Carbamate pesticides are widely used around the world to protect crops. In addition, they are used as biocides for industrial or other applications and in household products. Though carbamates are biodegradable compounds and bioaccumulation usually happens only to a low extend it is important to monitor produce to make sure enough time has elapsed between harvest and applying pesticides. Also, because of their high solubility, carbamates can leach into ground waters in porous soils and consequently find their way into drinking water supplies.
As part of FDA’s pesticide monitoring program individual lots of domestic and imported foods and feeds are sampled and tested for pesticide residues to enforce the tolerances set by EPA. There are 11 compounds mandated by USEPA Method 531.2 for drinking water but they represent only a fraction of the carbamates that require monitoring in domestic and imported products. Methyl carbamates are separated using a reversedphase column and then readily react with o-phthalaldehyde and a mercaptan after hydrolysis to form highly fluorescence compounds. This post-column reaction is the basis for official EPA Method 531.2 and AOAC Method 985.23.
This new expanded method is suitable for detecting a wide range of carbamates; post-column derivatization with fluorescence detection is a sensitive and selective method for residue analysis in water, food and feed samples. This method employs the same HPLC and post-column equipment and chemicals as USEPA Method 531.2 and will allow laboratories to increase the range of tested compounds.