CA2091347A1 - Method for determining the number of dissociable particles in liquids - Google Patents
Method for determining the number of dissociable particles in liquidsInfo
- Publication number
- CA2091347A1 CA2091347A1 CA002091347A CA2091347A CA2091347A1 CA 2091347 A1 CA2091347 A1 CA 2091347A1 CA 002091347 A CA002091347 A CA 002091347A CA 2091347 A CA2091347 A CA 2091347A CA 2091347 A1 CA2091347 A1 CA 2091347A1
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- CA
- Canada
- Prior art keywords
- electrodes
- process according
- liquid
- current
- liquids
- 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.)
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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
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/06—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a liquid
-
- 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
- G01N27/42—Measuring deposition or liberation of materials from an electrolyte; Coulometry, i.e. measuring coulomb-equivalent of material in an electrolyte
- G01N27/423—Coulometry
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Physics & Mathematics (AREA)
- Electrochemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Molecular Biology (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
- Electrostatic Separation (AREA)
Abstract
Abstract This invention relates to a method for determining the number of dissociable particles (ion pairs) in liquids, wherein an electric field is applied to a pair of electrodes which are positioned in a liquid and exhibit 2 reduced injection capability for charge carriers, wherein the electric current resulting from the electric field is subsequently integrated, and the determined integration value is then used as a measure of the number of dissociable particles originally contained in the liquid.
Description
Description The present invention relates to a method for determining the number of dissociable particles (ion pairs) in liquids.
Electrochemical methods for determining ions in liquids have 50 far been known. All of these methods are based on a conductivity measurement of a liquid. In said methods an electric voltage is applied to a pair of electrodes positioned in the liquid to be examined, and the resultant electric current is measured with the aid of a measuring device.
Dissociable particles constitute impurities in liquids and are normally present in a dissociated state or a non-dissociated state.
q specific equilibrium is established between these two states.
Only the momentarily dissociated particles that act as charge carriers can effect an electric current flow.
;
Said m~thods which are based on a conductivity measurement are therefore not suited for the exact determination of the number of dissociable particles in liquids because a part of the particles is always present in a non-dissociated form during such a measurement and can thus not contribute anything to the conductivity. ~oreover, when conventional electrodes are used, charge carriers are constantly injected into the liquid, whereby the result is also distorted.
., :' ' :
3 ~ 1 It is therefore the object of the present invention to indicate a method which permits a simple, but very accurate determination of the number of dissociable particles in a liquid.
In accordance with the invention, this object is attained through a method wherein an electric field is applied to a pair of electrodes that are positioned in a liquid and exhibit a reduced injection capability for charge carriers, wherein the electric current resulting from the electric field is subsequently integrated for a specific period of time, and the determined integration value is then used zs a measure of the number of dissociable particles originally contained in the liquid.
Developements of the invention are the sub~ect matter of the subclaims.
In the method of the invention, not only the particles that are already dissociated at the heginning of the method, but also the particles that are dissociated under the action of the electric field at a later time contribute to the measurement result, as the integration step is carried out over a certain period of time.
r~oreover, additional charge carriers are prevented from passing into the liquid and can thus not contribute to the current integral due to the use of special electrodes which exhibit a reduced injection capability for charge carriers. This increases the accuracy of the measurement.
The method is preferably carried out for a period of time which ~, .
'~ ~5~ ~ 3-~ends when the current flow does virtually not dPcrease any more.
Since certain residual currents always remain as a rule, one cannot wait until the current flow has stopped entirely. If there 3re residual currents of this kind, they must of course be left aut of consideration in the current integral.
After the integrating operation has been terminated, it can be assumed that all dissociable particles are in their dissociated state and have migrated to the electrodes as free ions. The remaining liquid is thus in a condition of high purity.
