Abstract
In the case of food adulteration or suicidal swallowing using dishwashing detergents, several extraction methods were evaluated to extract anionic, nonionic and amphoteric surfactants. Six extraction procedures: diatomaceous earth (ChemElut/chloroform or ethyl acetate), ion-pair liquid-liquid extraction (with methylene blue/chloroform), mixed-mode solid-phase extraction (SPEC PLUS DAU, C18 plus cation exchanger), C18-based solid-phase extraction (Sep-Pak Plus C18) and polymer-based reverse phase extraction (Oasis HLB) were tested. Eleven surfactants: fatty acid alkanolamide (AA), alkyl ether sulfate (AES), alkylglycoside (AG), alkylamine oxide (AO), alpha-olefin sulfonate (AOS-C=C), hydroxy-alkane sulfonate (AOS-OH), alkylamide propylbetaine (APB), fatty acid (FAT), alkylhydroxysulfobetaine (HSB), alkylbenzenesulofonate (LAS), and polyoxyethylene alkyl ether (POE), were extracted from spiked water and highest recoveries (91% for AES to 101% for AO) were obtained with Oasis HLB. On the assumption of food adulteration or stomach contents analysis, soy bean paste “miso” soup, yogurt and curry were spiked with dishwashing detergents and extracted using Oasis HLB. Extraction recoveries from these spiked foods were decreased (1% for LAS and FAT from yogurt to 78% for AO from curry) compared to extraction from spiked water. Except extraction of FAT from miso soup, protein precipitation by ethanol prior to Oasis HLB extraction was effective to improve extraction recoveries (67% for AA from yogurt to 101% for AA from miso soup).
