Table 1.

Optimization of extraction buffer using rat whole blood (n = 3)

Analyte	Composition of extraction buffer (water:acetonitrile)	Concentration (μM)
		Whole blood			Blood cells			Plasma
		Mean	SD	%CV	Mean	SD	%CV	Mean	SD	%CV
NAD+	0%:100%	NC	NC	NC	NC	NC	NC	NC	NC	NC
	20%:80%	18.28	3.89	21.3	31.53	6.00	19.0	NC	NC	NC
	40%:60%	124.05	13.98	11.3	203.81	33.78	16.6	NC	NC	NC
	60%:40%	141.35	10.45	7.4	212.89	26.45	12.4	NC	NC	NC
	80%:20%	135.60	25.70	19.0	232.44	22.34	9.6	NC	NC	NC
	100%:0%	200.78	40.22	20.0	380.82	130.19	34.2	1.91	NC	NC
NMN	0%:100%	NC	NC	NC	NC	NC	NC	NC	NC	NC
	20%:80%	NC	NC	NC	NC	NC	NC	NC	NC	NC
	40%:60%	5.54	1.53	27.6	9.96	0.76	7.6	NC	NC	NC
	60%:40%	5.88	0.83	14.1	12.58	0.92	7.3	NC	NC	NC
	80%:20%	6.25	1.20	19.2	12.23	1.03	8.4	NC	NC	NC
	100%:0%	6.45	0.19	2.9	12.03	0.65	5.4	NC	NC	NC

Lower limit of quantification: 1 μM (NAD⁺), 2 μM (NMN)

NAD⁺ nicotinamide adenine dinucleotide;

NMN nicotinamide mononucleotide;

NC not calculated, as the concentrations in most samples were below the limit of quantification (BLQ)