High-throughput biopolymer desalting by solid-phase extraction prior to mass spectrometric analysis

In the last 10 years mass spectrometry (MS) has become an important method for analysis of peptides, proteins and DNA. It was recently utilized for ac curate high-throughput protein identification, sequencing and DNA genotypin g. The presence of non-volatile buffers compromises sensitivity and accurac y of MS biopolymer analysis; it is essential to remove sample contaminants prior to analysis. We have developed a fast and efficient method for desalt ing of DNA oligonucleotides and peptides using 96-well solid-phase extracti on plates packed with 5 mg of Waters Oasis (R) HLB sorbent (Waters, Milford , MA, USA). This reversed-phase sorbent retains the biopolymer analytes, wh ile non-retained inorganic ions are washed out with pure deionized water. D NA oligonucleotides or peptides are eluted using a small amount (20-100 mul ) of acetonitrile-water (70:30, v/v) solution. The SPE desalting performanc e meets the requirements for MS applications such as protein digest analysi s and DNA genotyping. (C) 2001 Elsevier Science B.V. All rights reserved.