Table 2: Analytical parameters.

Method A Method B (nm) 601 662 Beer’s law limit (μg mL−1) 50.00–250.00 20.00–100.00 Molar absorptivity (Lmol−1 cm−1) 0.92 × 103 0.257 × 104 Sandell’s sensitivity (μg cm−2) 0.050 0.158 Limit of detection** (μg mL−1) 1.650 0.6626 Limit of quantification** (μg mL−1) 5.0000 2.0080 Regression equation* Slope () 0.0020 0.0049 Intercept () 0.0124 0.0203 Correlation coefficient () 0.9988 0.9988

* is the absorbance and the concentration in g mL−1. **Calculated according to ICH guidelines.