Optimization of Gentisides Extraction from Gentiana rigescens Franch. ex Hemsl. by Response Surface Methodology

Table 2

Analysis of variance for response surface quadratic polynomial model. SD: sources of deviation; SS: sum of squares; DF: degree of freedom; MS: mean square; : determination coefficient; : adjusted determination coefficient; CV %: coefficient of variation.

SD	SS	DF	MS	value	value
Model	3816.19	9	424.02	12.68	0.0015
	1.94	1	1.94	0.06	0.8165
	221.18	1	221.18	6.61	0.0369
	26.51	1	26.51	0.79	0.4029
	196.93	1	196.93	5.89	0.0457
	25.93	1	25.93	0.78	0.4078
	56.99	1	56.99	1.70	0.2331
	2935.05	1	2935.05	87.74	<0.0001
	189.85	1	189.85	5.68	0.0487
	23.24	1	23.24	0.69	0.4321
Residual	234.16	7	33.45
Lack of fit	52.99	3	17.66	0.39	0.7674
Pure error	181.17	4	45.29
Cor. total	4050.35	16
	0.9422		Adeq. precision	10.122
	0.8679		C.V. %	7.11
Pred.	0.7208		PRESS	1130.88