US3883414A - Detector of trace substance in water - Google Patents

Detector of trace substance in water Download PDF

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Publication number
US3883414A
US3883414A US455326A US45532674A US3883414A US 3883414 A US3883414 A US 3883414A US 455326 A US455326 A US 455326A US 45532674 A US45532674 A US 45532674A US 3883414 A US3883414 A US 3883414A
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sample
cell
detector
flow
electrolyte
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Taitiro Fujinaga
Katuo Miura
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Shibata Kagaku Kikai Kogyo Kabushiki
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Shibata Kagaku Kikai Kogyo Kabushiki
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/18—Water
    • G01N33/1813—Specific cations in water, e.g. heavy metals
    • 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

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  • the present invention provides a new device and method for automatically detecting and regulating and/or removing concentrations of various substances in aqueous solutions, such as for example, regulating the degree of pollution of urban rivers or industrial effluents, by electrolyzing the ions of these substances dissolved therein through a flow electrolyte cell; then depositing and condensing or dissolving, automatically and with high accuracy, continuously or discontinuously, according to the respective electrolytic potentials of these substances.
  • an appropriate color developer is added to the sample to be tested or analysed; the tone and density of the color thus developed are checked against a reference sample.
  • This colorimetric method is called Absorptiometry.
  • the light from a hollow cathode lamp suitable for the sample to be tested is passed through a hydrogen or acetylene flame.
  • the sample is then continuously sprayed into this same flame, and pollutant substances in the sample become atomic. If one or more pollutants are present, a component of the light from the hollow cathode lamp which has a wavelength specific to that of the pollutant to be detected is absorbed and in consequence the amount of this specific component of light which goes into a detector diminishes.
  • the content of that sample substance can be determined from the preset gauge line for the wavelength specific to that subtance. This is called Atomic Absorptiometry.
  • a trace of quick silver is dripped into an electrolyte containing the sample to be tested,
  • a current vs. voltage curve is drawn for the mercury, acting as an electrode, a stepped-curve is obtained showing the potential posi tion representing the substance and the current volume representing the concentration of the substance. From these values, the composition of the substance and its concentration can be known. This is called d-c Polarography. a-c Polarography and Rectangular Wave Polarography are other variations of the Polarography technique.
  • Atomic Absorptiometry method is not suitable as a continuous monitor because of the necessity to use a specific light source-lamp for each substance to be detected.
  • the lamps therefore, have to be switched for each different substance which is very inconvenient.
  • a hot flame of hydrogen or acetylene is needed, posing a safety hazard.
  • the measurement gives merely data relative to the reference sample, thus one does not obtain absolute values of the substance measured.
  • none of these methods can condense and detect within the same device trace quantities of pollutants existing in the sample, nor can it detect the effect of purification of the sample electrolyte, nor can it eliminate irrelevant contents from the sample being tested.
  • the present invention provides a new method and apparatus, free from the adverse limitations of conventional means, for high-accuracy quantitative and qualitative analysis of substances, even in minute concentrations dissolved in urban rivers or industrial effluents from plants and mines and of solutions in general which may contain substances desired to be monitored.
  • the invention device can be made fully automatic, thereby significantly reducing the time and labor needed for measurement and, in addition, rendering the whole device reliable and safe.
  • a supporting electrolyte containing a sample of the substances to be detected is passed through the inventive apparatus in a flow path comprising successiveively from the charging side the following components:
  • the sample injector with or without electrical connection to the potentiostat of the first occuring of the two (or more) flow electrolyte cells on the sample discharging side (down stream) of the injector is connected to a program-controller.
  • a flow electrolyte cell equipped with a potentiostat, having the function of purifying the sample thereby leaving only the desired sub stance in the sample prior to entry of the sample into the sample injector.
  • the electrolyte cell is sometimes referred to hereinafter as a purification cell.
  • Each of the flow electrolyte cells located downstream of said sample injector in the flow path are connected to a potentiostat capable of superimposing an alternat ing current (ac) on its respective cell.
