Untargeted Metabolomics by HS-SPME-GC×GC-ToFMS of Volatile Organic Compounds in Bronchoalveolar Lavage Fluids from Patients Diagnosed with Pulmonary Diseases

Abstract

Various lung diseases exist and affect hundreds of millions of people of all ages worldwide. The available treatments usually focus only on decreasing the symptoms rather than thoroughly treating the disease. The aim of this study is to implement and optimise a comprehensive and robust method to discover potential metabolites that could lead to more targeted treatments. In this regard, HS-SPME-GC×GC-ToFMS was optimised for the analysis of bronchoalveolar lavages (BAL) from patients diagnosed with various lung diseases, using a mixture of BAL samples (i.e., pooled QC BALF). This study highlighted that the normal column combination (Rxi®-5ms × Rxi®-17Sil MS) is the most suitable configuration due to its comprehensive extraction performance. Owing to its multiple phases allowing the extraction of a wider range of molecular weights and volatilities, the PDMS/CAR/DVB fibre gave the most accurate results in comparison with the five-assessed SPME fibres. Finally, 40 °C and 30 min were found to be the best compromise between extraction time and incubation temperature. This optimal response was reached by implementing a design of experiment based on a central composite design approach. Moreover, an exploratory statistical analysis was performed on the analysed samples using the optimised method. The outcome of such statistical evaluation was the determination of potentially significant metabolites associated with each investigated disease.