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Elemental analysis in biological samples generally is achieved using flame atomic absorption spectrometry (AAS) and graphite furnace AAS (GFAAS). Flame AAS is fast, easy-to-use, and economical, but insufficiently sensitive for assays such as Se in serum and Pb/Cd in whole blood. These measurements require use of the more sensitive GFAAS. Inductively coupled plasma-mass spectrometry (ICP-MS), despite its low detection limit capabilities and wide elemental range, has had relatively little impact to date on biomedical analysis because of the popularly held conception that it is complex to use and expensive. In recent years, the instrumentation has been simplified and purchase, running, and maintenance costs have fallen. As a result, clinicians are becoming more interested in ICP-MS, although the perception that it is still much more expensive than GFAAS remains. This article provides a comparison of the costs of ICP-MS and GFAAS for biomedical sample analysis and illustrates the performance of ICP-MS for..

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With electron ionization (EI) used in most gas chromatography–mass spectrometry (GC–MS) applications, the molecular ion typically is broken apart into multiple fragment ions during the EI process.

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This article discusses the key components of a typical liquid sample introduction system for inductively coupled plasma spectroscopy, and offers troubleshooting tips for problems commonly encountered by practitioners.

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September 2006. The authors rapidly acquire complete vibrational spectra in the fingerprint region using a single femtosecond laser for broadband coherent anti-Stokes Raman scattering (CARS) microscopy to image spatially variant compositions of condensed-phase samples.

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September 2006. The authors rapidly acquire complete vibrational spectra in the fingerprint region using a single femtosecond laser for broadband coherent anti-Stokes Raman scattering (CARS) microscopy to image spatially variant compositions of condensed-phase samples.

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This article compares different CCD platforms by outlining CCD and EMCCD noise sources as well as an explanation of the two calculations to arrive at the signal-to-noise ratio for each. The data presented will show that a liquid nitrogen-cooled CCD camera still is the proper choice for low light level applications, such as Raman spectroscopy.

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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.

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Surface-enhanced Raman spectroscopy (SERS) has been studied extensively over the last few decades with many advances in preparation of SERS substrates and coatings. While the bulk of the research in SERS substrate preparation has been devoted to pushing detection limits to higher sensitivity for measurement of single samples, the application of SERS to high-throughput analysis has been largely ignored. In this article, we present the use of commercially available SERS-coated microtiter plates in a dedicated Raman microtiter plate reader, enabling high-throughput trace analysis measurements. This article also describes the SERS substrate, the high-throughput plate reader, and preliminary results from samples representing trace analysis of explosives, nerve agents, pharmaceuticals, and biological compounds.

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In this article, we present a method that provides prompt detection of the presence of cancer cells inside the 2-mm margin of tissue surrounding the tumor after excision using spatially offset Raman spectroscopy (SORS). SORS was developed to detect subtle changes in soft tissue spectra in the 100–2000 ?m range and tested on excised breast tissues. The results display a very high specificity and sensitivity (100% and 95%, respectively) of classification between positive and negative tumor margins. SORS is a clinically feasible method, suitable for the real-time, intraoperative assessment of tumor margins at the micrometer level.

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The authors discuss current approaches for increasing throughput in MS analyses, including improved software information flow, data management and effective sample preparation, and how researchers should consider each of these with regard to their own needs.

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Given the wide range in polarity of the components of mesquite flour, it is advantageous to study the health benefits of this flour using methods that combine the complementary approaches of reversed-phase and aqueous normal phase LC.

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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.

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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.

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Photonic crystal fibers are novel optical waveguides that offer promising alternatives for various sensing applications. This article describes an experiment in which the absorption spectrum of acetylene was measured to demonstrate the effectiveness of photonic bandgap fibers for high sensitivity gas detection. Methane also was studied to determine the same capability in weakly absorbing gases.

