Application Notes: General

The analysis of the molar mass distribution of polyethylene and polypropylene resins by GPC/SEC has always been considered a demanding task because of the requirement of high temperature operation for dissolution and complex hardware design, which often results in high maintenance cost, in particular related to the autosampler/injector and detector units, and in other problematic and consuming tasks such as solvent handling added to column fragility, sample degradation, or detector sensitivity–stability.

Acidic mobile phases have found widespread applications in the reversed-phase HPLC separation of many important pharmaceutical and environmental compounds.

The term ionic liquid refers to organic salts with relatively low melting points (below 100 °C) that usually consist of an organic cation or anion and a counterion, in either organic or inorganic form.

Various techniques exist for cutting capillary tubing. In this note we revisit these methods and provide guidelines for selecting the most appropriate method.

Since 2001 when they became available in North America, monolithic silica HPLC columns have become valuable analytical tools in the R&D and methods development laboratories.

This article describes the use of combined ion chromatography-mass spectrometry (IC–MS) and ion chromatography-inductively coupled plasma mass spectrometry (IC-ICP–MS) to analyse potentially harmful compounds.

Tobacco specific nitrosamines (TSNA) are a group of carcinogens found only in tobacco products and are formed from nicotine and related alkaloids during the production and processing of tobacco and tobacco products.

The analysis of anions and cations is critical during quality control. In this example, all major ionic components in mineral water are identified and quantified in a single run, with no sample preparation or concentration step.

Homeland security requirements create the need for portable mass spectrometers, with ion detectors capable of performing at elevated pressure.

In the past few decades, single enantiomers and stereoisomers have overtaken achiral molecules in the percentage of approved drugs in the market. Because isomers can have different biological/pharmacological/toxicological properties, authorities, such as the European Pharmacopoeia and the FDA, have asserted escalated emphasis on controlling isomer content in drug compounds and require that stereoisomers, "be treated as separate drugs and developed accordingly" with rare exception. The separation and quantification of stereoisomers is therefore of great importance, especially when considering pharmaceutical compounds (1).

Viruses are packets of infectious nucleic acid (either DNA or RNA) surrounded by a protective coat consisting of a large number of protein subunits. Since viruses can cause various diseases - some life-threatening - characterizing virus particles thoroughly in terms of their size distribution, aggregation, and absolute counts-per-unit volume is of extreme importance.

Rapid sample preparation using the CUSTODIONâ„¢ solid phase microextraction (SPME) syringe was applied to chemical warfare agents (CWAs), CWA simulants, by-products, and precursors. The samples were analyzed quickly and reliably with a sample-to-sample cycle time of less than 3 min using the GUARDIONâ„¢-7 portable capillary gas chromatograph toroidal ion trap mass spectrometer (GC–TMS).

Over-expression of recombinant proteins is commonly used for the production of protein reagents in industry and academia. Problems often occur relating to the stress put on the cells to deal with this huge increase in synthesis. Cellular proteins that are part of the protein synthesis machinery are often up-regulated under such conditions. Large quantities of the recombinant protein can be bound to these cellular proteins, making purification difficult.

Protein phosphorylation is one of the most prevalent intracellular protein modifications, regulating numerous cellular processes including cell differentiation, proliferation, and migration. Approximately 30% of cell proteins are phosphorylated at any given time and changes in protein phosphorylation often signal developmental or pathological disorders (1). To better understand the role of protein phosphorylation, it is important to separate the phosphorylated forms of a given protein.

The new ultrafleXtremeâ„¢ exceeds all current expectations of MALDI-TOF/TOF technology: A proprietary kHz smartbeam-IIâ„¢ MALDI laser integrated with a novel FlashDetectorâ„¢ and re-engineerd electronics makes it the only MALDI-TOF/TOF on the market to provide kHz acquisition in MS and MS-MS modes. It generates a new level of data quality in applications such as LC-MALDI proteomics, high resolution tissue imaging based biomarker discovery or Top-Down Sequencing.

