The Application Notebook-09-01-2012

September 01, 2012

Gas chromatography coupled with tandem mass spectrometry (GC–MS-MS) operated in MRM mode is a powerful technology for multi-residue analysis in complex food matrices. Good GC separation combined with MS-MS selectivity facilitates monitoring hundreds of MRM transitions within a short cycle time which allows for analysis of large number of compounds in complex food matrices. Nevertheless, MRM method development is time consuming and labor-intensive, which mainly comes from mapping retention time, MRM transition set-up and post-data processing.

September 01, 2012

Water samples from six urban and rural locations were extracted and analyzed by GC?GC–TOFMS. GC?GC–TOFMS provided an analysis approach for the detection of known EDCs as well as other non-targeted persistent pollutants.

September 01, 2012

Rapid and highly resolved chromatographic separations of proteins are becoming increasingly important to meet the growing demands for faster analyses, greater reliability and overall increased column performance. Additionally, highly selective and efficient separations for peptide and impurity profiling have grown among the biopharmaceutical industry, with an ever increasing need to obtain greater peak capacities.

September 01, 2012

New roles and applications in the areas of science and technology are continuously being found for synthetic polymers. Specifically, the use of synthetic polymers in medicine is growing, as these polymers offer unique and versatile platforms for applications such as implants, medical devices, surgical adhesives, drug delivery vesicles, and injectable polymer-drug conjugates (1,2). As the applications of synthetic polymers increases, there is a manifested need for methods to accurately and precisely characterize the materials.

September 01, 2012

Blockcopolymers such as SBS (styrene-butadiene-styrene) are an important product class and a typical example of complex polymers. In addition to the molar mass distribution, a chemical composition distribution may also be present in copolymers. While GPC–SEC is the established method for the determination of molar mass averages and distribution, gradient HPLC can be applied to separate based on chemical composition.

September 01, 2012

One fast, simple QuEChERS extraction for a broad range of pesticides.

September 01, 2012

The amount of benzene in gasoline is a concern because it is a known human carcinogen, and exposure to it has been linked to detrimental health effects. The challenge with the analysis lies in the complex composition of gasoline, which consists of hundreds of different compounds. Reformulated gasoline also contains additives to produce more complete combustion and subsequent lower emissions of harmful compounds.

September 01, 2012

When performing LC–MS-MS analysis, phospholipids are perhaps one of the most troublesome components of bioanalytical samples. The presence of phospholipids not only reduces the column lifetime and sensitivity but can also cause a phenomenon known as ion suppression.

September 01, 2012

Ultra sensitive LC–MS-MS quantification of steroids is particularly difficult due to the presence of countless other steroid interferences, many isobaric, in human plasma. In particular, for compounds such as ethinylestradiol (EE), where the required detection limit (LOD) is 1 pg/mL, this challenge is even greater. Not only must one use the highest sensitivity MS system, but both LC and sample preparation must also be carefully optimized for selectivity.

September 01, 2012

Tolterodine, a quaternary ammonium compound, is used to treat urinary incontinence. To create the drug substance, tolterodine is paired with tartrate to form tolterodine tartrate. This drug substance can then be used to create drug products. One way to confirm the amount of a drug substance in a drug product is to assay for its counterion.

September 01, 2012

N-Methylcarbamates are widely used agricultural pesticides. For their determination, reversed-phase high-performance liquid chromatography (RP-HPLC) with fluorescence detection following postcolumn derivatization, per U.S. EPA Methods 531.2 and 8318, is typically used.

September 01, 2012

Gel permeation chromatography (GPC), also referred to as size exclusion chromatography (SEC), when applied to polyolefins analysis (Polyethylene, PE and Polypropylene, PP) has been considered a demanding task due to the high temperature required for operation and the use of hazardous chlorinated solvents for resin dissolution.

September 01, 2012

Residuals of pesticides widely used in agriculture are monitored in foods for human consumption through the use of statutory maximum residue levels (MRLs). Regulation EC 396/2005 adopted in the European Union sets MRLs for over 500 pesticides in over 300 food commodities, many at a default value of 0.01 mg/kg (the typical routine analytical method limit of determination).

September 01, 2012

During the manufacturing process of industrial gases, volatile oligomers of compressor fluids can enter the product stream. These impurities are typically within specification, but failure of a diaphragm or seal can spike the concentration in a fill batch and the industrial gas no longer meets product specifications. A screening method has been developed to extract, identify and quantitate chlorotrifluoroethylene-based impurities from the compressor fluid using a CUSTODION? solid phase microextraction (SPME) syringe and a TRIDION?-9 person-portable gas chromatograph–toroidal ion trap mass spectrometer (GC-TMS). The compounds were separated and detected rapidly in less than 5 min analysis time.

