## 8 Homo- and Heteronuclear Two-Dimensional (2D) NMR Analysis of Human Saliva
### Sample Size Considerations and MV Power Calculations
Moreover, \(<\)10% of participants donated saliva samples that appeared to display a mixed host- and microbiome-derived distribution of metabolites. Figure 12: \(Cont.\)  
Future Perspectives for Clinical Salivary NMR Bioanalysis and Monitoring with Low-Field Benchtop NMR Spectrometers  
Unfortunately, high-resolution, high-field NMR spectrometer facilities for routine metabolomics screening programs are restrictive to many researchers since both university and commercial facilities containing, or with access to, such unwieldly instruments with large superconducting magnets are somewhat limited, and the expense involved also hampers such studies. However, recently some major developments with low-field (e.g., 60 MHz), non-stationary NMR spectrometers, which do not require such large cryogenic systems, have demonstrated the applicability of this novel technique to the multicomponent analysis of human urine and its value in the diagnosis and monitoring of type 2 diabetes in human participants [159]. Hence, here we also demonstrate the applications of this analytical strategy to determine the metabolic status of HSS samples, and its future potential for routinely screening for oral health and perhaps physiologically remote extra-oral conditions at patient point-of-contact sites such as dental surgeries, health centers, and pharmacies. Although LF benchtop NMR analysis is now frequently employed for determinations of the yields, extents, and rates of synthetic organic/inorganic chemistry reactions [160], along with chemical education applications [161; 162], this approach may  
Figure 12: High-field (0.80–2.45 ppm) regions of the 600 MHz \({}^{1}\)H NMR spectra of WMS supernatant samples donated by participants that have (**a**) oral microbiome (PC2)-, (**b**) admixed host and oral microbiome (PC1/PC2)-, and (**c**) host (PC1)-dominant metabolite profiles. Resonances of metabolites loading strongly on PCs 1 and 2 are color-coded blue and red, respectively (e.g., lactate, N-acetyl storage compound and glutamate for PC1; and _n_-caproate, _n_-butyrate, propionate, acetate, 5-aminovalerate, alanine, etc., for PC2). Resonances of biomolecules that load significantly on both PCs 1 and 2, for example acetoin, pyruvate, and succinate, are color-coded green. Assignments: 1, _n_-caproate-CH\({}_{3}\); 3, _n_-butyrate-CH\({}_{3}\); 7, valine-CH\({}_{3}\); 8, valine-CH\({}_{3}\)/isoleucine-CH\({}_{3}\); 10, leucine-CH\({}_{3}\); 11, propionate-CH\({}_{3}\); 12, iso-butyrate-CH\({}_{3}\); 15, Ethanol-CH\({}_{3}\); 17, 3-D-hydroxybutyrate-CH\({}_{3}\)/\(\beta\)-Fucose-CH\({}_{3}\); 18, lactate-CH\({}_{3}\); 19, acetoin-CH\({}_{3}\); 20, alanine-CH\({}_{3}\); 21, _n_-butyrate-\(\beta\)-CH\({}_{3}\); 22, 5-aminovalerate-\(\beta\)-\(\gamma\)-CH\({}_{3}\); 27, senicioate-CH\({}_{3}\); 28, *glutarate-\(\beta\)-CH\({}_{2}\); 29, thymine-CH\({}_{3}\); 30, acetate-CH\({}_{3}\); 32, proline-\(\gamma\)-CH\({}_{2}\)/N-acetylneuraminate-C\({}_{3}\); 33, hyalurono/glycoprotein carbohydrate side-chain N-acetylsugar-NHCOCH\({}_{3}\) functions; 34, N-acetylglutamate-/N-acetylaspartate-NHCOCH\({}_{3}\) (2 resonances); 35, N-acetylglucosamine-/N-acetylneuraminate-NHCOCH\({}_{3}\); 36, *unsigned N-acetylated metabolite-NHCOCH\({}_{3}\) (2 resonances); 39, _n_-butyrate-\(\alpha\)-CH\({}_{2}\); 40, propionate-CH\({}_{2}\); 42, 5-aminovalerate-\(\alpha\)-CH\({}_{2}\); 43, glutamate-\(\gamma\)-CH\({}_{2}\); 44, pyruvate-CH\({}_{3}\); 46, succinate-CH\({}_{2}\) ’Indicates tentative assignment. also provide useful clinical diagnostic and/or prognostic tracking information in human patients when biofluids are non-invasively screened. However, our recently conducted investigations focused on the quantitative LF NMR analysis of human saliva was found to be unfortunately limited to only five or so metabolites with the most prominent 1H NMR resonances in view of metabolite sensitivity issues and the superimposition of signals at this low operating frequency (Figure 13).