  • FIG. 1 is a comprehensive block diagram illustrating an embodiment of the device according to the present invention
  • FIG. 2 is a sectional view explaining a flow electrolyte cell.
  • FIG. 3 is a circuit diagram of the flow electrolyte cell employed as a chromatography cell, showing its working principle.
  • FIG. 4 is a graph showing the comparative state of dissolution of tin and lead in a hard-to-dissolve hydrochloric acid solution in a flow electrolyte cell of the present invention.
  • FIG. 5 is a graph showing the state oftin and lead dissolved in a flow electrolyte cell of the invention in which a-c is superimposed over the electrolytic potentials of tin and lead.
  • FIG. 6 is a circuit diagram of a potentiostat used in the present invention as connected to an 11-0 superimposing circuit.
  • FIG. 7 is an exploded isometric view of a sample injector of the present invention.
  • FIG. 8 is an illustrative scheme of an electromagnetic valve.
  • FIG. 9 is a graph showing the state of copper and lead dissolved when the sample concentration has been continuously registered by a recorder using the two flow electrolyte cells on the supporting electrolytedischarging side of the sample injector of the invention, as the detector cell.
  • FIG. 10 is a graph showing the state of copper and lead dissolved when the sample concentration has been registered discontinuously in the same way as in FIG. 9, with the sample charged at definite intervals.
  • FIG. 11 illustrates the programming scheme in the case of FIGS. 5 and 10.
  • FIG. 12 is a graph showing the dissolved states of cadmium, lead and copper as registered by a recorder when a trace sample has been condensed using one of the flow electrolyte cells on the supporting electrolytedischarging side of the sample injector as a chromatography column and where measurement has been made using the other flow electrolyte cell as the detector cell.
  • FIG. 13 illustrates the programming scheme in the case of FIG. 12.
  • FIG. 14 illustrates the circuit diagram and working principle of the automatic potential switch circuit in the case of FIG. 13.
  • a supporting electrolyte in the supporting electrolyte reservoir I is charged at a constant rate into the flow pipe 2 by a constant-output pump 3 installed in said pipe 2 and then discharged out through a flow meter 4.
  • the filter cell 6 and the flow electrolyte cells 10, II are structured as shown in FIG. 2, wherein to the two ends of a column membrane 12 made of conventional porous glass are attached non-porous lead terminal col umns WEI and WE2, the column membrane and lead columns being filled with a working electrode 13 composed of glassy carbon grains. Both ends of said terminal columns are blocked with fritter glass, one end having an inlet 14 and the other an outlet 15 for the supporting electrolyte.
  • the outside of the column membrane is wound with, for example, a platinum wire, forming an auxiliary electrode 18, which is housed within but spaced from a casing 21 designed to contain a depolarizing electrolyte, which casing is provided with an inlet 19 and an outlet 20 for the depolarizing electrolyte to enter and discharge.
  • the tip of a salt bridge 23 electrically links with a reference electrode 22 penetrating the casing 21, containing the depolarizing electrolyte, coming close to the column membrane 12, but without reaching it.
  • the lead terminal column WEI and WE2 are each fitted with a working electrode lead wire 24 and 25.
  • the working electrode lead wires, 24, 25, and an auxiliary electrode lead wire 26 are connected to the flow electrolyte cell 10.
  • a reference electrode lead wire 27 is connected to the reference electrode 22 and respectively connected to three potentiostats 5, 8, and 9.
  • the inlet 14 and the outlet 15 for the supporting electrolyte in the filter cell 6 and the flow electrolyte cells 10, ll communicate with the flow pipe 2; and each inlet 19 and outlet 20 for each depolarizing electrolyte in all cells communicate with a common flow pipe 28 for the depolarizer, which will be described later.
  • the potentiostats 5, 8, 9 serve to give an appropriate potential to the working electrode 13 in reference to the reference electrode 22, thereby controlling the current between the auxiliary electrode 18 and the working electrode 13.
