Determination of atmospheric sulfur dioxide without tetrachloromercurate(II) and the mechanism of the Schiff reaction

Journal Article · Wed Oct 01 04:00:00 EDT 1980 · Anal. Chem.; (United States)

DOI:https://doi.org/10.1021/ac50062a031· OSTI ID:6790939

Dasgupta, P K; DeCesare, K; Ullrey, J C

Formaldehyde (7 mM) buffered at pH approx. 4 is used to stabilize atmospheric SO/sub 2/ as hydroxymethanesulfonic acid. Equilbrium data for the above reaction are presented. Sulfite, liberated from the compound by base, is added to acidic pararosaniline for color development by the Schiff reaction, and absorbance is measured at 580 nm. The procedure has been optimized with regard to acidity and reagent concentrations. The method is comparable to the West-Gaeke method in absorption and recovery efficiency, sensitivity, and precision. No unusual interferences are observed due to O/sub 3/, NO/sub 2/, and transition-metal ions, except Mn(II). A novel ion chromatographic procedure to determine hydroxymethanesulfonate and sulfate in the same sample is also described. Enhancement of sensitivity in the colorimetric method by solvent extraction has been studied. Investigations into the mechanism of the Schiff reaction and structure of the products have established the validity of the alkylsulfonic acid theory. Mechanistically an aminocarbinol seems to be the first intermediate, which undergoes subsequent nucleophillic substitution by bisulfite ion. To account for the high absorptivity of the product, we suggest that the sulfonic acid group is significantly ionized.

• Research Organization: Univ. of California, Davis
• OSTI ID: 6790939
• Journal Information: Anal. Chem.; (United States), Journal Name: Anal. Chem.; (United States) Vol. 52:12; ISSN ANCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400104* -- Spectral Procedures-- (-1987)
ABSORPTION SPECTROSCOPY
ALCOHOLS
ALDEHYDES
AMINES
AROMATICS
BUFFERS
BUTANOLS
CHALCOGENIDES
CHROMATOGRAPHY
COMPARATIVE EVALUATIONS
DYES
ELEMENTS
ESTERS
EXTRACTION
FORMALDEHYDE
HYDROXY COMPOUNDS
IMINES
INTERFERING ELEMENTS
ION EXCHANGE CHROMATOGRAPHY
KINETICS
MANGANESE
METALS
OPTIMIZATION
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PENTANOLS
REACTION KINETICS
SCHIFF BASES
SEPARATION PROCESSES
SOLVENT EXTRACTION
SPECTROSCOPY
SULFATES
SULFONIC ACID ESTERS
SULFONIC ACIDS
SULFUR COMPOUNDS
SULFUR DIOXIDE
SULFUR OXIDES
TRANSITION ELEMENTS