Author

Latest:

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).

Latest:

Grapefruit juice was analysed by gradient UHPLC for naringin - a major flavanoid in grapefruit juice that gives it its bitter taste. A ZORBAX Rapid resolution HD (RRHD) StableBond-C18 2.1 ? 150 mm, 1.8 ?m column was able to resolve over 60 peaks, including naringin in 7 minutes, and was re-equilibrated in just three minutes by operating at a high flow rate (0.8 mL/min). The high pressure generated (965 bar) is well within the 1200 bar operating range of the RRHD column and 1290 Infinity LC.

Latest:

A review of the role of Solid-phase Microextraction (SPME) in quality control (QC) in the fish oil industry.

Latest:

A novel method that significantly improves the accuracy and reliability of "unknown" compound identification for volatile organic compounds by GC-MS is described.

Latest:

In drug discovery, determining information about the extent of metabolism and the elucidation of metabolite structures is a vital step for lead optimization and drug scaffold refinement. The identification and characterization of metabolites plays an important role in both the drug discovery and development phases, as unsuitable pharmacokinetics (bioavailability and drug distribution), toxicity, and adverse drug reactions might be linked to metabolic instability. Historically, metabolite identification was carried out after a compound had been chosen for drug development. However, to reduce candidate failures attributed to toxicity effects, many pharmaceutical companies now conduct these experiments in the earliest phases of candidate drug selection.

Latest:

Mycotoxin testing awareness has increased as countries involved in world trade of raw agriculture and processed consumer products rely on a safe global food supply

Latest:

AB Sciex Application Note

Latest:

Mark Schure spoke to LCGC Europe’s Lifetime Achievement Award winner, Hernan Cortes, about his career with Dow Chemical, multidimensional chromatography, the evolution of mass spectrometry (MS), and the direction that liquid chromatography (LC) is taking.

Latest:

Several approaches for purifying difficult samples more efficiently for discovery research support are mentioned in this paper. These approaches use mass triggered HPLC on various specialty columns.

Latest:

Guest authors from South Africa review the application of membranes in the extraction, preconcentration, and separation of various contaminants in food.

Latest:

Latest:

Co-occurrence of several mycotoxins (deoxynivalenol, zearalenone, T-2-toxin, HT-2 toxin) produced by field fungi, such as Fusarium graminearum and Fusarium culmorum, requires several analysis methods for their characterization. A reliable method for the determination of type A- and B-trichothecenes and zearalenone in cereal-based samples is presented. To achieve optimal mass spectrometric detection, electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) were compared. Best results were obtained with ESI by implementing a two-period switching for the ionization polarity. The limit of quantification differs for each individual substance within the range 1–10 ppb. Mean recoveries using a standardized clean-up procedure were in the 54–93% range.

Latest:

Transforming "standard" gradient HPLC systems into extremely fast gradient systems is readily achievable with proper application of chromatographic principles, particularly temperature control, combined with utilization of advanced HPLC columns. Bottom line: You don't have to buy a new LC to achieve ultra high quality and speed!

Latest:

Latest:

Signal-to-noise of a chromatographic peak from a single measurement has been used determine the performance of two different MS systems, but this parameter can no longer be universally applied and often fails to provide meaningful estimates of the instrument detection limits (IDL).

Latest:

Dionex has developed a new standard for flow-through solvent extraction which allows accelerated solvent extraction (ASE®) of matrices that have undergone acid or alkaline pretreatment or digestion. The new ASE 150 and ASE 350 systems use extraction cells and post-cell solvent pathways constructed of Dionium™ material. This pH-hardened substance resists corrosion under acidic or alkaline conditions used in standard pretreatments, widening the scope of ASE applications and significantly expanding its capabilities.

Latest:

After 32 years as a columnist, John Hinshaw writes his final “GC Connections” article, examining how GC has changed over the years and considering where it might go in the future.

Latest:

Because it is extremely rapid, biomarker discovery and identification using liquid chromatography–mass spectrometry (LC-MS), including both ion-trap and triple-quadrupole LC–MS, is well established. Fractionation of complex samples before LC–MS-MS analysis might be necessary to identify the proteins, greatly increasing the number of analyses required. In this case, there is ongoing debate regarding knowing whether the protein is identified correctly, knowing how much prior fractionation is needed to reduce complexity to the point where low-abundance proteins can be detected reliably, and balancing specificity with sensitivity.

Latest:

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.

Latest:

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.

Latest:

Urea and allantoin are added to cosmetic products for skin protection and regeneration, especially for the treatment of dry skin, and analyzed for QC purposes. As polar compounds, they are not ideal for reversed-phase HPLC separations. Neutral hydrophilic compounds like urea and allantoin are best analyzed by hydrophilic interaction chromatography (HILIC). Traditional HILIC columns use silica modified with a hydrophilic group such as diol or cyano. Analytes are adsorbed and subsequently eluted with mobile phases containing high percentages of organic solvent (>75%).

Latest:

Due to economic crisis all over the world it is a time of cost-friendly analyses. Superficially porous and monolithic columns are the tools to serve this purpose. These columns are new generation and can be used for ultrafast separations. This article describes the state-of-the-art for these stationary phases for high performance liquid chromatography (HPLC). The emphasis has been placed on their preparation, properties, applications, comparison, and future perspectives. It has been observed that superficially porous columns may be the choice of future for ultrafast separations.

Latest:

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.

Latest:

In the last decade, research on the detection of all groups of doping agents has been investigated by LC-MS, and routine LC-MS screening applications are now available for almost all classes of doping agents.

Latest:

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.

Latest:

The SHISEIDO CAPCELL PAK C18 MGIII is an HPLC column packed with a silicone polymer-coated phase, providing excellent peak profiles for basic compounds under acidic conditions, and generating ultimately minimized column bleeding in LC–MS.

Latest:

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.

Latest:

Benefits of elevated-temperature seperations in LC are discusssed.

Latest:

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.

Latest:

This article discusses the analysis of a wide range of CWAs at current exposure limits and describes a number of recent beneficial developments in TD and associated analytical technologies for the identification and quantification of CWAs at these levels.