GB2023846A - Measurement electrode system - Google Patents
Measurement electrode system Download PDFInfo
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- GB2023846A GB2023846A GB7920119A GB7920119A GB2023846A GB 2023846 A GB2023846 A GB 2023846A GB 7920119 A GB7920119 A GB 7920119A GB 7920119 A GB7920119 A GB 7920119A GB 2023846 A GB2023846 A GB 2023846A
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- electrode
- electrode system
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- 238000005259 measurement Methods 0.000 title claims abstract description 11
- 239000007787 solid Substances 0.000 claims abstract description 7
- HTXDPTMKBJXEOW-UHFFFAOYSA-N iridium(IV) oxide Inorganic materials O=[Ir]=O HTXDPTMKBJXEOW-UHFFFAOYSA-N 0.000 claims abstract description 3
- 229910052751 metal Inorganic materials 0.000 claims abstract description 3
- 239000002184 metal Substances 0.000 claims abstract description 3
- 229910044991 metal oxide Inorganic materials 0.000 claims abstract description 3
- 150000004706 metal oxides Chemical class 0.000 claims abstract description 3
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims description 4
- 238000004458 analytical method Methods 0.000 claims description 4
- 150000002500 ions Chemical class 0.000 claims description 3
- 238000000034 method Methods 0.000 claims description 3
- 230000002441 reversible effect Effects 0.000 claims description 3
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 claims description 2
- 229910052946 acanthite Inorganic materials 0.000 claims description 2
- 229910052741 iridium Inorganic materials 0.000 claims description 2
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical group [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 claims description 2
- 229910000457 iridium oxide Inorganic materials 0.000 claims description 2
- HBEQXAKJSGXAIQ-UHFFFAOYSA-N oxopalladium Chemical compound [Pd]=O HBEQXAKJSGXAIQ-UHFFFAOYSA-N 0.000 claims description 2
- 229910052763 palladium Inorganic materials 0.000 claims description 2
- 229910003445 palladium oxide Inorganic materials 0.000 claims description 2
- 229910052703 rhodium Inorganic materials 0.000 claims description 2
- 239000010948 rhodium Substances 0.000 claims description 2
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 claims description 2
- 229910003450 rhodium oxide Inorganic materials 0.000 claims description 2
- 229910052709 silver Inorganic materials 0.000 claims description 2
- FSJWWSXPIWGYKC-UHFFFAOYSA-M silver;silver;sulfanide Chemical compound [SH-].[Ag].[Ag+] FSJWWSXPIWGYKC-UHFFFAOYSA-M 0.000 claims description 2
- 239000007788 liquid Substances 0.000 abstract description 4
- 239000000243 solution Substances 0.000 description 15
- BAWFJGJZGIEFAR-NNYOXOHSSA-O NAD(+) Chemical compound NC(=O)C1=CC=C[N+]([C@H]2[C@@H]([C@H](O)[C@@H](COP(O)(=O)OP(O)(=O)OC[C@@H]3[C@H]([C@@H](O)[C@@H](O3)N3C4=NC=NC(N)=C4N=C3)O)O2)O)=C1 BAWFJGJZGIEFAR-NNYOXOHSSA-O 0.000 description 11
- 238000006243 chemical reaction Methods 0.000 description 10
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 10
- WQZGKKKJIJFFOK-VFUOTHLCSA-N beta-D-glucose Chemical compound OC[C@H]1O[C@@H](O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-VFUOTHLCSA-N 0.000 description 7
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 description 6
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 6
- 239000008103 glucose Substances 0.000 description 6
- 229930027945 nicotinamide-adenine dinucleotide Natural products 0.000 description 6
- BOPGDPNILDQYTO-NNYOXOHSSA-N nicotinamide-adenine dinucleotide Chemical compound C1=CCC(C(=O)N)=CN1[C@H]1[C@H](O)[C@H](O)[C@@H](COP(O)(=O)OP(O)(=O)OC[C@@H]2[C@H]([C@@H](O)[C@@H](O2)N2C3=NC=NC(N)=C3N=C2)O)O1 BOPGDPNILDQYTO-NNYOXOHSSA-N 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 5
- 229910052697 platinum Inorganic materials 0.000 description 5
- 239000000523 sample Substances 0.000 description 5
