Flow Chemiluminescent Determination of Chromium in Stainless Steel

Abstract

A simple and rapid flow injection (FI) chemiluminescence (CL) method is described for the skill free-determination of chromium in stainless steel. The method is based on the measurement of light emitted from the CL system, Brilliant sulfoflavine (BSF)-H₂O₂-NaOH-CH₃CN. The CL is considered to be BSF-sensitized emission, which results from the energy transfer to BSF from singlet oxygen molecules produced through the decomposition of H₂O₂ by Cr³⁺. Interferences from Fe³⁺ and Ni²⁺ are reduced by the addition of citrate. The analytical results for stainless steel samples by the proposed method agreed well with the certified values for chromium. The advantages of the proposed method are that Cr³⁺ can be determined with a short analysis time (30 samples/h), good repeatability (ca. 1% R.S.D. in stainless steel analysis) and without any special pretreatment.