Automatic headspace sampling for determination of ethylene dibromide residues in cereals.
The possibility was investigated to apply a commercially available automatic head-space sampler in trace analysis of ethylene dibromide (EDB, 1,2-dibromoethane), in cereals. Samples of rice and wheat flour were thermostatted in closed vials at 70 degrees C for 30 min. The top gas was then automatically introduced into a gas chromatograph equipped with an electron capture detector. Quantitation was performed using external standards (untreated samples spiked with solutions of EDB in N,N'-dimethylacetamide). The relative standard deviation of the method was 3.4% for rice and 4.5% for wheat flour, at a residue level of 0.008 mg/kg. The detection limit was 0.001 mg/kg (the official EC residue tolerance is 0.01 mg/kg). Preliminary experiments with other fumigants were carried out as well. The headspace technique in question has the following advantages over other methods for determining EDB residues in cereals: 1. No sample pre-treatment like extraction, steam distillation, purge and trap etc.; 2. Automated sample handling; 3. "Clean" chromatograms.
D001322:Autoanalysis; D002849:Chromatography, Gas; D002523:Edible Grain / Q000032:analysis*; D015946:Ethylene Dibromide / Q000032:analysis*; D005433:Flour / Q000032:analysis; D006842:Hydrocarbons, Brominated / Q000032:analysis*; D012275:Oryza / Q000032:analysis; D010573:Pesticide Residues / Q000032:analysis*; D014908:Triticum / Q000032:analysis
D006842:Hydrocarbons, Brominated; D010573:Pesticide Residues; D015946:Ethylene Dibromide