The use of multivariate curve resolution methods to improve the analysis of muramic acid as bacterial marker using gas chromatography–mass spectrometry: An alternative method to gas chromatography–tandem mass spectrometry

In analysis of muramic acid (MA) as bacterial marker, two dominant disturbing factors lead the researchers to use gas chromatography–tandem mass spectrometry (GC–MS/MS) technique instead of gas chromatography–mass spectrometry (GC–MS). These factors are the trace concentration of MA and fundamental disturbance of base line mass channels in GC–MS technique. This study aimed to utilize multivariate curve resolution (MCR) methods combined with GC–MS to improve the analysis of MA. First, the background and noise in GC–MS analysis were corrected and reduced using MCR methods. In addition, the MA overlapped peaks were resolved to its pure chromatographic and mass spectral profiles. Then the two-way response of each component was reconstructed by the outer product of the pure chromatographic and mass spectral profiles. The overall volume integration (OVI) method was used for quantitative determination. The MA peak area was decreased dramatically after the background correction and noise reduction. The findings severely ratify the appropriateness of using MCR techniques combined with GC–MS analysis as a simple, fast and inexpensive method for the analysis of MA in complex mixtures. The proposed method may be considered as an alternative method to GC–MS/MS for thorough analysis of the bacterial marker.