Measuring nitrite and nitrate in microdialysate
Brain nitrite production during global ischemia and reperfusion: an in vivo microdialysis study
Ringer’s solution (140 mM NaCl, 4 mM KCl, 1.26 mM CaCl2,and 1.15 mM MgCl2; pH 7.4) was perfused at a constant flow rate of2 Ìl/min. The perfused dialysates were collected every 10 min in thesample loop of an automated sample injector connected to an automatedNO detector-HPLC system without air contamination (ENO-20; Eicom).
1. NO2 / NO3 levels are highly sensitive to air in small microdialysate samples. An autoinjector should be used so that the sample never comes in contact with air.
2. Bacterial contamination of the microdialysis tubing will degrade NO2/NO3 so levels will read too low: tubing, syringes, etc. should be cleaned with bleach after use.
3. Plasticware, including tubing and the probe, will be contaminated with nitrate/nitrite during the manufacturing process. The entire system (including the probe)should be flushed with aCSF for 3 hours before use to wash this away.