A rapid dispersive liquid–liquid microextraction of antimicrobial onion organosulfur compounds in animal feed coupled to gas chromatography-mass spectrometry?

Analytical MethodsANAL METHODS-UK Pub Date: 2020-05-18 DOI: 10.1039/D0AY00632G

Abstract

A rapid analytical procedure is proposed for determining two antimicrobial onion organosulfur compounds, propyl disulfide (PDS) and propyl propane thiosulfonate (PTSO), in animal feed. The use of PTSO as a natural ingredient in animal feed is allowed due to its antimicrobial activity against pathogenic organisms. Two analytical methodologies using gas chromatography coupled to mass spectrometry (GC-MS) are compared. After the extraction of the compounds from animal feed with acetonitrile, dispersive solid phase extraction (DSPE) as a cleaning stage with C18, or dispersive liquid–liquid microextraction (DLLME), using 100 μL of CHCl3, was tried. Both the methods were validated using a pig feed sample and the best results were achieved by DLLME. This technique provided cleaner extracts, five-times greater linear ranges and lower detection limits than simple cleaning due to the enrichment factor achieved. The relative standard deviation decreased from 22% with DSPE to 13% with DLLME. The usefulness of the DLLME-GC-MS methodology was tested by analysing 10 different samples of chicken, calf, hen, cow and fish feed. The concentrations of PDS were in the 0.1–1.7 μg g?1 range and those of PTSO were between 0.09 and 2.1 μg g?1

Graphical abstract: A rapid dispersive liquid–liquid microextraction of antimicrobial onion organosulfur compounds in animal feed coupled to gas chromatography-mass spectrometry
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