A Simple and Ultra-Sensitive LC/MS/MS Method for Analysis of N-Methyl Carbamates in Water
N-methyl carbamate pesticides are widely used due to their broad range of activity. Water sources can be polluted by
carbamates through surface water runoff from areas such as agriculture fields, golf courses, and residential properties.
Human and animal studies have suggested that long-term, low-level exposure to carbamates can cause adverse health
effects, including nervous system and neuromuscular effects, and persistent neurobehavioral changes. Carbamates to human health effects are considered to be “additive.” The toxicity of a combination of two or more pesticides is equal to the sum of the toxicity of each individual of pesticide.
To monitor N-methyl carbamates in water, all the current methods use sample enrichment techniques such as liquidliquid
extraction or solid-phase extraction (SPE). For example, US EPA Method 8318 starts with liquid-liquid extraction,
followed by HPLC and post-column derivatization and fluorescence detection. With this Method, the reported limit
of detection (LOD) varies from 1.7 to 9.4 μg/L.* A recently published SPE-LC-ESI-MS method by J.M.F. Nogueira, et al.(1) improved the detection sensitivity of carbamates in water to 0.03 μg/L. While this method is very sensitive, it still requires SPE for sample enrichment.
A simple, fast, and sensitive LC/MS/MS method is described below for high throughput identification and quantitation of N-methyl carbamates in water. This new method can quantitatively monitor carbamate pesticides at the level of 0.02 μg/L without any sample enrichment step. Quantitation at 0.02 μg/L is well below the maximum allowed levels of
0.1 μg/L for individual and 0.5 μg/L total established by the European Union for drinking water quality.(2)