Fast and Efficient Purification of Synthetic Peptides by Solid-phase Extraction

Purification of peptides is often the most difficult part of the process used to obtain the compounds [1]. Several methods are used for isolation and subsequent purification of the post-synthesis mixture. Depending on the properties of the peptide and the types of impurity, commonly used techniques are ion-exchange chromatography and gel filtration [2,3]. The standard method for isolation is high-performance liquid chromatography [4,5], which enables separation of substances with negligible differences between their chemical structures. Unfortunately, the need for specialised equipment and columns and high buffer consumption makes this method relatively expensive. Solid-phase extraction (SPE) is a method originally developed for concentration of synthetic, biological, and environmental samples before analysis by conventional methods [6]. SPE can also have other applications, for example removing impurities from samples and isolation of analytes from biomatrices [7]. This method is essentially a short chromatographic separation with a variety of the applications. Four general extraction me-