• An innovative multifumigant residue detection method based on HS-SPME sampling technology with gas chromatograph-mass selective detection (GC-MSD) analysis was established, including phosphine, methyl bromide, cyanogen, sulfuryl fluoride, ethylene oxide, propylene oxide, ethyl bromide, and ethyl formate;
• The first report of a sorption study of the process of physical sorption and chemisorption of residual fumigant in fruit and food matrices by an HS-SPME-GCMS method;
• Consider the effect of time on fumigant behavior in dried fruit, grain, and nut;
• The LODs of the fumigants were in the range of 0.03 to 1.99 ng/g.
Background: Fumigants are approved in many countries and used to treat food, feed, and seed. The amount of residue that remains in fumigated materials is measured and reported.
Objective: The optimization and validation of a high-sensitivity headspace solid-phase microextraction gas chromatograph mass spectrometer (HS-SPME-GCMS) method for determination of eight fumigant residues-phosphine, methyl bromide, cyanogen, sulfuryl fluoride, ethylene oxide, propylene oxide, ethyl bromide and ethyl formate-in a range of food matrices were developed. The food matrices included grain, oilseed, dried fruit, and nut.
Methods: The new method was used to determine residue levels from a fumigant complex in food matrices by monitoring the change of the absorption of spiked standards and desorption of fumigant from fumigated samples.
Results: Based on the observation, the process of physical sorption and chemisorption was defined. The equilibrium time of the sample analysis was chosen at 5 hours. The LODs of the fumigants were in the range of 0.03 to 1.99 ng/g. Response to a range of diluted authentic standards gave significant linear regressions (r² > 0.9983), and the RSDs were ?8.7% at the 3 ng/g level of aged spiking standard, except for sulfuryl fluoride, for which the LOD was 1.99 ng/g and the RSD value was 39.7% (6.64 ng/g).
Conclusions: The performance of the HS-SPME-GCMS method was more sensitive than the use of a gas syringe, except for sulfuryl fluoride.
*Original abstract titled Optimization and Validation of HS-SPME-GCMS Method for Determination of Multifumigant Residues in Grain, Oilseeds, Nuts, and Dry Fruit online at https://www.ncbi.nlm.nih.gov/pubmed/31097055