Post-Column Derivatization and Quantitative Determination of Vanillin in Ice cream and Custard Powder by High Performance Liquid Chromatography Technique (HPLC)

Abstract

An analytical method for quantitative determination of vanillin in ice cream and custard powder was established. The milk proteins were removed by precipitation and the vanillin content of the food products was extracted by liquid-liquid extraction (LLE). The separation of the analyte was achieved in an ODS hypersil C18 column maintained at 30^oC. Acetonitrile/10 % Acetic acid in distilled water 55:45 (v/v) was used as the mobile phase. The measurement was made with a UV/fluorescent detector at 280 nm and a flow rate of 1.0 mL/min. Direct injection of the extract into the HPLC proceeded without interference from excess solvent before post-column derivatization and the retention time was 2:18 min, thus allowing this method to be applied for routine analysis of vanillin in food products. The calibration curve was linear over the concentration range of 2-10 μgmL^-1. A correlation regression of the order 0.99 was obtained and the vanillin concentration in the food products ranged from 8.09 ± 0.18 ↔ 14.61±0.06 μgmL^-1 in ice cream and11.11 ± 0.01 ↔ 15.23±0.15 μgmL^-1 in custard powder respectively. The respective limit of detection and quantification of the vanillin in the food products was 0.05 μgmL^-1and 0.17 μgmL^-1. The relative standard deviation which is a measure of precision was less than 3% (n = 10). The percentage recovery of the analyte was 87 %, all the validated data obtained in this study was higher than the acceptable daily intake for the vanillin in the food samples analyzed except for the Golden scoop ice cream. This method is well suited for the simultaneous and convenient analysis of vanillin in a vanilla enriched ice cream and custard powder to evaluate the quality of the vanilla extract and determine the quality of the food products for human consumptions.

Keywords: Precipitation, Interference, Quantification and Validated