Gas Chromatography−Mass Spectrometry Determination of Phosphine Residues in Stored Products and Processed Foods

Abstract

A gas chromatography-mass spectrometry (GC-MS) method was used for the quantitative confirmation of phosphine residues in stored products and processed foods. An established extraction technique was utilized for the preparation of headspace samples, which were analyzed by GC-MS and gas chromatography-nitrogen-phosphorus detection (GC-NPD). Wheat, oats, maize, white rice, brown rice, cornflakes, tortilla cornchips, groundnuts, and raisins were validated, showing excellent agreement between detectors when spiked at levels equivalent to 0.001 and 0.01 mg/kg phosphine and for samples containing incurred residues. The GC-MS method was reproducible and accurate when compared to the GC-NPD method and allowed five samples to be quantified in a working day. Subambient GC-MS oven temperatures were most suitable for phosphine residues ranging from 0.001 to 0.005 mg/kg, and a GC oven temperature of 100 degrees C was appropriate for residues >0.005 mg/kg. The method was sufficiently robust to be evaluated for other similar commodities as the need arises.

Rapid Method for Determination of Phosphine Residues in Wheat

“…Finally, the LOD of 0.026 μg/g was satisfactory being below the MRL of 0.1 μg/g (FAO/WHO 1983). The micro-GC-TCD method showed sensitivity and precision similar to those obtained with other published GC methods, which require much longer extraction times and cleanup steps (Nowicki 1978;Mauldin et al 1996Mauldin et al , 1997Corley et al 1998;Scudamore 1986Scudamore , 1998Norman and Leonard 2000;Brockwell 1978;Hilton and Robinson 1972). The main advantage of the micro-GC-TCD was the potential for "in-field" applications by using a portable equipment with lower cost as compared to more expensive conventional GC instruments.…”

“…In some works, PH 3 was distilled from 10% H 2 SO 4 attack of the wheat sample by boiling the solution in a sealed flask and by releasing the headspace gas into a vacuum flask for gas chromatography (GC) determination (Nowicki 1978;Scudamore 1986Scudamore , 1998Norman and Leonard 2000;Brockwell 1978). An alternative procedure was to hydrolyze phosphide with acid and to trap the released PH 3 in toluene in a two-phase system of water and toluene (Mauldin et al 1996(Mauldin et al , 1997Corley et al 1998;Hilton and Robinson 1972).…”

Residue Levels and Risk Assessment of Pesticides in Pistachio Nuts in Iran

“…Moreover, phosphine residuals were found in stored products such as pistachio nuts by gas chromatography and mass spectrometry. The results of the analysis showed very low levels of phosphine in the pistachio samples [20].…”

Importance of Ammonium Molybdate Test in Aluminium Phosphide Poisoning: A Case Study.

“…Using filters impregnated with silver nitrate [11] and ion chromatographic methods [12] were recruited to determine phosphine in the bio-samples. Gas chromatographic procedure in survivors [13][14][15] and post-mortem specimens [16] has been developed for the measurement of phosphine levels.…”