A smart-phone-based electrochemical platform with programmable solid-state-microwave flow digestion for determination of heavy metals in liquid food

Abstract

This work introduces an inexpensive and user-friendly electrochemical platform for heavy metal determination in liquid food. Smart-phone connectivity, solid-state-microwave flow digestion and nano-Au-modified electrode are synchronously studied. A smart phone is adopted as the information terminal for universal purposes. A solid-state-microwave digestion device is developed to provide programmable digestion for liquid food in a digestion path. Microwave power curve and flow rate in digestion are studied and optimized. A nano-Au-modified electrode, as well as a homemade potentiostat and other electrodes, is used as a tool for electrochemical analyses. Behaviors of this method are evaluated with electrical measurement and stripping voltammetry. This method is used for sensing Cd²⁺, Pb²⁺ and Hg²⁺ in cow milk, orange juice and apple juice. It provides a sensitive response to ≥2 μg L^-1 target ion, and shows satisfying stability and good accuracy in a task up to 72 h.

Keywords: Electrochemical sensor; Liquid food; Solid-state microwave; Wireless connectivity.