Improvement of X-ray fluorescence sensitivity by dry ashing method for elemental analysis of bee honey

Elements, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Rb, and Sr in bee honey samples were determined using an improved dry ashing (DA) method for XRF with Mo-secondary target (Mo-XRF). The sensitivity of the DA method was significantly improved in comparison to the wet ashing (WA) and the direct (D) methods. The limits of detection (LODs) obtained by DA (3.4–0.007 µg/g) method were better by an order of magnitude than those obtained by WA (34.0–0.120 µg/g) and D (61.2–0.270 µg/g) methods. Further improvements in the sensitivity of the DA-XRF were achieved by using a Cu-secondary target for the excitation of the elements of K, Ca, Ti, Cr, and Mn. In this instance, the LODs were in the range of 0.220–0.024 µg/g. The results of DA-XRF analysis revealed a very good accuracy with errors less than 7.1% and a precision with a relative standard deviation (RSD) better than ± 8.8%.The improved DA-XRF analysis was applied for the determination of the above mentioned elements in several Syrian bee honey samples. The results were comparable to those obtained by the atomic spectrometry method with correlation coefficients better than 0.9927.