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New Generation of GC/High Resolution TOF-MS: APCI/APLI Source for Increased FlexibilityA new APCI/APLI source enables a high resolution TOF-MS to be coupled on LC and GC, thus increasing flexibility and performance of TOF-MS in combination with GC.
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The Thermally Tuned Tandem Column Approach to Optimizing Selectivity in HPLCThe authors compare thermally tuned tandem column separations with single-column optimization strategies.
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Accelerated Discovery and Quantitation of Lipids in Complex ExtractsThe authors discuss analytical methods for lipidomics.
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Separation, Identification, and Quantitation of Water-Soluble Vitamins by HPLCThe authors set out to perform a separation of seven water-soluble vitamins without the use of ion-pair reagents.
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Chemometrical Experimental Design-Based Optimization Studies in Capillary Electrophoresis ApplicationsA synopsis of our work detailing the use of chemometric response surface methodology (RSM) in two capillary electrophoresis (CE) studies is described.
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LC–MS-MS Determination of Malachite Green and Leucomalachite Green in Fish ProductsAlthough 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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High Resolution UHPLC Analysis of Naringin in Grapefruit JuiceGrapefruit 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.
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Solid-Phase Microextraction (SPME) in the Fish Oil IndustryA review of the role of Solid-phase Microextraction (SPME) in quality control (QC) in the fish oil industry.
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Improving the Confidence of Unknown Compound Identification by First Responder Mobile GC–MS Laboratories...A novel method that significantly improves the accuracy and reliability of "unknown" compound identification for volatile organic compounds by GC-MS is described.
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GSH Conjugate Metabolite Identification with a Hybrid Triple- Quadrupole–Linear Ion-Trap Instrument and Automated Software-Driven Method DevelopmentIn 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.
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Aflatoxin B1, B2, G1, G2 Food Safety Testing Prior to Automated SmartPrep® Extractor Solid-Phase ExtractionMycotoxin testing awareness has increased as countries involved in world trade of raw agriculture and processed consumer products rely on a safe global food supply
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Pesticide Residues Screening in Food Samples Using High Resolution and Accurate Mass LC–MS–MSAB Sciex Application Note
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Hernan CortesMark 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.
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Approaches to Singleton Achiral Purification of Difficult Samples for Discovery Research SupportSeveral 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.
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Extraction and Preconcentration of Residues and Contaminants in Food Samples Using Membrane TechniquesGuest authors from South Africa review the application of membranes in the extraction, preconcentration, and separation of various contaminants in food.
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Analysis of Fusarium Toxins Using LC–MS-MS: Application to Various Food and Feed MatricesCo-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.
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Fast Gradient LC Using Your Existing InstrumentationTransforming "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!
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Why Use Signal-To-Noise As a Measure of MS Performance When It Is Often Meaningless?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).
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Automated Extraction Technique for Improved Recovery of PhenolsDionex 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.
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32 Years Connecting with Gas ChromatographyAfter 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.
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Protein Identification in Complex Mixtures: A Comparison of Accurate-Mass Q-TOF and Ion-Trap LC–MSBecause 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.
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Characterization of PEGylated Lysozyme by Size Exclusion and Ion Exchange ChromatographyPEGylation, 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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Study of Free Radical Fragment Ions Generated from ESI-CID-MS-MS Using LTQ and LTQ Orbitrap Mass SpectrometersStudies 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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Determination of Urea and Allantoin in CosmeticsUrea 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%).
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Superficially Porous and Monolithic Columns for Ultrafast Separations in HPLCDue 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.
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Study of Free Radical Fragment Ions Generated from ESI-CID-MS-MS Using LTQ and LTQ Orbitrap Mass SpectrometersStudies 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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Detection of Doping Agents by LC–MS and LC–MS-MSIn 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.
