Application Notes

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.

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.

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.

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.

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 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.

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).

The Wisconsin Department of Natural Resources (DNR) Modified Gasoline Range Organics (Wisconsin GRO) Method is used to determine gasoline and gasoline components in water and soil. The optimal hydrocarbon range is from C6-C10 with a boiling point range from 60 ?C–220 ?C (1). The analysis of Wisconsin GRO is vital in determining the "composition and the origin of such products including weathered fuels leaking from underground storage tanks, spills in pipe lines and run-off from surface transportation" (2).

Method 552.1 is a GC method for determination of haloacetic acid and Dalapon in drinking, ground, raw, and other waters at any stage of treatment. This application uses a silica-based quaternary amine anion exchange cartridge, with exceptional recoveries.

Gel filtration chromatography is the primary method used to analyze the amount of aggregate and dimer present in a therapeutic protein sample. A BioSep 2000 column is used to analyze EPO samples to determine difference in the amounts of aggregate present.

Using a bonded zwitterionic stationary phase, ZIC?-HILIC, polar organic acid counter ions such as methylsulfonic acid can easily be retained, to aid simultaneous analysis of basic pharmaceutical APIs together with their counter ions.

The popularity of diet soft drinks containing aspartame requires the analysis of thousands of samples for quality control purposes each year. These analyses are typically carried out with some fraction of organic modifier in the eluent, leading to the generation of thousands of gallons of hazardous organic waste. This note shows the "green" analysis of several commercial diet soft drinks in combination with a 100% water mobile phase.

This study demonstrates how the ultrahigh-performance of 1.7 ?m core-shell columns can be utilized in the laboratory in order to realize significant cost savings.

In December 2008, the United States FDA recognized rebaudioside A (reb. A) purified from Stevia rebaudiana (Bertoni) as Generally Recognized as Safe (GRAS) as a sugar substitute in foods. As a result, stevia products have become popular tabletop and beverage sweeteners. Two steviol glycosides, stevioside and reb. A, are largely responsible for the desired sweet flavor, with reb. A preferred for sweeteners (1).

Agilent Application Note

In this review, practical principles and guidelines for designing LC?LC methods are given.

In this review, practical principles and guidelines for designing LCxLC methods are given.

The isolation of α-Methylstyrene from the crude reaction mixture seems easy. However the reaction mixture contains some dimethyl sulfoxide and the oily wetting agent from the sodiumhydride.

Phospholipids are important compounds for the formation of bilayer membranes in biological systems.

The demand for faster throughput in LC–MS drug discovery labs has increased throughout the years.

BioPharma Compass is a fully automated solution for the rapid characterization of biopharmaceutical products such as proteins, peptides, RNA, and DNA.

Application of core-shell technology to the USP assay for ibuprofen to reduce analysis time and increase sample throughput and productivity, while improving the sensitivity of the assay for the determination of ibuprofen related compound C, a known degradation product with adverse health effects.