DETERMINATION OF LEAD BY ELECTROTHERMAL VAPORIZATION MICROWAVE-INDUCED PLASMA-ATOMIC EMISSION-SPECTROMETRY AFTER FLOW-THROUGH ELECTROLYTIC DEPOSITION IN A GRAPHITE TUBE PACKED WITH RETICULATED VITREOUS CARBON

A simple method is described for the determination of lead in salt sol utions by microwave-induced plasma atomic emission spectrometry (MIP-A ES). Traces of Pb were preconcentrated electrochemically in a flow sys tem incorporating a flow-through cell with a graphite tube packed with reticulated vitreous carbon serving as the working electrode. After w ashing the cell with water the tube was placed into the graphite furna ce coupled to the capillary of an argon MIP operated in a surfatron. A fter the tube had been dried the plasma was ignited and the evaporatio n temperature was applied to the tube. The evaporated deposit was tran sported by argon gas into the plasma for excitation. A detection limit of 0.2 ng ml-1 of Pb in 1 ml of preconcentrated sample solution was a chieved.