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Sample Preparation Steps (sample + preparation_step)

Distribution by Scientific Domains

Chemistry	80%

Selected Abstracts

Serum protein profiling by solid phase extraction and mass spectrometry: A future diagnostics tool?

PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 6 2009
Anne K. Callesen
Abstract Serum protein profiling by MS is a promising method for early detection of disease. Important characteristics for serum protein profiling are preanalytical factors, analytical reproducibility and high throughput. Problems related to preanalytical factors can be overcome by using standardized and rigorous sample collection and sample handling protocols. The sensitivity of the MS analysis relies on the quality of the sample; consequently, the blood sample preparation step is crucial to obtain pure and concentrated samples and enrichment of the proteins and peptides of interest. This review focuses on the serum sample preparation step prior to protein profiling by MALDI MS analysis, with particular focus on various SPE methods. The application of SPE techniques with different chromatographic properties such as RP, ion exchange, or affinity binding to isolate specific subsets of molecules (subproteomes) is advantageous for increasing resolution and sensitivity in the subsequent MS analysis. In addition, several of the SPE sample preparation methods are simple and scalable and have proven easy to automate for higher reproducibility and throughput, which is important in a clinical proteomics setting. [source]

Continuous shipboard sampling system for determination of triple oxygen isotopes and O2/Ar ratio by dual-inlet mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 23 2006
V. V. S. S. Sarma
A continuous shipboard sampling system was developed for the determination of the isotopic composition of the triple oxygen isotopes and oxygen to argon (O2/Ar) ratios in dissolved air. In this system, dissolved air is separated by a hollow fiber membrane degassing module. This system collects dissolved air quantitatively and rapidly. The sample flow rate through the membrane is critical for the fractionation of the oxygen isotopes and the O2/Ar ratio and should be <2 mL/min. Fractionation of oxygen between the liquid and gas phase of the air-saturated water was found to be similar to that of earlier reports. The advantages of this method over existing techniques include rapid collection of samples (30 min/sample), high efficiency in extraction of gases from the liquid phase, and the lack of a sample preparation step (e.g. degassing). Copyright © 2006 John Wiley & Sons, Ltd. [source]

Effective elimination of nucleic acids from bacterial protein samples for optimized blue native polyacrylamide gel electrophoresis

ELECTROPHORESIS, Issue 14 2009
Jingdan Liang
Abstract Nucleic acids remaining within bacterial protein samples from Streptomyces lividans and Escherichia coli were found to interfere significantly with blue native polyacrylamide gel electrophoresis (BN-PAGE), a technique used frequently for analyzing bacterial protein complexes in proteomics studies. We have used ultracentrifugation and/or precipitation of cell lysates with streptomycin sulfate to eliminate nucleic acids from total and/or membrane protein samples. Nucleic acid-binding proteins were first enriched by precipitation with streptomycin sulfate, and contaminating nucleic acids were then eliminated by precipitation by adding polyethyleneimine. The performance of BN-PAGE was found to be dramatically improved by these sample preparation steps. [source]

Microfluidic chips for mass spectrometry-based proteomics

JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 5 2009
Jeonghoon Lee
Abstract Microfluidic devices coupled to mass spectrometers have emerged as excellent tools for solving the complex analytical challenges associated with the field of proteomics. Current proteome identification procedures are accomplished through a series of steps that require many hours of labor-intensive work. Microfluidics can play an important role in proteomic sample preparation steps prior to mass spectral identification such as sample cleanup, digestion, and separations due to its ability to handle small sample quantities with the potential for high-throughput parallel analysis. To utilize microfluidic devices for proteomic analysis, an efficient interface between the microchip and the mass spectrometer is required. This tutorial provides an overview of the technologies and applications of microfluidic chips coupled to mass spectrometry for proteome analysis. Various approaches for combining microfluidic devices with electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) are summarized and applications of chip-based separations and digestion technologies to proteomic analysis are presented. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Determination of urinary androgen glucuronides by capillary electrophoresis with electrospray tandem mass spectrometry

BIOMEDICAL CHROMATOGRAPHY, Issue 4 2009
Sung-Hee Cho
Abstract Capillary electrophoresis,electrospray tandem mass spectrometry (CE-ESI/MS/MS) is a simple and highly sensitive method for quantifying seven urinary androgen glucuronides. The urine samples were diluted and filtered through a membrane filter, and the filtrate was injected into a CE-MS/MS system without further sample preparation steps such as extraction and derivatization. The calibration ranges were 0.01,5 µg/mL for glucuronides of androsterone and 11, -OHAn-3G, and 5,500 ng/mL for glucuronides of 11-ketoAn, DHEA, testosterone, epitestosterone and DHT. The linearity of the method was 0.992,0.998, and the limits-of-detection at a signal-to-noise ratio of 3 were 5,10 ng/mL. The coefficients of variation were in the range of 4.0,9.0% for intra-day assay and 4.1,9.8% for inter-day assay. The proposed method may be applicable to metabolic profiling in both quantitative and qualitative analysis. Copyright © 2008 John Wiley & Sons, Ltd. [source]