Field Evaluation of an Electrochemical Probe forin SituScreening of Heavy Metals in Groundwater

Abstract

The use of an electrochemically based probe for in situ determination of heavy metals in groundwater is described. The in situ probe, consisting of a microlithographically fabricated iridium ultramicroelectrode array sensor (UMEA), a custom-built miniaturized potentiostat and microcontroller, is connected to a laptop computer for control and data acquisition. The utility of this probe for rapid on-site screening of heavy metals was shown by conducting a proof-ofconcept field demonstration at a metals contaminated landfill site located at Hanscom Air Force Base in Bedford, MA. Using the electroanalytical technique of square wave anodic stripping voltammetry (SWASV), the sensor was used to measure both the labile and total pH <2 forms of copper, lead, cadmium, and zinc at the parts-per-billion level. The on-site and in situ measurements were compared to laboratory-based electroanalytical measurements and to contract laboratory U.S. EPA Method 200.7 ICP analysis. The results indicate that in situ electroanalytical measurements of labile metal species are feasible, providing a rough estimation of metals concentrations and trends in their behavior. The in situ and on-site results agree to within an order of magnitude with the laboratory determinations. This study demonstrates that such electroanalytical-based devices may be of value for an initial, rapid, low-cost, screening of heavy metal contaminated sites.

Determination of Selenium(IV) at a Microfabricated Gold Ultramicroelectrode Array Using Square Wave Anodic Stripping Voltammetry

“…We have previously shown that an ideal way to accomplish this is by using microlithographic fabrication technology with standard silicon wafers as the substrate on which to pattern the desired metal UME array [31,32]. The combination of this technology with the fast and sensitive technique of square wave anodic stripping voltammetry (SWASV) [33] has recently been shown to be advantageous for on-site and in-situ environmental detection of several metals [34]. The adaptation of this technology to ASV of Se 0 /Se 4þ on a gold UME array could provide a substantial improvement for onsite rapid analysis for selenium.…”

Sensores eletroquímicos: considerações sobre mecanismos de funcionamento e aplicações no monitoramento de espécies químicas em ambientes microscópicos

“…Sofisticados métodos para "screenprinting" surgem rotineiramente na literatura [43][44][45][46] e a possibilidade de fabricação de microeletrodos isolados ou na forma de "arrays", os quais viabilizam ganho de sensibilidade e abrem perspectivas para monitoramento multielementar 47,48 , impulsionam pesquisas com vistas a aplicações rotineiras dos dispositivos.…”

Effect of the sp2/sp3 Ratio in a Hybrid Nanocarbon Thin Film Electrode for Anodic Stripping Voltammetry Fabricated by Unbalanced Magnetron Sputtering Equipment

“…An Hg electrode has been used as a working electrode for ASV; 2,3 however, Hg has been avoided in recent years because of its toxicity. Therefore, alternative metal electrodes, such as Ir, 4,5 Au, [6][7][8] Ag 9 and Bi, 10 have been investigated. Unfortunately, they did not perform as well as the Hg electrode.…”