UHPLC Determination of 6 Preservatives in the Extract of Plant

A method of UHPLC for the determination of 6 preservatives, including benzoic acid, sorbic aicd, methylparaben, ethylparaben, propylparaben and butylparabe, in extract of plant was proposed. The sample was extracted with methanol (1+1) solution, and separated on ACQUITY UPLCTM BEH C18 chromatographic column (2.1 mm×50 mm, 1.7 μm) with mixtures of acetonitrile and 5 mmol·L-1 ammonium acetate solution (containing 0.1% acetic acid) with different mixing ratios as mobile phase in the gradient elution, and determined with photodiode array detector. Linear relationships between values of peak area and mass concentration of 6 preservatives were kept in the definite ranges, with detection limits (3S/N) in the range of 0.02-0.22 mg·L-1. The proposed method was applied to the analysis of samples of the extracts of plants, giving values of recovery and RSD′s (n=5) in the ranges of 97.8%-114% and 1.0%-4.7% respectively.