electrode；
(5) preparation of CNTs/poly (L-Arg) electrode
CNTs electrode is taken to be put into the arginine PBS mixed solution prepared, concentration is identical with step (3)；Use circulation
Voltammetric scan, scanning range be -1 ~ 2V sweep speed be 50mV/s, three-electrode system it is identical as step (1)；Spent after deposition from
Son is rinsed well rear spare, obtains CNTs/poly (L-Arg) electrode；
(2) CNTs/poly (L-Arg) electrode is to Pb2+Detection:
By obtained CNTs/poly (L-Arg) electrode first in 50 mL, difference is shown in acetate buffer solution (ABS) use of pH=5
A certain amount of Pb is added until curve is stablized in pulse voltammetry scanning afterwards2+Standard solution, in the pre- richness of -0.7 V under stirring condition
Collection stands 20 s after a certain period of time；Observe the differential pulse voltammetry volt-ampere curve from the V of -1 V ~ 0, oxidation peak current in recording curve
Value, the temperature of experiment are 25 ± 0.1 DEG C.
2. a kind of detection method of the total lead of environment water according to claim 1, it is characterised in that: in the step (1)
The glass-carbon electrode diameter that working electrode is selected is 3 mm.
3. a kind of detection method of the total lead of environment water according to claim 1, it is characterised in that: in the step (2)
H2SO4And HNO3The concentration ratio of mixed solution is 3:1.
4. a kind of detection method of the total lead of environment water according to claim 1, it is characterised in that: in the step (2)
The preenrichment time is 120s.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102645479A (en) * | 2012-04-19 | 2012-08-22 | 湖南大学 | Lead ion specific detection sensor and preparation method and using method thereof |
| CN104280448A (en) * | 2014-10-17 | 2015-01-14 | 扬州大学 | Method for measuring concentration of lead ions in PM2.5 |
| CN105717174A (en) * | 2016-02-22 | 2016-06-29 | 山东省科学院新材料研究所 | Electrochemical detection method for detecting trace heavy metal ions in water with modified graphene oxide composite modified electrode |
-
2018
- 2018-12-27 CN CN201811611614.8A patent/CN109613079A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102645479A (en) * | 2012-04-19 | 2012-08-22 | 湖南大学 | Lead ion specific detection sensor and preparation method and using method thereof |
| CN104280448A (en) * | 2014-10-17 | 2015-01-14 | 扬州大学 | Method for measuring concentration of lead ions in PM2.5 |
| CN105717174A (en) * | 2016-02-22 | 2016-06-29 | 山东省科学院新材料研究所 | Electrochemical detection method for detecting trace heavy metal ions in water with modified graphene oxide composite modified electrode |
Non-Patent Citations (2)
| Title |
|---|
| QIAN CAO等: "Electrochemical immunosensor for casein based on gold nanoparticles and poly(l-Arginine)/multi-walled carbon nanotubes composite film functionalized interface", 《BIOSENSORS AND BIOELECTRONICS》 * |
| 张萌芽: "碳基复合物修饰电极的制备及其在重金属检测和甲醇催化氧化中的应用", 《中国优秀硕士学位论文全文数据库 工程科技I辑》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110887889A (en) * | 2019-11-28 | 2020-03-17 | 上海应用技术大学 | Analysis method for rapid detection of heavy metals in water body |
| CN110887889B (en) * | 2019-11-28 | 2022-10-14 | 上海应用技术大学 | Analysis method for rapid detection of heavy metals in water body |
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