Optimized HPLC-UV Methodology for the Simultaneous Quantification of Multiple Preservatives in Jordanian Yogurt Products

A method based on high-performance liquid chromatography with a UV detector (HPLC-UV) was developed for the simultaneous determination of sorbic acid, benzoic acid, and natamycin in yogurt. The method does not require time-consuming, labor-intensive pre-treatment processes or complicated procedures. Using a C18 150 mm × 4.6 mm, 3.0 µm column (Roc) at 25 °C, the target analytes were separated within 5 minutes with high sensitivity and selectivity. The mobile phase consisted of trifluoroacetic acid (0.1%) in water containing 100 mM sodium acetate, trifluoroacetic acid (0.1%) in acetonitrile, and trifluoroacetic acid (0.1%) in tetrahydrofuran, in a ratio of 70:20:10 (v/v). Using this mobile phase as an extraction mixture, recoveries ranged from 83.0% to 110.2% at spike levels between 2.5 µg/kg and 80.0 µg/kg. The relative standard deviations (RSDs) for these recoveries were below 10%. Intra-day precision and inter-day precision varied from 5.3% to 6.7% and 7.6% to 9.2%, respectively. Additionally, the limits of detection (LOD) were between 0.24 and 0.61 mg/L, and the limits of quantification (LOQ) ranged from 0.80 to 2.0 mg/L for sorbic acid, benzoic acid, and natamycin. Principal component analysis revealed that yogurt type had the greatest positive influence on preservative concentration, while the weight or volume of the yogurt package had the greatest negative influence.