Glyphosate (GP) is a non-selective, postemergence herbicide widely used for weed and vegetative control. Glyphosate itself
readily forms an N-nitroso derivative. Among the impurities of commercial glyphosate, N-nitrosoglyphosate (NNG) is of great
concern due to its toxicity. However the accepted methodology for NNG determination – proposed by Monsanto Agricultural Company
in 1986 (1) is difficult to implement due to complicated instrumentation and operating conditions and relatively low sensitivity.
This application note presents a simple and sensitive method combining an effective separation of Nitrosoglyphosate from Glyphosate
on anion exchange column with an improved single-step derivatization of NNG (2). Pickering Laboratories Vector PCX is uniquely
suited to handle highly corrosive reagents and is factory configured for Nitrosoglyphosate analysis. This advance in instrumentation
and methodology provides a rugged method that easily meets the new limit of 1 ppm NNG in Glyphosate formulations as set by
Food and Agricultural Organization of the United Nations (FAO) (3).
Since the reagent is highly corrosive, the post column derivatization system must be flushed with water methanol (80:20) after
running the samples.
(1) Monsanto Agricultural Products Company, Standard Analytical Method No. AQC-684-86,1986.
(2) Manuela Kim, Jorge Stripeikis, Fernando Inon, Mabel Tudino, Talanta 72 (2007) 1054–1058.
(3) FAO Specifications and Evaluations for Plant Protection Products: Glyphosate, N- (phosphonomethyl)glycine, evaluation
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