Real-time quantification for sulfite using a turn-on NIR fluorescent probe equipped with a portable fluorescence detector

Sulfur dioxide and its derivative sulfite widely existed in air, water as the environment pollutant. Sulfite is also commonly used as preservative and additive in fresh fruits, vegetables, wines and pharmaceutical materials. Due to sulfite is closely related with human diseases, it is very urgent for the sensitive and rapid quantification of sulfite in various samples. In our study, a turn-on near infrared (NIR) fluorescent probe (MDQ) was developed for sulfite detection based on a Michael addition reaction, with high sensitivity (LOD 4.16 nmol/L), selectivity and fast response time (400 s). Using MDQ, a quantify method for sulfite in traditional Chinese medicines (TCMs) was developed with the advantages of high precision, accuracy and convenient operation. Furthermore, according to the photophysical property of MDQ, a portable fluorescence detector is designed to quantify sulfite for TCMs and surface water in Dalian city of China. Therefore, the developed fluorescent probe MDQ and portable fluorescent detector as a rapid inspection instrument were successfully used to real-time monitor the sulfite in various complex samples.