Table 3: Analytical characteristics of the fixed time (15 min) method.

Parameters

FVS

λmax (nm)

615

Beer's law range (µg/mL)

3.0-36.0

Optimum photometric range (µg/mL)

6.5-32.0

Molar absorptivity (L/mol cm)

1.30 × 104

LOD (µg/mL)

0.23

LOQ (µg/mL)

0.71

Sandell's sensitivity (µg/cm2 per 0.001 absorbance unit)

0.080

Regression equationa

A = 0.0211C + 0.0477

Correlation coefficient, r

0.9998

aA = mC + b, where A is the absorbance and C is the concentration in µg/mL.