Sample No.

Provided (mM)

This Method (mM)

R.S.D. (n = 5)

1

4.37 ± 0.02

4.51 ± 0.03

−1.33

2

6.78 ± 0.03

6.70 ± 0.01

2.97

3

5.81 ± 0.02

5.91 ± 0.03

1.47