- HVYWMOMLDIMFJA-DPAQBDIFSA-N cholesterol Chemical compound C1C=C2C[C@@H](O)CC[C@]2(C)[C@@H]2[C@@H]1[C@@H]1CC[C@H]([C@H](C)CCCC(C)C)[C@@]1(C)CC2 HVYWMOMLDIMFJA-DPAQBDIFSA-N 0.000 description 4
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 3
- 102000006746 NADH Dehydrogenase Human genes 0.000 description 3
- 108010086428 NADH Dehydrogenase Proteins 0.000 description 3
- 108090000854 Oxidoreductases Proteins 0.000 description 3
- 102000004316 Oxidoreductases Human genes 0.000 description 3
- 239000003153 chemical reaction reagent Substances 0.000 description 3
- WQZGKKKJIJFFOK-SVZMEOIVSA-N (+)-Galactose Chemical compound OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@H]1O WQZGKKKJIJFFOK-SVZMEOIVSA-N 0.000 description 2
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 2
- 101710088194 Dehydrogenase Proteins 0.000 description 2
- WHUUTDBJXJRKMK-VKHMYHEASA-N L-glutamic acid Chemical compound OC(=O)[C@@H](N)CCC(O)=O WHUUTDBJXJRKMK-VKHMYHEASA-N 0.000 description 2
- LEHOTFFKMJEONL-UHFFFAOYSA-N Uric Acid Chemical compound N1C(=O)NC(=O)C2=C1NC(=O)N2 LEHOTFFKMJEONL-UHFFFAOYSA-N 0.000 description 2
- TVWHNULVHGKJHS-UHFFFAOYSA-N Uric acid Natural products N1C(=O)NC(=O)C2NC(=O)NC21 TVWHNULVHGKJHS-UHFFFAOYSA-N 0.000 description 2
- POJWUDADGALRAB-UHFFFAOYSA-N allantoin Chemical compound NC(=O)NC1NC(=O)NC1=O POJWUDADGALRAB-UHFFFAOYSA-N 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- WPYMKLBDIGXBTP-UHFFFAOYSA-N benzoic acid Chemical compound OC(=O)C1=CC=CC=C1 WPYMKLBDIGXBTP-UHFFFAOYSA-N 0.000 description 2
- 235000012000 cholesterol Nutrition 0.000 description 2
- 229940116269 uric acid Drugs 0.000 description 2
- BJEPYKJPYRNKOW-REOHCLBHSA-N (S)-malic acid Chemical compound OC(=O)[C@@H](O)CC(O)=O BJEPYKJPYRNKOW-REOHCLBHSA-N 0.000 description 1
- KVZLHPXEUGJPAH-DKWTVANSSA-N 2-hydroxypropanoic acid;(2s)-2-hydroxypropanoic acid Chemical compound CC(O)C(O)=O.C[C@H](O)C(O)=O KVZLHPXEUGJPAH-DKWTVANSSA-N 0.000 description 1
- MGTZCLMLSSAXLD-UHFFFAOYSA-N 5-oxohexanoic acid Chemical compound CC(=O)CCCC(O)=O MGTZCLMLSSAXLD-UHFFFAOYSA-N 0.000 description 1
- POJWUDADGALRAB-PVQJCKRUSA-N Allantoin Natural products NC(=O)N[C@@H]1NC(=O)NC1=O POJWUDADGALRAB-PVQJCKRUSA-N 0.000 description 1
- 239000005711 Benzoic acid Substances 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- RGHNJXZEOKUKBD-SQOUGZDYSA-N D-gluconic acid Chemical compound OC[C@@H](O)[C@@H](O)[C@H](O)[C@@H](O)C(O)=O RGHNJXZEOKUKBD-SQOUGZDYSA-N 0.000 description 1
- RGHNJXZEOKUKBD-UHFFFAOYSA-N D-gluconic acid Natural products OCC(O)C(O)C(O)C(O)C(O)=O RGHNJXZEOKUKBD-UHFFFAOYSA-N 0.000 description 1
- PHOQVHQSTUBQQK-SQOUGZDYSA-N D-glucono-1,5-lactone Chemical compound OC[C@H]1OC(=O)[C@H](O)[C@@H](O)[C@@H]1O PHOQVHQSTUBQQK-SQOUGZDYSA-N 0.000 description 1
- 108010050375 Glucose 1-Dehydrogenase Proteins 0.000 description 1
- 108010015776 Glucose oxidase Proteins 0.000 description 1
- 239000004366 Glucose oxidase Substances 0.000 description 1
- 229930195714 L-glutamate Natural products 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- LCTONWCANYUPML-UHFFFAOYSA-M Pyruvate Chemical compound CC(=O)C([O-])=O LCTONWCANYUPML-UHFFFAOYSA-M 0.000 description 1
- 108010092464 Urate Oxidase Proteins 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 150000001299 aldehydes Chemical class 0.000 description 1
- 229960000458 allantoin Drugs 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 235000010323 ascorbic acid Nutrition 0.000 description 1
- 229960005070 ascorbic acid Drugs 0.000 description 1
- 239000011668 ascorbic acid Substances 0.000 description 1
- 235000010233 benzoic acid Nutrition 0.000 description 1
- 239000000872 buffer Substances 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 238000004737 colorimetric analysis Methods 0.000 description 1
- 239000006196 drop Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000003487 electrochemical reaction Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 229930182830 galactose Natural products 0.000 description 1
