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1784260 
Technical Report 
Significance of rubidium bromide thermionic detector equipped with a gate electrode in the analysis of halogenated dicarbamate derivatives 
Martens, FK; Martens, MA; Soylemozoglu, T; Heyndrickx, AM 
1977 
PESTAB/78/0703 
Chromatog 
1 
PESTAB. An attempt was made to establish a gas chromatographic (GC) detection method which could improve the identification of halogenated and non-halogenated dithiocarbamate benzyl esters. Solutions of DMeC12, DEtC12, DMeB, and DEtB in methanol with concentrations ranging from 5 to 2000 ng/microliter were spiked with 20 ng/microliter of azobenzene and 5000 ng/microliter of octadecane, which served simultaneously as internal standard and as an indicator for variations in the nitrogen flame-ionization detection (NFID) conditions. However, DMeF5 DEtF5 solutions were spiked only with 20 ng/microliter azobenzene, because of interference with octadecane. A research chromatograph equipped with a rubidium bromide NFID and a variable gate electrode potential was used. The term peak inversion was used to describe the gradual deformation of a chromatographic peak as a function of the applied voltage on the gate electrode. Each compound, depending on its heteroatom content, inverts at a different gate electrode potential. The ratio of the area of the azobenzene peak to the area of the octadecane peak indicated unexpected variations in the detector parameters. Attempts to assign each test compound a fixed specific inversion potential were unsuccessful, due to an inadequate accuracy of the voltage supply to the gate electrode. When all the compounds were injected simultaneously, it was possible to determine the exact sequence of inversion.