On-chip detection and quantification of soap as an adulterant in milk employing electrical impedance spectroscopy

This study analyses the possibility of on-chip detection and quantification of soap as an adulterant into cow milk by employing Electrical Impedance Spectroscopy (EIS). This technique provides a simple, rapid, precise and cost-effective platform for milk quality monitoring. Variation of electrical parameters including the impedance, capacitance, conductance and current for 0.1%, 0.3%, 0.5%, 0.7% and 0.9% (w/w) of soap adulteration in milk are analyzed. The capacitance, conductance and current are observed to increase whereas impedance has been found to decrease with increasing soap content in the milk. Finally, the coefficient of sensitivity is extracted for the soap-adulterated milk samples and explained in terms of the measured conductance values.