THE STUDY OF THE ACCURACY DEPENDENCE OF XRF AEROSOL RESULTS ON THE NUMBER OF EMITTERS CUT FROM A SINGLE FILTER
The dependence of the accuracy of the X-ray fluorescence analysis (XRF) aerosol results on the number of emitters cut from the single loaded filter was studied. Analyses were performed using the synthetic "filters" in the form of the thin organic films of known analyte contents simulating real aerosol samples collected on the aspiration filters. The diameter of their working surface was 9 cm, which allowed to cut out 5 emitters with 3 cm diameter and to estimate the dependence of error of XRF results when varying the number ( n ) of emitters from 1 to 5. It was established that when using one emitter ( n = 1) cut out from the central part of the inhomogeneous "filter" the error (variation coefficient V<sub>ni</sub> ) in XRF results can reach 40%; when increasing their number the V<sub>ni</sub> value decreases, and when n = 5, it is about 6%, and this corresponds to a random error of the method. However, this procedure substantially increases the labor intensity of the analytical works. The applicability of the emitter was evaluated, consisting of the whole "filter" material of a working surface diameter of 9 cm. Under these conditions the background intensity increases, which reduces the contrast of the X-ray spectrum by 6 times. The contrast decreases only by 25% when using double-layer emitters. Thus, for XRF it is recommended to collect the aerosols on filters with 5 cm diameter and to measure the analytical signal from the material of the whole sample.