Application of Plackett-Burman and central composite designs for screening and optimization of factor influencing the chromatographic conditions of HPTLC method for quantification of efonidipine hydrochloride

Journal of Analytical Science and Technology

Table 4 Plackett-Burman design for statistical analysis and effect of independent variables on peak area and retention factor

Factors	Effect	Coefficient	Standard error coefficient	T value	p value
Peak area
Constant	–	6663	273	24.41	0.000
Wavelength	253	126	273	0.46	0.663
Saturation time	− 1534	− 767	273	− 2.81	0.038
Volume of DCM	− 634	− 317	273	− 1.16	0.298
Volume of triethylamine	341	170	273	0.62	0.560
Development distance	2770	1385	273	5.08	0.004
Activation of plate	− 281	− 141	273	− 0.52	0.628
Retention factor
Constant	–	0.5133	0.0284	18.10	0.000
Wavelength	0.0267	0.0133	0.0284	0.47	0.658
Saturation time	0.0200	0.0100	0.0284	0.35	0.739
Volume of DCM	− 0.0300	− 0.0150	0.0284	− 0.53	0.620
Volume of triethylamine	0.0467	0.0233	0.0284	0.82	0.448
Development distance	− 0.0633	− 0.0317	0.0284	− 1.12	0.315
Activation of plate	− 0.0800	− 0.0400	0.0284	− 1.41	0.218