Table 3. Intra-day and inter-day precision of measurements of standard solutions of dNTPs and NTPs.

Amount (pmol, 5 μl injected)	Intra-day precision		Inter-day precision
Spiked	Found ± SD	%CV	Found ± SD	%CV
dCTP
1	0.86 ± 0.06	7.3	0.86 ± 0.01	1.6
2	1.86 ± 0.09	5.1	1.83 ± 0.03	1.8
8	7.16 ± 0.26	3.7	6.88 ± 0.40	5.8
dTTP
1	1.20 ± 0.04	3.0	1.13 ± 0.05	4.2
2	1.95 ± 0.03	1.8	1.93 ± 0.01	0.4
8	8.73 ± 0.39	4.5	8.15 ± 0.51	6.3
dATP
0.4	0.43 ± 0.01	2.0	0.33 ± 0.01	3.2
0.8	0.82 ± 0.06	7.4	0.82 ± 0.05	5.5
2.5	2.75 ± 0.10	3.7	2.55 ± 0.12	4.5
dGTP
0.4	0.34 ± 0.04	12.7	0.35 ± 0.04	10.5
0.8	0.83 ± 0.04	4.7	0.79 ± 0.02	2.5
2.5	2.39 ± 0.15	6.2	2.35 ± 0.05	2.0
CTP
20	18.0 ± 0.6	3.1	18.6 ± 0.3	1.6
40	36.8 ± 3.0	8.1	36.6 ± 2.4	6.6
150	136 ± 2	1.5	135 ± 4	2.6
UTP
40	36.8 ± 1.1	2.9	38.8 ± 0.9	2.5
80	76.2 ± 2.9	3.9	82.1 ± 8.0	9.8
300	289 ± 6	2.2	303 ± 15	5.0
ATP
100	104 ± 5	4.7	106 ± 5	4.5
200	180 ± 7	3.7	173 ± 2	1.0
750	684 ± 34	4.9	654 ± 28	4.3
GTP
20	17.0 ± 0.8	4.6	18.7 ± 2.4	12.7
40	37.6 ± 1.6	4.2	34.6 ± 1.1	3.1
150	154 ± 6	3.6	152 ± 1.2	0.8