HPLC Determination and MS Identification of Dehydroabietic Acid and Abietic Acid in Propolis

Abstract

In the present study, the HPLC method on a C₁₈ column with on‐line spectrophotometric and fluorimetric detection was used for separation and determination of dehydroabietic acid and abietic acid in propolis. The samples of propolis tincture were prepared prior to the HPLC analysis. The mobile phase for isocratic elution was methanol‐water 87:13 containing 0.05% formic acid. Abietic acid was detected with spectrophotometric detection at 238 nm, and dehydroabietic acid was detected with fluorimetric detection (excitation 225 nm, emission 285 nm). The limits of determination (signal/noise ratio 10) were 100 ng/mL for dehydroabietic acid and 200 ng/mL abietic acid. The calibration graphs were linear over a wide interval from the limit of determination to 1 mg/mL. Analytical recovery and reproducibility exceeded more than 89%. The developed method was used for analysis of propolis from Slovakia. Mass spectrometry was used for identification of the studied acids. The results demonstrated that dehydroabietic acid was present in all tested samples of propolis. Its content was different (3.7 µg/g–44.7 µg/g of propolis) depending on the source of propolis.

Keywords:

• Propolis
• HPLC
• MS
• Resin acids

Acknowledgment

This work was supported by grants No. 1/2460/05 and 1/1186/04 provided by the Slovak Grant Agency.