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Mass spectrometers are effective for identifying and quantifying unknown molecules, such as disease-related proteins and small molecules in pharmaceutical research and medical diagnosis. In addition, mass spectrometry (MS) can be particularly powerful when analyzing molecules with complex structures, such as posttranslationally modified proteins. Among various MS approaches, high-resolution multistep tandem MS (MS-MS) is an emerging methodology for accurate identification of complex molecules. In this article, we describe a new approach for mass analysis with enhanced quantitative capability combined with high-resolution multistep MS-MS, where the dynamic range of quantitation covers four orders of magnitude.

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Hitachi High Technologies America, Inc.

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Ultrahigh performance liquid chromatography (LC)–time-of-flight mass spectrometry –(TOF-MS) and gas chromatography (GC)–TOF-MS are powerful approaches for screening target compounds and identifying or characterizing nontarget compounds in complex mixtures. The combination of accurate mass data and newly developed software enables truly generic screening methods with TOF-MS, and the confident detection, identification, and confirmation of small molecules in a range of application areas.

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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.

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Surface-enhanced Raman spectroscopy (SERS) is a widely studied technique capable of adding single-molecule detection capability to the rich information provided by Raman spectroscopy. in this aricle, the authors show an additional system gain of more than two orders of magnitude to SERS by using a dielectric microsphere resonator to capture and excite the target system.

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The authors discuss several sample types encountered in their laboratory for which Raman spectroscopy is the only reliable method of analysis. The technique is shown to be a routine and cost-effective tool for the industrial laboratory.

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Since it was first described in 1974, surface-enhanced Raman spectrometry (SERS) has been thought to offer significant potential for a range of different applications. The theoretical sensitivity and specificity envisaged for this powerful technique has engaged scientists for many years, but practical challenges have hindered its routine adoption. Now, a new approach combines a robust and reliable substrate with expertise in surface chemistry and molecular biology on a platform that can be adapted for a wide variety of Raman instrumentation and customized routine applications.

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This article provides an overview of the instrument platforms, tools, and workflow for analyzing pesticides.

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Therapeutic drug monitoring is performed routinely by liquid chromatography–mass spectrometry (LC–MS) using instrumentation and methods originally developed and systematically configured for the high-volume, high-throughput analysis of drugs of abuse. An example of LC–MS monitoring of the drug clozapine and its metabolite, desmethylclozapine, is detailed along with a description of the overall system architecture, workflow, and maintenance routines that support a large-scale clinical therapeutic drug monitoring program. The relative advantages of LC–MS over immunoassay and LC–UV, the current standard techniques for therapeutic drug monitoring, are discussed in the light of these results.

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This article examines temperature-induced effects on surface-enhanced Raman scattering of PHBA and MHBA adsorbed on silver colloidal particles.

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A new high-throughput LC–MS/MS method meets the challenge of eliminating matrix effects for monitoring, with high specificity, polar organic pesticides such as glyphosate in food and water, while meeting targeted limits of detection.

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Surface-enhanced Raman spectroscopy (SERS) has been studied extensively over the last few decades with many advances in preparation of SERS substrates and coatings. While the bulk of the research in SERS substrate preparation has been devoted to pushing detection limits to higher sensitivity for measurement of single samples, the application of SERS to high-throughput analysis has been largely ignored. In this article, we present the use of commercially available SERS-coated microtiter plates in a dedicated Raman microtiter plate reader, enabling high-throughput trace analysis measurements. This article also describes the SERS substrate, the high-throughput plate reader, and preliminary results from samples representing trace analysis of explosives, nerve agents, pharmaceuticals, and biological compounds.

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What does the accelerating adoption of PAT-based approaches to pharmaceutical manufacturing mean for the makers and users of spectroscopic systems?

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Gas chromatography combined with atmospheric-pressure chemical ionization (APCI) was used to analyze high-molecular-weight phthalates.

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The authors show how a multivariate curve resolution algorithm, called SIMPLe-to-use Interactive Self-modeling Mixture Analysis (SIMPLISMA), can facilitate the quantitative and qualitative analysis of difficult samples, and apply the algorithm to a technically challenging Raman spectra series for carbamazepine polymorphs.