Opto-electrochemical based dual detection of heavy metal compounds using a novel flow cell

An efficient sensing system that detects heavy metal compounds, by employing opto-electrochemical based dual detection technique, has been successfully developed. A novel microfluidic flow cell consisting of an inlet and outlet port with a reservoir volume of 25 μl was designed and fabricated using acrylic material. An electrochemical sensor with gold (Au) interdigitated electrodes (IDE) on a glass substrate was used for the electrical impedance spectroscopy (EIS) of various heavy metal compounds. EIS performed on cadmium sulfide (CdS) and mercury sulfide (HgS) yielded picomolar (pM) concentration detection levels. Selective detection of heavy metal compounds was made possible based on optical signals produced in the Raman emission spectra. The response of this dual detection sensing system is analyzed and presented in this paper.