  • a sample reservoir 29 is constantly supplied with the sample to be analyzed from a pump 30, the excess sample being discharged through a discharge pipe 31 out of the sample reservoir.
  • the sample solution in the reservoir 29 goes first through an impurity-removing flow electrolyte cell (for purification) 34 equipped with a potentiostat 33 which is installed at a point along sample-supply pipe 32, which pipe then delivers the pure sample to the sample injector 7. Supporting electrolyte is also charged into the sample injector from flow pipe 2 by force of a constantoutput pump 35, ultimately to mix with the sample, as will be described later.
  • Said potentiostat 33 and said flow electrolyte cell 34 used in this embodiment are of the entirely same constitution as the abovementioned potentiostats 5, 8, 9 and flow electrolyte cells 6, 10, 11.
  • this process of sample injection may be continuous or discontinuous; in the case of discontinuous injection the sample is dis charged out of the injector device according to a predetermined program. while the supply is suspended.
  • the sample injector 7 is constituted as shown in FIG. 7. Namely, between two disks of the same profile 36, 37 there is inserted (tightly as to prevent leakage but allow rotation) a sample-supply disk 38 of the same profile with a desired thickness matching the sampling amount as will be later described.
  • a rotatable solenoid coil 39 is fixed-centered to the outside surface of the disk 36 with the solenoid stem 40 extending through the center of the disk 36 and fixed to the center of the samplesupply disk 38.
  • the sample injector is actuated as follows: each time the rotatable solenoid coil 39 receives an electric signal programmed by a programcontroller 54, described later, the solenoid stem 40 and the sample-supply disk 38 rotates by 60.
  • the sample-supply pipe 32a connected to the orifice 41 of the disk 37 may, if desired, be switched to either sample-supply pipe 32b or through a three-way tube 47 to the flow pipe 2b for the supporting electrolyte, by means of a switching electromagnetic valve 46 manually or automatically by a programcontroller 54 to be described later.
  • the flow pipe 20 connected to the orifice 42 is connected via a three-way tube 47 to the flow pipe 2b; and the nitrogen gas-supply pipe 45a connected to the orifice 43 is connected to an appropriate discharge pipe.
  • the depolarizing electrolyte in the depolarizing electrolyte reservior 48 is sent by the constant-output pump 49 inserted in the depolarizer flow pipe 28, to the side of the auxiliary electrode 18 of the filter cell 6 and the flow electrolyte cells 10, ll, 34; it goes through the inlet 19 into the depolarizing electrolyte casing 21. After constantly restoring and replenishing the function of the electrolyte for the auxiliary electrode 18, the depolarizing electrolyte continuously flows to the outlet 20, to be discharged out of the device.
  • the nitrogen gas supplied from a nitrogen gas tank 50 is divided by the 2-way branch off pipe 51 inserted in the nitrogen gas-supply pipe 45.
  • One divided part of the supply passes through the flowmeter 52 for flow rate control and regulation and is then forced into and through the sample reservoir 29, to dispel any dissolved oxygen in the sample solution.
  • the other part of the gas supply divided by the branch-off pipe 51 also passes through a similar flowmeter 53 and, depending on the action of an electromagnetic valve 55 automatically switched by a programcontroller 54, to be described later, serves to force the supporting electrolyte remaining in the through-hole 44 of the samplesupply disk 38 in the sample injector 7 out of that device, or if so programmed it may be into the supporting electrolyte reservoir l, to dispel dissolved oxygen in the supporting electrolyte.
  • FIG. 8 the details of the electromagnetic valve are illustrated. Nitrogen gas passing out of the flowmeter 53 normally flows from the nitrogen gas-supply pipe 450 of the flowmeter 53 to the nitrogen gas-supply pipe 45b of the supporting electrolyte reservoir 1; but when the electromagnetic valve 55 receives an electric signal from the program-controller 54, the flow of the nitrogen gas changes from the nitrogen gas-supply pipe 450 of the flowmeter 53 to the nitrogen gas-supply pipe 450 of the sample injector 7.
