Tentative method of test for sulfur dioxide content of the atmosphere (West--Gaeke method). [Spectrophotometrically as pararosaniline methyl sulfonic acid]

Journal Article · Wed Jan 01 04:00:00 EST 1975 · Annu. Book ASTM Stand.; (United States)

OSTI ID:7356874

Concentrations of SO/sub 2/ in the atmosphere of 0.003 to 5.0 ppM are determined spectrophotometrically as the intensely colored pararosaniline methyl sulfonic acid at 548 nm. The SO/sub 2/ is absorbed by aspirating a measured air sample through a solution of potassium or sodium tetrachloromercurate. EDTA is added to this solution to complex heavy metals that can interfere by oxidation of the SO/sub 2/ before the formation of the dichlorosulfitomercurate. After absorption, any ozone in the solution is allowed to decay to prevent its interference. The nitrite anion that might be formed by absorption of oxides of nitrogen is destroyed by the addition of sulfamic acid. The absorber solution is then treated with formaldehyde and specially purified acid-bleached pararosaniline containing phosphoric acid to control pH. These react with the bisulfite anion to yield the intensely colored sulfonic acid at pH 1.6. (BLM)

• OSTI ID: 7356874
• Journal Information: Annu. Book ASTM Stand.; (United States), Journal Name: Annu. Book ASTM Stand.; (United States) Vol. 26; ISSN ASTSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400104* -- Spectral Procedures-- (-1987)
500200 -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
AIR
CHALCOGENIDES
CHEMICAL ANALYSIS
FLUIDS
GASES
MONITORING
OXIDES
OXYGEN COMPOUNDS
SPECTROPHOTOMETRY
STANDARDS
SULFUR COMPOUNDS
SULFUR DIOXIDE
SULFUR OXIDES