DETERMINATION OF TRACE AMOUNTS OF BORON I N HIGH-PURITY GRAPHITE BY ICP-MS

A graphite sample(10 g) was mixed with proper amounts of calcium carbo nate (25 mg) and was ashed at 880-degrees-C under an oxygen stream. Th e ash was dissolved with hydrochloric acid for the determination of bo ron by ICP-MS. The analytical results of various graphite samples by t he proposed method were in good agreement with those of the curcumin s pectrophotometric method. The relative standard deviations were 2.6 ap proximately 9.5% for samples which contained 0.05 approximately 0.008 mug g-1 levels of boron. The determination limit of boron was improved by this method in comparison with the curcumin method from 0.1 mug g- 1 to 0.004 mug g-1 in the case of 10 g graphite samples.