Evaluation of three common methods of bulk lipid quantification in soft tissues of marine benthic invertebrates

Different analytical methods are used in biochemical laboratories to quantify lipid content in marine organisms, but the comparative utility of these protocols has not been assessed yet. This study evaluated three common methods of bulk lipid determination in the soft tissues of macrobenthic invertebrates in terms of their yield and labour intensity: the gravimetric method and two colourimetric methods of Marsh and Weinstein (1966) and Frings and Dunn (1970). Lipids were first extracted from three macrofaunal species, which were sampled in the coastal zone of the Gulf of Gdańsk (southern Baltic Sea): mussel Mytilus trossulus, shrimp Crangon crangon and polychaete Hediste diversicolor, using the Bligh and Dyer extraction technique (Bligh & Dyer, 1959). All tested methods proved accurate, precise and reproducible but differed in validation parameters and workload. The Marsh and Weinstein method provided an analytical procedure of the highest precision and recovery, the lowest limit of detection; however, it was laborious. The gravimetric method was the least labour-intensive but had the poorest validation parameters. The Frings and Dunn method produced more reliable results than the gravimetric method, but was the most time-consuming.