  • the potentiostats 8 and 9 are linked to a reporting device, such as a conventional two-pen recorder 56, which makes it possible, with use of the flow electrolyte cells 10, H as the detector cell, to make simultaneous output recordings of both the potentiostats 8, 9 and with use of the flow electrolyte cell 10 as the chromatography cell to make the output recording of only the potentiostat 9.
  • a reporting device such as a conventional two-pen recorder 56, which makes it possible, with use of the flow electrolyte cells 10, H as the detector cell, to make simultaneous output recordings of both the potentiostats 8, 9 and with use of the flow electrolyte cell 10 as the chromatography cell to make the output recording of only the potentiostat 9.
  • the sample injector 7, the potentiostat 8 and the electromagnetic valve 55 are linked to the programcontroller 54, which performs the following functions; supplying alternately with the supporting electrolyte.
  • EXAMPLE 1 In this example, a sample is to be analyzed and the results recorded on a continuous and simultaneous basis, for concentrations of copper and lead.
  • the potentiostat 5 sets a particular potential such that only the supporting electrolyte flows into the filter cell 6 and no impurities go into the path of the flow pipe 2 downstream of the filter cell 6. Thus, the supporting electrolyte is purified.
  • the potentiostat 8 sets such a potential of the flow electrolyte cell 10 that electrolytic deposition of copper alone takes place continu ously in the flow electrolyte cell 10.
  • the potentiostat 9 sets such a potential of the flow electrolyte cell 11 that satisfactory electrolytic deposition of lead takes place continuously in the flow electrolyte cell 11.
  • the potentiostat 33 sets such a potential of the flow electrolyte cell 34 that only copper and lead can flow out of said cell; thus the sample is purified with no other substances than copper and lead allowed to go into the sample-supply pipe 32 in the path downstream of the flow electrolyte cell 34.
  • both the flow electrolyte cells 10, 11 act together as a detector cell, with the result that the sample concentration. ie, the temporal changes of copper and lead concentrations, as illustrated in FIG. 9, are simultaneously and continuously registered by the two-pen recorder 56.
  • EXAMPLE 2 This example illustrates application of the invention when a sample is discontinuously analyzed for its copper and lead content and the results recorded.
  • the program-controller 54 in the device is used, its constitution being illustrated in FIG. 11.
  • a cam 62 is integrally formed on the circumference ofeither of the two disks 60, 61 in this case, say, 60. Both disks are fixed to a shaft 59 of a synchronous motor 58 rotating continuously at uniform speed.
  • the circuit of a microswitch 63 is switched ON" at constant intervals, thereby sending an electrical signal to the solenoid coil 39 of the sample injector 7, and thus the sample supply disk 38 is intermittently rotated by 60.
  • a defined amount of the sample enters through hole 44 of the sample-supply disk 38 by virtue of this intermittent rotation and is carried by the supporting electrolyte in the flow pipe 2 connected to the sample injector 7. Together with the supporting electrolyte, the sample intermittently enters the orifice 42 of the disk 37 and the three-way tube 47 into the flow electrolyte cell 10.
  • a cam 65 on disk 61 turns the circuit of the mircoswitch 64 to ON" at the same time as the circuit of microswitch 63 is being turned ON by the other disk 60.
  • These cams have the effect of holding said microswitch 64, as well as microswitch 63 ON” for a certain duration, and then turning them OFF.
  • Said microswitch 64 continues sending an electric signal to the electromagnetic valve 55 while its circuit is held ON, during which time the nitrogen gas is forced from the nitrogen gas supply pipe 45 into the through-hole 44 of the sample-supply disk 38, thereby cleaning the through-hole 44 of the residual samples or supporting electrolyte.
  • the potentiostats 5, 8, 9, 33, setting the same potentials, perform the same functions, as in Example 1.
  • both the flow electrolyte cells I0, 11 act as the detector cell, one of them, i.e., cell 10 electrolytically depositing copper and the other, electrolytically depositing lead.
