抄録
A simple and reliable semimicro-method for sulfur dioxide (SO2) and sulfite ion (SO32-) in small scale samples is developed on the basis of the standard pararosaniline method. The amount of the solution for colorimetry is minimized to one twenty-fifth (1.0ml) by using a microcell (2×10 mm; volume, 0.5 ml). In addition, precisely calibrated ad justable pippettes with pushbutton operation and 2. 5 ml small stoppered test tubes are used for small size solutions and for simplification of the coloring. The precision of this method was about 1% in coefficient of variation; slightly lower than that of the standard method, but it is high enough for general purposes.
The micro-bubbler was devised to transfer SO2 in gas samples in containers to 0.68 ml absorbing solution (0.04 M potassium tetrachloromercurate, TCM) and the microsyringe (10 or 100 μl) sampling technique was studied out for small size liquid samples. The semimicro-method with these techniques was applied to the analysis of SO2 of 1 ppm or above in 100 ml gas samples taken in a 200 ml syringe, a gas sampling tube and a Mylar bag and of SO32- of 2μg/ml or above in 10μl rain drops.
