This standard GB/T 223.42-1985 specifies a method for the determination of tantalum in steel and alloys, using ion exchange separation-bromophthaloglucinol red spectrophotometry. This method is suitable for the determination of tantalum in steel, alloy steel, superalloys and precision alloys, and the determination range is 0.010% to 0.50%. In acidic solution, tantalum reacts with bromophthaloglucinol red to form a blue-violet complex. In order to exclude interfering elements such as iron, titanium, molybdenum, aluminum, zirconium, bismuth, niobium, etc., ion exchange is used to separate, and bismuth is masked by EDTA. The standard details the required reagents and their preparation methods, such as muriatic acid, hydrofluoric acid, bromoocetyltrimethylamine, etc., to ensure the accuracy and Reliability of