Direct, Selective, and Rapid Measurement of HCN at Sub-ppb Levels Using HiT-CD-IMS: Applications to Cell Culture and Breath Analysis.

This study demonstrates the use of a research-grade ion mobility spectrometer combined with a high-temperature negative corona discharge ionization source (HiT-CD-IMS) to detect hydrogen cyanide (HCN) emitted by Pseudomonas aeruginosa (PA) cultures and in human breath. The HCN spectrum revealed distinct peaks for CN-, CNO-, and (CN)2- ions, with a resolving power of 63, successfully overcoming potential interferences such as the H2S peak by optimizing the experimental conditions. This approach achieved an estimated limit of detection (LOD) of 0.18 ppb. The method was applied to monitor HCN production in PA cultures, demonstrating a clear correlation between bacterial growth and HCN emission. Additionally, breath samples from the mouth cavity and nose-exhaled samples showed measurable HCN concentrations in the range of 40-300 ppb and below 10 ppb, respectively. The technique's ability to measure HCN in complex biological environments with high sensitivity, even in the presence of water vapor and common respiratory compounds, underscores its potential for noninvasive detection of Pseudomonas aeruginosa in infections.