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Automated solid-phase extraction (SPE) has been used extensively with liquid chromatography–tandem mass spectrometry (LC–MS-MS) to facilitate high-throughput analysis in the pharmaceutical, diagnostic, and forensic toxicology areas. In this work, we demonstrate the use of a systemized approach to SPE method development and LC–MS-MS analysis. This approach provides dramatic savings in analysis time and takes advantage of new innovations in high performance liquid chromatography (HPLC) columns to provide the cleanest extracts for LC–MS injection.

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The nanoLC LIT-TOF approach combines multiple capabilities that improve the ability to characterize complex protein mixtures significantly.

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Surfactants present a real challenge to the analytical chemist as they are a very complex class of chemical compounds.

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Dilute formic acid solutions in methanol were found to decline in acid content with time, the extent of the decline depending upon the initial amount of water present in these solutions. The effect of the formic acid concentration change upon the separation of peptides using high performance liquid chromatography (HPLC) is examined briefly.

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Soft ionization MS using GC–APCI-MS and GC–SMB-MS offers complementary identification power for the characterization of natural products, as illustrated by the identification of alkanes, sterols, long chain alcohols, and derivatized polar compounds in tobacco leaf extracts described here.

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PEGylation, the process by which polyethylene glycol (PEG) chains are attached to protein and peptide drugs is a common practice in the development of biopharmaceuticals to prolong serum half-life and improve pharmacokinetics of a drug. There is increasing demand for chromatographic methods to separate the modified isoforms from the native protein. This application note describes the use of size exclusion and ion exchange chromatography for the characterization of PEGylated lysozyme.

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Studies of odd-electron CID behaviors reveal that free radical fragmentation is structure-dependent and is directly correlated with the functional groups that stabilize the newly-formed free radicals.

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The determination of inorganic elements in food substances is critical for assessing nutritional composition and identifying food contamination sources. The inorganic elements of interest can be divided into two classes: nutritional and toxic. It is important to determine the levels of both sets of elements accurately to assess both the nutritional and the harmful impacts of food substances. Nutritional elements such as Mg, P, and Fe are present at high levels (milligrams per kilogram), while toxic elements such as Pb, Hg, and Cd should be present only at trace levels (nanograms or micrograms per kilogram).

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With the globalization of trade, food production and distribution have become truly international businesses. When we dine out, the fish might come from Japan, the rice from Australia, the spices from China, and the strawberries from Mexico. We take it for granted that the food we eat is safe and free from contamination that could make us seriously ill.

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In size exclusion chromatography, obtaining calibration curves over a wide range of molecular weights is a difficulty investigators often encounter when analyzing polymers with a broad molar mass distribution. To overcome this problem two procedures are typically used. One option is to use multiple columns of different pore sizes linked together in series. A second is to use a column packed with a mixed bed resin of different pore sizes at an optimized mix ratio. However, problems can occur with both of these methods, which include distortion of the chromatogram or deviations between the actual calibration curve and the calibration curve approximated from data obtained from the molecular weight standards.

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Root diseases caused by soilborne plant pathogens are responsible for billions of dollars of losses annually in food, fiber, ornamental, and biofuel crops. The use of pesticides often is not an option to control plant diseases because of economic factors or potential adverse effects on the environment or human health. For this reason, many Americans are now buying pesticide-free organic foods. Organic agriculture has few options for controlling pests and thus must make full use of natural microbial biological control agents in soils that suppress diseases.

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Guest authors show how mixed modes can be used successfully in the optimization of protein purification, and discuss how various experimental parameters can be used to regulate the binding of proteins to mixed-mode sorbents.

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A commentary on maintaining and growing technical competencies and the effort that is required.

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Protein and peptide analysis via tandem mass spectrometry (MS-MS) has resulted in a wealth of information regarding protein identification, structure, and abundance levels over the past 10 years. Techniques such as neutral loss scanning and collision-induced dissociation (CID) have been especially helpful in facilitating the identification of a multitude of previously unknown sites of protein phosphorylation. However, many of the techniques used to obtain this information are labor intensive and work inconsistently. To address this problem, much effort has been put forth to find alternative methods of fragmenting peptides and proteins that are less difficult and applicable to a wide gamut of peptide classes. Examples of recently developed dissociation techniques include infrared multiphoton dissociation (IRMPD) and electron transfer dissociation (ETD). The implementation of these new techniques has widened the spectrum of peptides amenable to tandem mass spectral analysis.

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In general, polymer-based columns have a broad pH range (pH 2 to 13), and some have high temperature tolerance (up to 150°C or higher). Considerably large selectivity changes can be obtained by varying analysis temperature and mobile phase pH. Having control on these two parameters over wide ranges can be especially useful in method development.

