A specific gas chromatographic method for residues of organic nitrogen pesticides

Abstract

The principles of gas chromatography, pyrolysis, conversion of nitrogen to ammonia, conductivity, and coulometry are well known and various combinations of these methods have been used for many years. Coulson (1965) suggested the possible use of these principles as a means of determining micro amounts of nitrogen compounds. Coulson (1966) also described a micro method of nitrogen detection where the eluent from a gas Chromatographic column was passed through nickel sulfate-treated quartz wool with hydrogen at 800° to 820° C. and the resulting ammonia was measured by an electrolytic conductivity cell, `Tek Meulen (1924) described a nickel-on-magnesium-oxide catalyst for the conversion of nitrogen to ammonia at 440° C. Westlake and Gunther ( 1967) make reference to the determination of nitrogen by means of the Coulson conductivity cell. Martin (1966) and Albert (1967) also used the Ter Meulen catalyst and a coulometric cell for determining nitrogen in petroleum oils. This present report describes a micro-procedure developed for determining pesticide residues containing nitrogen. The procedure has been used with various modifications since 1965 and found most satisfactory as a specific nitrogen detection method. It provides a ready means of analyzing a large number of samples with minimums of time, reagents, apparatus, and manipulation. Satisfactory degrees of accuracy and sensitivity are obtained by this method with minimum cleanup of most sample extracts. Although it was developed for use in pesticide residue work, it undoubtedly will be found useful in many other fields where it is desirable to analyze nitrogen compounds.