The following relation always exists between the dissociated particles (ion pairs) Al , which are- withdrawn from the liquid per volume unit during the action of the electric field, and the flown current I:
t ~E - e ~ lt o where e is the elementary charge and V the volume.
qfter a sufficiently long time has passed, all dissociable particles are present in dissociated form and have migrated to the electrodes, so that the current flow is stopped. The number of the dissociable particles ND which are initially present in the liquid per volume unit is therefore:
= r.l D r t ~
It is of course assumed in the explanations given above that the liquid as such is either hardly dissociable or even undissociable and that the current flow is therefore substantially caused by impurities alone.
1 3 ~ ~
Flectrodes of a reduced injection capability may be of the following types:
So-called passivated electrodes may e.g. be used.
These are electrodes whose capability to inject electrons has been considerably reduced through a suitable pretreatment. '~Jith commercial brass electrodes. a passivation can e.g. be accomplished in the following, very simplified way:
The pair of electrodes to be passivated are placed in a cell with propylene carbonate (PC) and a field strength or force of e.g. 10 k'J/cm is applied thereto. After some time the electrodes are passivated. In the case of brass electrodes and pr the passivation can possibly be recosnized by the brownish discoloration of the electrode surfaces. The electrodes passivated in this way may then be used in the method of the invention.
qnother possibility of reducing the in~ection capability of commercial, untreated (bare) electrodes consists in covering these electrodes with ion-exchange membranes in the direction of interception. The membranes prevent the ions from entering into the liquid volume.
Cinally, it has also been found that the iniection capability of electrodes can be reduced by placing a layer consisting of a material with a high dielectric constant between the untreated ~bare) commercial electrodes and the liquid to be examined. It would therefore be obvious to cover the electrodes with such a material. However, since it has been found in tests that although , ~ 3~ ~
ceramics are especially suited for preventing an in-ection, these cannot be brought nto the desired shape without ar,y problem, the following assembly has been preferred in tests that have so far been carried out:
A plate of a ceramic material is placed between the liquid and a respective electrode, so that the liquid is located ~etween the two plates, and the electrodes can be secured to the plate sides facing away from the liquid.
The present method is preferably performed using a field of some 'c~l/cm. Tt is thus possible to carry out the method within a sufficiently short period of time, and it can he assumed that all dissociable particles will be dissociated.
~lthough proof has not been furnished yet, it can be assumed that a complete dissociation of all dissociable particles is only possible from a certain field strength onwards. A considera~le dissociation could already be observed at field strengths of about 1C0 ~I/cm when propylene carbonate (C) W35 used as the liquid and the electrodes employed were passivated ones. It can basically be said that in the presence of great field strengths the method takes 31ace more rapidly because the dissociation v210city 4 for th2 particles is increased hy great field strengths.
Commercial devices which are designec for such a purpose can be used for measuring and recording the resultant current.
These are e.g. storage oscilloscopes or current measuring instruments including a recording unit. The rasultant current integral can be deduced through estimation or with the aid of h Y~ 'J ~ 3 '~
planimetry methods from the current curves recorde- by said devices. ~f course, it is also possible to use devices which are capable of determining the integration value autom2tically. The method of the invention is preferably used for liquids having high dielectric constants.
Since the dissociable particles are contaminations of the liquid to be examined, it is possible to predict the purific2tion time for the liquid by determining the number of dissociable particles.
If one proceeds on the assumption that the current drop follows a specific function, e.g. an exponential function, tho current integral to be rec~oned with can be reliably predicred on the basis of a short measurement by determining the relevant time constant~
Hence, in this case the method need not be continued until the current has approximately fallen to the value of tbe unavoicable residual currents. ronventional storage oscilloscores are especially well suited for observing the current drop and for esti~atino the time constant. As is generally !~nown, the integral of an exponential function is the product of time constant znd initial value. ~ence, the followinc 2~uation is a~-licahl2 t3 the number of dissociable particles per volume unit:
r ~3o ~/9 ~
where r stands for the time constant of the exponential function and I Dis the initial current value.
qn embodi~ent in which the number of dissociable particles in t , 3 ~ ~
propylene carbonate (~r) is determined shall now be described with reference to the accompanying drawing, in which:
-I~. 1 shows an apparatus for carrying out the metho~;
-IG. 2 shows a suitable measuring cell for the methcc;
-IG. 3 shows the current curve obtained during the conduction of the method.
