Emerging Electrochemical Sensor Based on Bimetallic AuPt NPs for On-Site Detection of Hydrogen Peroxide Adulteration in Raw Cow Milk

A long history about milk adulteration with hydrogen peroxide (H2O2) is extensively reported worldwide. According to fast degradation of H2O2 in raw cow milk, the detection of H2O2 is very challenging. In this study, a highly sensitive non-enzymatic electrochemical sensor has been developed for detecting H2O2 in adulterated milk. The bimetallic gold-platinum nanoparticles (AuPt NPs) are used as electrocatalysts to selectively enhance electrochemical signal of H2O2. The screen-printed carbon electrode (SPCE) modified with proper Au:Pt molar ratio of AuPt alloy NPs exhibits good electrocatalytic activity toward electro-reduction of H2O2 adulterated in both ultra-high temperature processing (UTH) and raw milk samples. This sensor holds great potential for determination of H2O2 in UHT milk. The good sensitivity and low limit of detection (LOD) are calculated to be 152.9 mu A mM(-1) cm(-2) and 4.8 mu M, respectively. In addition, this sensor shows good reproducibility (%RSD < 4%) with long-term stability upon 4 months. Applicability of our sensor coupled with portable electrochemical analyzer-simulator is demonstrated by performing analysis of H2O2 adulteration in raw cow milk sample. The linear response was found in the range of 2.5 to 5000 mu M with sensitivity and low LOD of 155.5 mu A mM(-1) cm(-2) and 2.5 mu M, respectively. This good sensing efficiency arises from the synergistic electrocatalysis effect of bimetallic AuPt NPs on SPCE surface. This finding provides alternative practical method with high sensitivity for on-site and real-time monitoring of H2O2 adulteration in raw milk.

Automated summary

A highly sensitive non-enzymatic electrochemical sensor has been developed for detecting H2O2 adulteration in milk. The sensor exhibits good sensitivity and low limit of detection, as well as long-term stability and reproducibility.