Automated determination of cadmium and lead in whole blood by computerized flow potentiometric stripping with carbon fibre electrodes

✍ Scribed by Lena Almestrand; Daniel Jagner; Lars Renman

• Publisher: Elsevier Science
• Year: 1987
• Tongue: English
• Weight: 624 KB
• Volume: 193
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/s0003-2670(00)86139-5

✦ Synopsis

A sample pretreatment involving only the dilution (1 + 19) of two 0.2-0.4 ml sample aliquots with 0.5 M hydrochloric acid, with a standard addition to one of the aliquots, precedes the injection of each sample. The computer-controlled flow system used automatically executes a pre-programmed number of cycles on each sample pair before presenting the final result. Each cycle, which has a duration of 80 or 135 s for lead(I1) and cadmium(II), respectively, involves the display of the derivative stripping signal on a printer/plotter and integration of the stripping peaks generated. For lead(II), stripping is done in 0.5 M hydrochloric acid, which eliminates interferences from copper, though at the cost of a relatively high stripping rate, compared to the 5 M calcium chloride used for cadmium(I1) The flow cell consists of a silver chloride-lined silver tube which acts as both reference and counter electrode, and a disposable carbon-fibre working electrode mounted in a PVC tube, which normally will operate for 50-200 cycles. The method was verified for whole blood reference standards and by comparison with results obtained by atomic absorption spectrometry.