All News
Rapid Perfluorinated Alkyl Acid Analysis by LC–MS/MS Increases Sample Throughput
July 1st 2017Perfluorinated alkyl acids are man-made fluorochemicals used as surface-active agents in the manufacture of a variety of products, such as firefighting foams, coating additives, textiles, and cleaning products. They have been detected in the environment globally and are used in very large quantities around the world. These fluorochemicals are extremely persistent and resistant to typical environmental degradation processes. As a result, they are widely distributed across the higher trophic levels and are found in soil, air, groundwater, municipal refuse, and landfill leachates. The toxicity, mobility, and bioaccumulation potential of perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), in particular, pose potential adverse effects for the environment and human health.
The Rapid Determination of Mycotoxins by LC–MS/MS
July 1st 2017Mycotoxins are secondary metabolites produced by several species of fungi and are considered one of the most significant contaminants of agricultural commodities, both in the field and in storage. Agricultural products that may be affected include cereals, spices, dried fruits, and various nuts. Although hundreds of mycotoxins are known, relatively few are considered to pose a significant health risk. Aflatoxins, in particular aflatoxin B1, are genotoxic and carcinogenic and may cause liver cancer in humans, whilst ochratoxin A and the trichothecenes HT-2 and T-2 can cause various toxic effects. Monitoring and control of certain mycotoxins is important within the food industry because of their potential toxicity at low levels to both humans and animals.
The Effect of Draw-Out Lens Diameter on Sensitivity of GC–MS Analysis
July 1st 2017Gas chromatography–mass spectrometry (GC–MS) allows isolation and identification of individual analytes within a complex mixture. Helium has traditionally been the first-choice carrier gas, owing to its inertness, performance, and relatively cheap price. Since 2001, however, helium has become increasingly expensive with a reported global increase in price of 500% between 2001 and 2016 (1). In 2012–2013, the global helium shortage increased the number of GC users switching to alternative carrier gases and improved the availability of information on their use.
Determination of Pesticides in Coffee with QuEChERS Extraction and Silica Gel SPE Cleanup
July 1st 2017Coffee is one of the most widely consumed beverages in the world, partly because of the stimulating effect of its caffeine content. Like most crops, the application of pesticides in coffee cultivation is a common practice to increase production yields. This application note details an optimized method for the extraction and cleanup of pesticide residues from coffee using a QuEChERS extraction procedure followed by a silica gel solid-phase extraction (SPE) cleanup.
On-Line MALS-QELS (Quasi‑Elastic Light Scattering)
July 1st 2017While on-line multi-angle light scattering (MALS) is one of the most important techniques for macromolecular characterization, it can be made even more versatile with the addition of a quasielastic light scattering (QELS, a.k.a. dynamic light scattering) module for determination of hydrodynamic radius. QELS can be added to a Wyatt MALS system as a WyattQELS™ module embedded in the MALS instrument, or by connecting the MALS flow cell to a batch DLS instrument such as a DynaPro® NanoStar® or Mobius® via optical fibre. The QELS instruments can be used to determine the hydrodynamic radius, rh , for a variety of samples in a continuous‑flow mode. The combined MALS-QELS system will measure simultaneously rg, rh, and the absolute molar mass.
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.
