Chromatographic Determination of Derivatives of p‐Hydroxybenzoic Acid in Melissa officinalis by HPLC

Abstract

This paper presents a fast method for the determination of phenolic compounds–benzoic acids in Melissa officinalis. Soxhlet extraction has been optimized for the isolation of benzoic acids (gallic acid, p‐hydroxybenzoic acid, protocatechuic acid, gentisic acid, vanillic acid, and syringic acid) from plant material. The conditions of Soxhlet extraction, such as solvent composition and extraction time were studied. The efficient extraction of benzoic acids was achieved with a mixture of methanol–water (80∶20, v/v) within 1 hour. Four RP‐18 chromatographic columns were tested for the separation of the compounds. The complete separation of six benzoic acids was achieved on two analytical columns. The basic chromatographic characteristics were evaluated and an HPLC method using Alltima C18–Rocket, one of the suitable columns, was validated for determination of analytes. A mobile phase, which consisted of acetonitrile and formic acid (0.074 mol/L) with a linear gradient at a flow rate 1.5 mL/min was applied for the determination of benzoic acids in extracts of plant material.

Keywords:

• p‐Hydroxybenzoic acid
• Melissa officinalis
• HPLC
• Determination

Acknowledgment

This work was supported by the Slovak Grant Agency for Science, VEGA (No1/2460/05).