Table 2.

Calculated mass fraction of in vitro–transcribed SARS-CoV-2 RNA derived from the measured concentration of the four NMPs by IDMS

	Digestion	CMP (μg/g)	UMP (μg/g)	AMP (μg/g)	GMP (μg/g)
Day 1	1	0.84	0.91	0.80	0.83
	2	0.87	0.89	0.80	0.84
	3	0.76	0.79	0.70	0.71
	4	0.74	0.81	0.70	0.73
	Mean	0.80	0.85	0.75	0.78
	CV (%)	7.8	6.9	7.7	8.6
Day 2	1	0.83	0.88	0.78	0.78
	2	0.80	0.85	0.76	0.78
	3	0.80	0.85	0.76	0.76
	4	0.86	0.83	0.72	0.73
	Mean	0.82	0.85	0.76	0.76
	CV (%)	3.5	2.4	3.3	3.1
Day 3	1–1	0.79	0.92	0.79	0.84
	1–2	0.79	0.92	0.81	0.84
	2–1	0.73	0.92	0.79	0.86
	2–2	0.79	0.92	0.81	0.82
	Mean	0.78	0.92	0.80	0.84
	CV (%)	3.8	0.0	1.4	1.9
Mean (3 days)		0.80	0.88	0.77	0.79
U (k = 2)		0.05	0.08	0.06	0.09