Design and operation of an autosampler controlled flow-injection preconcentration system for lead determination by flame atomic absorption spectrometry

摘要

Flow-injection manifolds are described which allow the preconcentrationof lead for flame atomic absorption determinations, usingcolumns contained within the sample loop of an injection valve. Aninterface was designed which allowed the valves and pump in thesystem to be controlled by an autosampler which enabled precisetiming of preconcentration and elution steps. The effects of sampleflow rate, buffer pH and buffer type for preconcentration andeluent concentration and flow rate were investigated in order toobtain optimum performance of the system. A 50-times improvementin detection limits over conventional sample introduction wasobtained for a sample volume of approximately 12 ml, preconcentrated for150 s. The injection of eluent, as opposed to the use of acontinuously flowing eluent stream, enabled this reagent to beconserved.