A new centrifugal device used in sample clean-up and concentration of peptides

Abstract

Publisher Summary A strong cation exchange membrane with hydrophobic character has been incorporated into an Amicon Microcon™ centrifugal device. The resulting unit has been shown to have a broad range of selectivity in that it recognizes both free amines and hydrophobic residues. This report presents the analytical sample preparation unit Microcon™-SCX to demonstrate high binding efficiency for a variety of samples. It is ideal for concentrating peptides or oligonucleotides, and for removing low molecular weight contaminants from sample prior to analysis—that is, mass spectroscopy, sequencing, amino acid, HPLC, and carbohydrate analysis. Microcon-SCX contains a hydrophobic strong cation exchange membrane adsorbing a variety of low molecular analytes to remove salts and contaminants from sample for concentrating a salt free sample in a volatile buffer. The high efficiency in binding of analytes at low pH is shown to occur within seconds during a brief centrifugation. Desorption of sample at either low or high pH in the presence of polar solvents can be achieved in volumes as low as 50 μl. Optimal desorption incorporates two consecutive 50 μl spins using 1,4 N ammonium hydroxide or 1,2 N hydrochloric acid in 50% methanol. A variety of application-specific desorbants is shown to achieve excellent sample recoveries.