Showing papers in "Journal of Chromatography A in 1999"

TL;DR: The objective of this review is to provide updated information about the most important features of the new solid-phase extraction (SPE) materials, their interaction mode and their potential for modern SPE.

TL;DR: This paper reviewed the most recent development and advances of chemical fingerprinting and data interpretation techniques which are most frequently used in oil spill identification studies, including recognition of relative distribution patterns of petroleum hydrocarbons, analysis of source-specific marker compounds, determination of diagnostic ratios of specific oil constituents, isotopic analysis, and several other emerging techniques.

TL;DR: The efficiency of the monolithic columns in CEC was significantly higher than in mu-HPLC in the same way as observed with capillary columns having conventional particulate packing, due to the relaxation of band-broadening with electroosmotic flow (EOF) with respect to that with viscous flow.

TL;DR: Due to its ability to measure isotope distribution at natural abundance level with great accuracy and high precision, GC-C-IRMS has increasingly become the method of choice in authenticity control of foodstuffs and determination of origin in archaeology, geochemistry, and environmental chemistry.

TL;DR: Comprehensive two-dimensional gas chromatography (GC x GC) provides a true orthogonal separation system that generates a peak capacity that is approximately equal to the product of the peak capacities of the two individual separation systems.

TL;DR: In this article, the origin and evolution of solute descriptors for use in the solvation parameter model applied to the classification of stationary phases and other materials by gas chromatography are described.

TL;DR: A new and accurate method to quantify ochratoxin A (OA) in table wine has been developed using commercial immunoaffinity columns for clean-up and high-performance liquid chromatography (HPLC) with fluorescence detection for quantification of the toxin.

TL;DR: Isoxanthohumol was the most abundant flavonoid in hopped beers, ranging from 0.04 to 3.44 mg/l, and the accuracy and precision were evaluated by replicate analyses of (spiked) samples.

TL;DR: Gradient elution reversed-phase high-performance liquid chromatography (RP-HPLC) was used for the determination of compounds occurring during the production of biodiesel from rapeseed oil to quantitate residual TGs in the final biodiesel product.

TL;DR: A perspective on the current technology, principles and applications of LC-MS is provided.

TL;DR: The rise and fall of supercritical fluids represents a lesson in the way analysts approach new techniques and how the authors might view other new separation developments at the end of this millennium.

TL;DR: The basics and implementation of expanded-bed chromatography, its advantages as well as problems encountered in the use of this technique for the direct extraction of proteins from unclarified feedstocks are addressed.

TL;DR: The role of gas chromatography as an analytical tool in combination with currently used or recently developed sample preparation techniques is described.

TL;DR: This review includes silylation artifacts identified in the laboratory by mass spectrometry during the last 20 years and references to those found in the literature are discussed in detail.

TL;DR: The principles of the different retention models that have been proposed are examined and the theoretical modifications needed when going from small ions to ionic macromolecules are discussed and the developed models are compared with the experimental results.

TL;DR: This review focuses on the basic principles of LC-ICP-MS, its historical development and the many ways in which this technique can be applied.

TL;DR: An overview on the current status of capillary electrophoresis (CE) and capillary electrochromatography (CEC) and the application, advantages and limitations of CEC are covered.

TL;DR: High-performance liquid chromatography coupled with positive-ion electrospray ionisation tandem mass spectrometry was used for the determination and confirmation of 13 sulphonamide drugs in environmental water samples in the low ng/L-range and the compound sulphamethoxazole was detected in low amounts but could not be positively confirmed.

TL;DR: The suitability of pressurized liquid extraction in medicinal plant analysis was investigated and a significant economy in time and solvents was realized, while extraction yields of the analytes were equivalent or higher.

TL;DR: A HPLC method was developed to quantify rhamnolipid species in a bacterial biosurfactant mixture and to confirm the reliability of theHPLC method, the biosurfacts mixtures and the HPLC isolated species were further analyzed.

TL;DR: In this article, a new method was described for distinguishing between animal fats preserved in ancient pottery using on-line gas chromatography-13 combustion-isotope ratio mass spectrometry (GC-C-IRMS).

TL;DR: The parameters proposed quantitatively characterize the RP-HPLC stationary phases and provide a rational explanation for the differences in retention patterns of individual columns observed when applying the conventional empirical testing methods are proposed.

TL;DR: Several commercially available plastic materials used as substrates in the fabrication of microfluid channels for biochemical analysis showed a high degree of non-specific adsorption of IgG as indicated by a decrease in the electroosmotic flow mobility in post-incubation testing.

TL;DR: A chemiluminescence reaction detector was developed for the detection of polyphenols separated by HPLC and has been successfully applied to the determination of chlorogenic acid and rutin in real tobacco samples.

TL;DR: The emphasis of this review is on miniaturized sample clean-up, sample introduction techniques and on both established and more recent detection techniques for microcolumn LC.

TL;DR: In this paper, it was shown that the most important contribution to dispersion in liquid chromatography comes from the flowing part of the mobile phase, rather than slow mass transfer within the porous particles normally used in HPLC.

TL;DR: A headspace sample is a gas sample which has been previously in contact with a liquid or solid sample from which volatile compounds were released into the gas with subsequent analysis by gas chromatography as mentioned in this paper.

TL;DR: In this article, a review of recent developments of the analysis of volatile organic compounds (VOCs) in ambient air and natural waters is presented, focusing on recent applications of liquid-liquid extraction and the dynamic headspace technique, and new techniques such as the application of membranes.

TL;DR: The results of this work indicate that the pore network model and expressions presented could allow one, for a given porous adsorbent, adsorbate, ligand (active site), and interstitial column fluid velocity, to determine in an a priori manner the values of the intraparticle interstitial velocity and pore diffusivity within the monolith or within the porous Adsorbent particles as the fractional saturation of the active sites changes.

TL;DR: Octanol-water partition coefficients (Kow) for 57 terpenoids were measured using a RP-HPLC method and log Kow values calculated by the atom/fragment contribution method gave the best correlation with the HPLC values when compared to fragment and atomistic methods.