亚硝酸盐对氨水法测定碳氧血红蛋白的影响

Effect of Blood-harbored Nitrite on Determination of Carboxyhemoglobin via Ammonia

探究血液中亚硝酸盐的存在对氨水法测定碳氧血红蛋白的结果影响及影响机理,为使用氨水法测定排除干扰,为准确定性定量测定血液中的碳氧血红蛋白提供参考依据。利用紫外-可见分光光度仪在高级读数模式下测定不含亚硝酸盐的不同碳氧血红蛋白含量系列检材血样,再向该系列检材血样中分别加入不同浓度亚硝酸盐后在同等条件下测定碳氧血红蛋白含量,分析含量变化规律,探究亚硝酸盐对氨水法测定碳氧血红蛋白产生影响的原因。结果表明,血液中亚硝酸盐的存在会导致使用氨水法测定碳氧血红蛋白时出现假阳性并能使碳氧血红蛋白含量较低的阳性检材血样的测定值增大。在使用氨水法对需要进行碳氧血红蛋白测定的血样进行定性定量分析时,应重视可能出现的诸如亚硝酸盐或其他具有类似化学性质的毒物的存在造成的影响,防止误判。

Hiemal fire heating and pickles eating could sometimes make carbon monoxide and nitrite co-occurrently appear into some specific living conditions,resulting in the relevant poisoning incidents.However,both the carbon monoxide and nitrite are usually such low of their concentration in blood that it is difficult to judge the true cause of poisoning from just one and/or two of them by the superficial symptoms on corpse because nitrite will affect the accuracy of the commonly-used ammonia method to determine the carboxyhemoglobin harbored with blood.Through exploration of influence of contentdifferent nitrite on ammonia-determination of carboxyhemoglobin and the involving mechanism,this paper was purposed to provide support and principle reference for accurate qualitative and quantitative determination of carboxyhemoglobin via ammonia under elimination of interference from nitrite and other analogous substances.With ultraviolet visible(UVVis)spectrophotometer set at the advanced reading mode,the carboxyhemoglobin was respectively ammonia-determined of its contents in series of blood samples without nitrite and with addition of concentration-various nitrite,hence having the reasons explored into why nitrite influences the determination of carboxyhemoglobin via ammonia and the content threshold of influence.The presence of nitrite in blood does lead to false positive results when the blood-harbored carboxyhemoglobin is determined via ammonia with UV-Vis spectrophotometer,or have the content-low carboxyhemoglobin increased of its determined value.Nevertheless,the carboxyhemoglobin,if high concentration in blood,will receive less influence and just decrease its determined value slightly,thus leaving behind an overall relatively tiny effect.In principle,the content of carboxyhemoglobin is determined via ammonia through the calculation based on subtraction of the absorbance of carboxyhemoglobin at the corresponding wavelength from that of oxygenated hemoglobin.Therefore,with ability of the coexisting nitrite to have the oxygenated hemoglobin decreased of its content and the consequent absorbance,the ammonia method is certainly not able to deliver the accurate qualitative and quantitative determination of related carboxyhemoglobin.Accordingly,when there is the possibility of co-existence of carbon monoxide and nitrite or other analogous substances at a case scene,the comprehensive judgement should manage to consider the carboxyhemoglobin content and chemical properties of all involving substances so as to prevent misjudgment.