Rapid Characterization of Tanshinone Extract Powder by Near Infrared Spectroscopy

Table 7

Comparison of different preprocessing methods of the partial least squares model for the content of tanshinone IIA/mg·g⁻¹.

Preprocessing method	LVs	Calibration set				Validation set
			RMSEC	RMSECV	BIAScal		RMSEP	RPD	BIASpre
Raw	10	0.9893	0.0043	0.0093	0.0036	0.9484	0.0060	2.0	0.0055
S-G smooth	13	0.9952	0.0029	0.0091	0.0019	0.9932	0.0044	2.7	0.0029
Normalization	10	0.9939	0.0033	0.0063	0.0027	0.9716	0.0043	2.7	0.0039
S-T	12	0.9965	0.0025	0.0066	0.0020	0.9921	0.0034	8.1	0.0022
MSC	14	0.9984	0.0017	0.0044	0.0014	0.9943	0.0024	5.0	0.0017
S-G 1st	8	0.9953	0.0029	0.0060	0.0021	0.9957	0.0019	6.2	0.0015
S-G 2nd	4	0.9915	0.0039	0.0056	0.0027	0.9955	0.0021	5.6	0.0016
Baseline	10	0.9899	0.0022	0.0055	0.0033	0.9529	0.0048	2.5	0.0041
SNV	11	0.9973	0.0018	0.0037	0.0018	0.9977	0.0015	3.6	0.0018
WDS	9	0.9772	0.0063	0.0106	0.0045	0.9532	0.0059	2.0	0.0046