Total reflection X-ray fluorescence analysis using polycapillaries. A comparison with conventional setups

The possibility of producing parallel X-ray beams with low divergence by means of half monolithic polycapillaries gives the impression to be useful in total reflection X-ray fluorescence (TXRF) experiments. On one hand, the use of polycapillaries facilitates the alignment and the setup of the experiment. As expected, the spectra registered in the experiment shown low background and good signal–noise ratio. On the other hand, the intensity of photons on the samples when polycapillaries are employed is lower than in other configurations, which produces a loss of efficiency for the excitation of the sample mainly for light elements. In this work, different TXRF experiments were carried out and the minimum detection limits attained were compared with the ones obtained from TXRF using polycapillaries. The results indicate that the decrease of intensity produced by polycapillaries is imposing when detection limits are analyzed. Nevertheless, detection limits are better than conventional XRF. The possibility of employing non-symmetrical polycapillaries could eventually improve the detection limits so as to be equivalent to the conventional TXRF setups.