Detection of Na2S2O4 bleaching agent contaminated in bean sprout using an electronic nose

Sodium hydrosulfite (Na 2 S 2 O 4 ) is widely considered as the most common bleaching agent for bean sprouts. However, this chemical is harmful to human health, especially to the digestive system and metabolism. The present work aims to develop an efficient and ecologically-friendly method for the detection of sodium hydrosulfite using an electronic nose based on metal oxide semiconductor gas sensors. An array of different eight gas sensors was used to measure sodium hydrosulfite volatile as present in the bleached sprouts. The signals from gas sensors were collected and analyzed using the Principal Component Analysis (PCA) via a monitoring computer. From the PCA, the volatility data can be clearly distinguished into two groups: (i) bleached and (ii) non-bleached as divided by the PC1 axis. Moreover, PC1 is capable of generating a calibration curve for quantitative analysis. Our method is demonstrated to be an effective performance for detecting sodium hydrosulfite with the sensitivity as low as 0.01 g/L.