Biological, Medical, and Clinical Analysis

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Herbs and their extracts are currently being used for preventive and therapeutic goals. Consequently, the identification and quality control of these natural products is becoming increasingly important. Fingerprint chromatography is accepted as an appropriate identification and quality evaluation technique for medicinal herbs. This article reviews the development procedure of a fingerprint and different ways to handle the fingerprint data.

Capillary electrophoresis (CE) is increasingly being used in vaccine analysis. Applications include vaccine quantification, purity assessment, process monitoring, characterization and nucleic acid analysis. CE has been used because it offers advantages over other techniques. Vaccine manufacturers such as Sanofi-Aventis, Merck and Wyeth are actively investigating the use of CE for vaccine analysis. While CE can be considered a mature technique, its application to vaccine release and characterization has been limited. It is difficult to ascertain if its use is expanding because there are still a small amount of publications, but given the inherent advantages of CE and the need for better analytical techniques in vaccine analysis, the application must be growing. This article illustrates some of the uses of CE in vaccine analysis.

SCM-4 - The 4th International Symposium on the Separation and Characterization of Natural and Synthetic Macromolecules

Michael Balogh begins a three-part overview series, answering questions about mass spectrometers, their use and capabilities, and including links to more detailed further reading in readily available articles written for the nonspecialist.

A synopsis of our work detailing the use of chemometric response surface methodology (RSM) in two capillary electrophoresis (CE) studies is described.

A very useful construct in engineering and analytical chemistry is the concept of a time-invariant linear system. The properties of the system (as for a mathematical function) are defined by a relationship between the response and the excitation, and ...

Researchers from Fourth Military Medical University (Shanxi, China) have developed a method for separating and determining hydrophobic compounds in Cnidium monnieri, an herbal remedy.

The authors meet the need for a method for the determination of cytosine purity by developing a hydrophilic interaction chromatography (HILIC) method with demonstrated advantages in comparison to other separation techniques.

Guest Editor Peter Schoenmakers provides an introduction to LCxLC, and then goes on to talk about peak capacity, sample dimensionality, phase orthogonality, and some of the successes of the technique and the obstacles yet to be overcome.

Successful characterization of protein posttranslational modifications (PTMs) is critical to our understanding of many biological processes. Unfortunately, attempts to describe PTMs often prove experimentally difficult and result in ambiguous conclusions. As technologies in the field of mass spectrometry (MS) continue to improve, people are turning increasingly to mass spectral techniques for PTM characterization. Recently, novel modes of peptide fragmentation have emerged that are giving scientists greater ability to elucidate protein posttranslational modification. One example is electron-capture dissociation (ECD), an alternative fragmentation mechanism for use in peptide analysis via tandem mass spectrometry. ECD selectively cleaves N-Cα bonds of the peptide backbone, yielding c- and z-ions without the loss of labile PTMs. ECD therefore holds advantages over conventional fragmentation techniques such as collisionally induced dissociation (CID), which often cleave PTMs from the peptide backbone,..

In gradient mode, the quality of the analysis will be influenced by the performance of the proportioning and mixing of the eluents at any time during a given chromatogram.

This installment of "Directions in Discovery" will review current phosphorylation enrichment techniques with a focus on new developments.

This month's installment of "Column Watch" is the second part of a two-part series in which columnist Ron Majors examines the trends and highlights in columns and consumables at Pittcon 2008.

Reducing or, if possible, eliminating the use of organic solvents is an important goal in terms of environmental conservation, human health and the economy.

Vitamin D is a group of fat-soluble prohormones that helps the body absorb calcium and maintain proper levels of calcium and phosphorus in the blood. A vitamin D deficiency results in impaired bone mineralization and leads to bone-softening diseases, such as rickets in children and osteomalacia and osteoporosis in adults, as well as autoimmune and nervous system diseases. A vitamin D overdose can raise blood levels of calcium and cause gastrointestinal symptoms and kidney disease. High blood levels of calcium also can cause heart rhythm abnormalities and calcinosis, the deposition of calcium and phosphate in the body's soft tissues.

