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Several papers have appeared in the literature describing the determination of antimony, where antimony(V) is extracted into the organic phase and the organic solutions directly analyzed by atomic absorption spectrometry (AAS). This paper describes a procedure where antimony from the organic solution is reductively stripped into an aqueous phase and analyzed for antimony by AAS. The advantage of the method for a routine process control laboratory is highlighted.

A flow injection (FI) in-valve-mini-column packed with Chelex-100 resin is proposed for on-line sample pretreatment for some metal ions, namely, Cd(II), Pb(II) and Zn(II), prior to simultaneous determination using ion chromatography (IC). A solution containing a mixture of the cations was first passed through the in-valve-mini-column, followed by on-line elution. The eluate was then flowed further to an injection valve and was injected into an ion chromatograph. Conditions of the system were optimized. A single standard calibration was possible. The recoveries of cations were found to be in the range of 95-105%. The developed method was applied to the accurate analysis of zinc ore samples.

A flow-injection, cold-vapor atomic absorption spectrophotometric method was developed for the determination of trace amounts of mercury in a proposed zinc ore concentrate Standard Reference Material (SRM 113b). The samples were digested with nitric and hydrochloric acids in closed Teflon digestion vessels. The experimental details for sample preparation and the flow injection method are discussed. The effect of matrix and various acid concentrations on the extraction and subsequent analysis of mercury were also studied. The method has a detection limit of 0.08 μg Hg/g in the sample. A certified reference material (CZN-1) was analyzed and the results obtained agreed well with the certified value.

In the zinc electro-winning process arsenic is considered a "problem impurity". Its determination should be fast, accurate and simple to help in-plant control for its effective removal during the iron purification stage. Such a method is presented which is applicable to all zinc concentrates, lead concentrates and smelter residues, with various compositions and matrix components. Results for certified reference samples and for recovery of standard additions are very good.

A sensitive method for the spectrophotometric determination of indium with 1-(2-pyridylmethylideneamine)-3-(salicylideneamine)thiourea is proposed. A yellow complex is formed at pH 4.5 (succinate buffer) in a medium containing 40% dimethylformamide, and the absorbance is measured at 415 nm. The molar absorptivity is 6.2 × 10 4 l.mole −1 .cm −1 . The relative standard deviation of the procedure is 1.5%. The method has been applied to determination of indium in a nickel alloy and three zinc ores, with prior isolation of indium by co-precipitation with ammonia and extraction into n-butyl acetate from 5 M hydrobromic acid.