New Device of High Sensitive and Simplified Detection System for Sulfur by Means of Mist-Gas Phase Chemiluminescent Reaction Associated with Skill-free Technology in Steel Analysis

Abstract

In relation to a skill-free technology in steel analysis, a new mist-gas phase chemiluminescent detection system for sulfur was devised to be coupled with a flow injection technique. The proposed system was composed of two manifolds of 8.0×10^-4M KMnO₄ and 1.0×10^-4M riboflavine phophate at pH 2.5 adjusted with H₂SO₄ and H₂S in N₂ balance and a chemiluminescent detection system. The reaction cell was made by a spherical glass flask of about 100 mm i.d.. An outlet of the spherical glass was connected with the nebulizer system, which was constructed by the triplicate tubing system of 0.5 mm i.d. brass, 5 mm i.d. pyrex glass having 0.8 mm i.d. at the edge and 4.5 cm i.d. vinyl chloride at the inside in order. The analysis was performed by a 5 sec injection of the chemiluminescent reagents at 10 ml/min into the continuous H₂S sample flow at 7.5 l/min. Sulfur content was indirectly determined in terms of that of H₂S. The chemiluminescent reaction scheme of H₂S was supposed to be same as in that of SO₂. In the optimized operating condition, the lower detection limit was 0.5 ppm and a calibration for the determination was linear between 0.5 ppm and 3.0 ppm. A reproducibility of the determination was less than 1% in terms of RSD at more than 10 repeating runs in 0.5 ppm, 1.0 ppm and 2.0 ppm H₂S concentrations. Analytical time required was less than 10 s for one sample. Their analytical figure of merits were usable for the skill-free grade technique in future.