Iodine is an essential nutrient in seawater, seafood, and iodine-enriched foods, such as iodized table salt. The most common forms of iodine in the diet are iodide and iodate, with additional iodo-organic compounds providing a small fraction of the bio-available iodine. Iodine deficiency affects thyroid hormone production and leads to developmental diseases, goiter, and paralysis (1).

Since the introduction of high-performance liquid chromatography (HPLC) nearly 40 years ago, many improvements have been made to column stationary phases to achieve faster, more efficient separations. HPLC columns containing superficially porous (sometimes called fused-core) particles have recently gained increasing attention. Though this technology is not entirely new, it has been improved to the point where rapid, highly efficient separations can be achieved for some applications.

Illegal drug use worldwide is at an all time high. Forensic laboratories are seeing increased sample loads creating an immediate need for fast and accurate analysis to positively identify confiscated materials in criminal investigations. This application highlights the value of gas chromatography with time-of-flight mass spectrometry (GC-TOFMS) for drug testing in forensic laboratories. A method was developed to successfully identify twenty drugs of abuse in 4.5 min. This GC-TOFMS method shows good chromatographic peak shape for even the most challenging drug analytes; even the peak shapes for amphetamine and methamphetamine were exceptional considering they were analyzed underivatized. The total ion chromatogram (TIC) for the twenty drug analytes is shown in Figure 1.

Measure UV-absorbing compounds in consumer products and characterize the UV absorption spectra of the individual components by employing high-speed liquid chromatography with photodiode array detection.

Synthetic fused silica capillary tubing is a vital component in many scientific techniques. The general perception is that most laboratory glass products are fragile and easy to break. The opposite is true of fused silica capillary; with its protective coating it is both strong and durable when handled properly.

D-Mannose-6-phosphate (M-6-P) is a terminal monosaccharide of some asparagine-linked (N-linked) oligosaccharides and is also part of an important intermediate in N-linked oligosaccharide biosynthesis. Some lysosomal glycoproteins require M-6-P terminated oligosaccharides for proper targeting and function. Lack of M-6-P or genetic defects in its synthesis or subsequent processing can result in a variety of diseases.

This application note describes a fast LC method for the analysis of water-soluble vitamins using a Thermo Scientific Hypersil GOLD aQ column.

Using HILIC with highly efficient ethylene bridged hybrid (BEH) particles results in faster methods that exhibit improved polar retention, higher sensitivity, enhanced chromatographic resolution and significantly improved column lifetime.

LC/GC approaches to analysis are attractive because they combine the selectivity of solid-phase sorbents in the first dimension with the separating power and peak capacity of capillary GC in the following dimensions.

Hydrophilic interaction liquid chromatography (HILIC) offers unique advantages for the separation of very polar compounds when compared to reversed-phase chromatography. A new silica based HILIC phase was developed to provide additional selectivity options in HILIC separations. The separation of water soluble vitamins on the new TSKgel NH2-100 HILIC column and on the well known TSKgel Amide-80 HILIC column demonstrates the differences in selectivity.

Solid phase microextraction (SPME) is a well established sampling technique that is often used to isolate volatile organic components in gaseous mixtures.

The Biochrom 30 Amino Acid Analyser is a well established analytical instrument for clinical diagnosis as its IVD approval allows the diagnosis of inborn errors of metabolism such as Phenylketonuria.

Thermal agility is a term that describes the ability of an oven to heat up and cool down. Both steps comprise the complete cycle time which, in turn, determines sample throughput. Fast GC accessories provide an attractive means of increasing sample throughput because they are easy to implement and deliver reliable performance at low cost. They require little or no bench space and do not incur additional costs for consumables and support equipment such as autosamplers, data acquisition software, and computers. Fast oven cooling is especially attractive because methods do not have to be re-validated since the separation parameters remain unchanged.