VOLATILIZATION OF METHYL BORATE IN IRON MATRIX - DETERMINATION OF BORON IN STEEL BY ICP ATOMIC-EMISSION SPECTROMETRY

A rapid and reliable method for the determination of boron by ICP-AES in steels is described. The procedure is based on a discontinuous gene ration of methyl borate, in concentrated sulphuric acid and phosphoric acid medium, after injecting 45 mul of methanol in 20 mul of sample. The gaseous methyl borate and excess methanol are fed into the ICP tor ch via the intermediate tube by a flow of 430 ml/min Ar carrier gas, w ithout disturbing the discharge. This work simplifies drastically the existing methodology of boron analysis in steels. Acid-soluble boron h as been determined, but acid-insoluble boron can also be determined. T he determination is carried out without iron interferences, with a rep roducibility of 1.90% r.s.d. for a concentration of 20 mug/ml, and an absolute detection limit of 20 ng of total boron, working with a solut ion volume of 20 mul.