title: Enrichment and desalting of tryptic protein digests and the protein depletion using boron nitride.
abstract: Sample preparation still remains a great challenge in modern bioanalysis and the interest in new efficient solid phase extraction (SPE) materials still remains high. In this work, hexagonal boron nitride (h-BN) is introduced as a new SPE material for the isolation and enrichment of peptides. The h-BN is isoelectronic and structurally similar to graphite. It has remarkable properties including good thermal conductivity, excellent thermal and chemical stability and a better oxidation resistance than graphite. BN attracts increasing interest because of its wide range of applicability. In the present work, the great potential of h-BN, as a new SPE-material, on the enrichment, preconcentration and desalting of tryptic digest of model proteins is demonstrated. A special attention was dedicated to the efficient enrichment of hydrophilic phosphopeptides. Two elution protocols were developed for the enrichment of peptides compatible for subsequent MALDI-MS and ESI-MS analysis. In addition, the recoveries of 5 peptides and 3 phosphopeptides with wide range of pI values utilizing h-BN materials with different surface areas were investigated. 84-106% recovery rate could be achieved using h-BN materials. The results were compared with those obtained using graphite and silica C18 under the same elution conditions, and lower recoveries were obtained. In addition, h-BN was found to have a capability of protein depletion, which is requisite for the peptide profiling.
authors.affiliation: Institute of Analytical Chemistry and Radiochemistry, Leopold-Franzens University, Innrain 80-82, Innsbruck 6020, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Fischnaller
authors.affiliation: Institute of Analytical Chemistry and Radiochemistry, Leopold-Franzens University, Innrain 80-82, Innsbruck 6020, Austria.
authors.forename: Rainer
authors.initials: R
authors.lastname: Köck
authors.affiliation: Institute of Analytical Chemistry and Radiochemistry, Leopold-Franzens University, Innrain 80-82, Innsbruck 6020, Austria. Electronic address: rania.bakry@uibk.ac.at.
authors.forename: Rania
authors.initials: R
authors.lastname: Bakry
authors.affiliation: Institute of Analytical Chemistry and Radiochemistry, Leopold-Franzens University, Innrain 80-82, Innsbruck 6020, Austria.
authors.forename: Günther K
authors.initials: GK
authors.lastname: Bonn
mesh_terms: D001896:Boron Compounds / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D011506:Proteins / Q000737:chemistry* / Q000302:isolation & purification* / Q000378:metabolism; D012822:Silicon Dioxide / Q000737:chemistry; D052616:Solid Phase Extraction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014357:Trypsin / Q000378:metabolism*
chemical_list: D001896:Boron Compounds; D010455:Peptides; D011506:Proteins; C017282:boron nitride; D012822:Silicon Dioxide; D006108:Graphite; D014357:Trypsin
keywords: Boron nitride; Desalting; Enrichment; Peptides; Protein depletion; Recovery rates