The measuring cell 1 which is illustrated in FI5. 1 serves to receive the propylene carbonate 3 to be examined. ~ ~air of passivated electrodes 2 are connected to a source of voltage ~c. A
current recording device 4 is positioned between one of the electrodes and the voltaoe source. The recorder ~ o; the current recor~ing device prints the current curve as a function of time.
Tbe method is commenced by closing switch 7.
The electrodes are spaced from each otl1er at a distance of e.g.
Q.5 cm. The applied voltage is between 100 and 10D0 '1. The resultant field has a strength of 200 to 2Q00 ll/cm.
The followins main i~purities have analytically been d2termined for Fropylene carbonate:
Codium chloride, tetramethyl armonium bromide, propanediol, water.
These impurities are predominantly ~resent in the p~m range. The ratio of dissociated particles '! to dissociable particles !3 before the application of a field is called the dissociaticn degree ~
~ 13). This degree is 10 if propylene carbonate is contaminated with water, 10 4 if contaminated with propanediol and between 0.1 and 1 if contaminated with sodium chloride or tetramethyl ammonium bromide.
, ~ - ' fi ~I~. 2 shows a concrete embodiment of a measurins cell. As becomes apparent, this is a closed measuring cell ~. 'lectrodes 1 contained therein are covered with ion-exchange membranes ~. Alternatively, the passivated electrodes shown in FI,. 1 could o,~ course be ernployed.
The current curve obtained during the conduction o; the method is depicted in ~I~, 3.
After switch 7 in ~I~. 1 has been closed, a field will ~uild up at the passivated electrodes 2. The resultant current which is mainly a dissociation current is sensed by the current recording device 4 an~ .l!ustrated in ,-I5. 3. As becomes zp~arent ~rom -IG. 3, the current has an exponentially docr2asins course. ~~ter about ' minutes the current reaches a value T~ ';elow whicn it does virtually not fall any more. The residual currents that are ~lways present zre responsi~le for this value.
'~hen the integral which is enclosed by the current curve is deter~ined between the times zero and five minutes, the intecration portion which is hatched in -IG. 7 and created ~y the residuzl currents must not be taken into account.
-urthermore, it can ~e seen that the current curve illustrated in -IG. ~ has a kink in its initial ~ortion. This '~in'< is the result of two overlapping ?rocesses- At the ~eginning the particles that are 21ready present in dissociated form predominantly contri~ute to the current flow. This leads initially to a great current flow T o ~hich decr22ses very rz?idly with a time constant r,. In the further course the current curve is thus determinee by the pzrticles that are newly ~issociated in a continuous wcy. This 3 ~
dominating current Jortion decroases in accordznc- with a time constant ~2.
The currznt ~rop is recorded ~y recorder ~ illust ztec in -I5. 1.
The arza enclosed by the current curve can be reacily determined by plani~etry on the ~asis of the recorde~ current c_rve. s already stated above, the hatched area in ~IG. 3 is not t. be considered in the current integral ~ecause this portion is due :5 residual currents.
If the current intesral is known, the followins e.uation applies to the particle number per volume unit ~'D' as exists initially in the liquid:
1\/~ ~ e. ~ ~ e.~
where n stands for the whole charge caused ~y the ~issociation currents:
"ith propylene car~onate having an initial conduc-ivity of c*1~ 1û
~/cm, a value of -~19 13l!cm is Gotzined for ~'~
T;nese two values ccnstitute a concrete measuremen: esult. rf course, there is ~asicall~/ no fixed relation het_oon concuctivity and the nur,her of .issoci_~le particles ''Dbecause the initial conductivity is substantizlly determined ~y the '~lnd of impurities and the corresponding rissociation regrees of these p2rticles.
The present method has turned out to ~e very advantageous with regard to operations carried o~t in connection with the purification of propylene carhonate, with passivated electrodes being produced zt the same time.
