Level K’ T  (Rs)
A: pH of mobile phase
2.6 -0.2 2.8 1.22 3.4
2.8 0 2.13 1.23 3.4
3 0.2 2.2 1.4 3.2
Mean ± S.D (n=6) 2.13 ± 0.3 1.23 ± 0.020 3.4 ± 0.1
B: Flow rate (mLmin-1)
0.8 -0.2 2.1 1.45 3.32
1 0 2.3  1.44 3.36
1.2 0.2 2.4 1.42 3.37
Mean ± S.D (n=6) 4.3 ± 0.212 1.44 ± 0.015 3.36 ± 0.026
C: Percentage of water in mobile phase (V/V)
25 -5 2.6 1.42 3.38
30 0 2.3  1.43 3.36
35 5 2.5 1.46 3.33
Mean ± S.D (n=6) 2.36 ± 0.070 1.43 ± 0.025 3.36 ± 0.025
C: Wavelength (nm)
225 -5 2.5 1.42 3.38
230 0 2.3  1.43 3.36
235 5 2.4 1.45 3.32
Mean ± S.D (n=6) 2.3 ± 0.070 1.43 ± 0.015 2.36 ± 0.030
K’= Capacity factors, N = Theoretical plates, T =  Tailing factor Rs=Resolution
Table 5: Robustness of the method (n=6).