A review in the sample preparation of aqueous solutions combined with X-ray fluorescence detection

Elemental analysis of liquid matrix using X-ray fluorescence (XRF) spectrometry suffers some technical drawbacks involving significant errors in obtained data. The main problem of liquid samples include a high X-ray scatter background which often leads to too low signal-to-noise ratio, and many different chemical and physical extraction techniques have been proposed prior to XRF analysis to overcome such problem. Recent analytical developments are summarized in the present review for the extraction and isolation of trace elements in XRF detection. Two main operation modes can be distinguished: (1) solid-phase extraction including disc, quasi-solid, particles, and electrodeposition; (2) liquid-phase extraction including supported liquid membrane and liquid-phase microextraction.