Investigation of Acid-Base Indicator Property of Plumbagin from Plumbago zeylanica Linn

Table 5

Effects of the indicator on the intraday precision of the method.

HCl/NaOH (mL)			CH3COOH/NaOH (mL)			Assay of ibuprofen powder (% purity)			Assay of ibuprofen BP tablets (% content)
Morning	Afternoon	Evening	Morning	Afternoon	Evening	Morning	Afternoon	Evening	Morning	Afternoon	Evening
10.18	10.18	10.18	11.00	11.14	11.09	98.80	99.64	100.63	96.00	97.70	99.60
10.18	10.18	10.09	11.08	11.25	11.09	99.30	99.64	100.63	97.82	98.50	98.51
10.18	10.18	10.09	11.08	11.25	10.98	98.80	100.10	100.10	96.87	98.30	99.22
10.27	10.09	10.09	11.08	11.25	10.98	99.80	100.10	100.63	96.80	97.80	98.40
10.09	10.09	10.18	11.00	11.14	10.98	99.30	99.64	100.10	97.67	97.00	98.92
10.09	10.09	10.09	10.90	11.25	10.90	99.80	99.64	100.10	96.90	99.30	98.43
Mean = 10.17 ± 0.028	Mean = 10.14 ± 0.049	Mean = 10.12 ± 0.019	Mean = 11.02 ± 0.029	Mean = 11.21 ± 0.023	Mean = 11.00 ± 0.030	Mean = 99.30 ± 0.183	Mean = 99.79 ± 0.097	Mean = 100.40 ± 0.119	Mean = 97.01 ± 0.270	Mean = 98.10 ± 0.322	Mean = 98.85 ± 0.200
RSD = 0.67%	RSD = 0.49%	RSD = 0.46%	RSD = 0.65%	RSD = 0.51%	RSD = 0.67%	RSD = 0.45%	RSD = 0.24%	RSD = 0.29%	RSD = 0.68%	RSD = 0.80%	RSD = 0.50%