Simplified extraction and cleanup for multiresidue determination of pesticides in lanolin.
In the proposed method, a light petroleum solution of lanolin (wool fat) is adsorbed on diatomaceous earth in an Extrelut column, and the pesticides are eluted with acetonitrile saturated with light petroleum. After evaporation to a small volume, the extract is subjected to solid-phase extraction (SPE) on a C-18 column. The acetonitrile eluate is evaporated to dryness and the residue is taken up in light petroleum. Organophosphorus pesticides are determined by temperature-programmed gas chromatography (GC) on a wide-bore column using a flame photometric detector in the phosphorus mode. Organochlorine pesticides are determined after miniaturized Florisil cleanup by classic GC on an OV-17/QF-1 packed column, using an electron capture detector. This procedure is more rapid and straightforward than the time-consuming AOAC extraction method, 29.014. Cleanup was better and the results obtained were comparable. Recoveries for 13 organochlorine and organophosphorus pesticides, frequently found in lanolin, ranged from 80 to 90%.
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Nestec Ltd, Central Quality Assurance Department, Vevey, Switzerland.
D002849:Chromatography, Gas; D007809:Lanolin / Q000032:analysis*; D010573:Pesticide Residues / Q000032:analysis*; D012997:Solvents
D010573:Pesticide Residues; D012997:Solvents; D007809:Lanolin