FLUORINATION ASSISTED ELECTROTHERMAL VAPORIZATION INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION-SPECTROMETRY FOR A DIRECT DETERMINATION OF CHROMIUM IN BIOLOGICAL-MATERIALS

Polytetrafluoroethylene (PTFE) was used as a fluorinating agent in order to facilitate a direct analysis of Cr in biological materials by electrothermal vaporization-inductively coupled plasma atomic emission spectrometry. The electrothermal vaporization parameters and the PTFE amount were optimized experimentally. The effects of different matrices on the emission signal of Cr were investigated in detail. Under the optimal conditions, the detection limit of Cr is 1.4 ng ml-1 and RSD 3.8% at 0.03-mu-g ml-1. The proposed method has advantages of sensitivity, simplicity, rapidity and no-chemical pretreatment, and has been applied to a direct determination of trace Cr in serum.