CA1141435A - Electrode system with a reference electrode deprived of liquid junction, for voltameter measurements - Google Patents
Electrode system with a reference electrode deprived of liquid junction, for voltameter measurementsInfo
- Publication number
- CA1141435A CA1141435A CA000329156A CA329156A CA1141435A CA 1141435 A CA1141435 A CA 1141435A CA 000329156 A CA000329156 A CA 000329156A CA 329156 A CA329156 A CA 329156A CA 1141435 A CA1141435 A CA 1141435A
- Authority
- CA
- Canada
- Prior art keywords
- electrode
- reference electrode
- oxide
- electrode system
- measurements
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
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
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- 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
ABSTRACT OF THE DISCLOSURE
In an electrode system for polarographic measure-ments, the improvement consisting in that the usual re-ference half-cell is replaced by a solid electrode, such as a 2nd species electrode, the potential of which is stabilized by a constant ionic concentration of a solu-tion introduced in the liquor to be tested.
Combinations suitable for such a solid electrode are, for example, of the type metal/oxide of such metal:
Ir/IrO2 is a suitable combination.
In an electrode system for polarographic measure-ments, the improvement consisting in that the usual re-ference half-cell is replaced by a solid electrode, such as a 2nd species electrode, the potential of which is stabilized by a constant ionic concentration of a solu-tion introduced in the liquor to be tested.
Combinations suitable for such a solid electrode are, for example, of the type metal/oxide of such metal:
Ir/IrO2 is a suitable combination.
Description
. i . .
; ! , . . .
~3LECTRODE SYSTEM WITH A REFERENCE
ELECTRODE DEP RIVED O F LIQUID JUNCTION, FOR VOLTAMETER
MEA~;URE~IENTS . -:
This invention relates to a novel electrode system which permits to effect polarographic or volta-meter measurements in a particularly advantageous manner.
The ~oltameter system in question is composed by a working electrode, a referellce electrode, and an auxiliary electrode, immersed in a solution which con-tains a constant concentration of ions, with respect to which the reference electrode is reversible. The refe-rence electrode is a second-species electrode, or is of the metal/metal oxide type.
- It is well known that the recordal of current intensity/voltage plots, as obtained under appropriate conditions, is the basis of an important analytical pro-cedure, which is indicated as a polarographic or volta-meter analysis. This procedure3 in addition to permit-ting the simultaneous determination, both qualitative and quantitative, of many cations and anions and also of a great number of orgaric substances which can be ~lectrochemically reduced and o~idized, is capable of - 20 solving several problems of chemical nature such as those or the determination of the constitution of certain sub-stances, the study of reaction mechanisms, the evalua-tion of equilibrium constants, the determination of sta-."` . ~
: :
; ! , . . .
~3LECTRODE SYSTEM WITH A REFERENCE
ELECTRODE DEP RIVED O F LIQUID JUNCTION, FOR VOLTAMETER
MEA~;URE~IENTS . -:
This invention relates to a novel electrode system which permits to effect polarographic or volta-meter measurements in a particularly advantageous manner.
The ~oltameter system in question is composed by a working electrode, a referellce electrode, and an auxiliary electrode, immersed in a solution which con-tains a constant concentration of ions, with respect to which the reference electrode is reversible. The refe-rence electrode is a second-species electrode, or is of the metal/metal oxide type.
- It is well known that the recordal of current intensity/voltage plots, as obtained under appropriate conditions, is the basis of an important analytical pro-cedure, which is indicated as a polarographic or volta-meter analysis. This procedure3 in addition to permit-ting the simultaneous determination, both qualitative and quantitative, of many cations and anions and also of a great number of orgaric substances which can be ~lectrochemically reduced and o~idized, is capable of - 20 solving several problems of chemical nature such as those or the determination of the constitution of certain sub-stances, the study of reaction mechanisms, the evalua-tion of equilibrium constants, the determination of sta-."` . ~
: :
2.
bi-ity constants of complexes and many others.