"ith the method of the invention it is possi~le io determine the contamination ce~ree of the propylene car~onate in a simple and very accurate manner. In particular, it is possi~le to predict 1, 2~ ~ 3'17 the purification time for the propylene car~onate.
It can be assumed that the present method will be cf very oreat advantage to the determinaticn of the number of dissoc~a~le particles in li~uios with hish dielectric constants, as are used in electrostatic machinery.
', ' ' . ~, :
': .
Electrochemical methods for determining ions in liquids have 50 far been known. All of these methods are based on a conductivity measurement of a liquid. In said methods an electric voltage is applied to a pair of electrodes positioned in the liquid to be examined, and the resultant electric current is measured with the aid of a measuring device.
Dissociable particles constitute impurities in liquids and are normally present in a dissociated state or a non-dissociated state.
q specific equilibrium is established between these two states.
Only the momentarily dissociated particles that act as charge carriers can effect an electric current flow.
;
Said m~thods which are based on a conductivity measurement are therefore not suited for the exact determination of the number of dissociable particles in liquids because a part of the particles is always present in a non-dissociated form during such a measurement and can thus not contribute anything to the conductivity. ~oreover, when conventional electrodes are used, charge carriers are constantly injected into the liquid, whereby the result is also distorted.
., :' ' :
3 ~ 1 It is therefore the object of the present invention to indicate a method which permits a simple, but very accurate determination of the number of dissociable particles in a liquid.
In accordance with the invention, this object is attained through a method wherein an electric field is applied to a pair of electrodes that are positioned in a liquid and exhibit a reduced injection capability for charge carriers, wherein the electric current resulting from the electric field is subsequently integrated for a specific period of time, and the determined integration value is then used zs a measure of the number of dissociable particles originally contained in the liquid.
Developements of the invention are the sub~ect matter of the subclaims.
In the method of the invention, not only the particles that are already dissociated at the heginning of the method, but also the particles that are dissociated under the action of the electric field at a later time contribute to the measurement result, as the integration step is carried out over a certain period of time.
r~oreover, additional charge carriers are prevented from passing into the liquid and can thus not contribute to the current integral due to the use of special electrodes which exhibit a reduced injection capability for charge carriers. This increases the accuracy of the measurement.
The method is preferably carried out for a period of time which ~, .
'~ ~5~ ~ 3-~ends when the current flow does virtually not dPcrease any more.
Since certain residual currents always remain as a rule, one cannot wait until the current flow has stopped entirely. If there 3re residual currents of this kind, they must of course be left aut of consideration in the current integral.
After the integrating operation has been terminated, it can be assumed that all dissociable particles are in their dissociated state and have migrated to the electrodes as free ions. The remaining liquid is thus in a condition of high purity.
The following relation always exists between the dissociated particles (ion pairs) Al , which are- withdrawn from the liquid per volume unit during the action of the electric field, and the flown current I:
t ~E - e ~ lt o where e is the elementary charge and V the volume.
qfter a sufficiently long time has passed, all dissociable particles are present in dissociated form and have migrated to the electrodes, so that the current flow is stopped. The number of the dissociable particles ND which are initially present in the liquid per volume unit is therefore:
= r.l D r t ~
It is of course assumed in the explanations given above that the liquid as such is either hardly dissociable or even undissociable and that the current flow is therefore substantially caused by impurities alone.
1 3 ~ ~
Flectrodes of a reduced injection capability may be of the following types:
So-called passivated electrodes may e.g. be used.
These are electrodes whose capability to inject electrons has been considerably reduced through a suitable pretreatment. '~Jith commercial brass electrodes. a passivation can e.g. be accomplished in the following, very simplified way:
The pair of electrodes to be passivated are placed in a cell with propylene carbonate (PC) and a field strength or force of e.g. 10 k'J/cm is applied thereto. After some time the electrodes are passivated. In the case of brass electrodes and pr the passivation can possibly be recosnized by the brownish discoloration of the electrode surfaces. The electrodes passivated in this way may then be used in the method of the invention.
qnother possibility of reducing the in~ection capability of commercial, untreated (bare) electrodes consists in covering these electrodes with ion-exchange membranes in the direction of interception. The membranes prevent the ions from entering into the liquid volume.
