ABSTRACT
A method for the determination of trace elements such as lead, arsenic and mercury in cream cosmetics by total reflection X-ray fluorescence spectrometry (TXRF) with suspension sampling was developed. The mixed solvents of water,tetrahydrofuran,methanol and were used to disperse paste, cream, and additives of triton X-100 to promote the test liquid uniform. The test suspension fluid were taken into the sample carrier,drying and then introduced into TXRF. Poly(1-vinylpyrrolidone-co-vinyl acetate) (P(VP-co-VAc)) was added to curing sediments,inhibiting proliferation. Triton X-100 and P(VP-co-VAc) were found to have the function of reducing mercury loss in the drying process. The loss of elements in the drying process and the effect of triton X-100 and P(VP-co-VAc) were investigated. The effect of cream matrix, element interference, spectral line and the inner standard were discussed. The calibration curves for quantitative analysis were established using matrix standards, so the error of software decomposition peak and the error caused by thick sample were avoided within a certain range. In this work,the linear correlation coefficients of Pb,As and Hg calibration curve were greater than 0.998 The detection limit of Pb,As and Hg in the solution were 0.005,0.004 and 0.006 μg/mL,respectively. Relative standard diviations(RSDs, n=11) of Pb, As and Hg were 7.8%-14.9%,6.6%-13.3% and 7.6%-14.6% respectively. The results of Pb, As, and Hg in cream cosmetics determinated by this method agreed with those obtained from inductively coupled plasma atomic emission spectrometry and the value of standard reference material. The TXRF method was proved to be accurate,simple and valuable in determination of trace heavy metal ions in cosmetic samples.