Magnus Rogeberg

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On-line solid phase extraction (SPE)-liquid chromatography (LC) allows for automated, sensitive, precise and selective bioanalysis. It is a common feature in miniaturized- or nano LC systems, which are well suited for applications requiring high sensitivity and/or treatment of limited samples (laser micro-dissection samples, rare cancer stem cells, etc.).(More)
Porous layer open tubular (PLOT) polystyrene divinylbenzene columns have been used for separating intact proteins with gradient elution. The 10 microm I.D. x 3 m columns were easily coupled to standard liquid chromatography-mass spectrometry (LC-MS) instrumentation with commercially available fittings. Standard proteins separated on PLOT columns appeared as(More)
The single-run resolving power of current 10 μm id porous-layer open-tubular (PLOT) columns has been optimized. The columns studied had a poly(styrene-co-divinylbenzene) porous layer (~0.75 μm thickness). In contrast to many previous studies that have employed complex plumbing or compromising set-ups, SPE-PLOT-LC-MS was assembled without the use of(More)
Zwitterionic-hydrophilic interaction liquid chromatography (HILIC) has been found very appropriate for separation of polar compounds and peptides with post-translational modifications (PTMs) such as phosphorylation and glycosylation. In this study, a column switching system based on zwitterionic-HILIC silica based monolith columns was used for enrichment(More)
The effect of temperature on separation using reversed-phase monolithic columns has been investigated using a nano-LC pumping system for gradient separation of tryptic peptides with MS detection. A goal of this study was to find optimal conditions for high-speed separations. The chromatographic performance of the columns was evaluated by peak capacity and(More)
Reliable, sensitive and automatable analytical methodology is of great value in e.g. cancer diagnostics. In this context, an on-line system for enzymatic cleavage of proteins, subsequent peptide separation by liquid chromatography (LC) with mass spectrometric detection has been developed using "sub-chip" columns (10-20 μm inner diameter, ID). The system(More)
Deposition of insoluble amyloid plaques is one of the known hallmarks of Alzheimer's disease. Amyloid beta 1-42 is the main component in these plaques, and the soluble oligomers of this peptide are believed to contribute to synaptic degradation and dementia. Enzymatic hydrolysis of amyloid beta is important to keep its tissue concentration low to avoid(More)
The amyloid beta (Aβ) peptide is the main constituent of the plaques characteristic of Alzheimer's disease (AD). Measurement of Aβ1-42 in cerebrospinal fluid (CSF) is a valuable marker in AD research, where low levels indicate AD. Although the use of immunoassays measuring Aβ1-38 and Aβ1-40 in addition to Aβ1-42 has increased, quantitative assays of other(More)
Amyloid beta (Aβ) is a peptide derived from processing of the membrane bound amyloid precursor protein and is a main constituent in amyloid plaques in Alzheimer's disease (AD). The excess Aβ in AD brain may be caused by altered Aβ metabolism, including reduced enzymatic degradation. Our previous enzymatic study of Aβ degradation revealed that intracellular(More)
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