Although it may prove to have limited applicability in the long term, an SPE method with ODS columns for the removal of non-lipid contaminants from crude extracts of polar lipids, such as those of brain lipids, appears to have some merit [40]. In essence, a crude chloroform-methanol extract was diluted with methanol-water and poured into the reservoir of an ODS column; the eluent was diluted with methanol-water and passed through the column again, then the process was repeated. The pure lipids were obtained by elution with chloroform-methanol (1:2, v/v), or the acidic complex lipids could be eluted before the remaining phospholipids, cerebrosides and cholesterol by a two-stage procedure. In addition, gangliosides could be recovered as a distinct fraction if necessary. While the procedure would appear to be of doubtful value for tissue extracts rich in simple lipids, such as triacylglycerols, it would be worth evaluating it for microbial lipids or for extracts of photosynthetic tissue, for example