Table 5 Robustness of the proposed method at concentrations of 150 ngband⁻¹ for Trp and 300 ngband⁻¹ for Try for absorbance and fluorescence mode detection

No variation*

100.98 ± 1.26

99.09 ± 0.29

98.70 ± 0.30

100.31 ± 0.67

Detection wavelength

278 nm

99.99 ± 0.3

223 nm

103.35 ± 1.10

278 nm

98.91 ± 0.52

223 nm

98.78 ± 0.14

282 nm

100.34 ± 0.7

227 nm

99.45 ± 1.06

282 nm

100.35 ± 2.02

227 nm

102.03 ± 0.07

Mobile phase compositions (Acetonitrile: ethyl acetate: BR buffer pH 9.0)

4.9: 2.1:2

101.88 ± 3.22

100.43 ± 1.51

97.72 ± 1.19

99.57 ± 0.74

5.1:1.9:2

98.07 ± 1.12

95.78 ± 2.04

99.29 ± 0.61

97.48 ± 0.11

pH of the mobile phase

8.9

100.04 ± 2.18

100.87 ± 2.89

98.82 ± 0.96

97.12 ± 1.77

9.1

105.07 ± 1.96

99.58 ± 0.13

100.13 ± 2.49

99.49 ± 0.74

Migration distance

63 mm

99.93 ± 0.11

100.16 ± 0.31

101.57 ± 1.44

100.91 ± 1.13

67 mm

98.38 ± 1.99

100.32 ± 1.21

100.59 ± 2.67

98.80 ± 1.14

Saturation time

23 min

99.96 ± 1.58

99.56 ± 0.05

99.74 ± 1.17

100.83 ± 0.91

27 min

100.29 ± 2.26

101.06 ± 0.92

99.55 ± 1.18

97.78 ± 0.76