Medicinal Plants Classification Biosynthesis and ... - Index of

Non-Invasive Near Infrared Spectroscopic Techniques for the Characterization...
1.0
0.8
0.6
0.4
0.2
0
reflectance
4440 -OH
H O/EtOH
2
5352 -C=O
-COOH
2 ndovertone
5742 -CH
2
overtone
5808 -CH
2
-CH
3
overtone
7212 C-H str. + C-H def.
-CH
2
EtOH
-CH
3
4200 5400 6600 7800 9000 cm -1
Figure 3b. 1 st derivative of the NIR-spectrum with characteristic vibrations
0.32
0.30
0.28
0.26
0.24
0.22
0.20
0.18
0.16
0.14
NIR values
ng/µl
2
R = 0.95421
HPLC values
ng/µl
0.16 0.18 0.20 0.22 0.24 0.26 0.28 0.30
Figure 4. Calibration curve for 3´,4´,5´-trimethoxyflavone. Correlation between LC and NIRS
In order to control the solvent composition a calibration curve with a correlation
coefficient of 0.99530 for the determination of the water content was calculated for which the
reference data were received by Karl-Fischer titration (Figure 5a). In the same way also the
correlation of the ethanol content between the gas chromatographic and the NIRS method
showed a coefficient of 0.99701 (Figure 5b).
261