Rapid determination of lead, cadmium and thallium in cements using electrothermal atomic absorption spectrometry with slurry sample introduction

 A method is proposed for the determination of Pb, Cd and Tl in cements by ETAAS. The samples are suspended in a medium containing 10% v/v ethanol and 1% v/v both conc. nitric and hydrofluoric acids and are directly introduced into the electrothermal atomizer. The drying stage is performed by programming a 400 °C temperature, a ramp time of 5 s and a hold time of 30 s on the power supply to the atomizer. No ashing step is used. Atomization is carried out at 2100, 1800 and 1700 °C for Pb, Cd and Tl, respectively. For Cd determination, ammonium dihydrogen phosphate is added to the suspension medium. No modifier other than hydrofluoric acid is required for the Pb and Tl determination. It is shown that the results obtained by using direct calibration with aqueous standards for five commercial samples agree with those found by means of the standard additions method. Received: 29 March 1996/Revised: 24 May 1996/Accepted: 30 May 1996