Analytical validation and comparative study of HPLC, spectrophotometric and titration method for determination of benzoic acid in food products

Abstract

The objective of this work was to validate the analytical method and evaluate the detection limit of benzoic acid in food with using chromatographic, spectroscopic and titration techniques. An experiment was carried out by spiking benzoic acid in tomato ketchup and benzoic acid was extracted in methanol and analyzed by HPLC, UV-visible spectrophotometer and titration method. In HPLC method S/N ratio of standard benzoic acid was observed 3: 1 at 1 μg/mL concentration and 10: 1 at 4 μg/mL concentration of benzoic acid, Hence LOD and LOQ of benzoic acid were 1 and 4 μg/mL, respectively. The coefficient of correlation value (r) was 0.9998 for standard benzoic acid in concentration range of 10, 50, 100, 500 and 1000 μg/mL. The recovery of spiked standard benzoic acids in tomato ketchup sample was observed in the range of 98.83-100.47 %. The λmax of standard benzoic acid was observed at 230 nm. In spectrophotometric method, coefficient of correlation value r = 0.9995 for standard benzoic acid in the range of 1, 3, 5, 8 and 10 μg/mL concentration was observed. Recovery of spiked standard benzoic acid in ketchup sample was observed between 97.25-99.54 %. With using titration technique, determined LOD was ≥ 50 μg/mL. Coefficient of correlation value r = 0.9993 was obtained for standard benzoic acid at 5 level calibration concentration in the range of 50, 100, 150, 200 and 250 μg/mL recovery of standard benzoic acid in spiked sample was between 97.48-98.98 %. This work indicates the selection of analytical method for benzoic acid determination as per the required detection limit (DL) in food products. RP-HPLC method can be used for detection limit of benzoic acid in the range of 1 μg/mL to above concentration. UV-visible spectrophotometric method can be used for benzoic acid analysis in the range of 1 μg/mL to 10 μg/mL concentration. Titration technique can be useful for ≥ 50 μg/mL concentration of benzoic acid in food products.