The electrode sys-tems which are used in pola-rographic measurements can be comprised, in general, of 2 or 3 electrodes.
In the first case; the e.m.f is applied bet-- ween the working electrode and the reference electrocle and the current flowing betwaeD the two electrodes is measured.
In the second case, by using a potentiostatic system, an e.m.f. is applied between an auxiliary ele-ctrode and the working electrode in such a way that the desired e.m.E. exists between the working electrode and the reEerence half-cell.
Tl1e current flowing through the working electro-15 de is recorded as a function of the preset e.m.f.
As a rule, a three electrode system is compo--sed by :
1. Working electrode (a mercury drop, Pt~ Au~ gra-phite and others) ao 2. Auxiliary electrode (Pt)
bi-ity constants of complexes and many others.
The electrode sys-tems which are used in pola-rographic measurements can be comprised, in general, of 2 or 3 electrodes.
In the first case; the e.m.f is applied bet-- ween the working electrode and the reference electrocle and the current flowing betwaeD the two electrodes is measured.
In the second case, by using a potentiostatic system, an e.m.f. is applied between an auxiliary ele-ctrode and the working electrode in such a way that the desired e.m.E. exists between the working electrode and the reEerence half-cell.
Tl1e current flowing through the working electro-15 de is recorded as a function of the preset e.m.f.
As a rule, a three electrode system is compo--sed by :
1. Working electrode (a mercury drop, Pt~ Au~ gra-phite and others) ao 2. Auxiliary electrode (Pt)
3. Reference hal*-cell (Hg/Hg2 Cl2/KCl) ~ Hg/Hg2 so 4/K2 so 4 ) li (Ag/Ag Cl/KCl~
The most prominent problems stemming from the 25 use of reference hal-f-cells having an intern~l solution of their own and a liquid ~junction are :
- The physical dlmensions cannot be reduced beyond certain limits so that the use in miniaturised system becomes auwkwa~d ;
- The liquid connection between the solution being tested and the internal solution of the half-- 9 ~ 4~4~
cell originates the so-called liquid junction potential, the minimization of which is cumbersome, said potential being m~reover variable as a function of the nature of the solution being tested;
- The sample of the solution being tested is po~luted by the internal solution of the half-cell, and vice-versa;
- The reference half-cell requires~a comparatively frequence of upkeep operations.
We have now found, that which is the subject matter of this invention, that it is possible to have the conventional reference half-cell replaced by a solid electrode, for example one of the 2nd species, the potential of which is stabilized by a constant concentration of ions (with respect to which the electrode in ques-tion is reversible) introduced in the solution to be tested.
- Thus, the present invention provides an electrode system comprising a working electrode, a solid reference elec-trode and an auxiliary electrode. The solid reference electrode is of a second species type or of metal/metal oxide type and -the three electrodes are immersed in a solution containing a constant concentration of ions relative to which the solid reference electrode is reversible.
Examples of suitable reference electrodes are the fol-lowing: 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 cons-tant concentration of F in the solution being tested); Ag/AgCl, AG/Agl and Ag/AgBr (with constant concentration of Cl , 1 and Br ions, respectively, in the solution being tested); Ag/Ag2S
(with a constant concentration of either;Ag or of S in the solution being -tested).
By exploiting the electrode system of the present invention, which can comprlse, for example, a wor~ing elec-trode:and:an auxiliary electrode, both of platinum,:and:an I:r/IrO2 reference electrode, it is possible, . . ' .
, :1~4~435 when working i.n~a:solu-tion of;a ~uffer, to m~nitor:an electro-chemical reaction on the working electrode which has been biassed to:a determined ~oltage relative to the reference elec-trode.
The electrode system:according to the present in~en-tion tenders the ad~vantage that it is not impaire~ by~ any of the shortcomings enumerated:above for the systems using re-ference hall-cells with:an internal solution of their own. A
fringe benefit is that the three individual electrodes can readily be assembled into:a single entity, even of:a reduced size, and which can be adapted to measurements of microscopical-scale volumes of the solution to be tested.
