Compound quantification and identification process
All significant molecules (those with the highest concentration or the ones most important for their activities) are identified by HPLC-ESIHR-MSMS. Among them, one or two molecules are used as internal standards and are separately quantified by qNMR (incertitude ± 4.5%).
An HPLC-CAD (charged Aerosol Detector) is performed.
CAD produces a response which is similar but not fully identical from a non-volatile molecule to another, as shown by Robinson et al. 20171, and Schilling et al. 20192.
Our laboratory, the Institut des Substances Végétales, developed a proprietary algorithm to recalculate the signal in order to obtain identical responses between different molecules within a relative incertitude range of ± 7.5 %.
Download PDF summary of the analytical methods.
To check the validity of quantitative values provided in the Certificate of Analysis, a retest is performed every 12 months following the manufacture date indicated on the CoA, during 3 years.
Retests are performed on the quantitative values and the HPLC profile’s compliance is checked.
A new Certificate of Analysis is then produced, available to customers on request.
The retesting date is specified on the product’s label and on its Certificate of Analysis. It is also indicated on the Analytical Results Card enclosed in each qRE box.
(1) Use of Calculated Physicochemical Properties to Enhance Quantitative Response When Using Charged Aerosol Detection. Max W. Robinson, Alan P. Hill, Simon A. Readshaw, John C. Hollerton, Richard J. Upton, Sean M. Lynn, Steve C. Besley, and Bob J. Boughtflower. Anal. Chem. 2017, 89, 1772−1777
(2) Quantitative structure-property relationship modeling of polar analytes lacking UV chromophores to charged aerosol detector response. Klaus Schilling & Jovana Krmar & Nevena Maljurić & Ruben Pawellek & Ana Protić & Ulrike Holzgrab. Analytical and Bioanalytical Chemistry. 2019, 411, 13, 2945–2959