Microemulsion electrokinetic chromatography for separation and analysis of curcuminoids in turmeric samples

• Published in: Journal of separation science 2006-03, Vol.29 (5), p.666-676
• Main Authors: Nhujak, Thumnoon, Saisuwan, Warangkana, Srisa-art, Monpichar, Petsom, Amorn
• Format: Article
• Language: English
• Subjects: Animals; Antioxidants - analysis; Aroma and flavouring agent industries; Biological and medical sciences; Buffers; Chromatography, Micellar Electrokinetic Capillary - methods; Curcuma - chemistry; Curcumin - analogs & derivatives; Curcumin - analysis; Curcuminoids; Food industries; Fundamental and applied biological sciences. Psychology; General pharmacology; Medical sciences; Microemulsion electrokinetic chromatography; Molecular Structure; Organic solvent; Pharmacognosy. Homeopathy. Health food; Pharmacology. Drug treatments; Plant Extracts - chemistry; Reproducibility of Results; Resolution; Selectivity; Solvents - chemistry; Surface-Active Agents - chemistry
• ISSN: 1615-9306; 1615-9314
• DOI: 10.1002/jssc.200500333

Microemulsion EKC (MEEKC) was developed for quantitative analysis of curcuminoids, such as curcumin (C), demethoxycurcumin (D), and bis‐demethoxycurcumin (B). MEEKC separation of curcuminoids was optimized, and a change in resolution was explained using a modified equation for resolution in MEEKC without electroosmosis. The suitable MEEKC conditions for separation of curcuminoids were obtained to be the microemulsion buffer containing 50 mM phosphate buffer at pH 2.5, 1.1% v/v n‐octane as oil droplets, 180 mM SDS as surfactant, 890 mM 1‐butanol as cosurfactant, and 25% v/v 2‐propanol as organic cosolvent; applied voltage of –15 kV; and separation temperature 25°C. Achieved baseline resolution of C : D and D : B was obtained with Rs ˜2.4 and analysis time within 18 min. In addition, high accuracy and precision of the method were obtained. This MEEKC method was used for quantitative determination of individual curcuminoids in medicinal turmeric capsules and powdered turmeric used as coloring additive in food, with simple sample preparation such as solvent extraction, dilution, and filtration, and without cleaning up by SPE.