Abstract
As one of the analytical applications to welfare supporting technologies, the most simplified single line flow injection (FI) system was successfully designed for sulfur determination by solution chemiluminescence detection. The reaction flow cell in the detection system was equipped with commercial Nalgen capillary tubing of 1 mm i.d. and 2 mm o.d. spiraled to ca. 5 cm size. The photomultiplier tube {R 376, made by Hamamatsu Photonics Co. Ltd. (Shizuoka Pref.)} was used for chemiluminescence detection. The chemiluminescent reaction using an emitter (Rhodamine B) and a non-ionic surfactant (Tween 80) was based on the dissolved oxygen oxidation of sodium hydrogen sulfite. Rhodamine B and Tween 80, which contributed to chemiluminescence enhancement, also played key roles in energy transfer and a surfactant micellar effect,respectively. The lower detection limit and the determination range of the proposed method were 2.0×10−6 M and 2.0×10−6 M to 1.5×10−5 M using 20 μl sample injections of sodium hydrogen sulfite, respectively. The analytical time required was less than 10 s for one sample. The reproducibility in 10 repeated runs by 20 μl sample injections of 1.4×10−5 M sodium hydrogen sulfite was 2% in terms of the relative standard deviation. The selectivity of the proposed method was good, and 1×10−5 M of foreign compounds gave no interference to coexistence in 1×10−4 M sodium hydrogen sulfite. Both of the amount and chemical species of the exhausted material in the present method were smaller in compared to those in the iodometric sulfite anion determination method (JIS method).