- 229950006191 gluconic acid Drugs 0.000 description 1
- 235000012208 gluconic acid Nutrition 0.000 description 1
- 229960003681 gluconolactone Drugs 0.000 description 1
- 235000019420 glucose oxidase Nutrition 0.000 description 1
- 229940116332 glucose oxidase Drugs 0.000 description 1
- 229930195712 glutamate Natural products 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 229940049920 malate Drugs 0.000 description 1
- BJEPYKJPYRNKOW-UHFFFAOYSA-N malic acid Chemical compound OC(=O)C(O)CC(O)=O BJEPYKJPYRNKOW-UHFFFAOYSA-N 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000010907 mechanical stirring Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- MINVSWONZWKMDC-UHFFFAOYSA-L mercuriooxysulfonyloxymercury Chemical compound [Hg+].[Hg+].[O-]S([O-])(=O)=O MINVSWONZWKMDC-UHFFFAOYSA-L 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 229910000371 mercury(I) sulfate Inorganic materials 0.000 description 1
- YFBPRJGDJKVWAH-UHFFFAOYSA-N methiocarb Chemical compound CNC(=O)OC1=CC(C)=C(SC)C(C)=C1 YFBPRJGDJKVWAH-UHFFFAOYSA-N 0.000 description 1
- KHPXUQMNIQBQEV-UHFFFAOYSA-L oxaloacetate(2-) Chemical compound [O-]C(=O)CC(=O)C([O-])=O KHPXUQMNIQBQEV-UHFFFAOYSA-L 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- -1 pH 7 Substances 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 239000008363 phosphate buffer Substances 0.000 description 1
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 description 1
- 229910052939 potassium sulfate Inorganic materials 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 239000012047 saturated solution Substances 0.000 description 1
- 210000002966 serum Anatomy 0.000 description 1
- 239000012086 standard solution Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- 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
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/416—Systems
- G01N27/48—Systems using polarography, i.e. measuring changes in current under a slowly-varying voltage
-
- G—PHYSICS
- 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
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/28—Electrolytic cell components
- G01N27/30—Electrodes, e.g. test electrodes; Half-cells
- G01N27/327—Biochemical electrodes, e.g. electrical or mechanical details for in vitro measurements
- G01N27/3275—Sensing specific biomolecules, e.g. nucleic acid strands, based on an electrode surface reaction
- G01N27/3277—Sensing specific biomolecules, e.g. nucleic acid strands, based on an electrode surface reaction being a redox reaction, e.g. detection by cyclic voltammetry
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Biochemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Physics & Mathematics (AREA)
- Analytical Chemistry (AREA)
- Molecular Biology (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Measuring Or Testing Involving Enzymes Or Micro-Organisms (AREA)
- Investigating Or Analysing Biological Materials (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Abstract
A measurement electrode system comprises a working electrode, an auxiliary electrode and, instead of a conventional reference half-cell, a solid electrode, such as a 2nd species electrode, the potential of which is stabilized by a constant ionic concentration of a solution introduced in the liquid to be tested. Combinations suitable for such a solid electrode are, for example, of the metal/metal oxide type such as Ir/IrO2. The invention overcomes the disadvantages associated with reference half-cells. The electrodes are connected in a polestrostat circuit, and may be incorporated in a single, solid supporting member. <IMAGE>
Description
SPECIFICATION
Electrode system suitable for use in voltametric measurements
This invention relates to an electrode system suitable for use in voltametric measurements.
