TABLE 1.

Calibration curves from one batch of the validation section.

Nominal concentration (ng ml−1)	Mean concentration (ng ml−1)	RSD (%) (n = 3)	RE (%)
0.2	0.188	10.94	−6.17
1	0.921	6.66	−7.87
5	4.698	3.79	−6.05
10	10.623	14.46	6.23
20	19.950	3.02	−0.25
30	28.805	6.36	−3.98
40	40.173	6.19	0.43
50	54.749	4.02	9.50