title: Determination of trace concentrations of dissolved nitric oxide in a biological buffer.
abstract: 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.
authors.affiliation: 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
authors.forename: E A G
authors.initials: EA
authors.lastname: Demoncheaux
authors.forename: P J
authors.initials: PJ
authors.lastname: Foster
authors.forename: C D
authors.initials: CD
authors.lastname: Borland
authors.forename: A P L
authors.initials: AP
authors.lastname: Smith
authors.forename: T W
authors.initials: TW
authors.lastname: Higenbottam
authors.forename: M B
authors.initials: MB
authors.lastname: Davies
mesh_terms: D017022:Flow Injection Analysis / Q000379:methods; D008163:Luminescent Measurements; D009569:Nitric Oxide / Q000032:analysis*; D014665:Vasodilator Agents / Q000032:analysis*
chemical_list: D014665:Vasodilator Agents; D009569:Nitric Oxide