  • the variations of copper and lead concentrations at constant intervals as illustrated in FIG. 10 can be simultaneously and continuously registered by the twopen recorder.
  • EXAMPLE 3 In this example, trace concentrations of copper, lead and cadmium in a sample are first condensed in a first cell and then their respective concentrations detected by means of a second cell and recorded.
  • the program-controller 54 in the invention is used; its constitution and the constitution of the potentiostat 8 are illustrated in FIGS. 3, l3 and 14.
  • shaft 67 of the synchronous motor 66 running continuously at uniform speed is coupled to a condensing disk 68, a first electrolytic deposition disk 69, a second electrolytic deposition disk 70 and a third electrolytic deposition disk 71.
  • cams 72 to 75, inclusive Upon the circumferences of these disks are integrally formed cams 72 to 75, inclusive, which turn corresponding microswitches 76 to to ON or OFF.”
  • the next cam 73 sets the next microswitch 78 ON.”
  • the next cam 74 sets the microswitch 79 to ON.
  • the microswitch 76 is linked to the electromagnetic valve 46 of the sample injector 7; while the electromagnetic valve 46 is receiving an ON"-signal, the sample continues to be carried together with the supporting electrolyte via the flow pipe 2 into the flow electrolyte cell 10.
  • the potentionstat 8 has an automatic potential switch cir cuit 57, as illustrated in FIG. 3 and 14 built therein, such that it gives a plus potential to lead terminal column WE2 of the flow electrolyte cell 10 and a minus potential to the lead terminal column WEI, thereby causing a potential gradient in the working electrode 13.
  • the switching action of the automatic potential switch circuit 57 takes place automatically as the result of the microswitch 77 to 80 being set ON" or OFF" by the disks 68 to 71 which are rotated by the synchronous motor 66.
  • symbol 8 represents a variable directed current source; the right side of the Figure illustrates the working principle of chromatography.
  • the bottom-most symbols 1, 2, 3, 4 denote the switching order to potential and potential gradient, the arrow in the transverse direction showing the switching direction.
  • the voltage values given up and down respectively indicate the potential changes in the lead terminal column WEI and WEZ.
  • the synchronous motor 66 is turned ON after the flow electrolytc cell 34 has been given by the potentiostat 33 a potential which permits sample to flow out containing only the three elements copper, lead and cadmium.
  • the microswitches 76 and 77 go ON, causing the sample to be supplied to the working elec trode 13 of the flow electrolyte cell 10, while at the same time the potentiostat 8 creates in the working electrode 13 the first potential gradient which causes electrolytic deposition of each element.
  • all the el ements are successively electrolytic-deposited with condensation; copper in the vicinity of the lead terminal column WE2, lead at the center, and cadmium in the vicinity of the lead terminal column WEI.
  • the suceeding flow electrolyte cell II as the detector cell and giving thereto a potential for detection of copper, i.e,, the last element to be detected, by the potentiostat 9, the quantities of electricity corresponding to the condensed amounts of cadmium, lead and copper as illustrated in FIG. I2 can be registered by the recorder 56 and thus the concentrations of the three elements in the sample can be found from the registered quantities of electricity and the flow rate of the sample.
  • EXAMPLE 4 This example illustrates intermittent analysis of a sample containing many elements wherein there is little difference in the respective electrolytic potential of said elements to accomplish complete separation of these elements and recording their concentrations.
  • the units other than the potentiostat 8 are the same as those employed in Example 2 and perform the same functions,
  • the d-c power supply circuit 82 in the potentiostat 8 is connected to an ac superimposing circuit 83.
  • the tin and lead dissolving potential, as superimposed with ac can be applied to the working electrode 13.
  • 84 is an ac voltage generator
  • 85 is a signal control
  • 86 is a control amplifier.
  • the supporting electrolyte is hydrochloric acid solution and, using the potentiostat 8 and the device thus programmed, tin and lead contained in the sample can be separately detected.
