Coupling of planar chromatography to mass spectrometry

Publication year: 2010Source: TrAC Trends in Analytical Chemistry, In Press, Accepted Manuscript, Available online 21 August 2010Gertrud, Morlock , Wolfgang, SchwackCoupling of planar chromatography to mass spectrometry (MS) and especially ambient MS …

Publication year: 2010
Source: TrAC Trends in Analytical Chemistry, In Press, Accepted Manuscript, Available online 21 August 2010

Gertrud, Morlock , Wolfgang, Schwack

Coupling of planar chromatography to mass spectrometry (MS) and especially ambient MS is a relatively new field of great interest. The direct sample access at ambient conditions and the feasibility to obtain mass spectra free of contamination within a minute or even within seconds highly contributes to the progress of planar chromatography. Targeted recording of mass spectra on zones of interest is performed after evaluation of the chromatogram, thus providing high efficiency. Reported approaches for coupling are divided into elution-based and desorption-based techniques. Devices of both categories are commercially available. As a consequence of increasing importance, a rethink of the...

Preservation of inorganic arsenic species in environmental water samples for reliable speciation analysis

Publication year: 2010Source: TrAC Trends in Analytical Chemistry, In Press, Accepted Manuscript, Available online 21 August 2010A., Ramesh Kumar , P., RiyazuddinPreservation of arsenic species in environmental water samples is important to produce re…

Publication year: 2010
Source: TrAC Trends in Analytical Chemistry, In Press, Accepted Manuscript, Available online 21 August 2010

A., Ramesh Kumar , P., Riyazuddin

Preservation of arsenic species in environmental water samples is important to produce representative species-distribution data. However, published literature on preserving arsenic speciation is confusing and contradictory, predominantly because of the reactions of the Fe(II)/Fe(III) redox system and the microbe-mediated arsenic-species transformations. Field filtration, refrigeration and storage in the dark are prerequisites for stabilization of As(III)/As(V). Filtration removes suspended matter and most microbes, refrigeration suppresses most biotic and abiotic reactions, and storage in the dark avoids photochemical reactions of Fe(III) and As(III). There are reagents that inhibit the oxidation of Fe(II), but the efficiency of preservation depends on the sample matrix...

Analysis of pharmaceuticals by NIR spectroscopy without a reference method

Publication year: 2010Source: TrAC Trends in Analytical Chemistry, In Press, Accepted Manuscript, Available online 18 August 2010Marcelo, Blanco , Anna, PegueroUsing near-infrared (NIR) spectroscopy for quantitative analysis requires the application o…

Publication year: 2010
Source: TrAC Trends in Analytical Chemistry, In Press, Accepted Manuscript, Available online 18 August 2010

Marcelo, Blanco , Anna, Peguero

Using near-infrared (NIR) spectroscopy for quantitative analysis requires the application of multivariate-calibration techniques and careful selection of representative samples in order to construct accurate calibration models from NIR spectra using partial least squares (PLS). Developing an appropriate set of samples for calibration is difficult and complex, since the quality of models obtained and their prediction ability depends on the selection of these samples.For this work, we developed a new approach to constructing calibration sets for quantifying the active pharmaceutical ingredient (API) and excipients in pharmaceutical tablets. The operating procedure involves using an appropriate experimental design to prepare a set of...

Review of analytical figures of merit of sensors and biosensors in clinical applications

Publication year: 2010Source: TrAC Trends in Analytical Chemistry, In Press, Accepted Manuscript, Available online 10 August 2010Celine I.L., Justino , Teresa A., Rocha-Santos , Armando C., DuarteAlthough the development of clinical sensors and biose…

Publication year: 2010
Source: TrAC Trends in Analytical Chemistry, In Press, Accepted Manuscript, Available online 10 August 2010

Celine I.L., Justino , Teresa A., Rocha-Santos , Armando C., Duarte

Although the development of clinical sensors and biosensors has increased in recent years, improvements in sensitivity, selectivity, limits of detection, fast response and miniaturization are yet to be attained. Health care appears to provide the best opportunity for sensor development. Among the wide range of different sensors and biosensors, electrochemical biosensors are the most common in the clinical field, due to their high sensitivity and selectivity, portability, rapid response time and low cost. This article provides an up-to-date overview of the analytical performance of sensors and biosensors in clinical applications by discussing recent improvements, particularly due to the impact of...