Department of Chemistry, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555, Japan.
Anal Chem. 2009 Aug 15;81(16):7031-7. doi: 10.1021/ac901131d.
A novel method is proposed to measure NO in breath. Breath NO is a useful diagnostic measure for asthma patients. Due to the low water solubility of NO, existing wet chemical NO measurements are conducted on NO(2) after removal of pre-existing NO(2) and conversion of NO to NO(2). In contrast, this study utilizes direct measurement of NO by wet chemistry. Gaseous NO was collected into an aqueous phase by a honeycomb-patterned microchannel scrubber and reacted with diaminofluorescein-2 (DAF-2). Fluorescence of the product was measured using a miniature detector, comprising a blue light-emitting diode (LED) and a photodiode. The response intensity was found to dramatically increase following addition of NO(2) into the absorbing solution or air sample. By optimizing the conditions, the sensitivity obtained was sufficient to measure parts per billion by volume levels of NO continuously. The system was applied to real analysis of NO in breath, and the effect of coexisting compounds was investigated. The proposed system could successfully measure breath NO.
提出了一种测量呼吸中一氧化氮（NO）的新方法。呼吸中的 NO 是哮喘患者的一种有用的诊断手段。由于 NO 的水溶性低，现有的湿化学 NO 测量方法是在去除预先存在的 NO(2)并将 NO 转化为 NO(2)后，对 NO(2)进行测量。相比之下，本研究利用湿化学直接测量 NO。通过蜂窝状微通道洗涤器将气态 NO 收集到水相中，并与二氨基荧光素-2（DAF-2）反应。使用微型探测器测量产物的荧光，微型探测器包括一个蓝光发光二极管（LED）和一个光电二极管。发现，在吸收溶液或空气样品中加入 NO(2)后，响应强度显著增加。通过优化条件，获得的灵敏度足以连续测量体积分数为十亿分之一的 NO 水平。该系统应用于呼吸中 NO 的实际分析，并研究了共存化合物的影响。所提出的系统可以成功地测量呼吸中的 NO。
