Microprocessor-controlled instrument for the simultaneous generation of square wave, alternating current, direct current, and pulse polarograms

Abstract

With a square wave superlmposed onto a staircase potential ramp the technlque of square wave polarography (voltammetry) is shown to be capable of produclng data whlch enables square wave, DC, AC, pulse, and other polarograms (voltammograms) to be obtained from a single experlment. The method of data acqulsitlon and large number of methods of data presentation possible hlghllght the close slmllarltles of many polarographlc techniques rather than dlfferences more normally discussed in the literature. The ablllty to obtain the response for a range of polarographlc technlques from a single experlment with mlcroprocessor-based Instrumentation leads to a hlghly efflclent approach to analytlcal and klnetlc lnvestigatlons employing polarographlc and voltammetrlc met hods.The electrochemical technique of square wave polarography, SWP, was first reported by Barker and co-workers (1,2) at a dropping mercury electrode, DME. The technique was reviewed in 1975 by Sturrock and Carter (3) who noted that applications had been limited by the lack of good commercial instrumentation at reasonable cost. However, even by 1975, developments in theory and instrumentation in a limited number of laboratories, coupled with detailed data presenting analytical applications, indicated that square wave polarography should be an electroanalytical method of great advantage. Ramaley and Krause presented the theory for reversible systems (4) and examined the analytical usefulness of square wave voltammetry, SWV, at a hanging mercury drop electrode (HMDE) (5). The technique was then reexamined by Christie et al. who provided a more comprehensive theory for reversible systems including its application at the DME (6, 7). The only distinction made between SWP and SWV above is that the former is restricted to use of the DME, the latter being the more general term.In 1979, Boudrea and Perone stated that SWV may replace conventional differential pulse polarography, DPP, for quantitative determinations of electroactive species in solution (8). Recent editorial comment in the journal, ANALYTICAL CHEMISTRY, focused attention on this prospect (9). These editorial remarks now have catalyzed new activity in SWV as in the last year or so a great resurge in interest has emerged. Thus, new theory, applications, instrumental designs, and the appearance of modern commercially available instrumentation have been forthcoming in a very short period of time as perusal of ref 10 to 20 will indicate.The sensitivity of both square wave and differential pulse voltammetric techniques is excellent with detection limits in the to M concentration range (1-21). The main advantage claimed for SWV over DPP appears to be the possibility of using high scan rates which leads to a reduction in analysis time by allowing experiments to be performed on Present address:

Elevating Chemistry Research with a Modern Electronics Toolkit

“…Eventually, microprocessors were implemented in chemical laboratory instruments, such as differential titrator, 19 spectrofluorometer, 20 potentiostat, 21 potentiometric detection system, 22,23 polarograph, 24,25 liquid chromatograph, 26 chemiluminescence detector, 27 digital analytical balance, 28,29 and function generator. 30,31 The implementation of microprocessors for controlling the instrument and/or data acquisition 32−36 was indeed a breakthrough that improved the instrumentation for chemistry research and also enhanced the quality of experimental data. Moreover, some instruments, such as atomic emission spectrometer, 37 mass spectrometer, 38 and potentiometric detector for flow injection system, 39 were equipped with microcomputers for their control and/or data acquisition.…”

“…The development of integrated circuits (ICs) sowed the seeds to the birth of chip-sized microprocessors and microcontrollers in the late 1960s and early 1970s. , The introduction of chip-sized devices did not just reduce the overall size of a computational device but also facilitated their mass production and widespread use. Eventually, microprocessors were implemented in chemical laboratory instruments, such as differential titrator, spectrofluorometer, potentiostat, potentiometric detection system, , polarograph, , liquid chromatograph, chemiluminescence detector, digital analytical balance, , and function generator. , The implementation of microprocessors for controlling the instrument and/or data acquisition − was indeed a breakthrough that improved the instrumentation for chemistry research and also enhanced the quality of experimental data. Moreover, some instruments, such as atomic emission spectrometer, mass spectrometer, and potentiometric detector for flow injection system, were equipped with microcomputers for their control and/or data acquisition.…”

Enhancing Square Wave Voltammetry Measurements via Electrochemical Analysis of the Non-Faradaic Potential Window

“…21 However, EIS measurements can be timeconsuming and require additional hardware. AC voltammetry techniques have similarities to pulsed DC techniques, such as SWV, 22 with it being possible to form a square wave pulse from a combination of sine waves. 23 Through Fourier transformation and modeling of this response, it is possible to extract information on R and C, in addition to information on the faradaic process; 23 however, the analysis of data is not as immediately intuitive and requires simulation.…”

Multimode triple sampling polarography in the study of amalgamation and sphericity effects at the static mercury drop electrode

“…When computerized polarographs are employed, the current samplings can be stored individually and the flexibility in the use of the data is improved. This has been discussed by Anderson and Bond in a paper on the generation of ac, dc, pulse, and square wave polarograms from polarographic square wave recordings (8).…”