The advantages;and other features of the present in-vention will appear from the following non-restrictive descrip-tion with reference to the accompanying drawings, in which:
Figure 1 illustrates, by way of example only,.a possible embodiment of the electrode system according to the present invention;
Figure 2 shows a measurement cell which can be con-nected to a special polarographic instrument;:and Figures 3 and 4 represent results recorded on:a chartof a reaction trend measured in accordance with the present in-vention.
Having now reference,:at the outset, to Figure 1 the numeral 1 connotes the Ir/IrO2 electrode, 2 is the platinum working electrode, 3 the platinum auxiliary electrode, 4 is:a probe (optional) for controlling the temperature, 5 is the body of the electrode system,:and lastly, 6 is the assembly of the connectors for connecting the measurement instrument. ~he elec-trode system as now outlined, can be used for carrying out.a number of analyses. For example, it can be used for the follow-ing determinations:
~ ~1435 1. Determination of hydrogen peroxide,-for e~ample in connection With the e~olutio~ of the followin~ enzymic reactions:
glucose 1.1. 02 + Beta-D-glucose ~ D-gluconic acid ~ H202 oxidase .alcohol 1.2. 2 + alcohol . ~ Ald~hyde + H202 oxidase /
~- - 4 a 114~43~
.
.
1.3. 2 + uric acid Ur.icase allantoin + C02+H202 1.4. t D 1 t galactose~D 1 t h di ld 1.5. 2 + cholesterol id ~ 4-cholestan-3-one +
1.6, 2 + H20+ L-aminoacid -d ~ 2-ketoacid +
2. Determination of N.AD(P)H~ ____~NAD(P) ~ for example in connection with the evolution of the following enzymic reac-tions :
2.1. Pyruvate + NADH ,lac~ L-lactate + NAD+
2.2~ L-glutamate + H20 + ~AD (P)+ dehydrogenase glurate +NH3+
. NAD(P)H
2.3. Alcohol + NAD(P)+ alcohol ~ Aldehyde + NADH
de'hydrogenase 152.4. Glycerol + NAD+ ~lycero ~ Dihydroxyacetone+NADH
. de~ydrogënase .2.5. L-malate+~AD+ malate ~ oxalacetate+NADH
dè ~ rogenase 2.6. ~ -D-glucose~NAD(P) ~ g _~ D-gluconolactone +
dehydrogenase NAD(P)H
and others.
3~ Determination of biological substances and non-biological substances which were already present in the fluids to be tested, rather than generated in reactions such as the previously cited ones~
such as, for er~ampie : .
3.1. Uric acid 3.2. Ascorbic acid
The most prominent problems stemming from the 25 use of reference hal-f-cells having an intern~l solution of their own and a liquid ~junction are :
- The physical dlmensions cannot be reduced beyond certain limits so that the use in miniaturised system becomes auwkwa~d ;
- The liquid connection between the solution being tested and the internal solution of the half-- 9 ~ 4~4~
cell originates the so-called liquid junction potential, the minimization of which is cumbersome, said potential being m~reover variable as a function of the nature of the solution being tested;
- The sample of the solution being tested is po~luted by the internal solution of the half-cell, and vice-versa;
- The reference half-cell requires~a comparatively frequence of upkeep operations.
We have now found, that which is the subject matter of this invention, that it is possible to have the conventional reference half-cell replaced by a solid electrode, for example one of the 2nd species, the potential of which is stabilized by a constant concentration of ions (with respect to which the electrode in ques-tion is reversible) introduced in the solution to be tested.
- Thus, the present invention provides an electrode system comprising a working electrode, a solid reference elec-trode and an auxiliary electrode. The solid reference electrode is of a second species type or of metal/metal oxide type and -the three electrodes are immersed in a solution containing a constant concentration of ions relative to which the solid reference electrode is reversible.
