Biological, Medical, and Clinical Analysis

A highly sensitive analytical method for the analysis of tamsulosin in human plasma has been developed for use in bioanalytical studies. The solid-phase extraction (SPE) and UPLC–MS–MS methodologies are described, as well as performance against validation parameters.

Technological changes affecting how we access information - both in the depth of knowledge we can access and the speed - leads to some observations about electronic versus print media. First, anything committed to public view must be of high scholarly order, often serving as a prime resource for equations and things we can't or won't remember. Second, once words have been printed, the value of the meaning they impart decreases as new understanding takes shape.

Cytosine (chemical name 4-amino-2-hydroxypyrimidine) is a pyrimidine derivative with a hetereocyclic aromatic ring and two substituents (amine and keto groups) attached and is a polar compound of significant biological and pharmaceutical interest. In response to the intended use of bulk cytosine as a raw material in pharmaceutical manufacturing, a method for the determination of the purity of cytosine was developed.

Part III concludes the print version of our three-part series, "A Mass Spectrometry Primer," with the glossary to follow in a fourth and final installment.

While the "Validation Viewpoint" column has focused on conventional and recombinant pharmaceutical products, and at times, bioanalytical methods, we have just begun to think about method validation as it relates to -omics type studies.

This installment of SPP will compare and contrast the various types of polymeric and non-polymeric sorbents. The major advantages or polymeric sorbents will be discussed, and some applications will illustrate the versatility of polymeric SPE.

The combination of reversed-phase high performance liquid chromatography (RP-HPLC), atmospheric pressure ionization (API), mass spectrometry (MS) and tandem mass spectrometry (MS/MS) is ideal for determining and characterizing analytes in complex biological matrices. This review looks at the importance of parameters such as hydrophobicity, ionization properties, molecular mass and, partially, the molecular structure resulting from applied LC–MS–MS systems in analytical laboratories. The use of these parameters to investigate biomolecules and their unambiguous identification is also described.

The combination of reversed-phase high performance liquid chromatography (RP-HPLC), atmospheric pressure ionization (API), mass spectrometry (MS) and tandem mass spectrometry (MS/MS) is ideal for determining and characterizing analytes in complex biological matrices. This review looks at the importance of parameters such as hydrophobicity, ionization properties, molecular mass and, partially, the molecular structure resulting from applied LC–MS–MS systems in analytical laboratories. The use of these parameters to investigate biomolecules and their unambiguous identification is also described.

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The use of mass spectrometry (MS) in clinical diagnosis goes back to the early 1970s with the application of gas chromatography (GC)–MS to the determination of a variety of biologically significant molecules. Because GC requires a certain level of analyte volatility, and since most biologically active molecules are polar, thermolabile, and involatile, elaborate extraction and derivatization protocols needed to be devised to make GC–MS useful for the analysis of clinically relevant samples. To make sample analysis less difficult by MS there had been a significant amount of R&D invested over several decades aimed at coupling high performance liquid chromatography (HPLC) with MS since HPLC is a much better separation technology than GC for polar thermolabile biologically relevant molecules. This coupling was not without significant challenges; most of the LC–MS coupling techniques that evolved during the 1970s and 1980s were not very successful, and many of those that enjoyed some widespread..

Microemulsion liquid chromatography (MELC) is a recent development offering reduced sample preparation times for complex samples and generic separation conditions applicable to a wide range of solutes. This article introduces the concepts of MELC and discusses the possible benefits and future applications.

The 25th anniversary of the Montreux LC–MS symposium will be held at the Montreux Music and Convention Centre, Montreux, Switzerland from 12–14 November 2008.

Micellar liquid chromatography (MLC) is a reversed-phase liquid chromatographic mode with a solution of surfactant forming micelles as the mobile phase. The interaction of solutes with the stationary phase coated with surfactant monomers, combined with the increased solubilization capability of micelles, have profound implications with regard to retention, selectivity and efficiency. Practical steps that a chromatographer involved in MLC should consider when developing an analytical procedure are described, including mobile phase preparation, column conditioning and cleaning.

Metabolomics resource; Agilent updates electronic notebook; On-line chromatography training; Add-on PC ports

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).