Laboratoire d'Electrochimie Physique et Analytique, Ecole Polytechnique Fédérale de Lausanne, Station 6, CH-1015 Lausanne, Switzerland.
Anal Chem. 2013 Jul 2;85(13):6254-63. doi: 10.1021/ac400171e. Epub 2013 Jun 18.
A microchip electrospray emitter with a magnetic bead trap has been designed for solid-phase extraction-gradient elution-mass spectrometry (SPE-GEMS). The goal of this method is the detection of analytes at low concentrations and it is here demonstrated using reverse phase coated magnetic beads (Mbs) for the preconcentration and detection of the peptides. The sample is passed through the chip, and the peptides are retained and enriched in the trap. After washing, the peptides are released sequentially by stepwise gradient elution and electrosprayed for mass spectrometry analysis. This approach allows effective sample desalting, enrichment, sequential elution, and MS detection without the introduction of an additional separation step after SPE. Efficient preconcentration of model peptides by SPE and sequential release and analysis of peptides by GEMS were demonstrated for diluted sample solutions within the range of 1 μM to 10 nM. Fortified human blood serum, protein digest and fractions collected after protein digest OFFGEL separation were analyzed by SPE-GEMS allowing the detection of low abundance peptides usually not observed by direct mass spectrometry analysis. A mathematical model for gradient elution is proposed.
已经设计了一种带有磁珠阱的微芯片电喷雾发射器，用于固相萃取-梯度洗脱-质谱（SPE-GEMS）。该方法的目的是检测低浓度的分析物，这里使用反相涂层磁珠（Mbs）来进行预浓缩和检测肽。样品通过芯片，肽被保留并富集在阱中。洗涤后，肽通过逐步梯度洗脱顺序释放，并进行质谱分析。这种方法允许有效地进行样品脱盐、富集、顺序洗脱和 MS 检测，而无需在 SPE 后引入额外的分离步骤。通过 SPE 对模型肽进行高效预浓缩，并通过 GEMS 进行顺序释放和分析，对于稀释样品溶液，范围为 1 μM 至 10 nM。通过 SPE-GEMS 分析了经强化的人血清、蛋白质消化物和蛋白质消化 OFFGEL 分离后收集的馏分，允许检测通常通过直接质谱分析无法观察到的低丰度肽。提出了用于梯度洗脱的数学模型。
