The advantage of the mass spectral data in addition to the UV–Vis data is demonstrated when comparing Fibers B and C. Fiber extracts B and C could not be discriminated by isoabsorbance plots, showing that the fiber extracts contained the same number of dye components with similar colors. These spectra are displayed in Fig. 4. The chromatograms of these extracts contained several peaks that occurred at similar retention times, requiring further evaluation using the mass spectrometer. The mass spectra at the apex and at the tail end (at half-peak maximum) of the most abundant peaks of the chromatogram (at c. 10 min) were compared. Figure 5 shows the chromatograms and mass spectra of these two fibers. FIG. 5—(a) Chromatogram and mass spectra of Fiber B. The chromatogram (top), mass spectrum Scan 1 with m/z value of 322.2 (bottom left), and mass spectrum Scan 2 with mass-to-charge (m/z) value of 322.2 (bottom right). (b) Chromatogram and mass spectra of Fiber C. The chromatogram (top), mass spectrum Scan 1 with m/z value of 333.3 (bottom left), and mass spectrum Scan 2 with m/z value of 322.2 (bottom right).