Techniques for extending electrode serviceability and useful life in voltametric device

Abstract

This disclosure provides techniques for extending useful life of a reference electrode, as well as a novel voltametric system and measurement cell design and related chemistries. An automated, repeatable-use system features a reference electrode that directly immerses a metallic conductor into an analyte, with electrolytes (e.g., chlorides) used for measurement being separately added and removed for each measurement cycles; the metallic conductor can optionally be left exposed to clean dry air in between measurements. In one implementation, the system can be restricted to application with specific analytes (e.g., ground water) that are known in advance to be free of substances that could degrade reference electrode use or lifetime. Cleaning solutions can optionally be used that would not be practical with conventional (insulated) reference electrode designs. In another embodiment, a measurement cell can be configured to receive separated electrode modules, permitting independent cleaning/removal of the working electrode (or other electrodes).

1 . (canceled) 
     
     
         2 . A measurement cell for use with a voltametric measurement system, the measurement cell comprising:
 a housing defining a chamber, the housing having at least one port for the supply and removal of an analyte;   a working electrode supported by the housing, the working electrode having an electrode surface to contact the analyte within the chamber;   an auxiliary electrode supported by the housing, the auxiliary electrode having an electrode surface to contact the analyte within the chamber;   a half-cell-less reference electrode supported by the housing, the reference electrode having an electrode surface to contact the analyte within the chamber, wherein the electrode surface of the reference electrode comprises at least one of silver or silver chloride; and   an ultrasonic transducer supported by the housing, the ultrasonic transducer positioned relative to the housing and the reference electrode so as to, when actuated, direct ultrasound energy toward the electrode surface of the reference electrode to clean the electrode surface of the reference electrode in between successive voltametric measurements.   
     
     
         3 . The measurement cell of  claim 2 , wherein the electrode surface of the reference electrode comprises at least one of a silver wire or a silver chloride wire. 
     
     
         4 . The measurement cell of  claim 2 , wherein the housing comprises a plastic block. 
     
     
         5 . The measurement cell of  claim 2 , wherein the housing defines a recess to detachably receive the ultrasonic transducer in mating engagement with the housing, the recess and the mating engagement being structured such that ultrasonic energy is directed by the ultrasonic transducer, when actuated, through the chamber and directionally toward the electrode surface of the reference electrode. 
     
     
         6 . The measurement cell of  claim 5 , wherein the recess defined by the housing and a support structure for the ultrasonic transducer each comprise reciprocal threads, wherein the support structure for the ultrasonic transducer is to be screwed into the recess defined by the housing to provide the mating engagement. 
     
     
         7 . The measurement cell of  claim 2 , wherein the housing defines a recess to modularly and detachably receive the reference electrode into engagement with the housing. 
     
     
         8 . The measurement cell of  claim 2 , wherein the measurement cell comprises a sensor to detect a condition of the electrode surface of the reference electrode, the electrode surface of the reference electrode to be cleaned using the ultrasonic energy as a function of the condition. 
     
     
         9 . A measurement system, comprising:
 a measurement cell comprising,
 a housing defining a chamber, the housing having at least one port for the supply and removal of an analyte, 
 a working electrode supported by the housing, the working electrode having an electrode surface to contact the analyte within the chamber, 
 an auxiliary electrode supported by the housing, the auxiliary electrode having an electrode surface to contact the analyte within the chamber, 
 a half-cell-less reference electrode supported by the housing, the reference electrode having an electrode surface to contact the analyte within the chamber, wherein 
 the electrode surface of the reference electrode comprises at least one of silver or silver chloride, and 
 an ultrasonic transducer supported by the housing, the ultrasonic transducer positioned relative to the housing and the reference electrode so as to, when actuated, direct ultrasound energy toward the electrode surface of the reference electrode; 
   a voltametric measurement device to measure concentration of a metal substance using the working electrode, the auxiliary electrode and the reference electrode; and   an electronic control system to actuate the ultrasonic transducer between successive measurement cycles and to drain the measurement cell between successive measurement cycles.   
     
     
         10 . The measurement system of  claim 9 , wherein the electronic control system is to drain the chamber so as to expose the conductor surface of the reference electrode to clean dry air in between ones of the respective measurement cycles. 
     
     
         11 . The measurement system of  claim 9 , wherein the electronic control system is to automatically sequence addition of a preservative into the chamber of between ones of the respective measurement cycles. 
     
     
         12 . The measurement system of  claim 9 , wherein each analyte is in the form of an aqueous sample, and wherein said control system is to automatically initiate and sequence supply and removal of a respective aqueous samples for each of the successive measurement cycles on a calendared basis and is to automatically drain the measurement cell so as to expose the conductor surface to clean dry air in between the successive measurement cycles. 
     