Cinally, it has also been found that the iniection capability of electrodes can be reduced by placing a layer consisting of a material with a high dielectric constant between the untreated ~bare) commercial electrodes and the liquid to be examined. It would therefore be obvious to cover the electrodes with such a material. However, since it has been found in tests that although , ~ 3~ ~
ceramics are especially suited for preventing an in-ection, these cannot be brought nto the desired shape without ar,y problem, the following assembly has been preferred in tests that have so far been carried out:
A plate of a ceramic material is placed between the liquid and a respective electrode, so that the liquid is located ~etween the two plates, and the electrodes can be secured to the plate sides facing away from the liquid.
The present method is preferably performed using a field of some 'c~l/cm. Tt is thus possible to carry out the method within a sufficiently short period of time, and it can he assumed that all dissociable particles will be dissociated.
~lthough proof has not been furnished yet, it can be assumed that a complete dissociation of all dissociable particles is only possible from a certain field strength onwards. A considera~le dissociation could already be observed at field strengths of about 1C0 ~I/cm when propylene carbonate (C) W35 used as the liquid and the electrodes employed were passivated ones. It can basically be said that in the presence of great field strengths the method takes 31ace more rapidly because the dissociation v210city 4 for th2 particles is increased hy great field strengths.
Commercial devices which are designec for such a purpose can be used for measuring and recording the resultant current.
These are e.g. storage oscilloscopes or current measuring instruments including a recording unit. The rasultant current integral can be deduced through estimation or with the aid of h Y~ 'J ~ 3 '~
planimetry methods from the current curves recorde- by said devices. ~f course, it is also possible to use devices which are capable of determining the integration value autom2tically. The method of the invention is preferably used for liquids having high dielectric constants.
Since the dissociable particles are contaminations of the liquid to be examined, it is possible to predict the purific2tion time for the liquid by determining the number of dissociable particles.
If one proceeds on the assumption that the current drop follows a specific function, e.g. an exponential function, tho current integral to be rec~oned with can be reliably predicred on the basis of a short measurement by determining the relevant time constant~
Hence, in this case the method need not be continued until the current has approximately fallen to the value of tbe unavoicable residual currents. ronventional storage oscilloscores are especially well suited for observing the current drop and for esti~atino the time constant. As is generally !~nown, the integral of an exponential function is the product of time constant znd initial value. ~ence, the followinc 2~uation is a~-licahl2 t3 the number of dissociable particles per volume unit:
r ~3o ~/9 ~
where r stands for the time constant of the exponential function and I Dis the initial current value.
qn embodi~ent in which the number of dissociable particles in t , 3 ~ ~
propylene carbonate (~r) is determined shall now be described with reference to the accompanying drawing, in which:
-I~. 1 shows an apparatus for carrying out the metho~;
-IG. 2 shows a suitable measuring cell for the methcc;
-IG. 3 shows the current curve obtained during the conduction of the method.
The measuring cell 1 which is illustrated in FI5. 1 serves to receive the propylene carbonate 3 to be examined. ~ ~air of passivated electrodes 2 are connected to a source of voltage ~c. A
current recording device 4 is positioned between one of the electrodes and the voltaoe source. The recorder ~ o; the current recor~ing device prints the current curve as a function of time.
Tbe method is commenced by closing switch 7.
The electrodes are spaced from each otl1er at a distance of e.g.
Q.5 cm. The applied voltage is between 100 and 10D0 '1. The resultant field has a strength of 200 to 2Q00 ll/cm.
The followins main i~purities have analytically been d2termined for Fropylene carbonate:
Codium chloride, tetramethyl armonium bromide, propanediol, water.
