Development and validation of a novel HPLC-PDA method for the detection of preservatives in milk

In this research paper we introduce and validate an enhanced method for the detection of sodium benzoate and potassium sorbate in milk. Sodium benzoate and potassium sorbate are widely employed as preservatives in the food industry; however, their use to restrict microbial growth in milk is prohibited. Our novel method achieved performance indicators in accordance with the criteria outlined by the International Conference on Harmonization. The extraction process involved sample dilution in acetonitrile (1:1 v/v), followed by subsequent centrifugation, filtration and injection into a high-performance liquid chromatography system with a photodiode array detector. The detection and quantification limits for sodium benzoate were determined to be 0.204 and 0.618 mg/l, respectively, while for potassium sorbate, these values were 0.108 and 0.328 mg/l, respectively. The accuracy ranged from 92.67 to 99.53%, with pH 4.0 selected as the optimal condition to ensure adequate resolution of the preservatives. The proposed method stands out due to its simplicity and speed, using a single reagent in modest quantities during sample preparation. This approach reduces toxicity and minimizes the production of pollutants during disposal. Furthermore, the novel method requires less raw material and energy consumption, aligning with the principles of green chemistry. Its lower quantitation limits render it more sensitive when compared to the official analysis. The preparation, separation, and simultaneous detection of these preservatives in a short period of time make this method suitable for integration into industrial workflows.