Department of Surgery and Cancer, Imperial College London, St. Mary's Hospital, London W2 1PE, United Kingdom.
Division of Colon and Rectal Surgery, Chang Gung Memorial Hospital, Chang Gung University, Tao-Yuan City 33305, Taiwan.
J Am Soc Mass Spectrom. 2021 May 5;32(5):1215-1223. doi: 10.1021/jasms.1c00027. Epub 2021 Apr 8.
Volatile breath metabolites serve as potential disease biomarkers. Online mass spectrometry (MS) presents real-time quantification of breath volatile organic compounds (VOCs). The study aims to assess the relationship between two online analytical mass spectrometry techniques in the quantification of target breath metabolites: selected ion flow tube mass spectrometry (SIFT-MS) and proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS). The two following techniques were employed: (i) direct injection with bag sampling using SIFT-MS and PTR-ToF-MS and (ii) direct injection and thermal desorption (TD) tube comparison using PTR-ToF-MS. The concentration of abundant breath metabolites, acetone and isoprene, demonstrated a strong positive linear correlation between both mass spectrometry techniques ( = 0.97, = 0.89, respectively; < 0.001) and between direct injection and TD tube ( = 0.97, = 0.92, respectively; < 0.001) breath sampling techniques. This was reflected for the majority of short chain fatty acids and alcohols tested ( > 0.80, < 0.001). Analyte concentrations were notably higher with the direct injection of a sampling bag compared to the TD method. All metabolites produced a high degree of agreement in the detection range of VOCs between SIFT-MS and PTR-ToF-MS, with the majority of compounds falling within 95% of the limits of agreement with Bland-Altman analysis. The cross platform analysis of exhaled breath demonstrates strong positive correlation coefficients, linear regression, and agreement in target metabolite detection rates between both breath sampling techniques. The study demonstrates the transferability of using data outputs between SIFT-MS and PTR-ToF-MS. It supports the implementation of a TD platform in multi-site studies for breath biomarker research in order to facilitate sample transport between clinics and the laboratory.
挥发性呼吸代谢物可作为潜在的疾病生物标志物。在线质谱（MS）可实时定量分析呼吸挥发性有机化合物（VOCs）。本研究旨在评估两种在线分析质谱技术在目标呼吸代谢物定量中的关系：选择离子流管质谱（SIFT-MS）和质子转移反应飞行时间质谱（PTR-ToF-MS）。采用以下两种技术：（i）SIFT-MS 和 PTR-ToF-MS 的袋采样直接进样，（ii）PTR-ToF-MS 的直接进样和热解吸（TD）管比较。丰度较高的呼吸代谢物丙酮和异戊二烯的浓度在两种质谱技术之间呈强正线性相关（ = 0.97， = 0.89，均 < 0.001），直接进样和 TD 管之间也呈强正线性相关（ = 0.97， = 0.92，均 < 0.001）。经测试，大部分短链脂肪酸和醇类也呈现这种相关性（ > 0.80， < 0.001）。与 TD 法相比，直接进样采集袋中的分析物浓度明显更高。SIFT-MS 和 PTR-ToF-MS 对所有代谢物的检测结果都高度一致，大多数化合物的浓度均在 Bland-Altman 分析的 95%一致性限内。呼气呼吸的跨平台分析显示，两种呼吸采样技术之间具有很强的正相关系数、线性回归和目标代谢物检测率的一致性。该研究证明了在 SIFT-MS 和 PTR-ToF-MS 之间使用数据输出的可转移性。它支持在多站点研究中采用 TD 平台，以促进临床和实验室之间的样本运输，从而促进呼吸生物标志物研究。