Pyrethroids are synthetic chemical compounds similar to the natural chemical pyrethrins and commonly used as household insecticides and insect repellents. Typically, pyrethroids possess multiple stereogenic centers and individual stereoisomer can have widely differing biological activities. Rapid, reliable, and precise determination of the isomeric ratios of these chiral pesticides is of great importance not only for product formulation but also for the subsequent study on the pharmacokinetics and metabolism of the pesticides. High performance liquid chromatography with chiral stationary phases (CSPs) has been the predominant tool for separating chiral pesticides. However, the complexity of the pyrethroids resulting from the multiple stereogenic centers presents a special challenge for baseline resolution of all isomers. Numerous CSPs, many of which are not available commercially, have been created to separate synthetic pyrethroids with varying degree of success (1-7).

A total of fourteen cuts were defined because the retention time difference between several skin sensitizors was only slight.

This month's installment of "Column Watch" is the first of a two-part series in which columnist Ron Majors examines the trends and highlights in columns and consumables at Pittcon 2008.

In the last year, two new protein depletion products have been introduced, and these will be the focus of this month's installment of "Directions in Discovery."

This article aims to demonstrate the unique capability of resin-based mixed-mode solid-phase extraction (SPE) to achieve efficient extraction of basic drugs from plasma. Optimized pore size of the method minimizes retention of high molecular weight matrix components present in the biological fluid samples. The interferences are removed, ensuring extremely clean extracts for subsequent liquid chromatography?mass spectrometry-mass spectrometry (LC-MS-MS) analysis.

This article describes the method development and performance characteristics of the validated LFI assay and evaluates stability in human plasma.

Selective sample preparation techniques are particularly attractive for the analysis of trace amounts of small molecules in complex matrices. In this month's instalment, columnist Ron Majors covers the field of immunoextraction, a technique that employs immobilized antibodies to selectively capture specific analytes using molecular recognition via antibody–antigen interactions. Recently, the introduction of commercial products for specific high-volume environmental and food safety applications should spur further applications of this technique.

The 59th Annual Pittsburgh Conference and Exposition on Analytical Chemistry and Applied Spectroscopy (Pittcon 2008) will be held at the Ernest N. Morial Convention Center, New Orleans, Louisiana, USA, from 2–6 March, 2008. Pittcon 2008's Technical Program will be in the format of invited symposia, organized contributed oral sessions, contributed oral sessions, workshops, new product forums and poster sessions to cover the latest developments in the traditional and emerging disciplines of analytical chemistry and applied spectroscopy. Following on from last year's success, the networking sessions will be expanded.

BMC Pediatrics reports on a study characterizing total homocysteine (tHcy) levels at birth in preterm and term infants and identifing associations with intraventricular hemorrhage (IVH) and other neonatal outcomes such as mortality, sepsis, necrotizing enterocolitis, bronchopulmonary dysplasia, and thrombocytopenia.

In this month?s installment, columnist Ron Majors covers the field of immunoextraction, a technique that employs immobilized antibodies to selectively capture specific analytes using molecular recognition via antibody?antigen interactions. Recently, the introduction of commercial products for specific high-volume environmental and food safety applications has spurred further applications of this technique.

Polymer-based columns still are widely used in size-exclusion chromatography (SEC) and ion chromatography-ion-exchange chromatography - they have always been used in these modes, even back in 1987.

Assay Depot, an Internet marketplace for drug discovery services, today announced that Nanostream, provider of chromatography products and services to increase productivity in analytical laboratories at pharmaceutical and biotech companies, will join the company?s service provider network.

HPLC 2007 was held in Ghent, Belgium in June. Last month, columnist Ron Majors summarized some the important column developments as well as other Symposium highlights. This month, he winds up coverage with additional highlights in the areas of technology and applications. Among the topics covered are stationary phase preparation and characterization, multi-dimensional and comprehensive LC, temperature studies, detectors and an application overview.