It is well known that the recordal of current intensity/voltage plots, obtained under appropriate conditions, is the basis of an important analytical procedure, which is known as a polarographic or voltameter analysis.
This procedure, in addition to permitting the simultaneous determination, both qualitative and quantitative, of many cations and anions and also of a great number of organic substances which can be electrochemically reduced and oxidized, is capable of solving several problems of a chemical nature such as the determination of the constitution of certain substances, the study of reaction mechanisms, the evaluation of equilibrium constants, and the determination of stability constants of complexes.
The electrode systems which are used in polarographic measurements generally have two or three electrodes.
When two electrodes are employed, an e.m.f. is applied between a working electrode and a reference electrode, and the current flowing between these two electrodes is measured.
When three electrodes are employed, by using a potentiostatic system, an e.m.f. is applied between an auxiliary electrode and a working electrode in such a way that a desired preset e.m.f. exists between the working electrode and a reference half-cell. The current flowing through the working electrode is recorded as a function of the presete.m.f.
As a rule, a three-electrode system is composed by:
1. A working electrode for example a mercury drop, Pt, Au or graphite);
2. An auxiliary electrode (for example (Pt); and
3. A reference half-cell for example (Hg/Hg2 C12/KCI)
(Hg/Hg2SO4/K2SO4)or
(Ag/Ag Cl/KCI).
The most prominent problems stemming from the use of reference half-cells having an internal solution of their own and a liquid junction are: the physical dimensions cannot be reduced beyond certan limits so that their use in miniaturized systems becomes awkward; the liquid connection between the solution being tested and the internal solution of the half cell causes the so-called "liquid junction potential", the minimization of which is cumbersome, this potential being moreover variable as a function of the nature of the solution being tested; the sample of the solution being tested is polluted by the internal solution of the half-cell, and vice versa; and the reference half-cell requires frequent upkeep operations.
We have now found, and this is the basis of the present invention, that it is possible to replace the conventional reference half-cell by a solid reference electrode, for example one of the 2nd species or of the metal/metal oxide type, the potential of which is stabilized by a constant concentration of ions (with respect to which the electrode in question is reversible) introduced into the solution to be tested.
Thus the present invention provides an electrode system comprising a working electrode, a solid reference electrode and an auxiliary electrode, the three electrodes being immersed in a solution containing a constant concentration of ions relative to which the reference electrode is reversible.
Examples of suitable reference electrodes are the following: iridium/iridium oxide, palladium/palladium oxide, or rhodium/rhodium oxide (with a constant concentration of H+ in the solution being tested); a fluoride electrode (with a constant concentration of F- in the solution being tested); Ag/AgCI, Ag/Ag I or
Ag/Ag-Br (with a constant concentration of Cl-, 1- and Br- ions, respectively, in the solution being tested); and Ag/Ag2S (with a constant concentration of either Ag+ or S-- in the solution being tested).
By exploiting the electrode system of the present invention, which can comprise, for example, a platinum working electrode, a platinum auxiliary electrode, and an Ir/lrO2 reference electrode, it is possible, when working in a solution of a buffer, to monitor an electrochemical reaction on the working electrode which has been biassed to a determined voltage relative to the reference electrode.
The electrode system according to the present invention offers the advantage that it is not impaired by any of the shortcomings enumerated above for the known systems using reference half-cells with an internal solution of their own. A further benefit is that the three individual electrodes can readily be incorporated into a single device, which can be of a reduced size, and which can be adapted to measurements of microscopic scale volumes of the solution to be tested.
For a better understanding of the present invention and to show how the same may be carried into effect, reference will be made, by way of example, to the accompanying drawing, in which:
Figure 1 is a perspective view of an embodiment of an electrode system according to the present invention;
Figure 2 shows diagrammatically a measurement cell incorporating an electrode system in accordance with the present invention;
Figure 3 shows graphically the current intensity at the working electrode, plotted against reaction progress (time) for some of the samples; and
Figure 4 shows graphically on the vertical axis the height of the peaks (shown in Figure 3) for different samples, plotted against the concentration of glucose in the different samples, on the horizontal axis.
