Table 1 Analytical performance data of the calibration graphs for the determination of benzophenone by the proposed methods
From: Derivative spectrophotometric analysis of benzophenone (as an impurity) in phenytoin
Parameter | First derivative method (1D) | Third derivative method (3D) | Ratio derivative method (1DD) |
|---|---|---|---|
Wavelength λ (nm) | 257.6 | 263.2 | 272 |
Concentration range (μg/mL) | 1-10 | 1-10 | 1-10 |
Intercept (a) | 20.65 × 10-3 | 1.98 × 10-3 | -0.67 |
Slope (b) | 0.27 | 0.12 | 9.24 |
Correlation coefficient (r) | 0.9999 | 0.9999 | 0.9999 |
Standard deviation of the residuals, Sy/x | 4.77 × 10-3 | 5.14 × 10-3 | 0.21 |
Standard deviation of the intercept, Sa | 3.71 × 10-3 | 3.99 × 10-3 | 0.16 |
Standard deviation of the slope, Sb | 0.61 × 10-3 | 0.66 × 10-3 | 0.02 |
Relative standard deviation, % RSD | 0.83 | 1.10 | 0.97 |
Percentage error, % Error | 0.34 | 0.45 | 0.39 |
Limit of detection (LOD) (μg/mL) | 0.04 | 0.11 | 0.06 |
Limit of quantitation (LOQ) (μg/mL) | 0.13 | 0.34 | 0.18 |
D A1% (dl.g-1.cm-1)a | 2655 | 1181 | 9.24 × 104 |
D ε (L.mol-1.cm-1)b | 4.83 × 104 | 2.15 × 104 | 1.68 × 107 |