In this article, the role of a triple-quadrupole mass spectrometer in performing in vitro studies of compound metabolic stability and identification of Phase I and II metabolites is demonstrated.
Assay sensitivity is the lowest concentration at which a targeted analyte can be measured and is often limited by chemical background or co-eluting interferences. FAIMS in combination with liquid chromatography (LC) and zero neutral loss tandem MS was used to remove chemical background and co-eluting interferences from the analysis of linoleic acid in cancer cell extracts. Concentration of endogenous linoleic acid was determined from back-calculation of standard calibration samples fortified with deuterium-labeled linoleic acid. No internal standard was used. LC–MS-MS analysis of the cancer cell extracts resulted in an increase in signal-to-noise ratio of 10-fold. The assay sensitivity was increased 10 times over the traditional LC–MS-MS experiment exclusively due to the new FAIMS technology.
The acquisition of Raman spectra can be eased greatly through the use of surface-enhanced Raman spectroscopy (SERS). In this article, the authors discuss a new substrate technology that delivers reliable and consistent surface enhancement.
Mass spectrometry has long been a preferred tool for protein identification and biomarker discovery, but preparation of biological samples remains a challenge. Hindrances include the wide range of protein concentrations, sample complexity, and loss or alteration of important proteins due to sample handling. This article describes recent developments in sample fractionation technologies that are overcoming these challenges in interesting ways and are enabling in-depth proteomic studies that were not possible in the past.
An effective metabolite identification study should ideally include both qualitative and quantitative information that for both identifying metabolites, and determining the rate of clearance and the metabolic routes of the parent drug. Liquid chromatography–mass spectrometry (LC–MS) is considered the standard analytical technique for metabolite identification studies. To date, however, qualitative and quantitative information has always been obtained from two separation platforms: quadrupole time-of-flight (QTof) MS for the exact mass full-scan qualitative study, and tandem quadrupole MS for the multiple reaction monitoring (MRM) quantitative study. With advancements to QTof instrumentation, specifically, recent improvements in sensitivity and dynamic range, it is now possible to perform both qualitative and quantitative experiments on a single QTof mass spectrometer. This article describes a workflow that allows simultaneous qualitative and quantitative metabolite identification studies to be..
A newly discovered method is described for generating gas-phase ions from volatile and nonvolatile compounds. The method, matrix-assisted ionization (MAI), is both simple and sensitive, requiring only the vacuum inherent with all mass spectrometers and a suitable matrix, eliminating the need for lasers, electric fields, nebulizing gas, and even heaters to generate gas-phase ions. MAI is applicable for the direct analysis of drugs from biological fluids and tissue without prior purification. By placing matrix only on a specific surface area of interest and exposure to the vacuum of the mass spectrometer, ions are observed from compounds within the targeted surface area of tissue exposed to the matrix solution, thus allowing rapid and simple interrogation of “features of interest.” The limit of detection for drug standards is low attomoles and clean full mass range mass spectra are obtained from low femtomoles of the drug.
Confocal Raman microscopy can be useful when applied to all samples that are heterogeneous on the micrometer to millimeter scale and that generally can be investigated by Raman spectroscopy. This article presents examples of confocal Raman microscopy from various fields of application including pharmaceutical analysis and stress measurements in semiconductors.
Serum protein profiling using mass spectrometry (MS) is one of the most promising approaches for biomarker identification. The authors adopted a nano liquid chromatography (nLC)–linear ion trap time-of-flight (LIT-TOF) MS system and newly developed software known as information-based acquisition (IBA) to identify biomarkers in human serum. IBA is a data processing protocol for repetitive MS analyses. Peptides selected for the first-pass MS-MS analysis are automatically excluded from the MS spectrum such that subsequent MS-MS analyses are performed on different peptides to minimize overlapping analyses, resulting in the identification of relatively low-abundant peptides.
Attendees from the pharmaceutical industry and FDA discussed a range of topics, including new spectroscopic analysis techniques, chemical imaging, calibration, and current efforts at ASTM.
