• Four port (WPI #NOCHM-4) chambers accommodate WPI’s 2-mm sensors for nitric oxide (ISO-NOP), oxygen (OXEL-1), hydrogen peroxide, and WPI’s KWIK-TIP ion selective electrodes in combination with WPI’s 2 mm Dri-Ref™ reference electrodes. 
• Two additional top ports for injection of reagents using WPI’s MicroFil™ syringe needles 
• Closed chamber design greatly reduces the surface area of the solution exposed to air 
• One top port and up to three side ports configuration provides adequate space for convenient sample and electrode manipulation 
• Temperature control through an external circulating bath 
• The chamber can be used for nitric oxide and other species calibration at temperatures from 4-40 ºC

The measurement of NO and other reactive gases dissolved in solutions will be underestimated in stirred conditions if the solution is allowed to equilibrate with air. In the case of NO, accelerated decomposition occurs as the result of diffusion of NO from the solution into the gas phase and the reaction of NO with oxygen. This reaction with oxygen makes a significant and variable contribution to NO decomposition, and hence accuracy of measurement, at concentrations of NO between 0.1-5 µM. These problems can now be eliminated with the use of WPI’s two-port NOCHM or four-port NOCHM-4 closed chambers. The chambers consist of a close fitting cap through which a NO probe (ISO-NOP) or other electrode can be inserted. When the probe is in place and the cap is fitted to the chamber the surface area of the solution exposed to air is greatly reduced. Up to three optional side ports are also provided through which an oxygen electrode , WPI’s hydrogen peroxide, or KWIK-TIP ion selective electrodes in combination with WPI’s 2 mm Dri-Ref™ reference electrodes can be inserted.
The multi-port measurement chambers can be conveniently temperature-controlled by circulating water through the outer sleeve of the chamber using an appropriate heating/cooling circulator bath. The inner volume of the chamber (and hence sample volume) can be continuously adjusted in volume from 1.0 mL to 3.0 mL and is suitable for most cell suspension experiments.
 

P. S. Brookes, E. P. Salinas, K. Darley-Usmar, J. Eiserich, B. A. Freeman, V. M. Darley-Usmar, P. G. Anderson. “Concentration dependent effects of nitric oxide on mitochondrial permeability transition and cytochrome c release”. J. Biol. Chem. 275, 20474-9 (2000).