|Budget Amount *help
¥3,400,000 (Direct Cost : ¥3,400,000)
Fiscal Year 1999 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1998 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1997 : ¥2,200,000 (Direct Cost : ¥2,200,000)
A high sensitive method is described for the direct determination of tramp elements at the low ppm level in ferrous scrap based on stripping voltammetry without troublesome separation of iron matrix taking a lot of skill and time. The desired element in acidic medium was accumulated on and/or in a working electrode for a certain time, and the deposit was then electrolytically stripped at a scan rate of 20〜50 mV sィイD1-1ィエD1. A stripping curve was recorded by means of a differential pulse mode. The concentration of the desired element was determined by reference to a linear calibration curve (peak height or area vs. concentration) constructed with standard solutions. The interference of iron(III) was eliminated by reducing it to iron(II) with potassium iodide or L(+) -ascorbic acid or by adding phosphoric acid in order to complex iron (III). The possible interferences have been evaluated. Copper, arsenic, antimony, tin and molybdenum in iron and steel were determined by anodic stripping voltammetry, tellurium by cathodic stripping voltammetry, and chromium by adsorptive stripping voltammetry, with excellent precision and accuracy. Zinc, cadmium, and lead were simultaneously determined by anodic stripping technique, and copper, lead, and cadmium by constant-current stripping analysis. The relative standard deviations and the detection limits were several percents and 10ィイD1-8ィエD1〜10ィイD1-9ィエD1 M, respectively. The time required for an analysis was within 1 h. The advantages of the proposed methods include simple and rapid operations and lessening contamination hazards.