The trace sterols of the red alga Laurencia papillosa investigated by open tubular capillary column gas chromatography-mass spectrometry

Abstract

1. 1. An extract of the red alga Laurencia papillosa was examined for the presence of sterols by computerized gas chromatography-mass spectrometry with two different open-tubular capillary columns. 2. 2. Cholesterol was found to be the major component (about 97%) in agreement with findings in other red algae. 3. 3. The minor and trace sterols identified are 22-dehydrocholesterol, brassicasterol, 24-methylene-cholesterol, campesterol, sitosterol (or poriferasterol) and fucosterol. 4. 4. Several other C 27-, C 28- and C 29-sterols were detected including two 24-ethyl sterols for which the C 24 configuration could not be assigned. 5. 5. A trace of 28-isofucosterol was also indicated. 6. 6. The particular mass spectral properties of sterol t-butyl dimethylsilyl ethers allowed the rapid and simultaneous detection of the trace sterols by mass chromatography even in the presence of a huge excess of cholesterol without prior fractionation and concentration. 7. 7. The combined technique offers great potential for the ready detection of new trace sterols and possibly active sterol metabolites in variety of extracts.