An Environmental Automatic Monitoring System for Heavy Metals

Abstract

An automatic monitoring system was developed for simultaneous determination of trace zinc, cadmium, lead, copper, iron and arsenic in environmental aqueous media using electrochemical stripping voltammetry. The sensor was mercuryfilm silver-based electrode. With a potentiostat, several pumps and valves controlled by computer, the system realized in-situ real-time detection of the six heavy metal ions mentioned above without manual operation. Quantitative heavy metals analysis at parts-per-billion level was performed by standard addition method. One measurement can be completed in 20 min with only 10 ml sample.

Detection of sub-ppm traces of aqueous heavy-metal ions using micro-electro-mechanical beam resonators

“…Traditionally, to detect and avoid such contaminations, water samples are collected and transported to central laboratories for analysis. Most of the current water-monitoring techniques are based on atomic absorption spectroscopy and mass spectrometry [3,4]. Such techniques require very bulky and powerinefficient equipment for field work and require extremely time-consuming, costly and labor intensive procedures.…”

“…Such techniques require very bulky and powerinefficient equipment for field work and require extremely time-consuming, costly and labor intensive procedures. Therefore, low-cost, portable and easy to use ultra-sensitive sensors for the direct measurement of heavy-metal ions in water sources are of great interest [3][4][5]. Currently, the only available analytical technique suitable for on-site applications is anodic stripping voltammetry which is a very sensitive electrochemical technique [3].…”

“…Therefore, low-cost, portable and easy to use ultra-sensitive sensors for the direct measurement of heavy-metal ions in water sources are of great interest [3][4][5]. Currently, the only available analytical technique suitable for on-site applications is anodic stripping voltammetry which is a very sensitive electrochemical technique [3]. In this technique heavy-metal ions are first deposited on a platinum working electrode at a cathodic potential (preconcentration).…”

“…The position of each peak corresponds to the redox potentials of the respective heavy metal and the height of each peak is proportional to the concentration of the associated heavy-metal ion. Sensitivities in the order of a few ppb (10-100 nM) can be achieved using this technique [3][4][5]. However, such systems typically require integration of sophisticated mercury electrodes, Ag/AgCl reference electrodes and platinum counting electrodes, making them inconvenient and costly to fabricate and miniaturize using solid-state electronic micro-fabrication technologies [4,5].…”