  • a potential at which only the two elements, i.e., tin and lead in the sample can flow out is given by the potentiostat 33 to the flow electrolyte cell 34.
  • the detec tion potential for lead which is dissolved later, is given by the potentiostat 9 to the flow electrolyte cell 11.
  • the circuit of the synchronous motor 58 is switched ON," thereupon, the microswitch 63 goes ON, causing the sample to be supplied to the working electrode 13 of the flow electrolyte cell 10; at the same time the working electrode l3 receives the tin and lead dissolving potential as superimposed with a-c.
  • the two elements i.e., tin and lead, while repeating deposition and dissolution within the working electrode 13, gradually flow out of the flow electrolyte cell 10. Since there is a difference between tin and lead in the velocity of deposition and dissolution, that is, in the electrode reaction velocity, at first tin flows out of the flow electrolyte cell 10 and then lead does so.
  • the concentrations of these elements can be registered by the recorder 56 in a completely separated condition as illustrated in FIGv 5, though the waveforms of these elements may be overlapped as shown in FIG. 4 when a'c is not superimposed.
  • the nitrogen gas cleans the through-hole 44 of the sample-supply disk 38 in the sample injector 7 which has been circulated with the supporting electrolyte.
  • the working electrode 13 of the flow electrolyte cell 10 is first given such a potential that the two elements can be condensed and accumulated at the working electrode 13. Then the potential is switched by Moreover, quantitative analysis using the present invention is free from the effect of temperature. Being proportional to and dependent upon only the quantity of electricity applied, it is highly accurate and easy to the potentiostat 8 to an a-c superimposed potential at perate. which the two elements can be dissolved.
  • the device according to the present invention
  • the invented device may be said to be on the same level of capacility as atomic absorptiometry, but when it comes to the measuring range it has an outstanding feature of being able to measure over a wide range from less than PPb to percent under the same conditions. Therefore, if this de vice is utilized for analysis of industrial effluent, data can be collected regardless of whether the plant is operating in full capacity, operating at limited capacity or not operating, with significant variations of effluent concentration. because the device has a wide measuring range,
  • the invention is characterized by a remarkable feature in that it is highly reliable and safe as for example, a process instrument for work-step analysis or water-quality inspection device for field use, which demands long periods of op erations and its ability to condense a sample of trace concentration to such an extent that it can be detected.
  • sample-supply flow path includes a flow electrolyte call as a purification unit, in that the irrelevant substances in the sample can be eliminated and only those relevant to the effluent control or process control can be analyzed and measured.
  • the invention is unique and advantageous in that, with a programcontroller linked to the sample injector, or to the sample injector and the potentiostat for a flow electrolyte cell on the supporting electrolyte-discharing side of the injector, this flow electrolyte cell combination may be utilized as the chromatography cell, or as the detector cell, resulting in a number of industrial advantages such as laborsaving through automation of device, more accurate and easy detection and analysis of trace quantities of substances in the sample to be analysed.
  • the invention includes other configurations, arrangements and applications, such as for example, wherein: (l) following the sample injector, flow electrolyte cells are arranged in parallel, and solutions are charged at a definite proportion to find the concentration of the refer ence solution by one flow electrolyte cell and the concentration of references solution containing an element to be detected, by another flow electrolyte cell; thus, by measuring electrically the difference between the two results, the concentration or concentration change of the element can be found from the quantity of electricity thus measured; or, (2) following the sample injector, a number of flow electrolyte cells may be arranged for fractional collection and adjustment of a sample; thus the invention can be utilized as a means of bringing substances of different oxidized degrees to a single oxidized degree.
  • the invention may be applied as means of adjusting the concentration of an unstable compound like bromine water or as means of generating an organic radical, which generates monoanion radical through electrolytic reduction of anthraquinone.
  • the device of the present invention has the merit and advantage of being versatile in application and structure.
