Table 5. Intra- and inter-day precision of response.

Analytes	Precision of response
	Intra-day	Inter-day	Intra-day	Inter-day	Intra-day	Inter-day
Fat-soluble vitamins	100 ppb		500 ppb		1000 ppb
Retinol (A)	0.05	0.07	0.01	0.03	0.03	0.04
Ergocalciferol (D2)	5.02	8.70	3.41	5.04	2.14	3.20
D-α-Tocopherol (E)	0.05	0.07	0.01	0.02	0.04	0.05
Phylloquinone (K1)	0.16	0.22	0.04	0.06	0.12	0.15
Water-soluble vitamins	10 ppb		50 ppb		100 ppb
Thiamine (B1)	0.13	0.18	0.03	0.04	0.06	0.08
Riboflavin (B2)	0.82	1.06	0.32	0.43	0.93	1.56
Nicotinic acid (B3)	1.44	2.04	0.57	0.69	0.69	1.02
Nicotinamide (B3)	0.20	0.41	0.07	0.09	0.15	0.23
D-Pantothenic acid (B5)	7.26	8.52	2.21	2.85	1.86	3.22
Pyridoxine (B6)	0.13	0.23	0.06	0.07	0.12	0.20
D-Biotin (B7)	0.44	0.69	0.16	0.21	0.25	0.36
Folic acid (B9)	7.68	8.33	2.24	2.68	2.02	3.22
Cyanocobalamin (B12)	2.32	3.27	1.04	1.39	1.76	2.28