Abstract: A hydride generation system using a small concentric hydride generator combined with inductively coupled plasma atomic emission spectrometry (ICP-AES) was established to determine tin, arsenic, bismuth and antimony in a marine sediment material with L-cysteine as a pre-reductant. Influences of concentrations of three kinds of acids (HCl, HNO3 and HClO4), L-cysteine, and sodium tetrahydroborate(III) as well as sodium hydroxide were investigated. The interferences from transition ions were found to be insignificant for determination of the four elements in presence of L-cysteine. Under optimized conditions the detection limits were 0.6 ng/mL for arsenic(III), 0.8 ng/mL for antimony(III), 1.7 ng/mL for tin(IV), and 1.2 ng/mL for bismuth(III). The method was applied to determine the four elements in standard marine sediment materials and the results were in agreement with certified values.

Abstract: A method is described for the determination of chemical oxygen demand (C.O.D) in aqueous environmental samples by segmented flow injection analysis. KMnO4 solution used as both an oxidant and a spectrophotometric reagent and D-glucose as a standard. When the reaction temperature is 95°C, the residence time is about 8 min and a sample throughput of 80/h can be achieved. The detection limit and relative standard deviation are 2 mg/litre and 0.7%, respectively, and the recovery is 85-95%. Chloride ion up to levels of 1500 mg/litre does not interfere with the results. C.O.D compared with those obtained using the Japanese Industrial Standard method and agreed within an error range of ±10%.