The determination of trace-or ultra-trace amounts of elements becomes more and more important in fields such as environmental, biological, and material sciences.1-3 However, it is very difficult to determine trace-and ultra-trace elements directly even by the highly sensitive instruments now available, because the detection sensitivity is sometimes insufficient and the effect of matrices in samples can not be neglected. The enrichment of analyte elements together with the elimination of matrices in sample solutions are important to achieve the sensitivity with less interference from matrices in atomic spectroscopic methods, such as AAS, ICP-AES and ICP-MS. Of these methods, ICP-MS is an ideal analytical method for the simultaneous and highly sensitive determination of trace elements in various samples. However, there still remain some problems which should be solved in order to fully demonstrate the performance of ICP-MS, such as isobaric interference due to polyatomic ions, 4-9 sensitivity changes caused by co-existing major elements, 10-13 and relatively low capacity of ions in detector. Therefore, it is necessary to separate analyte elements from major components to obtain more reliable analytical results.The preconcentration methods using chelating resins have increasingly replaced the traditional liquid-liquid extraction methods which generally use great amounts of organic solvents to obtain high enrichment factors and often require laborious processes. Various types of solid phase collection/concentration methods using chelating resins, such as a batch method with Chelex-100, 14 a column method with chelating beads, 15 and a filtration method with a chelating disk, 16 have been developed to improve the sensitivity as well as to effect the elimination of interfering sample matrix prior to the ICP-MS measurement.In this study, iminodiacetate type of chelating resin fibers and strong anion exchange type of filter were used for collecting metal ions and metal oxonium anions. The main purposes of the present pretreatment procedure are to enhance the adsorption efficiency for many metal species, to downsize the experimental conditions, such as samples, reagents, materials, vessels and wastes, and to perform the rapid and simple operation (less than 30 min excluding the dissolution process). Compared to the conventional pretreatment methods, such as solvent extraction, batchwise and column separation methods with chelating resins, the proposed method has several advantages: small sample size, less consumption of reagents, short pretreatment time, less contamination and easy portability. In a practical sense, 5 ml (pH 6.0) of 0.2 M (1 M = 1 mol dm -3 ) ammonium acetate was used for the conditionings of resins and filters, and 2 -20 ml of 1 M nitric acid was used as an eluent. The enrichment factor from 2.5 to 20-fold can be easily attained by varying sample volumes from 5 to 40 ml with 2 ml eluent.Sample digestions for peach leaves (NIST 1547) and pond sediment (NIES No. 2) were carried out by a microwave digestio...

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