A Portable Integrated Electrochemical Sensing System for On‐Site Nitrite Detection in Food

Abstract Ensuring an appropriate nitrite level in food is essential to keep the body healthy. However, it still remains a huge challenge to offer a portable and low‐cost on‐site food nitrite analysis without any expensive equipment. Herein, a portable integrated electrochemical sensing system (IESS) is developed to achieve rapid on‐site nitrite detection in food, which is composed of a low‐cost disposable microfluidic electrochemical patch for few‐shot nitrite detection, and a reusable smartphone‐assisted electronic device based on self‐designed circuit board for signal processing and wireless transmission. The electrochemical patch based on MXene‐Ti 3 C 2 T x /multiwalled carbon nanotubes‐cyanocobalamin (MXene/MWCNTs‐VB 12 )‐modified working electrode achieves high sensitivity of 10.533 µA m m −1 and low nitrite detection limit of 4.22 µ m owing to strong electron transfer ability of hybrid MXene/MWCNTs conductive matrix and high nitrite selectivity of VB 12 bionic enzyme‐based ion‐selective layer. Moreover, the portable IESS can rapidly collect pending testing samples through a microfluidic electrochemical patch within 1.0 s to conduct immediate nitrite analysis, and then wirelessly transmit data from a signal‐processing electronic device to a smartphone via Bluetooth module. Consequently, this proposed portable IESS demonstrates rapid on‐site nitrite analysis and wireless data transmission within one palm‐sized electronic device, which would pave a new avenue in food safety and personal bespoke therapy.