Determination of Sodium Benzoate in Liquids Using a Piezoelectric Sensor Modified by a Molecularly Imprinted Polymer

A piezoelectric sensor was modified by a selective material on the basis of a molecularly imprinted polymer (MIP) with sodium benzoate (E211) imprints. The values of the imprinting factor and the selectivity coefficient of the MIP-E211-sensor were calculated to assess its ability to recognize target molecules. The results of the determination of sodium benzoate in liquids by the piezoelectric sensor and by HPLC were compared. The relative standard deviation of the results of the determination did not exceed 10%. The limit of detection for sodium benzoate using the MIP-sensor was 2 mg/L. The absence of a matrix effect on the analytical signal of the MIP-based piezoelectric sensor was revealed using the standard addition method. The concentration of sodium benzoate in soft drinks (Yes! Fruit, Chai Kholodnyi Zelenyi (Cold Green Tea), Aqua Minerale “Mint Lyme”) was determined using the MIP-based piezoelectric sensor.