| Popis: |
The ability to accurately and promptly detect low concentrations of nitrites (NO₂-), nitrates (NO₃-), and other nitrogen groups, in a range of biological tissues and fluids, is of significant benefit in biological research and for nitric oxide’s (NO) development as a drug. There are several methods used to carry out such analyses, but all vary in their accuracy, selectivity and efficiency. The groundwork for a standard analytical method that is accurate, sensitive, selective, and economical was established. Using a Sievers 280i Nitric Oxide Analyzer (NOA) with a novel, adapted protocol, it was demonstrated consistent measurement of nanomolar (nM) concentrations of nitrite and micromolar (μM) concentrations of total nitrogen groups (TNG) in various bovine biological fluids including blood, milk, urine, and a slurry derived from muscle and fat. Initially, the precision and accuracy of the NOA was tested and defined using nitrite and nitrate standard solutions. Once the testing parameters of the NOA had been established, the nitrite and nitrate levels in biological samples were measured. The various biological samples were spiked with specific concentrations of sodium nitrite or sodium nitrate. Biological fluid samples were analysed by injection into a purge vessel containing an acidified iodide solution or a heated acidified vanadium (III) chloride solution to convert nitrite or the total nitrogen groups to NO. This allowed sensitive analysis of NO through chemiluminescence by the reaction of NO with ozone and subsequent photon emission of the nitrogen dioxide radical (NO₂●). The limit of blank (LoB) and limit of detection (LoD) were used as a measure of reliability. This novel method was shown to have reliable and robust performance in the measurement of nM concentrations of nitrites and μM concentrations of TNGs in a range of biological tissues and fluids. |