For analysis of non-particulate solids, the diffuse reflection sampling technique may offer an easy, non-destructive method for mid-infrared measurements. Spectral results of a polypropylene face mask collected via diffuse reflection and attenuated total reflection (ATR) were compared.
Simple, fast, and reliable on-site hydraulic oil analysis should be an integral part of any preventative maintenance program. Since the majority of machine failures are contamination related, it is important to analyze the hydraulic fluid to monitor equipment condition and identify machine wear. Significant cost savings can result from early identification of machine failure, oil quality, handling and other problems. Oil analysis can detect changes in oil quality, contamination, wear and chemical differences. Benefits of this information include prolonged equipment life, reduced equipment downtime, and reduced overall maintenance costs. In addition, plants can increase intervals between oil changes, thus reducing waste oil, maintenance, and oil purchase costs.
The element selenium plays three distinct roles in biological processes, functioning in turn as a toxicant, a chemopreventive agent, and a heavy metal antagonist. This article discusses current research associated with each role, and how ICP-MS can be employed to better understand and utilize selenium's properties.
In this article, the role of a triple-quadrupole mass spectrometer in performing in vitro studies of compound metabolic stability and identification of Phase I and II metabolites is demonstrated.
Mass spectrometry has long been a preferred tool for protein identification and biomarker discovery, but preparation of biological samples remains a challenge. Hindrances include the wide range of protein concentrations, sample complexity, and loss or alteration of important proteins due to sample handling. This article describes recent developments in sample fractionation technologies that are overcoming these challenges in interesting ways and are enabling in-depth proteomic studies that were not possible in the past.
Improved Sensitivity with the New Apollow XRF ML-50 Detector on the Orbis Micro-XRF Analyzer
This article overviews several recent advancements in Raman components that are enabling high analytical performance in low-cost Raman instruments.
The authors discuss the use of electron-capture dissociation coupled with a linear ion trap time-of-flight mass spectrometer to investigate the structure of human transferrin.
As process analytical technology (PAT) moves out of the laboratory and into the plant and to the process stream itself, the question arises, "What is the best way to collect data from stream samples?" The author shows that this depends upon both the nature of the stream and the components to be measured.
This article discusses the role of recent LC developments in th quest for greater sensitivity, more complete sample characterization, and greater productivity.
Often, mass spectra of compounds found in water supplies are not found in mass spectral libraries. Ion composition elucidation (ICE) provides the elemental compositions of the ions observed in their mass spectra. This information is used to identify the compounds.
There are many situations in which it would be highly desirable to apply the benefits of Raman to larger volumes of solid material such as powders, tablets, and composites. Raman benefits such as minimal sample preparation, the ability to provide rich information on both organics and inorganics, and its ability to measure through glass and plastic packaging make it highly amenable to these kinds of samples.
The authors describe the in-line moisture measurement of a pharmaceutical granulation of lactose, microcrystalline cellulose, and crospovidone in a fluid bed granulator-dryer using top sprayed granulating liquid. A near-infrared (NIR) prediction model was developed for moisture on spectra collected during a calibration run. Subsequent granulations were analyzed for moisture content real-time throughout the granulation and drying process using the NIR process instrument.
Raman spectroscopy has been employed to detect Bacillus cereus spores, an anthrax surrogate, collected from a letter as it passed through a mail sorting system. Raman spectroscopy also has the ability to identify many common substances used as hoaxes. A three-step method also is described for the detection of dipicolinic acid extracted from surface spores by SERS.
In this article, the role of a triple-quadrupole mass spectrometer in performing in vitro studies of compound metabolic stability and identification of Phase I and II metabolites is demonstrated.
The acquisition of Raman spectra can be eased greatly through the use of surface-enhanced Raman spectroscopy (SERS). In this article, the authors discuss a new substrate technology that delivers reliable and consistent surface enhancement.
The authors present a novel technique for obtaining very high stability and reproducibility of a Raman spectrum, using grating corrected laser stabilization. An externally stabilized laser with a grating spectrometer provides exceptional quantum efficiency in the entire dynamic range. These components then are used to build a library of pharmaceutical raw materials and tested on samples of unknown material.