Level K’ T (Rs)
A: pH of mobile phase
2.8 -0.2 2.5 1.51 2.37
3 0 2.6 1.53 3
3.2 0.2 2.2 1.58 2.35
S.D n=6   0.21 0.04 0.01
B: Flow rate (mLmin-1)
0.8 -0.2 2.1 1.56 2.32
1 0 2.6 1.53 3
1.2 0.2 2.5 1.51 2.37
S.D n=6   0.28 0.03 0.03
C: Percentage of water in mobile phase (V/V)
90/10 -20 2.7 1.52 2.39
70/30 0 2.6 1.53 3
80/20 -10 2.4 1.57 2.32
S.D n=6   0.21 0.03 0.04
D: Wavelength (nm)
220 -5 2.7 1.52 2.39
225 0 2.6 1.53 3
230 5 2.5 1.59 2.33
S.D n=6   0.14 0.04 0.03

K’= Capacity factors, T = Tailing factor, Rs = Resolution
Table 5: Robustness of the proposed method.