April 8th 2025
Researchers from Agency for Science, Technology and Research in Singapore recently published a review article exploring how chromatography can be used to remove double-stranded RNA impurities during mRNA therapeutics production.
New Sample Fractionation Strategies for Proteomic Analyses by LC–MS
November 1st 2006Mass spectrometry has long been a preferred tool for protein identification and biomarker discovery, but preparation of biological samples remains a challenge. Hindrances include the wide range of protein concentrations, sample complexity, and loss or alteration of important proteins due to sample handling. This article describes recent developments in sample fractionation technologies that are overcoming these challenges in interesting ways and are enabling in-depth proteomic studies that were not possible in the past.
Analytical Limbo: How Low Can You Go?
September 1st 2006September 2006. In analytical chemistry, the continual quest for enhanced sensitivity and specificity - in gas chromatography (GC), this can be equated to separation power - remain the common goal in the development of new analytical methodologies. Today, GC is still the most widely used method for the analysis of volatile and semivolatile organic compounds. When coupled with the right choice of detector for the specific application, a wide linearity range and low limit of detection (LOD) can be met. For GC analyses, many approaches can be used to achieve greater sensitivity and lower LOD. They can be classified broadly into four categories: improved sampling (sample preparation) strategies; sample introduction methods; improved chromatographic performance; and alternative (selective–sensitive) detection transducers. This article provides an up-to-date review of existing and emerging chromatographic innovations, based upon these four strategies, that will improve sensitivity and detection limits of trace..
Mapping the history of human migration
September 1st 2006Applied Biosystems has joined the Genographic Project as a supporting sponsor for the generation of one of the world's largest databases of information, which will reveal the sources of humankind's diversity. The company has signed a multi-year agreement to provide laboratory research equipment and services to each of the ten participating global research centres. The terms of the agreement were not disclosed.
Chromatography for Bioanalytical Chemists
May 1st 2006This article looks at current practices in bioanalytical chemistry by examining and critically assessing the various parameters that can be altered to achieve high-speed results with high resolution in LC–MS applications. The decision to opt for gradient or isocratic elution is also discussed.
Interpretation of Isotope Peaks in Small Molecule LC?MS
April 1st 2006Biologists entering liquid chromatography?mass spectrometry (LC?MS) from a background of general LC rarely use their mass spectrometer to its full potential. Isotope peaks offer huge possibilities both in semi-quantitative interpretation of structure and in quantitative labelling studies. This article examines charge state, "easy" isotopes, such as chlorine, the slightly harder problem of sulphur compounds, and finally looks at a method for improved measurement of heavy labels in a metabolic study.
Amide Hydrogen–Deuterium Exchange: A Fast Tool for Screening Protein Stabilities in Chromatography
February 1st 2006Protein unfolding and aggregation can be serious considerations when designing laboratory and preparative chromatographic purification steps. This problem has been studied most thoroughly within the contexts of reversed-phase chromatography and hydrophobic interaction chromatography. However, there are currently no robust methods for resin selection capable of predicting adsorbed-phase protein stability as a function of amino acid sequence, secondary or tertiary structure, or resin characteristics.
HPLC Analysis of Nonvolatile Analytes Using Charged Aerosol Detection
A new detection method based upon aerosol charging was examined for its applicability and performance with high performance liquid chromatography (HPLC). Our results demonstrate universal detection of nonvolatile analytes with response magnitude that is independent of analyte chemical properties, four orders of magnitude dynamic range, low nanogram, lower limits of detection, and < 2% relative standard deviation response variability. Broad applicability was demonstrated for a range of methods including those using gradient elution, reversed phase, hydrophilic interaction, and ion chromatography; normal and narrow bore column formats; and in combination with other detectors (for example, UV detectors, evaporative light-scattering detectors, and mass spectrometers).
Choice of Buffer for the Analysis of Basic Peptides in Reversed-Phase HPLC
February 1st 2005Formic acid often is used for the analysis of peptides in proteomic studies by HPLC-MS, due to its volatility and reduced signal suppression. However, poorer chromatographic performance can be obtained in comparison with trifluoroacetic acid or nonvolatile phosphate buffers due to increased overloading, which can occur even for extremely small sample masses. Comparison of a highly inert silica-ODS and a wholly polymeric phase indicated that overloading effects on both are very similar and caused by the mutual repulsion of solute ions on the hydrophobic column surface.
HPLC Analysis of Nonvolatile Analytes Using Charged Aerosol Detection
A new detection method based upon aerosol charging was examined for its applicability and performance with high performance liquid chromatography (HPLC). Our results demonstrate universal detection of nonvolatile analytes with response magnitude that is independent of analyte chemical properties, four orders of magnitude dynamic range, low nanogram, lower limits of detection, and < 2% relative standard deviation response variability. Broad applicability was demonstrated for a range of methods including those using gradient elution, reversed phase, hydrophilic interaction, and ion chromatography; normal and narrow bore column formats; and in combination with other detectors (for example, UV detectors, evaporative light-scattering detectors, and mass spectrometers).