A Novel FI System for Chemical Analysis of Stainless Steels for Nickel Determination without Complicated Procedures and a Great Deal of Skill

A novel flow injection (FI) system is presented for the determination of nickel as one of major constituents in stainless steel. The in-line cation-exchange separation of nickel from matrix iron and chromium utilising tartrate solution as an eluent is directly coupled with photometric detection in a continuous flow system. The photometric detection system developed here exploits the formation of water soluble complex of nickel with dimethylglyoxime in the presence of iodine as oxidizing agent in a NaOH basic media. The FI manifold and the optimum reaction conditions were established in order to achieve the simple and precise determination of nickel. A sample solution prepared by dissolving steel sample in aqua regia and diluting to the volume with water can be directly injected into the flow injection system and thus no labonus complicated manual operations for pretreatment of sample solution is needed. The present FI system offers many advantages, especially with respect to simplicity and rapidity, permitting the precise determination of nickel in a wide range of contents % with a short analysis time (<15 min) and a precision less than 1% and without a great deal of skill. The analytical results by the proposed FIA system for four Japanese Iron and Steel Certified Reference Materials (JSS CRMs) agreed well with the cerified values for nickel.