The Application Notebook-09-01-2011

The Application Notebook
Pharmaceutical

February 01, 2012

Liposomes are made of lipid bilayers and are often used in drug delivery by encapsulating the core with therapeutic drugs. During liposome research, formulation, manufacturing, and quality control, it is of great importance to monitor liposome size and encapsulation.

Ultrahigh-performance TOF–MS is utilized for the identification of a common pharmaceutical compound's metabolites. Mass spectral analysis is combined with UHPLC and post-source fragment ion generation to facilitate analysis.

Diclofenac is a slightly acidic (pKa = 4.0) non-steroidal anti-inflammatory drug (NSAID) that has been used as a post operative pain reliever in adult and pediatric patients.

The types and amounts of sugar in animal feeds are as important as the amount of protein, minerals, and fats in the determination of nutritive value. We developed a simple and sensitive HPLC method for analyzing six sugars in animal feeds – sucrose, fructose, glucose, galactose, maltose, and lactose. Post-column derivatization reagents convert reducing and nonreducing sugars into fluorescent derivatives, which greatly improves the sensitivity and selectivity of the detection.

Analysis of semi-volatile organic compounds by GC–MS according to well-established methodologies requires integration of a complete system of GC–MS instrumentation and software for data interpretation, analysis, and reporting. While the overall process of analyzing these target compounds is a mature technique, there are continuous innovations that allow laboratories to meet lower detection limits and analyze new compounds to comply with changing regulations, with higher throughput and improved quality.

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Air pollution remains a global concern due to its impact on human health and the environment. Compounds known as "air toxics" are of particular importance in this respect, and US EPA methods TO-15 and TO-17 describe how to test air samples for the presence of these compounds.

The iDQuant? Standards Kit for pesticide analysis of certified reference material (ISP Guide 34, IOS/IEC 17025, and ISO 9001:2008) includes 204 pesticides in 10 mixes at a concentration of 100 ?g/mL. This kit has been designed to eliminate the need to source pesticides individually, and measure each one manually. This allows users to setup, verify, and validate the performance of pesticide screening methods faster.

EPA Method 8270D is used to determine a list of up to 243 semi-volatile organic compounds that are neutral, acidic, basic, and are soluble in methylene chloride. Semi-volatile water samples can contain varying amounts of suspended particulates and/or sediment due to either the source of the water, or the collection technique. By elevating the pH of semi-volatile samples, precipitates can form and result in an emulsion that can create problems for an efficient extraction with traditional techniques. These types of samples, due to their sediment content, have historically proven very challenging when using solid phase extraction (SPE).

Purification of active pharmaceutical ingredients (APIs) often yields high numbers of fractions, leading to a bottleneck of fractions to dry-down and subsequently analyze. UV-based fraction collection based on slope or threshold values offers some specificity and reduction in the number of fractions collected compared to basic time- or volume-based collection.

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In this application, we present the feasibility of NH2P-50 4E, polymer-based amino HILIC column, for the structure analysis of N-glycans in biological samples. Characterization of glycan is important since different biological properties of glycoprotein play unique roles on pharmacokinetics, stability, and antigenicity.

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The US EPA regulates the testing of 20 specific chlorinated pesticides under the official Method 8081. Zebron MultiResidue columns achieve baseline separation of all of these analytes with short run times, providing greater confidence in identification and increased lab productivity.

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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.

The Application Notebook
Food and Beverage

September 01, 2011

Bilberry (Vaccinium myrtillus L.) extracts are high in anthocyanin content and are widely used in nutritional supplements for improving visual acuity and treating circulatory disorders.

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Vitamin K is a group of structurally similar, fat-soluble vitamins that are needed for the post-translational modification of certain proteins, mostly required for blood coagulation but also involved in metabolic pathways in bone and other tissue.

According to law enforcement and health officials, "bath salts" are powerful synthetic stimulants, designed to be comparable in effect to cocaine or methamphetamine, carrying similar risks. Unlike cocaine or methamphetamine, these stimulants are currently legal in many parts of the United States and available at a low cost in many convenience stores and head shops.

