Table 4.

Constructed PLSR models with model parameters.

Data Pretreatment	Factors	R2 Model	RMSEC	R2 Pearson	RMSEP	Bias
Original	9	0.9845	0.0674	0.9861	0.0696	0.0106
First derivative	6	0.9844	0.0676	0.9790	0.0775	0.0042
Second derivative	6	0.9882	0.0589	0.9607	0.1122	−0.0237
Standard normal variate	5	0.9672	0.0980	0.9633	0.1074	−0.0149
Area normalization	6	0.9661	0.0997	0.9599	0.1118	−0.0314
Orthogonal signal correction	1	0.9919	0.0488	0.9958	0.0390	0.0061

RMSEC = root mean square error of calibration; RMSEP = root mean square error of prediction.