Sulfur dioxide sensing based

Sulfur Dioxide. Hensina Based on Sulfite Selective Membrane Electrode. The Hg(DCC)2 based sulfite selective electrode described above can be used as a transducer to devise new SO2 selective gas sensing systems according to the detection schemes depicted in Figure 1. The addition of the outer gas permeable membrane enables measurements to be made in the presence of ions which would normally be... 

By using different membranes, it is possible to obtain potentiometric sensors for gases such as sulfur dioxide or nitrogen dioxide. Such sensors employ similar (acid-base) or other equilibrium processes. These devices, along with their equilibrium processes and internal electrodes, are summarized in Table 6.2. Membrane coverage of other ion-selective electrodes (e.g., chloride) can be used for the sensing of other gases (e.g., chlorine). 

Multimembrane systems are another type of potentiometric sensor based on ISEs, wherein the ISE response is modified by an additional membrane of a different function. To this group of sensors belong gas-sensitive electrodes, with a hydrophobic membrane isolating the analyte firom the complex sample medium. The chemical reaction of the gaseous analyte with a component of the solution surrounding the ISE membrane proper directly produces the species to be sensed by the electrode. In food analysis, electrodes used for sulfur dioxide or ammonia belong to this group of sensors. 

Sulfur Chemiluminescence Detector. Another sulfur selective detector based on photometric sensing of a chemiluminescent reaction has become commercially available (Sievers Research, Inc., Boulder, CO). Similar to the FPD, the detection scheme of the SCD incorporates combustion of the GC column effluent in a hydrogen rich flame. However, the sulfur species detected is an excited state of sulfur dioxide (SO2 ), not... 

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