Analysis of triallate residues in cereals and soil by gas chromatography with ion-trap detection.
Triallate residues in barley seedlings and soil samples were determined by gas chromatography with ion-trap detection. Soil was extracted with methanol on a mechanical shaker, and plants were extracted with acetonitrile in a Sorvall homogenizer. After evaporation of the organic solvents, the residue was dissolved in hexane, and plants extracts were cleaned-up on an alumina column. Gas chromatographic analysis was carried out using a BP-1 fused-silica capillary column with helium as carrier gas. To quantitate residues the total-ion chromatogram was obtained and then the selected-ion monitoring chromatograms were displayed at m/z 86 for triallate and at m/z 154 for the internal standard, methyl-(4-amino-2-chloro)-benzoate. The average recovery through the method from barley and soil samples was always higher than 80%. The limit of detection in the selected-ion mode was 0.01 mg/kg. Barley and soil samples treated with triallate were also analysed. A good agreement was observed between results obtained by this method and by gas chromatography with nitrogen-phosphorus detection.
Herbicide Residues in Biota, Analysis of
Current extraction, derivatization and clean-up techniques, and instrumental methods are reviewed for the analysis of herbicide residues in biota. Sampling procedures are shown to be an integral part of the methodology. Herbicide analysis is seldom based on analyte-specific methods but is usually integrated into multiresidue methods (MRMs). Current methods generally utilize relatively small sample sizes and miniaturized apparatus to take advantage of advances in instrumental performance and detection of analytes. These methods reduce the amount of solvent used for sample preparation and help to minimize waste generation. As well as using less solvent, the resulting miniaturized methods tend to be generally cheaper, faster, and less labor-intensive than conventional methods and, furthermore, they reduce analyst exposure to hazardous materials. 
 
 
 
Mass spectrometry (MS), interfaced with high-resolution gas chromatography (GC), high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE), has become the detection method of choice for herbicide analysis. MS is well suited to the confirmation of target analytes and the tentative identification of unknown analytes. HPLC–mass spectrometers are becoming more widely available and less expensive. CE is a relatively new separation technique providing many advantages over traditional gas and liquid chromatography, including shorter analysis times and smaller injection volumes. There have been advances in the development of immunoassays primarily for the rapid screening for herbicide residues. These methods, once optimized, can facilitate high sample throughput at relatively low cost compared to conventional approaches. To date however, development has been limited to aqueous systems and little immunoassay work has been done for the direct determination of herbicides in biota.
Avian infectious bronchitis.
Avian infectious bronchitis (IB) is caused by the gammacoronavirus infectious bronchitis virus (IBV). The virus causes infections mainly in chickens and is a significant pathogen of commercial meat and egg type birds. IB is an acute, contagious disease characterised primarily by respiratory signs in growing chickens. In hens, decreased egg production and quality are often observed. Some strains of the virus are nephropathogenic and produce interstitial nephritis and mortality. The severity of IBV-induced respiratory disease is enhanced by the presence of other pathogens, including bacteria, leading to chronic complicated airsacculitis. Diagnosis of IB requires virus isolation or demonstration of viral nucleic acid from diseased flocks. Demonstration of a rising serum antibody response may also be useful. The widespread use of live and inactivated vaccines may complicate both the interpretation of virus isolation and serology findings. The occurrence of antigenic variant strains may overcome immunity induced by vaccination.