Gas chromatographic evaluation of some N-derivatives of intact carbaryl

Gas chromatographic (GLC) detection of aryl N-methylcarbamates as the N-acetyl-Clx or N-nitroso derivatives of the intact molecule was explored using carbaryl as the model compound. These derivatives were designed for use with the microcoulometric detector for chlorine and the solution conductivity detector for nitrogen but response to the electron capture detector was also studied. GLC characteristics of the derivatives were evaluated in terms of thermal stability and detector response. N-Trichloracetyl and N-nitroso carbaryl underwent extensive decomposition in the GLC system. Although the N-monochloroacetyl derivatives were also subject to thermal decomposition, they gave sufficient linearity and sensitivity with the microcoulometric detector for analysis at the residue level. N-Acetyl carbaryl was thermally stable and the response of electrolytic conductivity and the electron capture detectors were adequate for residue analysis.