Referring first to Figure 1, the illustrated electrode system comprises on Ir/lrO2 reference electrode, 1, a platinum working electrode 2, a platinum auxiliary electrode 3, a probe 4 (optional) for controlling the temperature, a housing body 5 of the electrode system, and an assembly 6 of the connectors for connection to a measurement instrument (not shown). Such an electrode system can be used for carrying out a number of analyses; for example, it can be used for the following determinations:
1.Determination of hydrogen peroxide, for instance in connection with the evolution of the following
enzymic reactions: 1.1 2 + beta-D-glucose glucose D-gluconic acid + H202 alcohol alcohol 1.2 2 + alcohol Oxjdasealdehyde + H202 1.3 O2 + uric acid uricase allantoin + CO2+H2O2 galactose 1.4 O2 + D-galactose D-galactohexodioldose oxidase
+ H2O2 cholesterol
1.5 O2 + cholesterol 4-cholestan-3-one +
oxidase
H2O2
L-aminoacid
1.6 2 + H2O+ L-aminoacid 2-ketoacid +
oxidase NH3+H2O2 2.Determination of NAD(P)H NAD(P)+, for example in connection with the evolution of the
following ensymic reactions: 2.1 Pyruvate + NADH lactate L-lactate + NAD+
dehydrogenase
2.2 L-glutamate + H20 + NAD(P)+ glutamate 2-keto
dehydrogenase glurate +NH3+ NAD(P)H
alcohol 2.3 Alcohol + NAD(P)+ aldehyde + NADH
dehydrogenase
2.4 Glvcerol + NAD+ glycerol dihydroxyhacetone+NADH
dehydrogenase malate
2.5 L-malate+NAD42 oxalacetate+NADH
dehydrogenase
2.6 ss-Dglucose+NAD(P)+glucose dehydrogenase D-gluconolactone +
NAD(P)H 3. Determination of biological substances and non-biological substances which are already present in
the fluid to be tested, rather than generated in reactions such as the previously cited ones, such as,
for example: 3.1 Uric acid 3.2 Ascorbic acid 4. Determination of all the substances which are usually detected by exploiting the conventional
electrode systems.
Additional operating details will become more clearly apparent from the following examples which are given only for illustrating the present invention without limiting the same.
EXAMPLE 1: Determination of gluclose according to the reaction pattern reported above under 1.1.
Materials:
1. Enzymic reagent, containing 75 mM phosphate, pH 7, and glucose-oxidase, 50 U/ml.
2. Commercial control sera
3. Standard solutions of glucose (50-100-150-200-300-500 mg/dl, (milligrams/decilitre)) in a saturated
solution of benzoic acid.
4. Measurement cell as illustrated in Figure 2, connected to the special polarographic instruments.
The cell shown in Figure 2 has an inlet 21 for introducing the enzymic reagent via an automatic metering device (not shown), a probe and electrodes 22 connected to a polarograph (not shown), a sample-charging pipette 23, a stirrer 24, an outlet sump 25 connected to a suction (not shown), and connections 26 from the electrodes 22 to the polarograph.
Method:
There were introduced 2 ml of enzymic reagent into the measurement cell, and 0.02 ml of serum or a standard was added. The polarograph was connected to a recorder for the recordal on a chart of the reaction trend. Peaks are obtained, such as depicted in Figure 3. The height of each peak is proportional to the concentration of glucose in the sample as shown in Figure 4.
For checking the accuracy, there were analyzed eight commercial sera and the results are tabulated the following table 1.
The comparison with the enzymic-colorimetric method (GOD-POD) has furnished the following data:
Number of samples 31
Equation of the regression line y = 0.94 x + 7.8
Correlation coefficient r = 0.985
Mean ofx 128.5 mg/dl
Mean ofy 128.0 mg/dl
maximum of x 325.0 mg/dl maximum of y 341.0 mg/dl
minimum ofx 57.0 mg/dl
minimum ofy 57.0 mg/dl
range of x 268.0 mg/dl
range of y 284.0 mg/dl T A B L E 1
Declared Found glucose Glucose
HYLAND Normal lot No.2 81.4 mg/dl (measured values: 76.4- 86.4 mg/dl 85.0 mg/dl
CLINICONTROL N lot 701 82.0" ( " " 75.0- 89.0 " ) 83.7"
PRECILIP lot763 104.0" ( " " 93.0-115.0 " ) 1175"
ORTHO I lor 1RO13N 86.6" ( " " 80.0- 92.2 " ) 82.5"
ORTHO II lot 1RO13B 126.0" ( " " 115.0-137.0 " ) 117.5"
ORTHO III lot 1RO13P 305.0" ( " " 280.0-330.0 " ) 285.0"
HYLAND Abnormal lot P02 200.0" ( " " 188.0-212.0 " ) 213.0"
CLINICONTROL A lot 702 199.0" ( " " 182.0-216.0 " ) 200.0" EXAMPLE2: Determination of NADH in the presence of NAD+.
