Journal of Analytical & Bioanalytical Techniques
Open Access

Abstract

Qualitative and quantitative analysis usually includes a sample preparation procedures, which today are still the weakest link and the time-determining step in the whole analytical method. However, due to the complex nature of the matrices and the low detection levels required by regulations, an effi cient sample preparation is an important aspect of analytical methods. Th is step is basically the most time-consuming part of an analysis, therefore, various attempts have been made to replace classical extraction techniques (leaching by mechanical shaking, ultrasound extraction, microwave-assisted extraction, supercritical fl uid extraction) in order to short the sample preparation time and simplify the procedure. Although Pressurised Liquid Extraction (PLE) has been designed and used mainly for organic compounds extraction, in recent years it has been successfully applied for extracting organometallic species. PLE is based on the use of solvents at a high pressure and/or high temperature without reaching the critical point, which improves effi ciency over classical extractions by shortening extractions times and reducing solvent volumes. Th e usefulness of PLE for total metal extraction from biological (GBW-08751 mussel tissue, DORM-2 dog-fi sh muscle, DOLT-3 dog-fi sh liver, TORT-2 lobster hepatopancreas, GBW- 07601 human hair, NIEST-03 Chlorella kessleri , NIES-09 Sargasso ), inorganic (PACS-2 marine sediment, GBW-0709 soil, IRANT-12-1-07 cambisol soil, IRANT-12-1-08 luvisol soil) and atmospheric particulate matter samples have been tested. Th e suitability of diff erent carboxylic acids (acetic acid, formic acid, oxalic acid, citric acid and ascorbic acid) and chelating solvents (EDTA, PHEN, 8HQ, CT, AMPAHC and DFC) as solvents for PLE, have been assayed to extract metals. Inductively Coupled Plasma ? Optical Emission Spectrometry (ICP-OES) has been used for the multi?element determination. Variables inherent to PLE (temperature, solvent concentration, static time, pressure, number of cycles, dispersing agent mass, fl ush volume and purge time) were simultaneously studied and optimised by applying an experimental design approach (Plackett?Burman design, PBD, and central composite design, CCD). High metal recoveries and short extraction times (when comparing to conventional sample pre-treatments) obtained, avoiding of extract handling (a fi ltration step is not required) and use of less toxic reagents/acids at low concentrations (environmental friendly procedures), allow to conclude that PLE can be a real, practical and promising procedure for total metal extraction from environmental samples.

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