Table 1: Sensitivity and regression parameters.

ParameterMethod AMethod B

, nm445460
Colour stability, min9060
Linear range, µg mL−11.5–21.02.0–32.0
Molar absorptivity ( ), L mol−1 cm−11.27 × 1047.57 × 103
Sandell sensitivity*, µg cm−20.02090.0350
Limit of detection (LOD), µg mL−10.010.16
Limit of quantification (LOQ), µg mL−10.020.49
Regression equation, **
Intercept ( )0.03580.0049
Slope ( )0.0420.028
Standard deviation of ( )9.98 × 10−29.98 × 10−2
Standard deviation of ( )5.53 × 10−33.39 × 10−3
Regression coefficient (r)0.99750.9997

Limit of determination as the weight in µg mL−1 of solution, which corresponds to an absorbance of measured in a cuvette of cross-sectional area 1 cm2 and = 1 cm.
, where is the absorbance, is concentration in µg mL−1, is intercept, and is slope.