September 01, 2012

Organochlorine pesticides are man-made organic chemicals with a history of wide spread use in both the United States as well as globally. Tending to be very persistent in the environment, they have found their way into sediments and drinking water supplies posing serious health risks. Organochlorines have a wide range of both acute and chronic health effects, including cancer, neurological damage, and birth defects. Many organochlorines are also suspected endocrine disruptors.

September 01, 2012

Monoclonal antibody isoforms differ in modifications of individual amino acid side chains, or the N- or C-terminus. Typical modifications are deamidation, phosphorylation, acetylation, methylation, oxidation, or glycosylation. Fast separation of monoclonal antibody isoforms is important for profiling and mass spectrometric determination. Isoforms may differ in biological activity and stability, making a thorough characterization and quantification of the isoforms necessary to ensure consistent product quality.

September 01, 2012

Poly(lactic-co-glycolic acid) (PLGA) is a copolymer based on glycolic acid and lactic acid. The two monomer units are linked together by ester linkages and form linear polyester chains. The obtained product is biodegradable and biocompatible, and it is approved by the Food and Drug Administration (FDA) for production of various therapeutic devices as well as for drug delivery applications.

September 01, 2012

LCGC is planning to publish the next issue of The Application Notebook special supplement in December. The publication will include vendor application notes that describe techniques and applications of all forms of chromatography and capillary electrophoresis that are of immediate interest to users in industry, academia, and government.

September 01, 2012

Avermectins are 16-membered ring macrolide drugs that are used as veterinary antihelmintics. The lowest allowable limit for these compounds in food products is set based on worldwide safety evaluations. Regulatory MRLs for avermectins can vary worldwide but are generally in the ppb concentration range. The sensitive analysis of avermectins in food products such as milk and meat can be challenging due to their complex sample matrices.

September 01, 2012

Often used for weed control, triazine herbicides have been found to have detrimental environmental and health effects. Much debate has focused on the level at which these compounds negatively impact health. To monitor and control human exposure to these herbicides, regulatory bodies have established allowable limits of triazines in drinking and wastewater.

September 01, 2012

This technical bulletin details the separation of 11 closely related nitroaromatic compounds, namely RDX, HMX, Nitrobenzene, 2-Nitrotoluene, Tetryl, 2,6-Dinitrotoluene, 4-Nitrotoluene, 1,3-Dinitrobenzene, 2,4-Dinitrotoluene, 2-amino 4,6-dinitrotoluene, 1,3,5-Trinitrobenzene. Our customers have reported that similar separations on silica-based phases produce run times as long as 30 min. Here we report a method on ZirChrom?-CARB at a column temperature of 125 ?C in under 4 min.

September 01, 2012

The health benefits of fish oil in one's diet has been widely established. Common edible fish sources include salmon, trout, tuna, swordfish, and others. The omega-3 fatty acids, EPA and DHA, in dietary supplements (capsules) are primarily derived from smaller oily fish, notably anchovy, horse mackerel, bunker, capelin, and sand eel.

September 01, 2012

Printing inks used on packing materials of consumer products contain colorants and pigments, binder systems, solvents, and additives. ASTM F 1884-04 (1), Standard Test Methods for Determining Residual Solvents in Packaging Materials determines residual solvents in packaging materials from printing processes utilizing solvent-based printing inks.

September 01, 2012

Throughout the drug development process, potential new drug candidates (or new chemical entities; NCEs) and their metabolites must be subjected to rigorous and extensive pharmacokinetic evaluations to determine their rates accumulation, metabolism, and excretion from the body. With regards specifically to the excretion, urinary excretion is typically the predominant route for the elimination of drugs and their metabolites, and urinary excretion profiling is an integral portion of the pharmacokinetic characterization of NCEs.

September 01, 2012

Acrylamide is a neurotoxic compound classified as a probable human carcinogen and genotoxicant (1). In 2002, researchers in Sweden uncovered the presence of acrylamide in certain fried and baked foods at relatively high levels (2).

September 01, 2012

This short review focuses on the physicochemical properties of core–shell particles and their resulting chromatographic efficiencies as they relate to the comparison of their mass transfer kinetics to those of columns packed with sub-2-?m fully porous particles.

September 01, 2012

Biofuels have emerged as an attractive alternative to fossil fuel. Biofuel refers to any fuel that is derived from biomass (typically, plant and animal waste). A common feedstock for bioethanol production is corn stover (leaves and stalks of maize plants left after harvesting). Corn stover processing involves acid treatment to release a mixture of water-soluble carbohydrates, followed by enzymatic reactions to convert the sugars to ethanol.

September 01, 2012

Pharmaceutical compounds are often difficult to analyze on C18 columns alone because they may be charged or have very similar structures. Imtakt Corporation has introduced a family of multimode columns that are able to overcome these separation challenges: Scherzo SS-C18, Scherzo SM-C18, and Scherzo SW-C18, containing C18, anion, and cation ligands.

