基于光腔衰荡光谱的呼吸丙酮分析仪设计与实现

目的 利用光腔衰荡光谱（CRDS）搭建了一套呼吸丙酮分析仪,以研究人体呼吸中的糖尿病潜在生物标志物丙酮,推动呼吸分析在临床疾病诊断或代谢监测中的应用.方法 选择266 nm紫外脉冲激光器作为光源,反射率为99.956％的高反镜组成衰荡腔,以光电倍增管（PMT）为探测器,在尺寸为60 cm×20 cm的铝板上搭建了一套可移动式呼吸分析仪.用不同体积分数的标准丙酮气体验证仪器的准确度与线性响应后,将其用于健康人体与糖尿病患者的呼吸样本测量.结果 实验测得高反射镜等效反射率为99.93％,仪器典型的衰荡时间基线平均值为2.386 4μs,稳定度为0.22％,对不同体积分数的丙酮样本具有线性响应（R2=0.99）,仪器检测极限为0.13×10-6（3σ准则）.结论 该呼吸分析仪具有良好的稳定性与重复性,可满足临床上人体呼吸的测量要求,并即将用于大量的临床呼吸测试以研究呼吸标志物与疾病之间的相关性.

Design and implementation of acetone breath analyzer based on cavity ringdown spectroscopy

Objective To construct a breath analyzer based on cavity ringdown spectroscopy （CRDS） to study breath acetone,the potential biomarker of diabetes and to promote application of breath analysis to clinical diagnostics and metabolic monitoring.Methods We selected ultraviolet laser with wavelength of 266 nm as light source,mirrors with reflectance of 99.956% as ringdown mirror and photomultiplier tube （PMT） as detector,the breath analyzer was constructed on an aluminum plate with size of 60 cm×20 cm.After validation by standard acetone gas samples with various concentrations,it was applied to the test of healthy and diabetic breath samples.Results The effective reflectance of mirrors was 99.93%,mean value of the typical ringdown time baseline was 2.386 4 μs and stability was 0.22%.Its response to standard acetone samples with various concentration was linear （R 2=0.99）,and the detection limit was 0.13×10-6 （3σ criteria）.Conclusions This breath analyzer has good stability and reproducibility,which can meet the requirement of clinical breath tests and may be applied to extensive breath tests to investigate the correlations of biomarkers and diseases.