Nitroso-R-salt spectrophotometric determination of cobalt in alloy steel

A better Nitroso-R-salt spectrophotometric method was established to determine cobalt content in alloy steel.The influence of various experimental parameters,including wavelength,buffer solutions, oxidant,acid types,heating time and coexist ions,on the accuracy and precision were investigated in detail. Combining with differential photometry,the high content of cobalt in alloy steel can be determined in the presence of the interference elements such as Fe,Cu,Ni and Cr etc.The relative error is under 3% and relative standard deviation is under 1%.The test result for the cobalt standard with high content is satisfactory.It was proved that the method we developed in this paper has wide linear range,good reproducibility, fast speed and high accuracy,which is suitable for quality control in industry.