SCREEN-PRINTED STRIPPING VOLTAMMETRIC POTENTIOMETRIC ELECTRODES FOR DECENTRALIZED TESTING OF TRACE LEAD

The utility of screen-printed electrodes for stripping voltammetric and potentiometric measurements of trace metals have been evaluated toward their exploitation of single-use decentralized testing. The mercury-coated screen-printed carbon electrodes, on a plastic strip, perform In a manner comparable to conventional hanging mercury drop and mercury-coated glassy carbon electrodes. Well-defined peaks are thus obtained for microgram per liter (ppb) concentrations of heavy metals following very short preconcentration times. The morphology of the resulting mercury film, as characterized by scanning electron microscopy, facilitates trace measurements in unstirred and nondeaerated solutions, as desired in many decentralized applications. Reproducible measurements of ppb lead in 100-mu-L drops are thus obtained. A detection limit of 30 ng/L (ppt) lead Is estimated following 10-min preconcentration. Convenient quantitation of lead in urine and drinking water samples is accomplished. Besides having great potential for single-use decentralized clinical or environmental testing, a highly stable response of the screen-printed electrode makes them very attractive for routine, low-cost, centralized operations.