This standard GB/T 223.38-1985 specifies the determination method of niobium content in steel and alloys, that is, analysis by ion exchange separation-weighting method. The hydrofluoric acid-muriatic acid solution containing niobium in the sample is treated with strong alkaline anion exchange Resin to separate niobium from iron, nickel, cobalt, copper, vanadium, tungsten, molybdenum, tantalum, titanium, zirconium and other elements. After niobium is masked with fluorine by Boricacid in the elute solution, copper-iron reagent settling is used in an acidic medium, and finally it is burned into five oxidation diniobium and weighed. The standard details the required reagents and their preparation methods to ensure the accuracy and Reliability of the determination.