Green, Cost-Effective Simultaneous Assay of Chloramphenicol, Methylparaben, and Propylparaben in Eye-Drops by Capillary Zone Electrophoresis

Table 1

Summary of validation results.

Parameter	Chloramphenicol	Propylparaben	Methylparaben
System suitability
Migration time (RSD (%), n = 6),	1.1	1.1	1.2
Peak area (RSD (%), n = 6)	1.3	1.5	1.5
Linearity
Concentration range (µg/ml)	1202.7–2806.2 7	6.7–15.7	55.5–129.5
Calibration curve	y = 2.3531x + 163.2	y = 7.3451x + 1.27	y = 8.747x + 58.58
R^2	0.9984	0.9991	0.9990
Repeatability (RSD (%), n = 6, 1 day)	1.0	1.2	1.3
Intermediate precision (RSD (%), n = 12, 2 days)	1.6	1.3	1.4
Precision requirement, in RSD (%), of AOAC International [14]	≤3.7	≤7.3	≤5.3
Accuracy (n = 3 at each level)
At 80% of working concentration
+Recovery range (%)	97.2–100.0	95.8–99.1	98.6–100.8
+RSD (%)	1.5	1.7	1.1
At 100% of working concentration
+Recovery range (%)	98.7–100.1	100.6–104.3	94.8–96.7
+RSD (%)	0.7	1.8	1.0
At 120% of working concentration
+Recovery range (%)	99.1–101.5	97.2–100.5	95.5–97.5
+RSD (%)	1.3	1.7	1.1
Accuracy requirements, in recovery rate (%), of AOAC International [14]	95–105	80–110	90–107
Limit of quantitation (µg/ml)	20.0	5.0	5.0
Robustness
Variation of voltage (3 levels, n = 3 for each level)
+RSD (%) of peak area	≤0.9	≤1.8	≤1.8
+RSD (%) of assay results	≤0.8	≤1.8	≤1.6
Variation of injection pressure (3 levels, n = 3 for each level)
+RSD (%) of peak area	≤0.9	≤1.6	≤1.7
+RSD (%) of assay results	≤0.9	≤1.8	≤1.5
One-way ANOVA for assay results using different experimental conditions	= 0.948 > 0.05	= 0.945 > 0.05	= 0.907 > 0.05