Fig. 1

Comparative characterization of Chlorella extracts versus FBS by LC–MS. a Perspective 3D surface plots are shown comparing UV chromatograms of FBS, CVE, and CGF samples (wavelengths 200–400 nm); each plot shows the mean normalized absorbance spectra of three replicate injections of the same sample type. Arrows indicate large, broad peaks around 260 nm present in CVE and CGF samples. b Normalized total ion chromatograms (TICs) are shown as the sum of signals of all m/z values from 400 to 1200 for FBS, CVE, and CGF samples; representative data shown are averaged spectra from three injections of the same sample type. c Scatter plot shows results of principal component analysis (PCA) on panel b MS TIC data; sample types are indicated by different colors with PC2 (circles) and PC4 (diamonds) values plotted on the same y-axis scale. d Perspective 3D surface plots show normalized mass spectra of FBS, CVE, and CGF samples; data shown are averages of three replicate injections. Dashed box indicates the region of interest where signal location/intensity appears similar across all three sample types (i.e., retention times from 15 to 21 min and m/z values from 800 to 1200). e Aligned mass spectra show the sum of all signals for retention times from 15 to 21 min at each whole integer m/z value from 800 to 1200; data are shown as mean normalized spectra of three replicate injections of the same sample. Red vertical lines indicate signals of relatively high abundance shared across all three sample types; table lists potential parent species for corresponding signals based on top candidates identified by a database (MassBank.eu) search