## 3 Results  
Figure 2 presents the smoothed (Figure 2a), and SNV (Figure 2b) NIR spectra of pure L-fucose, L-proline, and water. Figure 3 presents the 2 nd derivative (Figure 3a) NIR spectra of aqueous solutions of L-fucose and L-proline and water, and a close-up of the 2 nd derivative NIR spectra from 880 to 889 nm (Figure 3b). Figures 4 and 5 present the 2 nd derivative NIR spectra of aqueous solutions of L-proline and water, and saliva and water, respectively. The spectra of pure L-fucose and L-proline tablets are drastically different compared to that of water (Figure 2) as expected. The major differences are in the spectral regions 800-1250 nm and 1418-1867 nm. Spectral peaks of L-fucose and L-proline are in line with the current literature of their molecular groups [(62; 63; 64)] (Tables 3 and 4). Water has distinctive peaks at 970 nm, 1450 nm, and 1940 nm [(62; 65; 66)]. Two spectrometers were used in this study and the overlap of the spectra from both spectrometers is observed between 1000\(-\)1100 nm in Figures 2-5. A systematic order, marked with both black and green, was observed with aqueous L-fucose solutions of different concentrations and pure water (Figure 3a) within the wavelengths of 695-969 nm, 718-719 nm, 869-888 nm, 907-908 nm, and 1013-1029 nm. The 718-719 nm, 869-888 nm, and 907-908 nm are assigned to the 3 rd overtone CH stretching, and the 1011-1029 nm are assigned to the 2 nd overtone OH stretching [(62; 63; 64)]. The same comparison shows that L-proline solutions differ from pure water (Figure 4) within 778-784 nm and 819-820 nm, that is assigned to the 3 rd overtone NH stretching [(62; 63; 64)]. Wavelengths in the NIR spectra demonstrating a systematic order between aqueous biomarker solutions and pure water (Figures 3 and 4) are separately compared to the commonly known NIR signals of molecular groups [(62; 63; 64)] (Tables 3 and 4). Figure 2: The smoothed (**a**) and normalized (**b**) NIR spectra of L-fluose tablet, L-proline tablet, and pure water. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Wavelength Area (nm)** & **Wavelength Area (nm)** & **NIR Absorption Bands** \\
**Black** & **Green** & **Molecular Groups**[62; 63; 64] \\ \hline
695–696 & 695–696 & \\
718–719 & 718–719 & 3 rd overtone CH stretching \\  & 786 & 3 rd overtone CH stretching \\
869–888 & 880–888 & 3 rd overtone CH stretching \\
1011–1029 & 1019–1029 & 2 nd overtone OH stretching \& water \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Wavelength areas of L-fluose solutions that were recognized to have a systematic order from F1 \(\rightarrow\) F2 \(\rightarrow\) F3 \(\rightarrow\) F4 to water were marked black. The wavelength areas where the solutions were in order from F1 \(\rightarrow\) F2 \(\rightarrow\) F3 to F4 or F1 \(\rightarrow\) F2 \(\rightarrow\) F3 to water were marked green. The corresponding molecular groups are named on the right. Wavelengths under 680 nm belong to the UV-VIS region and are not of interest in this study. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Wavelength Area (nm)** & **Wavelength Area (nm)** & **NIR Absorption Bands** \\
**Black** & **Green** & **Molecular Groups [62; 63; 64]** \\ \hline
725 & 725 & 4 th overtone CH stretching \\
781–784 & 778–796 & 3 rd overtone NH stretching \\
819–820 & 819–820 & 3 rd overtone NH stretching \\
850–864 & 850–864 & 3 rd overtone CH stretching \\  & 1050 & 2 nd overtone N–H stretching, \\  & 1906 & 2 nd overtone O–H stretching \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Wavelength areas of L-proline solutions that were recognized to have a systematic order. Figure 1. \(\rightarrow\) P2 \(\rightarrow\) P3 \(\rightarrow\)P4 to water were marked black. The wavelength areas where the solutions were in order from P1 \(\rightarrow\) P2 \(\rightarrow\) P3 to P4 or P1 \(\rightarrow\) P2 \(\rightarrow\) P3 to water were marked green. The corresponding molecular groups are named on the right. Wavelengths under 680 nm belong to the UV-VIS region and are not of interest in this study.