Study of influence of toxical and nutritional elements on cell metabolism using combination of Raman spectroscopy and Laser-Induced breakdown spectroscopy

In this work on-line discrimination of six bacteria strains by means of the Multivariate discrimination analysis (MVDA) is presented. Principal components analysis (PCA) was selected as most suitable technique. Two analytical methods – Laser-Induced breakdown spectroscopy (LIBS) and Raman spectroscopy were equipped for chemical analysis of bacteria strains. In order to obtain the best possible bacteria strains differentiation, the data from both methods was analyzed in two ways separately and together. The data from both measurements was normalized separately and afterwards combined in one data frame for simultaneous analysis. This data frame contained information from both analytical methods. Moreover an influence of cultivation period for each bacteria strain was studied. It was determined that Raman spectroscopy is able to discriminate two bacteria strains and LIBS even four bacteria strains. Using combination of both methods the complete discrimination was achieved. From information of first principal component it was determined that most valuable information in LIBS data is not included in different elemental composition but rather in influence of matrix effect. Solely the LIBS was utilized for studying the effect of cultivation period. It was possible to observe transformation of four bacteria strains within 24 hours. Based on results of this work it is possible to assume that combination of Raman spectroscopy and LIBS, because of the complementary information, is suitable for fast discrimination of different bacteria species and strains. Moreover it was determined that LIBS is able to observe the transformation caused by cultivation period