Pesticide Residue Methods





Category Others
Class Name Multiclass Pesticide Residues
Method Title The Pesticide Analytical Manual Vol. I, Chapter 4, Selective Multi Residue Methods for N-Methylcarbamates, Acids and Phenols, Phenylurea Herbicides and Benzimidazoles
Method Date 2009/05/20
Method Type Screening, Quantitative
Scope and Application Analysis of various N-Methylcarbamates, Acids and Phenols, Phenylurea Herbicides and Benzimidazoles in fatty or nonfatty foods
Method Summary N-methylcarbamate insecticide residues, including carbamate metabolites, are extracted from various foods with methanol and cleaned up on a charcoal/celite column. Residues are then analysed by HPLC-FL involving post-column hydrolysis and derivatization where necessary. Residues without an N-methylcarbamate structure may also be analysed by modifying the determinative step. Acidic and phenolic residues are extracted with sulphuric acid and the extract cleanedup by GPC. Residues in the concentrated extract are methylated by ion pair alkylation and further cleaned up by Florisil column chromatography. The resulting methyl esters are determined by GLC. Phenylurea herbicide residues are extracted from nonfatty matrices with methanol followed by cleanup on a Florisil column prior to analysis by HPLC-FL involving post-column photodegradation and derivatization. Benzimidazoles residues are extracted from fruits and vegetables with methanol and methylene chloride (including acidification and alkalinization of the extract) and analysed by reverse phase ion pair HPLC-UV/FL.
Applicable Concentration Range Varying for N methylcarbamate. For example, the LOQs for carbofuran is 0.01 ppm and 0.02 ppm in high moisture and dry products, respectively. Varying concentrations for various acids and phenolics in a wide range of fatty and nonfatty foods. At least 14 phenylurea herbicides can be detected at concentrations of 0.05, 0.5, and 1.0 ppm in 14 nonfatty food products. The LOQ for residues of allophanate, Carbendazim thiabendazole, and thiophanate methyl in fruits and vegetables is 0.1 ppm. LOQs on UV vary with commodity. LOQ for Thiabendazole may improve to 0.01 ppm when using a fluorescent detector.
QC Requirements See Chapter 2 of The Pesticide Analytical Manual Vol. I
Method Performance/Validation Chapter 2 of The Pesticide Analytical Manual Vol. I
Method Source USFDA
Method SOP PDF icon SOP 
Citation Citation Pesticide Analytical Manual Volume I (PAM) 3rd Edition http://www.fda.gov/Food/FoodScienceResearch/LaboratoryMethods/ucm111455.htm