The development of a fully computerized system for sampled d.c. polarography with standard interfacing
✍ Scribed by M. Bos
- Publisher
- Elsevier Science
- Year
- 1976
- Tongue
- English
- Weight
- 619 KB
- Volume
- 81
- Category
- Article
- ISSN
- 0003-2670
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✦ Synopsis
A complete system, based on the online PDP-11 computer (Digital Equipment Corporation) was developed for computerized sampled d.c. polarography with direct digital control. The system includes compensation of ohmic cell resistance and processing of the polarographic data. The accuracy of the system in the determination of the various polarographic parameters is: diffusion current f 2 %, half-wave potential ?. 2 mV, and slope oi the log plot I 2 mV.
Process computers have been used to control [ 1, 21 and evaluate [3) stationary electrode polarography, and thr? idea of programming a digital online computer to perform sampled d.c.-polarography is not new [4 1. However, no reports about this subject have appeared in the literature, and important questions with regard to the accuracy and sensitivity that ran be obtained have remained unanswered. This investigation was started to answer these questions, and to evaluate different methods of processing polarographic data with respect to speed, accuracy and the amount of information cstractcd from the data. Multiparametric curve-fitting methods were chosen for the data processing, as these methods are also suitable for polaro&Taphic \vaves which have the diffusion plateau obscured, a rather common situation in polarographic analysis which greatly limits the possibilities of conventional polarography.
Finally this study was also undertaken to obtain a rough estimate of the total effort in the development of a fully computerized analytical method.
EXPERIhl ENTAL
Chemicais
Cadmium chloride (Analar). potassium chloride (Merck, reagent grade) and mercury (DRIJFHOUT, Polarographic grade) were used as received. Tetraethylammonium perchlorate (TEAP; Eastman) was recrystallized from ethanol (Merck, reagent grade) and dried in vacua at 40 "C.