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.
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.
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.
Benefits of elevated-temperature seperations in LC are discusssed.
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.
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.
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.
EPA is updating method 525.2. The CCL3 includes 104 analytes. UCT has evaluated the recoveries of these compounds, including the current list, using proposed changes to the method with the C18-based UCT ENVIRO-CLEAN? 83 mL Extraction Cartridge ECUNI525.
The authors set out to perform a separation of seven water-soluble vitamins without the use of ion-pair reagents.
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.
Endothall is a widely used herbicide for both terrestrial and aquatic weeds. Exposure to endothall in excess of the maximum contamination level (MCL) can cause illness. Endothall is regulated by the U.S.
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.
In this extended special feature to celebrate the 30th anniversary edition of LCGC Europe, leading figures from the separation science community explore contemporary trends in separation science and identify possible future developments. We asked key opinion leaders in the field to discuss the current state of the art in liquid chromatography column technology, gas chromatography, sample preparation, and liquid chromatography instruments. They also describe the latest practical developments in supercritical fluid chromatography, 3D printing, capillary electrophoresis, data handling, comprehensive two‑dimensional liquid chromatography, and multidimensional gas chromatography.
In March 2007, several North American manufacturers of pet food voluntarily issued nationwide recall notices for some of their products that were reportedly associated with renal failure in pets. The raw material wheat gluten, used to manufacture the pet food, was imported from China and was identified as the source of contamination.
This study describes the recovery of compounds above the boiling point of naphthalene achieved by optimizing the thermal desorption chemistry for the determination of volatile organic compounds ranging from C3 to C26 in soil gas samples using Method TO-17. Figures of merit such as breakthrough, precision, linearity, and detection capability are presented, in addition to an evaluation of its real-world capability at sites with moderate diesel and semivolatile polynuclear aromatic hydrocarbon (up to pyrene) contamination, in the presence of high humidity. This research has provided a means to determine a more representative composition of soil gas.
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.
MEPS uses a barrel insert and needle (BIN) device to reduce Solid-Phase Extraction (SPE) to a micro-scale suitable for small volume samples and for the online adaptation of conventional SPE techniques. Because the SPE cartridge (BIN) is incorporated into the needle assembly of a gas-tight syringe, MEPS is also a simple field-portable SPE device that may be operated manually without need for sampling pumps or, alternatively, may be incorporated into robotic samplers. MEPS devices are of glass and stainless steel construction allowing them to be fully immersed for sampling at depth or, alternatively, used at needle depth to avoid perturbing the stream from which the sample was drawn. An extension pole allowed MEPS to be used to sample back along pipes or down inspection vents. When sampling from drainage pits and open sumps, there was minimal requirement to remove grates to gain access. An extension pole also allowed sampling from outflows that were offensive and could be readily adapted for safe sampling of..
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!
A synopsis of our work detailing the use of chemometric response surface methodology (RSM) in two capillary electrophoresis (CE) studies is described.
The never-ending quest for separation media that enable efficient high speed/high throughput chromatography has led to the design of stationary phases in monolithic formats with both vastly improved mass transfer properties and reduced discontinuity. Historically, porous polymer monoliths have first emerged in the late 1980s/early 1990s followed by their silica-based counterparts in the mid 1990s. The common denominator for both organic and inorganic monoliths was originally their use in HPLC columns. However, the range of applications of monolithic materials grew significantly since their early times. This short review summarizes information about monoliths produced in different shapes such as discs, tubes, columns, polymer layer open tubes (PLOT capillaries), and microfluidic devices, and presents selected applications including chromatographic separations, sample preparation, and enzyme immobilization.
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.
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.
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.
Learn the latest techniques for improved chromatographic performance and throughput of AAV analysis.
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.
In this article, the authors discuss the need for protection against chemical attacks and the role of passive imaging spectroradiometers in the detection of remote chemical agents.