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The authors present results that suggest that high-throughput, high-coverage profiling capabilities, such as those afforded by GCxGC-TOF-MS, can impact the development of personalized medicine.

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A fast enantiomeric separation of a chiral aromatic amine was achieved, using ultra high pressure liquid chromatography and highly sulfated β-cyclodextrin (S-β-CD) as a chiral additive in the mobile phase. The stationary phase consisted of a core shell support with a particle size of 2.7 µm. Under these conditions the baseline separation was obtained within 2.5 min. The influence of the concentration of the additive, along with the thermodynamics of the separation, were studied. Molecular mechanics calculations were consistent with the experimental data for the order of elution, providing further evidence of these interactions. The enantiomeric separation at high temperature (90 °C) using only water as mobile phase also was achieved for the first time.

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Although not currently used in U.S. or European aquaculture, malachite green (MG) is still an effective and inexpensive fungicide that is used in other countries, particularly in Asia. During metabolism, MG reduces to leucomalachite green (LMG) (Figure 1), which has been shown to accumulate in fatty fish tissues. Trace levels of MG and LMG residues continue to be found in fish products. In a 2005 report, MG was found in 18 out of 27 live eel or eel products imported from China to Hong Kong local market and food outlets, resulting in a government recall and destruction of all remaining products (1).

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Mycotoxins, toxic secondary metabolites of several fungal species, represent food safety issues of high concern. Deoxynivalenol, the most abundant trichothecene mycotoxin, can be found worldwide as a contaminant of wheat, barley, maize and other cereals (1,2). The transmission of deoxynivalenol from barley into beer has been reported in several studies (3,4). Therefore, its levels should be controlled.

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A fast enantiomeric separation of a chiral aromatic amine was achieved, using ultra high pressure liquid chromatography and highly sulfated β-cyclodextrin (S-β-CD) as a chiral additive in the mobile phase. The stationary phase consisted of a core shell support with a particle size of 2.7 µm. Under these conditions the baseline separation was obtained within 2.5 min. The influence of the concentration of the additive, along with the thermodynamics of the separation, were studied. Molecular mechanics calculations were consistent with the experimental data for the order of elution, providing further evidence of these interactions. The enantiomeric separation at high temperature (90 °C) using only water as mobile phase also was achieved for the first time.

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A new, immobilized chiral stationary phase (CSP) based on a novel chiral selector for HPLC and SFC is described. Its unique selectivity as a complement to Daicel's other commercial immobilized polysaccharide CSPs is demonstrated.

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Ramipril impurities D and E are well-known degradation products of ramipril in the finished dosage form. A significant amount of an additional impurity was detected in ramipril tablets by an isocratic reversed-phase high performance liquid chromatography (HPLC) method on a short column. The structure of this impurity was proposed based on liquid chromatography–mass spectrometry (LC–MS) data using an electron spray ionization source. Structural elucidation using nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy was facilitated by a newly developed preparative isolation method. This impurity was characterized as (2R,3aR,6aR)-1-[(R)-2-[[(R)-1-(ethoxycarbonyl)-3-phenylpropyl]amino]propanoyl]octahydrocyclopenta[b]pyrrole-2-carboxylic acid (impurity L). Its identification, synthesis and characterization are discussed.

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The analysis of polar compounds in support of clinical and preclinical pharmacokinetic studies requires an analytical methodology capable of achieving ultra-low detection and quantification limits. The high sensitivity afforded by coupling HPLC with tandem mass spectrometry (MS–MS) has made it the technique of choice in this environment, but it is subject to the following limitations when reversed-phase liquid chromatography (RPLC) is used

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CAPCELL CORE ADME S2.7 (ADME) is a column packed with a novel stationary phase of superficially porous silica (core shell particle) modified by adamantyl functional groups.

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The nanoLC LIT-TOF approach combines multiple capabilities that improve the ability to characterize complex protein mixtures significantly.

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With the forthcoming USP monograph <1058>, many laboratories are in the process of reexamining their high performance liquid chromatography (HPLC) instrumentation qualification practices. This article demystifies the qualification procedures and proposes a well designed, easy and simple set of experiments upon which to establish internal standard operating procedures (SOPs) for the complete qualification of HPLC instruments. A key concept is the development of a consistent test system, comprised of premade test solutions, a prequalified HPLC column, standardized protocols, and validated software that can be prepared in-house or purchased commercially as a kit. This system can be applied to any HPLC system worldwide, to produce comparable test results under uniform conditions. The test system is designed to be rapid, with a comprehensive performance qualification being completed in about 2 h for isocratic, and 3 h for quaternary gradient systems.

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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,..