SCREEN-PRINTED ULTRAMICROELECTRODE ARRAYS FOR ON-SITE STRIPPING MEASUREMENTS OF TRACE-METALS

The properties and advantages of mercury-coated screen-printed electrode arrays for on-site stripping analysis of trace metals are described. These disposable composite electrodes are fabricated by a combination of thick-film printing and laser machining technologies, and offer a stripping performance comparable with that of traditional stripping electrodes. Scanning electron microscopy illustrates the attractive microdisk and interelectrode dimensions, which offer a non-linear diffusional flux during long stripping experiments. The stripping performance is not compromised by placing non-deaerated/quiescent sample drops on the strip, as desired for field monitoring of trace metals. Various experimental variables have been optimized to yield low detection limits (e.g. 0.1 mug/l lead for 4 min deposition) and good precision (e.g. relative standard deviation of 4.7% for ten repetitive measurements). The applicability to assays of drinking water and wine is illustrated.