Figure 1. Single-pulse 1D 1H NMR spectrum of a human salivary supernatant specimen. (a-c) Expanded 0.80-2.50, 2.55-4.20, and 6.85-8.50 ppm regions, respectively, of the 600.13-MHz single-pulse 1H NMR spectrum of a human salivary supernatant specimen (pH value 6.78). A typical spectrum is shown. Abbreviations: A, acetate-CH3; Ala I, alanine-CH3; Bu I, ß-hydroxybutyrate 
-CH3 group protons; Bu II, III, and IV, ß-hydroxybutyrate ß, ß', and 
protons, respectively (ABX coupling system); iso-But I and II, iso-butyrate-CH3 and -CH group protons, respectively; n-But I, II, and III, n-butyrate , ß, and protons, respectively; Chol, choline-N+(CH3)3; DMeN, dimethylamine-CH3; Eth I and II, ethanol-CH3 and -CH2 group protons, respectively; Form, formate-H; Gly, glycine-CH2; His I and II, histidine ABX ß protons; His III and IV, histidine imidazole ring protons; Lac I and II, lactate-CH3 and -CH protons, respectively; Leu I, II, III, and IV, leucine 
, , ß, and protons, respectively; MeGu, methylguanidine-CH3; MeN, methylamine-CH3; Meth, methanol-CH3; N-Ac, spectral region for acetamido methyl groups of N-acetyl sugars; Phe I and II, phenylalanine ABX ß protons; Phe III, phenylalanine ABX proton; Phe IV, V, and VI, phenylalanine aromatic ring protons; Prop I and II, propionate-CH3 and -CH2 group protons, respectively; Pyr, pyruvate-CH3; Sar I and II, sarcosine-CH3 and -CH2 group protons, respectively; Suc, succinate-CH2; TMAO, trimethylamine oxide ON(CH3)3; TMeN, trimethylamine-CH3; Tyr I and II, tyrosine ABX ß protons; Tyr III, tyrosine ABX proton; Tyr IV and V, tyrosine aromatic ring protons; and Val I and II, n-valerate and protons, respectively. Assignments of 1H NMR resonances to methylguanidine, sarcosine, n-valerate, and N-acetylsugars are tentative in this instance.
