title: On-line collection/concentration and detection of sulfur dioxide in air by flow-injection spectrophotometry coupled with a chromatomembrane cell.
abstract: A simple and rapid procedure for SO2 determination in air was developed by using a flow injection analysis (FIA) system coupled with a 3-hole chromatomembrane cell (CMC). The CMC was applied for the on-line collection/concentration of SO2 from air into a solution of 2 g l(-1) triethanolamine (TEA) solution as an absorbing solution: SO2 was converted to SO3(2-) in the alkaline absorbing solution. The solution containing absorbed SO2 was introduced into the carrier stream of the FIA system. The amount of SO3(2-) in the absorbing solution was measured by spectrophotometry with a mixed reagent of pararosaniline and formaldehyde, and was converted to the concentration of SO2 in the air sample. A calibration graph prepared by using standard sodium sulfite aqueous solutions was adopted for the determination of SO3(2-) in the absorbing solution. The SO2 concentration in indoor air examined was found to be 22.7 +/- 0.2 ppbv using 20 ml of air sample with the air flow rate of 5 ml min(-1), where the relative standard deviation was 1.7%. The detection limit for aqueous solutions and air samples were 6.9 x 10(-8) M and 0.48 ppbv, respectively. The measuring time for one sample was about 10 min when a 20 ml air sample was used. The interferences from common anionic species, formaldehyde and acetaldehyde, were also examined.
authors.affiliation: Department of Chemistry, Faculty of Science, Okayama University, 3-1-1 Tsushimanaka, Okayama 700-8530, Japan.
authors.forename: Piyanete
authors.initials: P
authors.lastname: Sritharathikhun
authors.forename: Mitsuko
authors.initials: M
authors.lastname: Oshima
authors.forename: Yanlin
authors.initials: Y
authors.lastname: Wei
authors.forename: Jürgen
authors.initials: J
authors.lastname: Simon
authors.forename: Shoji
authors.initials: S
authors.lastname: Motomizu