Determination of trace concentrations of dissolved nitric oxide in a biological buffer.
A new real-time method for measuring a trace concentration of nitric oxide (NO) in a complex matrix routinely used in pharmacological studies of its bioactivity is described. NO was quantified as a gas by chemiluminescence after extraction from a continuous liquid sample flow with a limit of detection of 0.042 nmol dm(-3) at a signal to noise ratio of 3. Theories to calculate the concentration of NO in the liquid sample flow from a direct measurement of NO in the extraction carrier gas are presented. The efficiency of extraction is determined by a stopflow experiment. An example is presented of the measurement of the steady-state concentrations of NO in Krebs-bicarbonate buffer at pH 7.4 and 37 degrees C when its liquid surface is sequentially exposed to gases containing various concentrations of NO in O2 plus CO2.
Demoncheaux
E A G
EA
Division of Clinical Sciences (South), School of Medicine and Biomedical Sciences, Floor F, University of Sheffield, Beech Hill Road, Sheffield, UK S10 2RX. e.demoncheaux@sheffield.ac.uk
Foster
P J
PJ
Borland
C D
CD
Smith
A P L
AP
Higenbottam
T W
TW
Davies
M B
MB
D017022:Flow Injection Analysis / Q000379:methods; D008163:Luminescent Measurements; D009569:Nitric Oxide / Q000032:analysis*; D014665:Vasodilator Agents / Q000032:analysis*
D014665:Vasodilator Agents; D009569:Nitric Oxide