A Highly Sensitive Electrochemical Sensor for Capsaicinoids and Its Application in the Identification of Illegal Cooking Oil
Wenjing Lyu,
Min Ding,
Ying Zhou,
Mengdan Jiang,
Yanru Li,
Yanxiang Ding,
Zhong Zhang,
Xue Wei,
Xiaoqing Zhang
Affiliations
Wenjing Lyu
Key Laboratory of Clinical Laboratory Diagnostics, Ministry of Education of China, School of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
Min Ding
Key Laboratory of Clinical Laboratory Diagnostics, Ministry of Education of China, School of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
Ying Zhou
Key Laboratory of Clinical Laboratory Diagnostics, Ministry of Education of China, School of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
Mengdan Jiang
Key Laboratory of Clinical Laboratory Diagnostics, Ministry of Education of China, School of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
Yanru Li
Key Laboratory of Clinical Laboratory Diagnostics, Ministry of Education of China, School of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
Yanxiang Ding
The First Clinical College, Chongqing Medical University, Chongqing 400016, China
Zhong Zhang
Material Evidence Identification Center, Chongqing Public Security Bureau, Chongqing 400016, China
Xue Wei
Key Laboratory of Clinical Laboratory Diagnostics, Ministry of Education of China, School of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
Xiaoqing Zhang
Key Laboratory of Clinical Laboratory Diagnostics, Ministry of Education of China, School of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China
Capsaicinoids, mostly from chili peppers, are widely used in daily life. Capsaicinoids are considered to be markers for the identification of illegal cooking oil (ICO), which is a serious threat to public health. The identification of capsaicinoids can help reveal food-related fraud, thereby safeguarding consumers’ health. Here, a novel and ultrasensitive method was established with a signal amplification strategy for the detection of capsaicinoids. AuNPs@Fe3O4 nanocomposites were functionalized with 4-aminothiophenol (4-atp). After diazotization, 4-atp on AuNPs@Fe3O4 reacted with capsaicinoids and formed capsaicinoids-azo-atp-AuNPs@Fe3O4. Ultimately, capsaicinoids-azo-atp-AuNPs@Fe3O4 was dropped onto the surface of a screen-printed carbon electrode (SPCE) and detected via the differential pulse voltammetry (DPV) method. AuNPs@Fe3O4 nanocomposites increased the specific surface area of the electrode. Moreover, the diazotization–coupling reaction enriched the analytes on the electrode surface. Liquid–liquid extraction was used for sample pretreatment. Under a pH value of 9.0 and concentration of 0.20 mol/L for the supporting electrolyte, the linearity of capsaicinoids in ICO is from 0.10 to 10.00 ng/mL, and the limit of detection (S/N = 3) is 0.05 ng/mL. This method is ultra-sensitive, reliable, and cost-effective for the detection of capsaicinoids. Herein, this method provides a promising tool for the identification of ICO.
