Miniature polarographic H2S sensors

The miniature PHSS design was based on the original design of the macro PHSS [41], The 2 mm diameter PHSS utilized a cylindrical polished-tip platinum anode that was electrically insulated along the side from a platinum cathode that was coiled around the core (Pig. 8.3). The core was housed in a 2mm outside diameter stainless steel cylindrical sleeve that served as an electrical shield and to which a 25 om thick H2S-permeable membrane was fixed to cover the tip. The reservoir between the sleeve and core 

FIGURE 8.3 Diagram of the miniature PHSS and respirometer system. The respirometer chamber Osft) is equipped with three sensors, the PHSS and PNOS in the chamber stopper and the POS diagonal to the chamber bottom, and has a minimum volume of 2 ml. Tissue is held on a support just above the stir bar for adequate perfusion. The miniature PHSS (right) is approximately 5 mm long and 2 mm outside diameter. The anode is polished at the tip, the cathode is coiled around the insulated anode, the H2S-permeable membrane is cemented to the stainless steel sleeve, and the 30 pL electrolyte volume covers both anode and cathode (after [41]). 

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