Analysis of Phosphine in Dried Foodstuffs via Headspace-GC-MSD

Phosphine is one of the most widely used, cost-effective and rapidly acting fumigants. In EU legislation , maximum residue limits for the sum of phosphine and phosphides in foodstuff are set to within a range of 0.01 and 0.1 mg kg-1, depending on the commodity. A highly sensitive headspace-GC-MSD method was developed achieving limits of quantitation as low as 0.1 μg kg-1; this enabled not only the monitoring of MRLs, but also the exposure of improper applications. In all, 115 samples of dried foodstuff from the local market such as cereals, nuts, and legumes were analyzed for phosphine residues. Of these, 35 samples contained phosphine in amounts exceeding 0.1 μg kg-1, while 14 samples (12 % of all) exceeded 1 μg kg-1. Interestingly, seven of these 14 samples were labeled as being from organic production, where phosphine application is not allowed. Monitoring activities will be continued.