Rubidium Sulfate Flame Detector: Effect of Design of Alkali Source and Anode on Sensitivity and Stability

Abstract

Abstract An improved alkali-flame detector using pure rubidium sulfate and an anode of new design were optimized for the quantitative determination of organophosphate pesticides. The performance of this detection system was evaluated for response to organophosphate standards, noise level, fluctuation of baseline, short- and long-term reproducibility at low pesticides levels, conditioning time of instrument, life and physical stability of alkali source, and required frequency of detector cleaning. Under optimum conditions the detector was sensitive to 1 pg pesticide standard. To define the parameters of the alkali flame detector, studies were made of different designs of the alkali source which influence flame configuration and the relationship of the position and shape of the anode to the flame. The most important parameter appears to be the method of introducing alkali vapor.