Examples of suitable reference electrodes are the fol-lowing: 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 cons-tant concentration of F in the solution being tested); Ag/AgCl, AG/Agl and Ag/AgBr (with constant concentration of Cl , 1 and Br ions, respectively, in the solution being tested); Ag/Ag2S
(with a constant concentration of either;Ag or of S in the solution being -tested).
By exploiting the electrode system of the present invention, which can comprlse, for example, a wor~ing elec-trode:and:an auxiliary electrode, both of platinum,:and:an I:r/IrO2 reference electrode, it is possible, . . ' .
, :1~4~435 when working i.n~a:solu-tion of;a ~uffer, to m~nitor:an electro-chemical reaction on the working electrode which has been biassed to:a determined ~oltage relative to the reference elec-trode.
The electrode system:according to the present in~en-tion tenders the ad~vantage that it is not impaire~ by~ any of the shortcomings enumerated:above for the systems using re-ference hall-cells with:an internal solution of their own. A
fringe benefit is that the three individual electrodes can readily be assembled into:a single entity, even of:a reduced size, and which can be adapted to measurements of microscopical-scale volumes of the solution to be tested.
The advantages;and other features of the present in-vention will appear from the following non-restrictive descrip-tion with reference to the accompanying drawings, in which:
Figure 1 illustrates, by way of example only,.a possible embodiment of the electrode system according to the present invention;
Figure 2 shows a measurement cell which can be con-nected to a special polarographic instrument;:and Figures 3 and 4 represent results recorded on:a chartof a reaction trend measured in accordance with the present in-vention.
Having now reference,:at the outset, to Figure 1 the numeral 1 connotes the Ir/IrO2 electrode, 2 is the platinum working electrode, 3 the platinum auxiliary electrode, 4 is:a probe (optional) for controlling the temperature, 5 is the body of the electrode system,:and lastly, 6 is the assembly of the connectors for connecting the measurement instrument. ~he elec-trode system as now outlined, can be used for carrying out.a number of analyses. For example, it can be used for the follow-ing determinations:
~ ~1435 1. Determination of hydrogen peroxide,-for e~ample in connection With the e~olutio~ of the followin~ enzymic reactions:
glucose 1.1. 02 + Beta-D-glucose ~ D-gluconic acid ~ H202 oxidase .alcohol 1.2. 2 + alcohol . ~ Ald~hyde + H202 oxidase /
~- - 4 a 114~43~
.
.
1.3. 2 + uric acid Ur.icase allantoin + C02+H202 1.4. t D 1 t galactose~D 1 t h di ld 1.5. 2 + cholesterol id ~ 4-cholestan-3-one +
1.6, 2 + H20+ L-aminoacid -d ~ 2-ketoacid +
2. Determination of N.AD(P)H~ ____~NAD(P) ~ for example in connection with the evolution of the following enzymic reac-tions :
2.1. Pyruvate + NADH ,lac~ L-lactate + NAD+
2.2~ L-glutamate + H20 + ~AD (P)+ dehydrogenase glurate +NH3+
. NAD(P)H
2.3. Alcohol + NAD(P)+ alcohol ~ Aldehyde + NADH
de'hydrogenase 152.4. Glycerol + NAD+ ~lycero ~ Dihydroxyacetone+NADH
. de~ydrogënase .2.5. L-malate+~AD+ malate ~ oxalacetate+NADH
dè ~ rogenase 2.6. ~ -D-glucose~NAD(P) ~ g _~ D-gluconolactone +
dehydrogenase NAD(P)H
and others.
3~ Determination of biological substances and non-biological substances which were already present in the fluids to be tested, rather than generated in reactions such as the previously cited ones~
such as, for er~ampie : .
3.1. Uric acid 3.2. Ascorbic acid
4. Determination of all the substances which are usual~ -ly detected by exploiting the conventional electro-de systems.
-.
13L4~4~
, 6.
