Electronic nose versus quadrupole mass spectrometry for identifying viral hepatitis C patients

Hepatitis C is a leading cause of liver disease and transplantation and is a significant burden on public health worldwide. This study aimed to apply the Electronic Nose (E-Nose) and quadrupole Mass Spectrometry (MS/MS) technologies for screening blood samples from hepatitis C patients and healthy controls. We analysed volatile organic compounds (VOCs) in the headspace over blood samples to identify those VOCs characteristic for diagnosing hepatitis C patients. The study comprised 150 acute hepatitis C patients with age range: 24-59 years, and mean age ±SD: 41.5 ± 12.8 years and 150 age-matched healthy controls (age range: 24-51 and mean age: 40.11 ± 4.89 years) from the Hospital of the Medical Research Institute, Alexandria University, Alexandria, Egypt. Collected blood samples were analysed qualitatively and quantitatively using the E-Nose and MS/MS techniques, respectively. Principal component analysis of the E-Nose 10-sensor responses accurately classified blood samples from hepatitis C patients and healthy controls. The first two principal components explained over 98.35% of the variance in signals with no false-positive (healthy controls) or false-negative (hepatitis C patients) results. MS/MS showed two fragmentation ions at m/z of 104 and 151 Da with the positive electrospray ionization mode (ESI+) in blood samples for hepatitis C patients, but not for healthy controls or background water samples. We identified the two specific fragmentation ions at m/z 104 and m/z 151 Da as malonic acid (MF: C₃ H₄ O₄ ; MW: 104.06 g/mol) and monosaccharide pentose (MF: C₅ H₁₀ O₅ ; MW: 150.13 g/mol) in VOCs of the headspace over blood samples for hepatitis C patients. This provides a rationale for developing diagnostic tests for hepatitis C virus based on altered trace VOCs concentrations using the relatively inexpensive, easy-to-use, portable and non-invasive E-Nose technology.