Analysis Of Pesticides In Food Research Articles

Pesticide Analysis in Food by MS

Pesticide Analysis in Food by MS

Residue analysis of pesticides in food by two-dimensional gas chromatography with capillary columns and parallel detection with flame-photometric and electron-capture detection

Two-dimensional gas chromatography on two capillary columns is used for pesticide residue analysis in food samples. Both columns are connected by effluent splitting to the selective flame-photometric and electron-capture detectors, which are linked on-line to independent data processing channels. About 100 halogenated and organophosphorus pesticides, together with three internal standards, are screened on the first column with methylsilicone as the stationary phase. The compounds are recognized by their retention data and response to the two selective detectors. In a second analysis, peaks eluted from the first column are transferred by means of pneumatic switching to the second column with phenyl cyanopropyl methylsilicone as the stationary phase. This cutting of narrow fractions can be executed with high accuracy and reproducibility (“live chromatography”) by using time programming of the cutting valve. The final identification of all investigated pesticides is achieved by evaluating the set of linked retention data and, additionally, the response ratio of the two detectors characteristic for each compound. The application of the method to two real food samples, fortified with chlorinated and organophosphorus pesticides, is demonstrated.

Automated capillary gas chromatographic analysis of pesticide residues in food

A method for multiresidue pesticide analysis in food is described. After a conventional clean-up, gas chromatographic analysis is performed in a gas chromatograph equipped with two fused-silica capillary columns coated with methylsilicone SP 2100 and methylphenylsilicone OV-17. The effluent from each column is split to electron-capture and nitrogen—phosphorus detectors, which are connected to a dual channel integrator. Therefore, from each gas chromatographic run parallel records of signals from the two detectors are obtained. Calibration of the system is carried out for the SP 2100 column with three test mixtures covering all pesticides. Additionally, four internal standards are included, two responding to the electron-capture detector and the other two to the nitrogen—phosphorus detector. Automated analysis is performed with test mixtures and food samples on the SP 2100 column overnight as a screening procedure. After selection of positive samples a confirmatory test and quantitation are carried out manually applying appropriate test mixtures according to the results of the screening runs.