! Additional operative details will become more clear-ly apparent from the scrutiny of the ensuing Examples which are given only for clarifying the invention with-out limiting same.
~XAMPLE ~ : Determination of glucose according to the reaction pattern reported above under 1.1 Materials :
. Enzymic reagent, containing 75 n~ phosphate buffers~
pH 7, and glucose-o~idase, 50 U/ml 2. Commercial control sera 3. S~andard solutions of glucose ( 50-100-150-200-300-500 mg/dl~ ~milligrams/deciliter) in a saturated solution of benzoi^ acid.
4.` Measurement cell of FIGURE 2, connected to the spe-cial polarographic instruments.
With reference to FIGURE 2 3 the reference numerai 1 indicates the path for introducing the enzymic reagen-t via an automatic metering device, 2 are the electrodes connected to the polarograph~ 3 is the sample-charging pipette, 4 is a stirrer, 5 the sump connected to a suct-ion system, 6 are the connections o~ the sensors to the polarograph.
Methods There are introduced 2 mls cf enzymic reagent in the measurement cell and 0.02 ml of serum or a s-tandara are added. The polarograph is 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 glu-cose in the sample ¦FIGURE 4).For checking the accuracy, there have been analyzed 11~ 5 ,.
. .
eight commercial sera and the results are tabulated in ~
T r~BL E 1. .
The compari~on with the enzymic~colorimetric method (GOD-POD) has furnished the following data :
S Number of samples : 31 Equation of the regression line : y = 0.94 x ~ 7.8 Correlation coefficient : r = o.4-85 Mean of x : 128.5 mg/dl (milligrams Mean of y : 128.0 mg7d~eciliter) maximum of x : 325.0 mg/dl maximum of y ; 341.0 mg/dl minimum of x : 57.0 mg/dl minimum of y : 57.0 mg/dl range of x : 268.0 mg/dl range of y : 284.0 mg/dl TABLE
'~
.
. .
114~3~j;
. . . _ ~=-=====
~ ~ o ~ U) U) ~ o o o ~ CO oo , o~ ~ oo ~ o ~ ,, ~, ~, ~
~======
bD _ o o o o o o ~
. . U~ ~ o ~ ~
~4 ~ ,.C~ ~ ~ ~ ~ .
CO oo ,, C~
o o o ,o o o o o ~ o ~ C`l t~ ~ ~ ,, oo oo CO
. .. -' d ~ tQ
~ o ~ ..
~ C~ ~
o bD
h tQ - = = = = = =
Q~
.
~ . .
~t oo ~ ~ _ = _ = = = =
¢ ~
~ O O ~ O O O O
El ....... o O ~
o c~ ~ o o G`
. C~ C`~ ~
C`l ~1 ~ _I .
--I ~) O O O (~ C`l o o. ~o P ~ k~ O O
Z t~
OOOOOOOO
.. . .`
~ ¢
O E-~ H ~7 Z Z p.... H H `~ C Z
O H H H H O
~Z H H O O O ~; H
~ æ ~ $ ~ c z H ~ ~ H
o o ~ ~) .
9- ~ .
EXAMPLE B : Determination of NADH in the presence of NAD~
A polarographic system has been used~ hav-ing the following operational parameters : :
Voltage : + 800 milliVolts~ mV
Full-scale value : 500 nA, nanoampere Mechanical stirring : at about 500 rpm Reaction volume : 10 mls of phosphate buffer 0005 M, pH 7.4 10Progressive values~ fronl 10 mcl to 100 mcl (millicenti-liters)~ were add~d to the sample~ of a 0.1 mg/ml (mil~
ligrams per mi.lliliter) of NADH and a continuous record-al was made of the intensity of the current relative to the reaction of ox.idation oE NADH to NAD .
15The responses of the instrument were proportional to the increase o the concentration of.NADH in the reaction cell, with a 7C rA si~nal for 0.14 millimol/
milliliter of NADH. ~.
