Electrochemical Detection of Salicylic Acid in Pickled Fruit/Vegetable and Juice

Salicylic acid (SA) is used as a preservative in food and a biocide in some consumer products. However, in some countries its use is prohibited. The main problem in the electroanalytical determination of SA is the formation of a passive film during the electro-oxidation of SA. To alleviate the passivation during SA measurement, the experiment was conducted by screen-printed carbon electrode (SPCE). While, differential pulse voltammetry (DPV) was essential for oxidation process to provide better sensitivity. Under conditions of optimized pH and electrolyte concentration, we have calibrated SA in the range of 0.001–0.2 mM, with and LOD of 1.6 μM. The relative standard deviation of the sensor responses to 40 µM and 100 µM SA (n = 20) was < 3%. SA recoveries in samples such as pickled green mustard, pickled bamboo shoots, pickled mango, pickled lime, pickle ginger and apple juice were found to be in the range of 84–113%.