These impurities are predominantly ~resent in the p~m range. The ratio of dissociated particles '! to dissociable particles !3 before the application of a field is called the dissociaticn degree ~
~ 13). This degree is 10 if propylene carbonate is contaminated with water, 10 4 if contaminated with propanediol and between 0.1 and 1 if contaminated with sodium chloride or tetramethyl ammonium bromide.
, ~ - ' fi ~I~. 2 shows a concrete embodiment of a measurins cell. As becomes apparent, this is a closed measuring cell ~. 'lectrodes 1 contained therein are covered with ion-exchange membranes ~. Alternatively, the passivated electrodes shown in FI,. 1 could o,~ course be ernployed.
The current curve obtained during the conduction o; the method is depicted in ~I~, 3.
After switch 7 in ~I~. 1 has been closed, a field will ~uild up at the passivated electrodes 2. The resultant current which is mainly a dissociation current is sensed by the current recording device 4 an~ .l!ustrated in ,-I5. 3. As becomes zp~arent ~rom -IG. 3, the current has an exponentially docr2asins course. ~~ter about ' minutes the current reaches a value T~ ';elow whicn it does virtually not fall any more. The residual currents that are ~lways present zre responsi~le for this value.
'~hen the integral which is enclosed by the current curve is deter~ined between the times zero and five minutes, the intecration portion which is hatched in -IG. 7 and created ~y the residuzl currents must not be taken into account.
-urthermore, it can ~e seen that the current curve illustrated in -IG. ~ has a kink in its initial ~ortion. This '~in'< is the result of two overlapping ?rocesses- At the ~eginning the particles that are 21ready present in dissociated form predominantly contri~ute to the current flow. This leads initially to a great current flow T o ~hich decr22ses very rz?idly with a time constant r,. In the further course the current curve is thus determinee by the pzrticles that are newly ~issociated in a continuous wcy. This 3 ~
dominating current Jortion decroases in accordznc- with a time constant ~2.
The currznt ~rop is recorded ~y recorder ~ illust ztec in -I5. 1.
The arza enclosed by the current curve can be reacily determined by plani~etry on the ~asis of the recorde~ current c_rve. s already stated above, the hatched area in ~IG. 3 is not t. be considered in the current integral ~ecause this portion is due :5 residual currents.
If the current intesral is known, the followins e.uation applies to the particle number per volume unit ~'D' as exists initially in the liquid:
1\/~ ~ e. ~ ~ e.~
where n stands for the whole charge caused ~y the ~issociation currents:
"ith propylene car~onate having an initial conduc-ivity of c*1~ 1û
~/cm, a value of -~19 13l!cm is Gotzined for ~'~
T;nese two values ccnstitute a concrete measuremen: esult. rf course, there is ~asicall~/ no fixed relation het_oon concuctivity and the nur,her of .issoci_~le particles ''Dbecause the initial conductivity is substantizlly determined ~y the '~lnd of impurities and the corresponding rissociation regrees of these p2rticles.
The present method has turned out to ~e very advantageous with regard to operations carried o~t in connection with the purification of propylene carhonate, with passivated electrodes being produced zt the same time.
"ith the method of the invention it is possi~le io determine the contamination ce~ree of the propylene car~onate in a simple and very accurate manner. In particular, it is possi~le to predict 1, 2~ ~ 3'17 the purification time for the propylene car~onate.
It can be assumed that the present method will be cf very oreat advantage to the determinaticn of the number of dissoc~a~le particles in li~uios with hish dielectric constants, as are used in electrostatic machinery.
', ' ' . ~, :
': .
Claims (10)
1. A process for determining the number of dissociable particles (ion pairs) in liquids, in which an electrical field is applied to a pair of electrodes located in the liquid, which has a small injection capacity for charge carriers, in which the electric current resulting due to the electrical field, which drops exponentially, is then integrated until the current substantially does not drop any longer, and in which the integration value ascertained between the points in time 0 and 5 is then used as a measure for the number of dissociable particles originally contained in the liquid.
2. A process according to claim 1, characterized in that a pair of passivated electrodes is used.
3. A process according to claim 1, characterized in that a pair of electrodes coated with ion exchanger membranes in the non-conducting direction is used.
