HIGH-CURRENT POWER-SUPPLY FOR ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRY

A new power supply for electrothermal atomization - atomic absorption spectrometry (ETA-AAS) with associated equipment for temperature contr ol is presented. The system is composed of two high current commercial batteries and a MOSFET switch which controls the temperature of the a tomizer by switching the current in an on-off way through a feedback l oop connected to a personal computer and suitably programmed periphera ls. The delivered power can be changed from 0 to 100% in 1% steps whic h gives the possibility of roughly controlling both the temperature at low power when the temperature sensor is not working and the heating rate. With this system, curves for which the simultaneous presence of all atoms injected in the atomizer is claimed, have been extended to P b, Ag, Tl and Zn. With a more conventional power supply previously use d, such a claim could be made only for Cd and Hg.