~ . .,
-.
13L4~4~
, 6.
! Additional operative details will become more clear-ly apparent from the scrutiny of the ensuing Examples which are given only for clarifying the invention with-out limiting same.
~XAMPLE ~ : Determination of glucose according to the reaction pattern reported above under 1.1 Materials :
. Enzymic reagent, containing 75 n~ phosphate buffers~
pH 7, and glucose-o~idase, 50 U/ml 2. Commercial control sera 3. S~andard solutions of glucose ( 50-100-150-200-300-500 mg/dl~ ~milligrams/deciliter) in a saturated solution of benzoi^ acid.
4.` Measurement cell of FIGURE 2, connected to the spe-cial polarographic instruments.
With reference to FIGURE 2 3 the reference numerai 1 indicates the path for introducing the enzymic reagen-t via an automatic metering device, 2 are the electrodes connected to the polarograph~ 3 is the sample-charging pipette, 4 is a stirrer, 5 the sump connected to a suct-ion system, 6 are the connections o~ the sensors to the polarograph.
Methods There are introduced 2 mls cf enzymic reagent in the measurement cell and 0.02 ml of serum or a s-tandara are added. The polarograph is 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 glu-cose in the sample ¦FIGURE 4).For checking the accuracy, there have been analyzed 11~ 5 ,.
. .
eight commercial sera and the results are tabulated in ~
T r~BL E 1. .
The compari~on with the enzymic~colorimetric method (GOD-POD) has furnished the following data :
S Number of samples : 31 Equation of the regression line : y = 0.94 x ~ 7.8 Correlation coefficient : r = o.4-85 Mean of x : 128.5 mg/dl (milligrams Mean of y : 128.0 mg7d~eciliter) maximum of x : 325.0 mg/dl maximum of y ; 341.0 mg/dl minimum of x : 57.0 mg/dl minimum of y : 57.0 mg/dl range of x : 268.0 mg/dl range of y : 284.0 mg/dl TABLE
'~
.
. .
114~3~j;
. . . _ ~=-=====
~ ~ o ~ U) U) ~ o o o ~ CO oo , o~ ~ oo ~ o ~ ,, ~, ~, ~
~======
bD _ o o o o o o ~
. . U~ ~ o ~ ~
~4 ~ ,.C~ ~ ~ ~ ~ .
CO oo ,, C~
o o o ,o o o o o ~ o ~ C`l t~ ~ ~ ,, oo oo CO
. .. -' d ~ tQ
~ o ~ ..
~ C~ ~
o bD
h tQ - = = = = = =
Q~
.
~ . .
~t oo ~ ~ _ = _ = = = =
¢ ~
~ O O ~ O O O O
El ....... o O ~
o c~ ~ o o G`
. C~ C`~ ~
C`l ~1 ~ _I .
--I ~) O O O (~ C`l o o. ~o P ~ k~ O O
Z t~
OOOOOOOO
.. . .`
~ ¢
O E-~ H ~7 Z Z p.... H H `~ C Z
O H H H H O
~Z H H O O O ~; H
~ æ ~ $ ~ c z H ~ ~ H
o o ~ ~) .
9- ~ .
EXAMPLE B : Determination of NADH in the presence of NAD~
A polarographic system has been used~ hav-ing the following operational parameters : :
Voltage : + 800 milliVolts~ mV
Full-scale value : 500 nA, nanoampere Mechanical stirring : at about 500 rpm Reaction volume : 10 mls of phosphate buffer 0005 M, pH 7.4 10Progressive values~ fronl 10 mcl to 100 mcl (millicenti-liters)~ were add~d to the sample~ of a 0.1 mg/ml (mil~
ligrams per mi.lliliter) of NADH and a continuous record-al was made of the intensity of the current relative to the reaction of ox.idation oE NADH to NAD .
15The responses of the instrument were proportional to the increase o the concentration of.NADH in the reaction cell, with a 7C rA si~nal for 0.14 millimol/
milliliter of NADH. ~.
