Feasibility Study on the Use of a Portable NIR Spectrometer and Multivariate Data Analysis to Discriminate and Quantify Adulteration in Fertilizer

Table 5

Optimum performance of different quantification models for fertilizer B.

Model	R^2	RMSECV	Bias	R^2	RMSEP	Bias	RPD
PLS	0.9523	0.0801	0.0054	0.9529	0.0898	0.0092	4.3444
iPLS	0.9613	0.0945	0.0004	0.9648	0.0908	−0.0007	3.8200
Bi-PLS	0.9664	0.0881	−0.0002	0.9676	0.0879	−0.0050	3.9460
Si-PLS	0.9767	0.0736	0.0007	0.9799	0.0692	−0.0012	5.0124
GAPLS	0.9736	0.0782	0.0004	0.9766	0.0742	0.0028	4.6746
		Variables			Selected wavelength range (nm)
PLS		331			740–1070
iPLS		17			757–773
Bi-PLS		47			757–773, 959–974, 1009–1022
Si-PLS		83			740–767, 824–851, 990–1016
GAPLS		331			740–1070