Electrochemical determination of sulfur dioxide in air samples in a closed-loop flow injection system
SO/sub 2/(g) in air samples is amperometrically determined in a closed-loop flow injection system by direct intercalation of the air sample into a carrier solution containing the binuclear form of the iron(III) complex with 1,10-phenanthroline acting as a regenerable chemical probe. The extent of reduction to the mononuclear iron(II) complex, ferroin, by reaction at the gas/liquid interface is amperometrically monitored with a three-electrode system at an applied potential of 0.964 V vs. Ag/AgCl reference electrode (working electrode, carbon paste). The ferroin produced in the reduction process is electrochemically oxidized back to the binuclear iron(III) complex permitting the implementation of a closed-loop system with regeneration of the main reagent. By application of a continuous-flow/stopped-flow operation, SO/sub 2/(g) can be determined in the range of 0.3-14.0 ppm (v/v) with relative standard deviations of about 3% (11 replicas) and at a rate of 25 samples per hour. By pretreatment of the carbon paste electrode with a surfactant solution, the same limit of detection can be achieved without need for stopping the sample plug, thus increasing the number of samples that can be determined per hour to 35.
- Research Organization:
- Universidad de Cordoba, Spain
- OSTI ID:
- 6814175
- Journal Information:
- Anal. Chem.; (United States), Vol. 59:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
54 ENVIRONMENTAL SCIENCES
AIR
QUANTITATIVE CHEMICAL ANALYSIS
AIR POLLUTION MONITORS
PERFORMANCE
SULFUR DIOXIDE
AMPEROMETRY
ELECTROCHEMISTRY
EXPERIMENTAL DATA
FLUID FLOW
INJECTION
IRON COMPLEXES
PHENANTHROLINES
TRACE AMOUNTS
AROMATICS
AZAARENES
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMISTRY
COMPLEXES
DATA
FLUIDS
GASES
HETEROCYCLIC COMPOUNDS
INFORMATION
INTAKE
MEASURING INSTRUMENTS
MONITORS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
SULFUR COMPOUNDS
SULFUR OXIDES
TITRATION
TRANSITION ELEMENT COMPLEXES
400102* - Chemical & Spectral Procedures
500200 - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)
400400 - Electrochemistry