  • a detector system for detecting impurities in water comprising:
  • first flow electrolyte cell means coupled to said supply means for purifying said supporting electrolyte, said first cell means including a casing and a potentiostat means;
  • c sample injector means including a sample reservoir coupled to said first cell means for injecting a sample containing said impurities into said system;
  • At least two additional flow electrolyte cell means including a second cell means coupled to said sample injector means and a third cell means coupled to said second cell means, said second and third cell means each including a casing and potentiostat means;
  • each said casing includes an auxiliary electrode and the depolarizer electrolyte flows through said casing to contact said auxiliary electrode;
  • f recorder means coupled to the potentiostats of said at least two additonal cell means for recording the output thereof, the output of said potentiostats being indicative of the amount of said impurities in said sample.
  • the detector of claim 1 further including a programcontroller means coupled to said sample injector means and the potentiostat of said second cell means for controlling the flow through said sample injector means and for controlling the potential of said potentiostat.
  • said switch circuit includes a variable resistor having a plurality of predetermined resistances.
  • said program con troller means includes a plurality of cam operated switches and a motor means for driving said cam.
  • sample injector means includes a flow electrolyte purification cell having a potentiostat for removing impurities other than said impurities which are detected from said sample.
  • the detector of claim I wherein the supply means and said sample reservoir are connected to a nitrogen gas-supply means for dispelling dissolved oxygen therein; and the sample injector means is connected to said nitrogen gas-supply means for forcing out any residual sample solutions and electrolyte thereinv 10.
  • said sample injector means injects the sample into the flow of supporting electrolyte.
  • said injector means comprises first, second, and third disks, said sec- 0nd disk being positioned between said first and third disks and rotatable with respect thereto wherein each disk has a plurality of aligned holes therein such that a sample is injected from said sample supply means into a hole in said second disk and when said second disk is rotated a predetermined amount of said sample is ejected from said hole into said supporting electrolyte.

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WO1995019566A1 (en) * 1994-01-13 1995-07-20 Buckman Laboratories International, Inc. A method and apparatus for controlling the feed of water treatment chemicals using a voltammetric sensor
US20040040842A1 (en) * 2002-09-03 2004-03-04 King Mackenzie E. Electrochemical analytical apparatus and method of using the same
US20050067304A1 (en) * 2003-09-26 2005-03-31 King Mackenzie E. Electrode assembly for analysis of metal electroplating solution, comprising self-cleaning mechanism, plating optimization mechanism, and/or voltage limiting mechanism
US20050109624A1 (en) * 2003-11-25 2005-05-26 Mackenzie King On-wafer electrochemical deposition plating metrology process and apparatus
US20050208670A1 (en) * 2004-03-22 2005-09-22 Wittenberg Malcolm B Detection of mercury in biological samples
US20050224370A1 (en) * 2004-04-07 2005-10-13 Jun Liu Electrochemical deposition analysis system including high-stability electrode
US20050247576A1 (en) * 2004-05-04 2005-11-10 Tom Glenn M Electrochemical drive circuitry and method
US20060102475A1 (en) * 2004-04-27 2006-05-18 Jianwen Han Methods and apparatus for determining organic component concentrations in an electrolytic solution
US7435320B2 (en) 2004-04-30 2008-10-14 Advanced Technology Materials, Inc. Methods and apparatuses for monitoring organic additives in electrochemical deposition solutions
US20080251108A1 (en) * 2004-09-17 2008-10-16 Kurita Water Industries Ltd. Sulfuric Acid Recycling Type Cleaning System and a Sulfuric Acid Recycling Type Persulfuric Acid Supply Apparatus
CN104458872A (zh) * 2014-12-17 2015-03-25 中国计量学院 一种测量水中重金属离子的装置

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JPS5292793A (en) * 1976-01-30 1977-08-04 Agency Of Ind Science & Technol Quantitative analysis apparatus for metals by electrolysis
JPS60207047A (ja) * 1984-03-31 1985-10-18 Mitsui Eng & Shipbuild Co Ltd 電量分析装置

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