September 01, 2012

This application note shows that unspecific reaction of adenosine triphosphate can be completely prevented due to the iron- and steel-free design using the Agilent 1260 Infinity Bio-inert Quaternary LC System.

September 01, 2012

Pickering Laboratories specializes in the manufacturing of cation-exchange columns and eluants for amino acid analysis. Post-column derivatization with Ninhydrin offers unmatched selectivity and reproducibility of the analysis for most challenging matrixes.

September 01, 2012

Positron emission tomography (PET) is one of the most powerful non-invasive diagnostic tools for tracing organ functioning. Quality control of the short-lived radiopharmaceuticals is challenging, not least because of the tough time limits, the radiation issue and the near nanomole radiotracer quantities.

September 01, 2012

Levels of benzene, toluene, ethylbenzene, xylenes, and styrene (BTEXS) are a concern in olive oil. These compounds find their way into olive trees and hence into olives and olive oil mainly as a result of emissions from vehicles, bonfires, and paints into ambient air near orchards. This analysis uses a PerkinElmer? TurboMatrix? 110 Headspace (HS) sampler with a Clarus? SQ 8 gas chromatograph–mass spectrometer (GC–MS) to achieve detection limits below 5 ng/g and concentrations up to 100 ng/g.

September 01, 2012

Natural gas and other gaseous fuels contain varying amounts and types of sulfur compounds which can be corrosive to equipment and can inhibit or destroy gas processing catalysts. Small amounts of sulfur odorants are added to natural gas and liquefied petroleum gases (LPGs) for safety purposes. Accurate measurement of sulfur species ensures proper process operation and odorant levels for public safety.

September 01, 2012

Aniline is an organic compound widely used in the polymer, rubber, pharmaceutical, and dye industries. Aniline and its derivatives (e.g., nitroanilines) are suspected carcinogens and are highly toxic to aquatic life. Because these compounds are thermolabile and polar, the traditional analytical methods require a derivatization step prior to GC analysis.

September 01, 2012

Selectivity is the most powerful tool to optimize separations in HPLC. This parameter is changed by using different bonded phases or by changing the mobile phase. In this work, Poroshell 120 columns with highly efficient 2.7 ?m superficially porous particles and the Agilent 1260 Infinity Series LC Multi-Method Solution were used to quickly evaluate method development choices for the analysis of steroids.

September 01, 2012

Low-molecular-weight heparins (LMWHs) are obtained by fractionation or depolymerization of natural heparins. They are defined as having a mass-average molecular weight of less than 8000 and for which at least 60% of the total weight has a molecular mass less than 8000.

September 01, 2012

This application note will highlight the extraction of EPA Method 508.1 analytes from an aqueous matrix. It will use the SmartPrep Extractor and the DryVap Concentrator system to achieve excellent recoveries while maintaining minimal user-interface.

September 01, 2012

This application note demonstrates the analysis of intact proteins using a Thermo Scientific Accucore 150-C4 (150 ? pore diameter) HPLC column. Analysis of six proteins ranging in mass from 6 to 45 kDa is carried out in 15 min with pressures compatible with conventional HPLC instrumentation.

September 01, 2012

Ion mobility spectrometry (IMS) has become widely accepted for the detection of chemical warfare agents, explosives, and narcotics as well as for pharmaceutical quality control and pesticide screening of food. Most currently available commercial IMS units have a resolving power of 10–60.

September 01, 2012

Thermo Scientific Application Note

September 01, 2012

Typical chiral stationary phase (CSP) screening paradigms utilize a single alcohol component as co-solvent in its mobile phase. Recent unexpected observations have demonstrated that mixed-alcohol mobile phases can enhance or even introduce peak resolution when none existed in a mono-alcohol system.

September 01, 2012

This application demonstrates that stringent sensitivity requirements for the detection of potentially harmful primary aromatic amines can be fulfilled when using an Agilent 1290 Infinity LC system equipped with the 1290 large volume injection kit.

September 01, 2012

Underground storage tanks (USTs) for various petroleum-based substances such as gasoline, diesel fuel, and fuel oil are monitored for leaks as authorized by the Resource Conservation and Recovery Act (RCRA).

September 01, 2012

Determination and quantification of amino acids are important in many fields. For the HPLC analysis of amino acids, cation exchange mode method has been used with post-column derivatization. Recently, use of reversed-phase mode method is also increasing. However, because of amino acids' hydrophilic nature, they are usually not well retained and have less selectivity by reversed-phase mode without pre-column derivatization steps. In contrast, HILIC mode is an ideal separation mode for hydrophilic compound analysis.

September 01, 2012

Click the title above to open the LCGC North America September 2012 Application Notebook, Vol 30 No s9, in an interactive PDF format.