The Application Notebook
Biological

September 01, 2011

Agarose is a polysaccharide produced from seaweed that forms a gel at room temperature. The characteristics of agarose gels depend on the agarose concentration, solvent, weight-average molar mass, and molar mass distribution. Powdered agarose, or agarose gel, needs to be heated in order to dissolve properly. Reheating a sample as well as other processing steps can change the agarose gel characteristics. This note describes the characterization of agarose by size-exclusion chromatography (SEC) and multi-angle light scattering (MALS) at an elevated temperature.

HPLC analysis of polar ionic compounds, such as catecholamines and siRNA, can be challenging due to the nature of their structures. Small polar compounds like catecholamines can be diffcult to retain and siRNA can be difficult to elute in reverse phase mode. The Scherzo Family of HPLC columns (SS-C18, SM-C18, and SW-C18) can overcome these challenges.

For successful chromatographic method development, it is advantageous to maximize the difference in column selectivity, or "selectivity space" investigated in order to minimize the number of critical analyte co-elutions.

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Fluoroacetate (Compound 1080) is a strong metabolic poison commonly used as a rodenticide and predacide (1). Due to the high level of toxicity when ingested (2), and no known antidotes, its use has been banned or restricted in many countries.

Chiral method development and chiral separations have been the main contributors to the popularity of supercritical fluid chromatography (SFC). The low viscosity and high diffusivity of the mobile phase in SFC allows for low pressure drops and fast chromatography, making it an attractive alternative to LC, especially for pharmaceutical applications. SFC is often 3–5 times faster than HPLC and often produces higher efficiency. SFC is now regarded as a standard separation support tool for chemical synthesis and development.

Coenzyme Q10, found naturally in the body, is involved in the production of body energy. Thus, heart, lung, and liver have the highest concentration of Q10.

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The update to the SANCO guidelines in 2009 recognized the power and potential of TOF mass spectrometry for pesticide screening applications. When compared with historical screening tools (such as the use of triple-quad mass spectrometry), high performance accurate mass TOF systems offer several advantages for screening applications. These advantages include better resolution, unlimited multiple target capabilities, and the possibility to perform comprehensive and/or retrospective analysis on samples in silico at will.

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The use of contrast agents in noninvasive diagnostics provides a specific and high-detailed picture of organs and makes it possible to differentiate between healthy and diseased tissue. Whilst radiocontrast agents (RCA) change the X-ray absorption of the radiographed organ relative to its surrounding tissue, contrast agents for magnetic resonance imaging (MRI) are based on the use of magnetic fields caused by charged elementary particles such as protons and electrons. Compared to traditional X-ray imaging, MRI uses no ionizing radiation. MRI is based on the same principles as NMR spectroscopy and thus takes advantage of the absorption and emission of energy in the radiofrequency range.

The Application Notebook
Articles

September 01, 2011

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. If your company is interested in participating in these special supplements, contact:

At the 2011 Pittsburgh Conference, Tosoh Corporation introduced a new line of high efficiency columns for the analysis of water-soluble polymers by gel filtration chromatography.

A new, simple, and sensitive sample preparation application for the extraction of a range of steroid hormones from human plasma at significantly low levels using ISOLUTE SLE+, an efficient alternative to traditional liquid-liquid extraction (LLE) for bioanalytical sample preparation, providing high analyte recoveries, no emulsion formation, and significantly reduced sample preparation time.

Risedronate, a pyridinyl bisphosphonate, is one of the most popular first-line drugs in the treatment of osteoporosis, Paget's disease, and other bone fragility conditions. In October 2010, the United States FDA approved a second-generation risedronate in a delayed-release formulation.

The Application Notebook
Biological

September 01, 2011

The quantification of derivatized amino acids by (U)HPLC with UV detection is one of the most widely used methods to date. Unfortunately, separation and detection of underivatized amino acids is difficult, as many of them are similar in structure, and few possess adequate chromophores.

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With more than 800 pesticides currently in use there is growing concern by government agencies about the effect of pesticide exposure on human health. While analytical techniques like GC or GC–MS have traditionally been used for pesticide analysis, LC–MS-MS has become the technique of choice due to speed, increased sensitivity, and reduced sample preparation. The following describes an LC–MS-MS method for screening of 534 pesticides in food products.

On June 14, 2011, the FDA issued stricter regulations on how sunscreen manufacturers can label over-the-counter sunscreen products. In the summer of 2012, manufacturers with an annual sale of $25,000 or more will have to characterize the active ingredients found in their sunscreens (1).