Abstract: Analyses of trace biologically essential or toxic ionic compounds found in the environment are very important. However, the lack of sensitivity and interference caused by coexisting components are often serious problems. To determine trace levels of metal ions without the above problems, new pre-concentration and analytical methods have been developed. Firstly, three methods for the selective pre-concentration of metal ions are shown below: 1) 3-Chloropyridazine-6-carbohydrazide was immobilized on glass beads supports to be used as a column packing material. Multi-metal ions were concentrated on the column and eluted selectively with several buffers and hydrochloric acid. The eluate was analyzed off-line by flame atomized-atomic absorption spectrometry (AAS). This method was able to determine sub-ppb levels of copper- and cadmium-ions in environmental samples. 2) Salicylideneamino-2-thiophenol was immobilized on the supports. Aluminum ion was concentrated selectively on the column and eluted with nitric acid. The eluate was analyzed off-line by flameless-AAS or on-line by flow injection analysis using pyrocatechol violet for a post-column colorimetric reagent. These methods were able to determine ppb-ppt levels of aluminum in environmental samples and were suitable for its state-analysis. 3) Bathocuproinesulfonic acid was immobilized on the supports. Copper ion was concentrated selectively on the column and eluted with nitric acid. The eluate was analyzed on-line by flow injection analysis using bathocuproinesulfonic acid. This method was able to determine sub-ppb levels of copper in environmental samples. On the other hand, to analyze simultaneously trace metal ions and anions, capillary electrophoresis was performed using ethylenediaminetetraacetic acid as an electrolyte component. Simultaneous determination of several ions in mineral waters was achieved by the system.

Abstract: Al3+ at parts-per-1012 to ppb levels was concentrated on a column of 2-(salicylideneamino)thiophenol (immobilized on glass beads), eluted with HNO3, and determined online by flow injection spectrophotometry with catechol violet or offline by AAS. Cu2+ at the same levels was concentrated on a column of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthrolinedisulfonic acid (I) (immobilized on glass beads), eluted with HNO3 and determined online by flow injection spectrophotometry with I. Inorganic anions and carboxy-anions at these levels were concentrated on an anion-exchange column, eluted with toluene-p-sulfonic acid and determined online by ion chromatography with spectrophotometric detection.