A polarographic system was used, having the following operational parameters:
Voltage : + 800 milliVolts, mV
Full-scale value 500 A, nanoampere
Mechanical stirring at about 500 rpm
Reaction volume 10 ml of phosphate buffer
0.05 M, pH 7.4
Progressive values, from 10 mcl to 100 mcl (millicentilitres), were added to the sample, of a 0.1 mg/ml (milligram per millilitre) of NADH and a continuous recordal was made of the intensity of the current relative to the reaction of oxidation of NADH to NAD+.
The responses of the instrument were proportional to the increase of the concentration of NADH in the reaction cell, with a 70 nA signal for 0.14 millimole/millilitre of NADH.
Claims (8)
1. An electrode system comprising a working electrode, a solid reference electrode and an auxiliary electrode, and three electrodes being immersed in a solution containing a constant concentration of ions relative to which the reference electrode is reversible.
2. An electrode system according to Claim 1, wherein the three electrodes are incorporated in a single solid supporting member.
3. An electrode system according to Claim 1 or 2, wherein the reference electrode is a second species type.
4. An electrode system according to Claim 1 or 2, wherein the reference electrode is of the metal/metal oxide type.
5. An electrode system according to Claim 1 or 2, wherein the reference electrode is iridium/iridium oxide, palladium/palladium oxide, rhodium/rhodium oxide, a fluoride electrode, Ag/AgCI, Ag/Ag Br, Ag/Ag I, or Ag/Ag2S.
6. An electrode system according to Claim 1, substantially as hereinbefore described with reference to, and as illustrated in, Figure 1 or Figure 2 of the accompanying drawing.
7. A method of analysis involving voltametric measurements, which includes the use of an electrode s system according to any preceding claim.
8. A method according to Claim 7, substantially as described in either of the foregoing examples 1 and 2.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT24640/78A IT1158856B (en) | 1978-06-16 | 1978-06-16 | ELECTRODIC SYSTEM WITH REFERENCE ELECTRODE WITHOUT LIQUID JUNCTION FOR VOLTAMMETRIC MEASUREMENTS |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2023846A true GB2023846A (en) | 1980-01-03 |
| GB2023846B GB2023846B (en) | 1983-03-30 |
Family
ID=11214235
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7920119A Expired GB2023846B (en) | 1978-06-16 | 1979-06-08 | Measurement electrode system |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS554591A (en) |
| CA (1) | CA1141435A (en) |
| DE (2) | DE2924117A1 (en) |
| FR (1) | FR2428839A1 (en) |
| GB (1) | GB2023846B (en) |
| IT (1) | IT1158856B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5144247A (en) * | 1991-02-14 | 1992-09-01 | Westinghouse Electric Corp. | Method and apparatus for reducing IR error in cathodic protection measurements |
| GB2293883A (en) * | 1994-06-30 | 1996-04-10 | Nok Corp | Electrochemical protein biosensor |
| WO1999046586A1 (en) * | 1998-03-10 | 1999-09-16 | Micronas Gmbh | Reference electrode |
| EP1172649A1 (en) * | 2000-01-25 | 2002-01-16 | Matsushita Electric Industrial Co., Ltd. | Measuring device using biosensor and biosensor used for it, and dedicated standard liquid |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS507615A (en) * | 1973-05-28 | 1975-01-27 | ||
| JPS5026614A (en) * | 1973-07-10 | 1975-03-19 | ||
| WO1986004679A1 (en) * | 1985-02-12 | 1986-08-14 | Commonwealth Scientific And Industrial Research Or | Voltammetric cell |
| DE3725597A1 (en) * | 1987-08-01 | 1989-02-09 | Siegert Gmbh | Ionometric sensor |
