Column Chromatography Essay

Detection and Purification

A Monascus pigments is a complex of azaphilone compounds, which can be separated by using various analytical techniques.

UV- Visible spectrophotometric methods

The UV-Visible spectrophotometric method is usually used for the confirmation of pigments produced by Monascus with taking absorbance at a respective wavelength. i.e. Yellow pigment at 400, Orange 470, and Red at 500 nm. The pure solvent or extract of unfermented substrate was always used as the blank (Carels and Shepherd 1977; Chen MH, 1993).

Column chromatography

For the isolation and purification of Monascus pigments, column chromatography had been extensively used from long time. However, its isolated pigments fraction is further need to purify by Thin Layer Chromatography and High Performance Liquid Chromatography (Vidyalakshmi et al. 2009). In 1975, Yoshimura M, et al. isolation, and purification of Monascus pigments through column chromatography by using Sephadex G-50 (3 cm × 5 cm) column with 0.1 M potassium phosphate buffer of pH 7.0 was used as effluent for flow rate of 0.5 mL/min. A number of column and eluants were preferred to isolation and purification of different Monascus pigments by researchers.

In 1983, Hin-Chung Wong and Philip E. Koehler used silica gel column, 2× 20 cm, 60- 200 mesh suspended in hexane

and NMR spectra were recorded in CD3OD and CDCL3 using a Bruker WM 500 spectrometer at room temperature [500 MHz (1 H NMR) and 125 MHz (13C NMR)]. From the results of spectral analysis found;9-hexanoyl-3-(2-hydroxypropyl)-6a-methyl-9,9a-dihydro-6H-furo[2,3-h]isochromene-6,8(6aH)-dioneand4-[2,4-dihydroxy-6-(3-hydroxybutanethioyloxy)-3methylphenyl]-3,4-dihydroxy-3,6-dimethylheptanoic acid. These pigments may have been better to used as colorants in food industry (Campoy S et al.