An efficient ethanol-based analytical protocol to quantify faecal steroids in marine sediments

The majority of the analytical methods for steroids in marine sediments are laborious and time consuming and involve the use of large volumes of organic (frequently chlorinated) solvents. A method has been developed utilising ethanol extraction with a rapid alumina-ethanol elution clean up, providing an environmentally friendly and inexpensive alternative. Recoveries of steroids (coprostanol, epicoprostanol, cholesterol, cholestanol, 5alpha-coprostanone and 5beta-coprostanone) ranged from 70 to 93% and compared favourably with more traditional analyses. Analytical performance was tested through analysis of reference material and concentrations recorded for coprostanol, cholesterol and cholestanol were close to the mean certified values and were within acceptable values. Relative standard deviations from triplicate analyses were small (6-12%). These initial tests also indicate that the simplified clean up (without fractionation) is not subject to interference in the quantification of the selected faecal steroids.