Discussion of parameters associated with the ultrasonic solid–liquid extraction for elemental analysis (total content) by electrothermal atomic absorption spectrometry. An overview

Ultrasonic solid–liquid extraction (USLE) of trace metals from biological and environmental samples and its subsequent quantification by electrothermal atomic absorption spectrometry (ET-AAS) is nowadays an emerging methodology in the analytical laboratory. However, this methodology is far from maturity as can be readily demonstrated from the controversial data reported by different workers. In the light of our own experience and a survey of published data, a general approach for USLE-ET-AAS is discussed, taking into account the different variables which affect ultrasonic solid–liquid extraction, namely, the ultrasonic device chosen for ultrasonic extraction (e.g. ultrasonic bath or ultrasonic probe), particle size, acid concentration, sonication time and sonication amplitude, sample mass and analyte-matrix binding.