Table 1.

Reproducibility of the quantification of each hydroxybutyrate in human saliva

Hydroxybutyrate	Mean ± SD (n = 12) (pmol)	Relative SD
		Sample preparation (%)	Error (SRM) (%)
3HB	56.0 ± 0.30	0.48	0.54
3HIB	49.0 ± 0.36	0.45	0.79
3HMB	3.7 ± 0.10	1.70	2.98
2HB	19.5 ± 0.84	5.28	3.45

Each butyrate was quantified in 5 µL of saliva collected from healthy subjects. Four samples were prepared and quantified in triplicate by HPLC–MS/MS. The results were analyzed by a one-way layout, in which the analytical errors were divided into two sources: sample preparation and SRM measurement

3HB 3-hydroxybutyrate, 3HIB 3-hydroxyisobutyrate, 3HMB 3-hydroxy-3-methylbutyrate, 2HB 2-hydroxybutyrate