LIQUID CHROMATOGRAPHY OF TRITERPENIC RESINS AFTER DERIVATIZATION WITH DANSYL CHLORIDE

Abstract

A chromatographic method using fluorescing derivatization was developed for the analysis of triterpenoids in natural resins. The separation was performed using a Luna-C₁₈ column, an acetonitrile-water eluant mixture, a flow-rate of 1 mL · min⁻¹. The fluorescent compounds were detected at 530 nm (excitation at 347 nm). A derivatization reaction of hydroxyl groups of triterpenoids using dansyl chloride is described; this process appeared unusual and provided some novelty. The detection limits were obtained in the range of 0.15–0.45 ng/mL (S/N = 3) for dansylated standard compounds. The described procedure allowed the simultaneous determination of twelve triterpenoids present in frankincense species (Boswellia carteri and B. frereana) and was successfully applied to an archaeological sample coming from an Egyptian mummy. Two other resinous materials, dammar and mastic resins employed in Cultural Heritage, were also studied, in which nine and seven triterpenoids are respectively characterized.

Keywords:

• dansyl chloride
• derivatization
• fluorimetry
• liquid chromatography
• natural resins
• triterpenoids

ACKNOWLEDGMENT

The authors wish to thank Pr. J.-C. Goyon of the Victor Loret Egyptologic Institute (University of Lyon II, France) for kindly making this archaeological sample available and Mr. M. Pryet (Les Encens du Monde – Asie Concept, Castelnau-le-Lez, France) for the supply of samples of commercial frankincense.

Notes

^a Water.

^b Acetonitrile.

^c Final run time for dammar resin.

^d Final run time for frankincense resin.

^e Final run time for both labeled resins.

^f Final run time for mastic resin.

^g final run time for dansyl mastic resin.

*The C20 configuration was not determined.

*The C20 configuration was not determined.

Chromatographic conditions: detection at 210 nm for standard compounds and fluorescence detection (λ_exc = 347 nm; λ_em = 530 nm) for dansyl derivatives.