etermination of 9 Preservatives in Baby Wet Wipes by High Performance Liquid Chromatography

The wipe sample (0.500 0 g) was cut and extracted with 5.00 mL of 80% (volume fraction) methanol solution by vortex oscillation for 3 min. After filtrating through 0.22 μm filter membrane, 9 preservatives in the filtrate were separated on a Diamonsil C₁₈ (2) column (4.6 mm×250 mm, 5 μm), with a mixture of methanol and 0.1% (mass fraction) phosphoric acid solution as mobile phase for gradient elution, and detected by a diode array detector, at the wavelength of 210 nm for imidazolidinyl urea, 5,5-dimethylhydantoin, 2-bromo-2-nitropropane-1,3-diol, benzethonamide and benzalkonium chloride, 230 nm for chlorobenzoate, 254 nm for chlorhexidine acetate, potassium sorbate and cetylpyridinium chloride. Linear relationships were found between chromatographic area peak and mass concentration of 9 preservatives in definite ranges, with detection limits (3S/N) in the range of 0.01-0.5 mg·L^-1. Test for recovery was made by standard addition method on the base of blank sample, giving results in the range of 77.2%-100%, with the relative standard deviations (RSDs,n=6) ranged from 1.2% to 8.4%. The proposed method was used to analyze 20 batches of baby wet wipes, and imidazolidinyl urea, 5,5-dimethylhydantoin, 2-bromo-2-nitropropane-1,3-diol, chlorhexidine acetate, potassium sorbate, benzethonamide were found in 15 batches of samples.