Advanced Solid Phase Extraction for Inorganic Analysis and Its Applications

Solid phase extraction (SPE) is usually considered to be superior to liquid-liquid extraction as a pretreatment method with regard to its simplicity, rapidity, and the ability to attain a high concentration efficiency when the concentration levels of the analytes to be collected/concentrated are at trace levels of sub-ppb to ppm. The collection and concentration of analytes at trace levels in analytical or process-scale separation with solid phase materials have been performed by using styrene/divinylbenzene co-polymer (SDB) with functional groups, octadecyl silanized silica (ODS), and ion exchange resins etc.. Recently, the selective extraction and pre-concentration of analytes at trace levels for improving the detection limits and the accuracy of analysis for metals in such samples containing large amounts of specific matrices as seawater, soil extracts, biological fluids and industrial solutions have been studied using various kinds of SPE, in which highly selective functional ligands, Such as chelating groups and molecular-recognition technology-based macrocyclic compounds have been introduced. The main SPE materials used were : (1) reversed-phase copolymers, (2) ion exchange resins, (3) aminocarboxylic acid-type chelating resins, and (4) molecular-recognition technology (MRT)-based resins. In this paper, several kinds of analytical applications of the SPE technique to metal analysis are summarized and demonstrated : they have been carried out by using Empore (TM) Disk of Anion-SR, Cation-S.R and Chelating resin, InertSep ME-1, and MetaSEP (R) of Hg-01, Hg-02, Pb-01 and Pb-02, which show excellent selectivity towards certain metal ions. The adsorption/collection of target analyte elements and the removal of interference matrices in samples Solutions by the SPE technique will reduce major spectral interferences, as well as physical interferences, and therefore such SPE pretreatment procedures will lead to improvements of the detection sensitivity in such analytical measurement methods as anodic stripping voltammetry (ASV), ICP-AES, ICP-MS, AAS, and XRF.