Determination of melamine in royal jelly and lyophilized powder using ultrasonically assisted extraction by ion-pair HPLC with UV detection

摘要

A rapid method for the analysis of melamine in royal jelly (RJ) and RJ lyophilized powder (RJLP) was developed using ion-pair RP-HPLC coupled with UV detector. The method utilized an optimized buffer system to avoid the elution of melamine near the column void volume and improve retention of melamine in a generic C8 chromatographic column. In addition, sample preparation included deproteination, ultrasonic-assisted extraction, and cleanup on a mixed-mode cation exchange extraction cartridge. The extraction procedure was optimized with regard to the amount of extraction solvent and the duration of sonication for RJ and RJLP samples. The following criteria were used to validate the HPLC-UV detection method: selectivity, linearity, precision, LOD, and LOQ. Correlation coefficient was higher than 0.999 by applying the linear regression model based on the least square method with a weighting factor (1/x). Precision was evaluated as repeatability and intermediary precision with RSD of less than 15%. The mean percentage recoveries of melamine were varied from 72.5 to 90.5% for RJ and RJLP. This approach will be of particular utility for the evaluation of melamine residue level and routine monitoring of melamine in RJ and RJLP samples.