A modified synthetic method has been developed for immobilization of 8-hydroxyquinoline on polyacrylonitrile fiber. The synthetic conditions, e.g. reagent concentration, reaction temperature and time, were optimized. The features of the newly-modified fiber are higher exchange capacity compared with most other materials containing immobilized 8-hydroxyquinoline, better mechanic characteristics, high stability at both high and low pH, and ease of synthesis. This modified fiber can concentrate and separate trace metals from matrices with higher concentrations of alkali and alkaline earth elements. To validate the characteristics of the modified fiber, trace metals Ag, Be, Cd, Co, Cu, Mn, Ni, Pb, and Zn in the certified reference materials river water (SLRS-4) and seawater (CASS-4, NASS-5, SLEW-3) were preconcentrated before determination by inductively coupled plasma mass spectrometry. Good agreement was obtained between the data obtained by this method and the certified values.Keywords 8-Hydroxyquinoline immobilized polyacrylonitrile fiber · Trace metals · Sea water · Inductively coupled plasma mass spectrometry
IntroductionInductively coupled plasma mass spectrometry (ICP-MS) is one of the most accurate, sensitive, and reliable techniques for the determination of trace metals and has been widely used for determination of trace elements in environmental samples. Its low tolerance of dissolved solids (<0.1%, w/v), however, prohibits the direct analysis of trace elements in seawater by ICP-MS, because of the problem of salt deposition on the torch, sampling interface, or ion lenses. In ICP-MS interferences fall broadly into two groups, "spectroscopic", and "non-spectroscopic" or "matrix effects". The extent of the interferences depends on many factors including extraction geometry, plasma and nebulizer system operating conditions, and, most importantly, on the nature of the analytes and matrix. To minimize interferences many approaches have been recommended, including instrument optimization, use of mixed gases and/or "dry" sample introduction, sample dilution, sample-matrix matching, and use of internal standards, etc.[1]. It should be pointed out that these interferences are usually related to the nature of the sample matrix and much can be done to minimize or even eliminate potential problems by careful sample preparation. It must be admitted that for simultaneous multi-element determination by ICP-MS in a complex matrix such as seawater separation and/or pre-concentration methods are the first choice [1,2,3].8-Hydroxyquinoline is a well-characterized chelating organic ligand. It can form covalent compounds with over 60 metal ions under controlled pH conditions, and its preference for transition and heavy metals to alkali and alkaline-earth elements is well known [4]. Trace elements are usually chelated with solution of 8-hydroxyquinoline and then extracted with organic solvent [5]. In comparison with the most commonly used solvent extraction enrichment procedures, however, column solid-phase extraction...