4. A process according to claim 1, characterized in that bare electrodes are used, and that they are separated from the liquid by a layer of a material with a high dielectricity constant, preferably made of ceramics.
5. A process according to at least any of the preceding claims, characterized in that an electrical field with a field intensity of more than 100 volts/cm is applied.
6. Use of the process according to at least any of the preceding claims for liquids with high dielectricity constants.
7. Use of the process according to claim 6 for propyl-ene carbonate.
8. Use of the process according to claim 6 or 7 for determining the purification times of liquids.
9. A device for carrying out the process according to at least any of claims 1 to 5, characterized by a receptacle for receiving the liquid, at least two spaced electrodes disposed in the recep-tacle, which have a low injection capacity, a voltage source electrically connected with the electrodes, and a current detection means for measuring and recording currents which is connected in series with the voltage source and the electrodes.
10. A device according to claim 10, characterized in that the current detection means is a storage oscillo-scope.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4028716.5 | 1990-09-10 | ||
| DE4028716A DE4028716A1 (en) | 1990-09-10 | 1990-09-10 | METHOD FOR DETERMINING THE NUMBER OF DISSOCIATIVE PARTICLES IN LIQUIDS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2091347A1 true CA2091347A1 (en) | 1992-03-11 |
Family
ID=6413977
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002091347A Abandoned CA2091347A1 (en) | 1990-09-10 | 1991-09-05 | Method for determining the number of dissociable particles in liquids |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP0548133A1 (en) |
| JP (1) | JPH06501097A (en) |
| KR (1) | KR930702671A (en) |
| CN (1) | CN1059966A (en) |
| CA (1) | CA2091347A1 (en) |
| DE (1) | DE4028716A1 (en) |
| FI (1) | FI931035A (en) |
| TW (1) | TW240293B (en) |
| WO (1) | WO1992004624A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4425347B1 (en) * | 2008-10-21 | 2010-03-03 | 北斗電子工業株式会社 | Method and apparatus for detecting the size of particles in a liquid |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RO75812A (en) * | 1974-06-05 | 1981-02-28 | Aluminium Pechiney,Fr | METHOD FOR THE CONTINUOUS DETERMINATION OF INTERNAL RESISTANCE OF AN ELECTROLYSIS UNIT AND INSTALLATION FOR APPLICATION OF THE PROCESS |
| US4009998A (en) * | 1975-09-05 | 1977-03-01 | Phillips Petroleum Company | Acid concentration measurement |
| JPS6453146A (en) * | 1987-01-09 | 1989-03-01 | Hitachi Ltd | Method and instrument for measuring electrical conductivity of solution and water quality control method |
-
1990
- 1990-09-10 DE DE4028716A patent/DE4028716A1/en not_active Withdrawn
-
1991
- 1991-09-05 JP JP3514573A patent/JPH06501097A/en active Pending
- 1991-09-05 CA CA002091347A patent/CA2091347A1/en not_active Abandoned
- 1991-09-05 WO PCT/DE1991/000717 patent/WO1992004624A1/en not_active Application Discontinuation
- 1991-09-05 EP EP91915871A patent/EP0548133A1/en not_active Ceased
- 1991-09-05 KR KR1019930700731A patent/KR930702671A/en not_active Application Discontinuation
- 1991-09-09 CN CN91108794A patent/CN1059966A/en active Pending
- 1991-09-25 TW TW080107544A patent/TW240293B/zh active
-
1993
- 1993-03-09 FI FI931035A patent/FI931035A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| DE4028716A1 (en) | 1992-03-12 |
| CN1059966A (en) | 1992-04-01 |
| FI931035A (en) | 1993-04-06 |
| JPH06501097A (en) | 1994-01-27 |
| FI931035A0 (en) | 1993-03-09 |
| EP0548133A1 (en) | 1993-06-30 |
| WO1992004624A1 (en) | 1992-03-19 |
| KR930702671A (en) | 1993-09-09 |
| TW240293B (en) | 1995-02-11 |
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