Routine Monitoring of Trace Arsenic in Water by Lab-on-a-chip Technology: a Preliminary Study

Abstract

Water contamination by Arsenic poses a serious risk for human health, due to its manifold toxic effects. The concern is mainly for drinking water, regarded as the most imperative route of Arsenic exposure to human beings. The maximum concentration limit for Arsenic in drinking water was fixed by World Health Organisation (WHO) at 10 µg L-1 but in many developing nations it is increased to 50 µg L-1 due to economic constraints to detect lower concentrations. In this scenario, the design of an affordable Arsenic sensor, for routine monitoring of water, is crucial. The answer to these requirements can be the lab-on–a-chip technology applied to a microfluidic device. Available detection methods for Arsenic are investigated, focusing on their potential application on a portable monitoring device: among them a colorimetric method, based on Rodamine B as indicator, and chronopotentiometry were selected as suitable for the required purpose. Preliminary laboratory tests were aimed to determine the limit of Arsenic concentration detectable by both the methods; the lower value of 1 µg L-1 was detected by chronopotentiometry, in good agreement with the required resolution of the measurement. Moreover, a process optimization adapted the method for the microfluidic technology. Obtained results point out the new developing lab-on-a-chip technology as good candidate to address the need for a capillary and frequent monitoring of Arsenic contamination of water by an easy and cheap portable device.