Determination of distearyl dimethyl ammonium chloride in textiles by reversed-phase and normal-phase liquid chromatography-electrospray ionization tandem mass spectrometry

A method of reversed-phase (RP)/normal-phase (NP)-liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) was developed for the determination of distearyl dimethyl ammonium chloride (DSDMAC) in textiles. The DSDMAC in textile was extracted by ultrasound-assisted extraction using methanol as extraction solvent under the conditions of 70 degrees C and 420 W within 30 min. The three quaternary ammonium compounds of DSDMAC were detected by LC-MS/MS in the selective reaction monitoring (SRM) mode. The limits of detection (LODs) (S/N = 3) of DSDMAC detected by RPLC-MS/MS and NPLC-MS/MS based on an amino-column were 0.1 mg/kg and 0.01 mg/kg, respectively. The recoveries of DSDMAC spiked in the eight different types of blank fabrics ranged from 85.5% to 103% with the relative standard deviations (RSDs) of 4.18% - 12.8% (n = 5) by RPLC-MS/MS method. Five laboratories were invited to take part in the validation of the method, and the RSDs of inter-lab were 7.3% - 9.4% on two reference samples. The method is fast, accurate and reproducible, and can meet the demands of the determination of DSDMAC in textiles.