Sudan black lipid blot – a rapid and simple method for quantification of lipids in biological samples

Bioanalytical techniques for the isolation and quantification of total lipids in biological samples are an integral part of lipidomic workflows and widely used tools for metabolic assessment at the cellular and organismic levels. The most widely used protocol for the isolation, extraction, and quantification of total lipids in biological tissues was originally introduced by Folch et al.. It requires a relatively large amount of tissue and large volumes of lipid extracts for reliable assessment of lipid content using the gravimetric technique. Here, we propose a new method to overcome the aforementioned challenges based on the hypothesis that the partitioning coefficient of the widely used lysochrome diazo dye Sudan Black B between the lipid extract and ethylene glycol can be used to indirectly estimate the absolute concentration of lipids. The proposed method demonstrates great precision and linearity, requires minimal equipment, and enables the analysis of total lipid content in biological specimens available only in limited amounts by reducing the requirements for the input quantity by >300-fold for some tissues (e.g. fecal samples). ### Competing Interest Statement The authors have declared no competing interest.