| DE3810186A1 (en) * | 1987-08-01 | 1989-10-05 | Siegert Gmbh | SENSOR FOR MEASURING THE ACTIVITY OF IONS AND METHOD FOR THE PRODUCTION THEREOF |
| DE3937577A1 (en) * | 1989-11-11 | 1991-05-16 | Lutz Ehrlich | Voltametric analysis cell - with holder cavity holding oversize mercury droplet |
| DE102010040057A1 (en) * | 2010-08-31 | 2012-03-01 | Endress + Hauser Conducta Gesellschaft für Mess- und Regeltechnik mbH + Co. KG | Electrochemical sensor, particularly pH-sensor, comprises measuring electrode and reference electrode for generating reference potential |
| US11259724B2 (en) * | 2014-03-12 | 2022-03-01 | Glucovation, Inc. | Electrochemical sensing system |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1426514A (en) * | 1965-02-27 | 1966-01-28 | Apparatus for studying solids comprising several compounds | |
| US3676321A (en) * | 1970-07-27 | 1972-07-11 | Honeywell Inc | Electrochemical oxygen demand system |
| US3910830A (en) * | 1974-04-08 | 1975-10-07 | Petrolite Corp | Flush mounted probe assembly |
| FR2331017A1 (en) * | 1975-11-07 | 1977-06-03 | Owens Illinois Inc | Determn. of glucose by oxidn. on supported glucose oxidase - and polarographic determn. of hydrogen peroxide formed, esp. for analysis of blood serum |
| US4073053A (en) * | 1976-02-27 | 1978-02-14 | Honeywell Inc. | Method of making an ion responsive electrode |
| JPS52126285A (en) * | 1976-04-16 | 1977-10-22 | New Cosmos Electric Co | Measuring method and apparatus for residual free chlorine concentration |
| JPS52126286A (en) * | 1976-04-16 | 1977-10-22 | New Cosmos Electric Co | Measuring apparatus for residual chlorine |
| FR2636943B1 (en) * | 1988-09-26 | 1991-04-12 | Rhone Poulenc Sante | PROCESS FOR THE PREPARATION OF SATURATED ALDEHYDES BY HYDROGENATION OF ALDEHYDES (ALPHA), (BETA) -UNSATURES |
-
1978
- 1978-06-16 IT IT24640/78A patent/IT1158856B/en active
-
1979
- 1979-06-05 CA CA000329156A patent/CA1141435A/en not_active Expired
- 1979-06-08 GB GB7920119A patent/GB2023846B/en not_active Expired
- 1979-06-15 FR FR7915476A patent/FR2428839A1/en active Granted
- 1979-06-15 DE DE19792924117 patent/DE2924117A1/en not_active Ceased
- 1979-06-15 JP JP7477779A patent/JPS554591A/en active Pending
- 1979-06-15 DE DE19797917122U patent/DE7917122U1/en not_active Expired
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5144247A (en) * | 1991-02-14 | 1992-09-01 | Westinghouse Electric Corp. | Method and apparatus for reducing IR error in cathodic protection measurements |
| GB2293883A (en) * | 1994-06-30 | 1996-04-10 | Nok Corp | Electrochemical protein biosensor |
| GB2293883B (en) * | 1994-06-30 | 1998-07-29 | Nok Corp | Method for measuring protein concentration using a protein biosensor |
| WO1999046586A1 (en) * | 1998-03-10 | 1999-09-16 | Micronas Gmbh | Reference electrode |
| US6572748B1 (en) | 1998-03-10 | 2003-06-03 | Micronas Gmbh | Reference electrode |
| EP1172649A1 (en) * | 2000-01-25 | 2002-01-16 | Matsushita Electric Industrial Co., Ltd. | Measuring device using biosensor and biosensor used for it, and dedicated standard liquid |
| EP1172649B1 (en) * | 2000-01-25 | 2009-06-03 | Panasonic Corporation | Glucose measuring device and method comprising biosensor and an exclusive glucose standard solution |
Also Published As
| Publication number | Publication date |
|---|---|
| CA1141435A (en) | 1983-02-15 |
| FR2428839B1 (en) | 1982-11-05 |
| DE7917122U1 (en) | 1982-09-30 |
| IT1158856B (en) | 1987-02-25 |
| FR2428839A1 (en) | 1980-01-11 |
| DE2924117A1 (en) | 1979-12-20 |
| GB2023846B (en) | 1983-03-30 |
| IT7824640A0 (en) | 1978-06-16 |
| JPS554591A (en) | 1980-01-14 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |