Investigating Advanced Approaches Based on Iso-Absorptivity Coefficient in Unresolved Spectral Signals of Binary Mixtures

Table 2

Assay parameters and validation sheet obtained by applying the proposed spectrophotometric methods.

Parameters	a-Centering		AS		AM		A-Sum
	OFX	DXM	OFX	DXM	OFX	DXM	OFX	DXM
Wavelength (nm)	D0 at 298	D0 at 239.5	D0 at 238		P at 238 nm		D1 at 246.5 nm
Calibration range^a (µg/mL)	1–10	3–10	3–10		3–10		2–10
Slope	0.1154	0.0382	0.0387		1.0012		0.0087
Intercept	−0.0084	−0.0008	−0.0008		−0.0011		−0.0017
Correlation coefficient (r)	0.9999	0.9998	0.9998		0.9999		0.9999
Mean^a	99.90	99.52	100.17		99.89		100.53
RSD%	0.666	0.515	0.931		0.449		0.516
Accuracy^ab	100.78 ± 1.061	99.97 ± 0.687	100.32 ± 1.002	99.55 ± 0874	99.32 ± 0.417	100.11 ± 0.744	100.54 ± 0.987	99.88 ± 0.552
Repeatability^ac	±0.56/0.559	±0.68/0.684	±0.47/0.474	±0.96/0.965	±0.63/0.633	±0.41/0.411	±0.54/0.541	±0.97/0.965
Interday precision^ac	±0.70/0.698	±0.71/0.711	±0.55/0.552	±1.11/1.105	±0.73/0.729	±0.63/0.632	±0.71/0.711	±0.97/0.977
Robustness^acd	100.06/0.785	99.23/0.884	100.33/0.877	99.52/0.987	99.99/0.719	100.98/1.050	100.41/0.963	99.87/1.114
System suitability RSD%^e	0.774	0.574	0.411	0.217	0.419	0.622	0.796	0.433

^aAverage of three experiments. ^bMean ± standard deviation of 3 concentrations of each drug (4, 6, and 8 µg/mL). ^cStandard deviation/relative standard deviation of 3 concentrations of each drug (4, 6, and 8 µg/mL). ^dRobustness was checked by testing the effect of the solvent (29, 31, and 32% methanol). ^eOFX and DXM (6 µg/mL).