Parameter | PHL | GUA impurity A | GUA | GUA impurity B | GUA impurity E | Acceptance criteria |
---|---|---|---|---|---|---|
Range | 50–1000 µg mL−1 | 5–100 µg mL−1 | NA | |||
Slope | 0.43 | 3.05 | 6.83 | 1.39 | 1.67 | |
Intercept | − 1.22 | − 1.71 | 5.27 | − 0.67 | − 2.40 | |
Standard error of the slope | 0.002 | 0.022 | 0.044 | 0.012 | 0.011 | |
Standard error of the intercept | 1.374 | 1.334 | 2.454 | 0.639 | 0.667 | |
Correlation coefficient (r) | 0.9998 | 0.9997 | 0.9997 | 0.9997 | 0.9997 | ≈ 1 |
Limit of detection | NA | 1.64 µg mL‒1 | NA | 1.42 µg mL‒1 | 1.61 µg mL‒1 | NA |
Limit of quantification | NA | 4.96 µg mL‒1 | NA | 4.31 µg mL‒1 | 4.87 µg mL‒1 | |
Accuracy (mean % ± SD) | 100.90 ± 0.95 | 99.76 ± 0.69 | 100.57 ± 0.58 | 99.39 ± 0.51 | 99.79 ± 0.84 | 98–102% |
Repeatability (RSD %) | 0.93 | 1.00 | 1.04 | 1.31 | 0.89 | ≤ 2% |
Intermediate precision (RSD %) | 1.08 | 1.11 | 1.11 | 1.40 | 0.95 | ≤ 2% |
Specificity (mean % ± SD) | 100.91 ± 0.65 | 99.82 ± 0.60 | 100.68 ± 0.88 | 99.52 ± 0.53 | 99.89 ± 0.74 | 98–102% |
Robustness: | ||||||
Peak area RSD% | 1.97 | 1.78 | 1.88 | 1.98 | 1.74 | ≤ 2% |
Retention time RSD% | 0.47 | 0.34 | 0.57 | 0.47 | 0.85 | ≤ 2% |