Comparing Extraction Methods for Biomarker Steroid Characterisation from Soil and Slurry

Clean water is a precious resource, and
policies/programmes are implemented worldwide to protect and/or improve water quality. Faecal pollution can be
a key contributor to water quality decline causing eutrophication through nutrient enrichment and pathogenic
contamination. The robust sourcing of faecal pollutants
is important to be able to target the appropriate sector and
to engage managers. Biomarker technology has the potential for source confirmation, by using, for example the
biomarker suite of steroids. Steroids have been used in
the differentiation of human and animal faeces; however,
there is no unequivocal extraction technique. Some of the
methods used include (i) Soxhlet extraction, (ii) Bligh
and Dyer (BD) extraction, and (iii) accelerated solvent
extraction (ASE). The less costly and time intensive
technique of ASE is particularly attractive, but a current
research gap concerns further comparisons regarding
ASE lipid extraction from soils/slurries compared with
the more traditional Soxhlet and BD extractions. Accordingly, a randomised complete block experiment was
implemented to assess differences between the three
extraction methods, differences between the different
sample types, and the interactions between these two
factors. Following GC-MS, it was found that there was
no significant difference between the results of the steroid
extraction methods, regardless of the type of sample
used, for the quantity of each steroid extracted. It was
concluded that ASE could be used confidently instead of
the more established steroid extraction methods, thereby
delivering time and cost savings.