Detection of phosphine residues in organic cereals

摘要

Cereals are usually checked for residues of phosphine fumigation with Draeger tubes. The detection limit of this method lies between 5 and 10 μg/kg. After sufficient cleaning and airing of the fumigated cereals no residues can be detected any more. A more sensitive and specific headspace GC/FPD method was adapted and applied to 47 samples of organic cereals. With a detection limit of 0.1 μg/kg, phosphine was found in five of ten rice samples and in one of three maize samples. The concentrations lied in the range of 0.3 to 2.5 μg/kg. All the other kinds of cereals were free from detectable phosphine. Further investigation is planned to clear up these findings.