Liquid-phase extraction combined with X-ray fluorescence spectrometry for the elemental determination.

X-ray fluorescence spectrometry (XRF) has been widely used for multi-element determination in various samples. However, when trace level determination is required, separation and preconcentration procedures are often used as a step before detection to avoid or reduce interferences and to increase sensitivity. Liquid-phase extraction (LPE) is one of the most well-known and applied pretreatment techniques associated with atomic spectrometry due to its simplicity, speed, and ease of automation. A review of methods involving LPE combined with XRF is presented. Methods described in the literature are discussed, involving conventional LPE and the three main categories of liquid-phase microextraction (LPME): single-drop microextraction (SDME), dispersive liquid–liquid microextraction (DLLME), and hollow fiber liquid-phase microextraction (HF-LPME). Characteristics of the methods are presented, considering experimental aspects, analytical features, advantages, and disadvantages. In addition, trends in the association between LPME techniques and XRF are presented. [ABSTRACT FROM AUTHOR]