NITROGEN-SELECTIVE DETECTOR FOR LIQUID-CHROMATOGRAPHY

A nitrogen-selective detector was developed for liquid chromatography (LC) and used directly on the effluent of a clean up column (SI-200A Silica Gel) as a means of rapidly screening a wide variety of materials for the existence of pesticide residues. By suitable modifications to each, a moving-wire transport system and a Hall conductivity detector were successfully combined and gave excellent nitrogen-selective liquid chromatograms. Chromatographic peak areas increased linearly with increasing wire velocity and oxidizer oven temperature and decreased exponentially with increasing LC column flowrate. The peak areas were a linear function (y = ax + b, r = 0.997) of concentration of sample on column. Relative responses were measured for 17 pesticides and metabolites. Linear or exponential solvent gradients of hexane/acetone gave good separations of mixtures. © 1979 Oxford University Press.