     
         13 . The measurement system of  claim 12 , wherein each aqueous sample comprises water, and wherein the measurement system further comprises an electronically-actuated sample extraction mechanism to intermittently draw water samples from a water supply, control of the electronically-actuated sample extraction mechanism to be sequenced by the electronic control system. 
     
     
         14 . The measurement system of  claim 13 , further comprising circuitry to effectuate a network connection, wherein the electronic control system is further to receive from a remote source, via the network connection, a command for initiation of a measurement cycle, and is to automatically sequence control of the electronically-actuated sample extraction mechanism and the voltametric measurement device, so as to responsively measure the concentration of the metal substance in one of the intermittently drawn samples from the water supply. 
     
     
         15 . The measurement system of  claim 9 , further comprising circuitry to effectuate a network connection and to transmit a measured concentration of the metal substance to a remote destination via the network connection. 
     
     
         16 . The measurement system of  claim 9 , wherein the housing defines a recess to detachably and modularly receive the ultrasonic transducer in mating engagement with the housing, the recess of the housing and the mating engagement being structured such that ultrasonic energy is directed by the ultrasonic transducer, when actuated, through the chamber and directionally toward the electrode surface of the reference electrode. 
     
     
         17 . The measurement system of  claim 16 , wherein the recess defined by the housing and a support structure for the ultrasonic transducer each comprise reciprocal threads, wherein the support structure for the ultrasonic transducer is to be screwed into the recess defined by the housing to provide the mating engagement. 
     
     
         18 . The measurement system of  claim 9 , wherein the housing defines a recess to modularly and detachably receive the reference electrode into engagement with the housing. 
     
     
         19 . The measurement system of  claim 9 , wherein the measurement system comprises a sensor to detect a condition of the electrode surface of the reference electrode, and wherein the control system is to actuate the ultrasonic transducer to clean the electrode surface of the reference electrode using the ultrasonic energy as a function of the condition. 
     
     
         20 . The measurement system of  claim 19 , wherein the sensor is an optical sensor and wherein the control system is to automatically actuate the ultrasonic transducer to clean the electrode surface of the reference electrode using the ultrasonic energy as a function of the condition satisfying a predetermined threshold. 
     
     
         21 . The measurement system of  claim 9 , wherein the measurement system comprises a fluidic transfer mechanism and a reservoir to provide an aqueous source of chlorides, and wherein the electronic control system is to sequence the fluidic transfer mechanism to automatically transfer a volume of the aqueous source of chlorides from the reservoir to the chamber for use during voltametric measurement. 
     
     
         22 . The measurement system of  claim 21 , wherein the aqueous source of chlorides comprises hydrochloric acid. 
     
     
         23 . The measurement system of  claim 21 , wherein the aqueous source of chlorides comprises potassium chloride. 
     
     
         24 . The measurement system of  claim 21 , wherein the reservoir is a first reservoir, wherein the measurement system comprises a second reservoir to provide an aqueous calibration standard, and wherein the electronic control system is to sequence the fluidic transfer mechanism to automatically transfer a volume of the calibration standard from the second reservoir to the chamber and is to calibrate concentration measurement using a spike test. 
     
     
         25 . A measurement system, comprising:
 a measurement cell comprising,
 a housing defining a chamber, the housing having at least one port for the supply and removal of an analyte, 
 a working electrode supported by the housing, the working electrode having an electrode surface to contact the analyte within the chamber, 
 an auxiliary electrode supported by the housing, the auxiliary electrode having an electrode surface to contact the analyte within the chamber, 
 a half-cell-less reference electrode supported by the housing, the reference electrode having an electrode surface to contact the analyte within the chamber, wherein the electrode surface of the reference electrode comprises at least one of silver or silver chloride, and 
 an ultrasonic transducer supported by the housing, the ultrasonic transducer positioned relative to the housing and the reference electrode so as to, when actuated, direct ultrasound energy toward the electrode surface of the reference electrode; 
   a fluidic transfer mechanism;   a reservoir to provide an aqueous source of chlorides;   a voltametric measurement device; and   an electronic control system to control supply of an analyte to the measurement chamber,
 the fluidic transfer mechanism to automatically transfer a volume of the aqueous source of chlorides from the reservoir to the chamber, 
 control the voltametric measurement device to measure concentration of a metal substance using the working electrode, the auxiliary electrode, the reference electrode, and the volume of the aqueous source of chlorides, and 
 control actuation of the ultrasonic transducer between successive measurement cycles and to drain the measurement cell between successive measurement cycles.