Rapid gas chromatographic method using nitrogen-phosphorus detection for N-nitrosodimethylamine in 2,4-D and MCPA herbicide formulations.
A simple and rapid analytical method has been developed for the determination of N-nitrosodimethylamine (NDMA) in amine salts of phenoxy herbicide formulations of 2,4-D and MCPA, plus mixtures of these with mecoprop and dicamba amine salts. Sample preparation consists of direct extraction using pre-packed disposable extraction tubes eluted with dichloromethane followed by cleanup on a disposable silica gel mini-column using ethyl acetate as eluting solvent. Samples are injected on-column for gas chromatography with a Megabore fused silica column; the NDMA is measured by a thermionic specific detector (TSD) that is selective for nitrogen-phosphorus (NP). A detection limit of 0.1 microgram/mL was easily attainable without any concentration step because the solvent volume is minimal. TSD and thermal energy analyzer (TEA) results have been compared and confirmed by gas chromatography/mass spectrometry. Recovery studies were performed as well as a reproducibility study on one of the 2,4-D formulations.
Scharfe
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Agriculture Canada, Laboratory Services Division, Ottawa, Ontario.
McLenaghan
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CC
D015084:2,4-Dichlorophenoxyacetic Acid / Q000032:analysis*; D008456:2-Methyl-4-chlorophenoxyacetic Acid / Q000032:analysis*; D002849:Chromatography, Gas; D004128:Dimethylnitrosamine / Q000032:analysis*; D006016:Glycolates / Q000032:analysis*; D009584:Nitrogen; D010758:Phosphorus
D006016:Glycolates; D015084:2,4-Dichlorophenoxyacetic Acid; D010758:Phosphorus; D008456:2-Methyl-4-chlorophenoxyacetic Acid; D004128:Dimethylnitrosamine; D009584:Nitrogen