~ . .,
Claims (3)
1. An electrode system comprising a working electro-de, a solid reference electrode and an auxiliary electrode, the solid reference electrode being of a second species type or of metal/metal oxide type, and the three electrodes being immersed in a solution containing constant concentration of ions relative to which the solid reference electrode is rever-sible.
2. An electrode system according to claim 1, wherein the three electrodes are incorporated in a single solid sup-porting member.
3. An electrode system according to claim 1 or 2, wherein the solid reference electrode is made of a material choosen in the group constituted by iridium/iridium oxide, palladium/palladium oxide, rhodium/rhodium oxide, fluoride, Ag/AgCl, Ag/AgBr, Ag/AgI, and Ag/Ag2S.
Applications Claiming Priority (2)
| 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 |
| IT24640A/78 | 1978-06-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1141435A true CA1141435A (en) | 1983-02-15 |
Family
ID=11214235
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000329156A Expired CA1141435A (en) | 1978-06-16 | 1979-06-05 | Electrode system with a reference electrode deprived of liquid junction, for voltameter measurements |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS554591A (en) |
| CA (1) | CA1141435A (en) |
| DE (2) | DE7917122U1 (en) |
| FR (1) | FR2428839A1 (en) |
| GB (1) | GB2023846B (en) |
| IT (1) | IT1158856B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2015138690A3 (en) * | 2014-03-12 | 2015-11-26 | Glucovation, Inc. | Electrochemical sensing system |
Families Citing this family (11)
| 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 |
| US5144247A (en) * | 1991-02-14 | 1992-09-01 | Westinghouse Electric Corp. | Method and apparatus for reducing IR error in cathodic protection measurements |
| US5653864A (en) * | 1994-06-30 | 1997-08-05 | Nok Corporation | Protein biosensor and method for protein measurement with the same |
| WO1999046586A1 (en) * | 1998-03-10 | 1999-09-16 | Micronas Gmbh | Reference electrode |
| JP3982133B2 (en) * | 2000-01-25 | 2007-09-26 | 松下電器産業株式会社 | Measuring device using biosensor and biosensor and dedicated standard solution used therefor |
| 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 |
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 |
| US4073052A (en) * | 1976-02-27 | 1978-02-14 | Honeywell Inc. | Method of making a reference 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 DE DE19797917122U patent/DE7917122U1/en not_active Expired
- 1979-06-15 DE DE19792924117 patent/DE2924117A1/en not_active Ceased
- 1979-06-15 JP JP7477779A patent/JPS554591A/en active Pending
- 1979-06-15 FR FR7915476A patent/FR2428839A1/en active Granted
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2015138690A3 (en) * | 2014-03-12 | 2015-11-26 | Glucovation, Inc. | Electrochemical sensing system |
| CN106572819A (en) * | 2014-03-12 | 2017-04-19 | 血糖测试仪股份有限公司 | Electrochemical sensing system |
| US20170273603A1 (en) * | 2014-03-12 | 2017-09-28 | Glucovation, Inc. | Electrochemical Sensing System |
| EP3116396A4 (en) * | 2014-03-12 | 2018-02-14 | Glucovation, Inc. | Electrochemical sensing system |
| US11259724B2 (en) * | 2014-03-12 | 2022-03-01 | Glucovation, Inc. | Electrochemical sensing system |
Also Published As
| Publication number | Publication date |
|---|---|
| DE2924117A1 (en) | 1979-12-20 |
| GB2023846A (en) | 1980-01-03 |
| DE7917122U1 (en) | 1982-09-30 |
| GB2023846B (en) | 1983-03-30 |
| IT7824640A0 (en) | 1978-06-16 |
| FR2428839A1 (en) | 1980-01-11 |
| JPS554591A (en) | 1980-01-14 |
| FR2428839B1 (en) | 1982-11-05 |
| IT1158856B (en) | 1987-02-25 |
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