Simultaneous quantification of verbenalin and verbascoside in Verbena officinalis by ATR-IR and NIR spectroscopy

Abstract Attenuated-total-reflectance infrared spectroscopy (ATR-IR) and near-infrared diffuse reflectance spectroscopy (NIR) in hyphenation with multivariate analysis was utilized to quantify verbenalin and verbascoside in Verbena officinalis . A new high performance liquid chromatography (HPLC) method as a reference was established and validated. For both vibrational spectroscopic methods test-set and cross validation were performed. Different data-pre-treatments like SNV, 1st and 2nd derivative were applied to remove systematic errors and were evaluated. Quality parameters obtained for the test-set validation revealed that ATR-IR (verbenalin: R 2  = 0.94, RPD = 4.23; verbascoside: R 2  = 0.93, RPD = 3.63) has advantages over NIR (verbenalin: R 2  = 0.91, RPD = 3.75; verbascoside: R 2  = 0.80, RPD = 2.35) in the given application.