Determination Of Nitrite In Urine And Plasma By Headspace Gas Chromatography

Nitrite, widely found in soil, water and food, is mainly in the form of sodiumnitritr(K). It shows a white crystalline powder, no smell, soluble in water, often used as apreservative, similar physical properties with salt, poisoning caused by eating regularly. Toeat by mistake, poison or intake lots of nitrite from vegetables. Therefore, It has importantsignificance to qualitative and quantitative nitrite in body fluid for saving lives and thedetection of poisoning case.Nitrite and sodium cyclamate had the reaction of acid reaction under acid conditionand detected the product of cyclohexanol. Cyclohexanol and nitrite continued to react andhad the product of cyclohexanol nitrous acid ester in acid condition. Cyclohexanol nitrousacid ester exists gaseous at room temperature, suitable for the quantitative detection byheadspace gas chromatogram.The principle was used to detect the nitrite in wine and food by some authors. Usually,nitrite was detected by mass spectrometry, ion chromatography and spectrum. Due to thecomplicated compositions of the human body fluid, the compositions had a greaterpollution on the instrument. Nitrite poisoning belongs to acute poisoning,there is often acollective poisoning incident, which requires a rapid and accurate detection. The articleused the above principle to discuss whether the reaction principle can be used in thedetection of nitrite in human body fluids, and searched for a quick, easy, accurate andefficient detection method.As, cyclohexanol nitrous acid ester was proportional to chromatographic responsevalue the concentration of nitrite, we can calculate the content of the nitrite in human bodyfluid on the basis of the linear relation. Through layer upon layer optimization ofexperimental conditions, to draw standard curve in the urine and plasma with the optimalexperiment scheme.Firstly, the Agilent7697A-7890A was used to research the high concentrationof standard curve in urine. The method of the minimum detection limit of0.5parts permillion, relative standard deviation was1.61%, the recovery is96.6%~102.1%. In order toavoid false positive results appeared in the sample, the Agilent7697A-7820A was used to research the low concentration of standard curve in urine. The method of the minimumdetection limit of0.125parts per million, relative standard deviation is2.62%, the recoveryis96.4%~102.9%.Secondly, According to the experimental data, the method is suitable to detect thenitrite in plasma.The lower limit of the method was1.0parts per million, relative standarddeviation was1.90%, the recovery was98.0%~103.5%.It is unable to detect the characteristic fragment ion peaks of cyclohexanol nitrousacid ester, therefore, the experimental condition is not applicable to the composition ofnitrite in blood for analysis.In the pre-processing and detection process, it has the advantages of simple operation,low interference, low detection limit, wide linear range to detect the nitrite in urine andplasma with this principle. Then, it would be well applied in a large quantities of thesample test. So far, it is an ideal method of detecting the nitrite in urine and plasma.