Table 2.

Optimal wavelengths selection of sample set 1 and 2 selected by 2nd derivative spectra and the PCA loadings of sample set 1 and 2 using sample average spectra.

Method	Sample Set 1		Sample Set 2
	Number	Wavelength (nm)	Number	Wavelength (nm)
2nd derivative spectra	13	443.53, 460.58, 507.12, 547.86, 557.78, 578.91, 592.63, 606.38, 637.75, 690.83, 706.69, 712.45, 730.32	16	443.53, 459.36, 507.12, 533.01, 547.86, 557.78, 578.91, 592.63, 606.38, 637.75, 650.34, 659.18, 690.83, 706.69, 712.45, 730.32
PCA loadings	15	439.89, 550.34, 551.57, 571.44, 595.13, 610.13, 650.34, 656.65, 673.08, 678.15, 704.81, 735.43, 752.08, 761.06, 950.13	16	439.89, 547.86, 549.1, 581.4, 596.38, 608.88, 649.08, 660.44, 678.15, 685.76, 692.1, 703.54, 734.15, 754.65, 761.06,950.13