The use of solid phase extraction columns in fatty acid purification

Solid phase extraction (SPE) columns with an aminopropyl bonded stationary phase are commonly used to isolate fatty acids. We tested SPE columns with tubes composed of three different materials, high density polyethylene (HDPE), HDPE coated with a fluorinated polymer similar to Teflonfi (FP-HDPE) and glass, to assess the effects of these products on the purity of fatty acid extracts derived from the different SPE columns. Products made of HDPE released significant levels of short chain (mainly C16 and C18) fatty acids during elution, while glass and FP-HDPE yielded little contamination. These results urge caution in the use of HDPE products during analysis of short chain fatty acids, especially in applications involving the use of stable isotope ratio values that could be significantly altered by small amounts of contaminants.