The LCGC Blog: Intact Protein Ion Transmission in a Triple-Quadrupole Mass Spectrometer
June 28th 2017I believe that the term “top-down proteomics” holds a particular connotation with respect to the use of ultrahigh-resolution mass spectrometers in people’s minds. And rightfully so. If one is to determine with confidence the sequence and charge state of a particular fragment ion generated in the gas phase, then high mass accuracy is a must. From the discovery side of things, where qualitative analysis is most important, this is not likely to change. However, when you turn to quantitative analysis, where you want to now monitor levels of a particular protein biomarker for the purpose of disease diagnosis, prognosis, or treatment, then invariably bottom-up strategies are the norm. Protein quantitation using top-down strategies, especially on low-resolution triple-quadrupole systems, have been largely ignored, until recently .
Thermo Fisher Joins European Food Integrity Project
June 20th 2017Thermo Fisher Scientific has been selected as a partner of INTELLItrace Work Package (WP) 18, part of the European Food Integrity Project aimed at developing a validation of untargeted methods to assure the quality, authenticity, and safety of the food chain.
Improving Foot and Mouth Vaccine Stability Using HPSEC
June 20th 2017Researchers from the Chinese Academy of Science in Beijing, China, have used high‑performance size-exclusion chromatography (HPSEC) and differential scanning calorimetry (DSC) to study the stabilization of inactivated foot and mouth disease virus.
Addressing the Challenges of Drug-to-Antibody Measurement
June 20th 2017Antibody–drug conjugates (ADC) are an emerging pharmaceutical technology, with the potential of being the true “magic bullet”. However, these inherently complex biomolecules have unique analytical challenges. One is the determination of the drug-to-antibody ratio (DAR). The average DAR and the drug distribution need to be monitored and could determine the success of an ADC. This article discusses the chromatographic methods used to determine DAR, including hydrophobic interaction chromatography (HIC), reversed phase, and liquid chromatography–mass spectrometry (LC–MS).
Extraction of Micropollutants From Size-Limited Solid Samples
June 12th 2017The quantitative extraction and subsequent purification of trace contaminants from (semi-)solid environmental and food matrices of regular size (that is, a few grams) is still recognized as a challenging task, typically accomplished through relatively complex off-line multistep treatment procedures. When these conventional sample preparation procedures are applied to the treatment of size-limited samples (of less than 1 g), the difficulties increase. This review discusses the different analytical strategies that can be adopted to overcome (or at least reduce) these difficulties when chromatographic techniques are involved for final instrumental determination.
Novel Sampling Technique For Sex Pheromone Analysis in Air
June 6th 2017A novel unit that integrates sampling and analysis for the determination of pest insect sexual pheromones in environmental air using fabric phase sorptive extraction (FPSE) and headspace gas chromatography coupled to mass spectrometry (HSGC–MS) has been developed at the University of Córdoba in Spain.
Tips & Tricks GPC/SEC: Product Registration and REACH
June 6th 2017Molecular mass is one of the central parameters required for product registration. Compared to low molar mass substances, the molar mass determination of macromolecular products is more difficult because the product is a mixture of chains with different lengths and, therefore, molar masses. Gel permeation chromatography/size-exclusion chromatography (GPC/SEC) is the standard technique to separate macromolecules by size and to measure the complete molar mass distribution as well as the molar mass averages. This technique therefore provides crucial information for product registration, including REACH.
Analysis of Residual Antimicrobials in Meat Using HPLC
June 6th 2017Analysis of residual antimicrobials in animal products is crucially important to ensure food safety. This article presents a simple, fast, and highly sensitive high performance liquid chromatography (HPLC) assay of regulated antimicrobials, as well as sample preparation and purification methods. Twenty-four different analytes of interest were investigated in beef, pork, and chicken meat samples.
Enantiomeric Separation of Privileged Scaffold Derivatives in Early Drug Discovery Using Chiral SFC
June 6th 2017Successful therapeutic intervention often requires chiral medicines because of the intrinsic chirality of protein drug targets, which consist of L-amino acids. Potency, efficacy, and safety can be highly dependent on the precise stereochemical geometry of the molecules. Determining the biological profile of individual enantiomers in the early stages of drug discovery is important for successful optimization towards clinical candidates. Here we demonstrate the benefits of supercritical fluid chromatography (SFC) with three chiral stationary phases exemplified by high frequency resolution of 41 out of 50 chiral derivatives of eight commonly used drug discovery scaffolds including 1,3-thiazoles, 1,3-benzothiazoles, pyranoquinolones, indoles, and leucolines.
The LCGC Blog: Getting the Best Repeatability from Your Quantitative Gas Chromatography
June 2nd 2017I’m often asked “what reproducibility should I expect to get from my [insert instrument manufacturer and model]?” So, most folks are referring to the repeatability aspects of precision, as in: “what relative standard deviation (usually expressed at %RSD) for peak area or quantitative result should I be able to achieve from repeat injections from a single vial of sample?”