Showing papers in "Journal of Chromatography A in 1998"

TL;DR: The method presented uses the entire chromatographic data matrices and does not require any preprocessing e.g., peak detection, and relies on piecewise linear correlation optimised warping (COW) using two input parameters which can be estimated from the observed peak width.

TL;DR: A high-performance liquid chromatographic (HPLC) separation method with photo-diode array (PDA) and mass spectrometric (MS) detection was developed to determine and quantify flavonols, flavones, and flavanones in fruits, vegetables and beverages.

TL;DR: The amino acid analysis technology needs further simplification and automation of the hydrolysis, chromatography and detection steps to withstand the pressure exerted by the other technologies.

TL;DR: For the determination of 18 antibiotics in water samples down to the lower ng/l range, an analytical multi method is presented and mean recovery rates were in excess of 70%, however, with one exception and a quantitation limit was set.

TL;DR: The results revealed differences between pulp and peel in all cases studied, and high levels of catechins and flavonol glycosides, especially rutin, were found in apple peels.

TL;DR: In this article, a sample solution is fed through a capillary tube and a high electric field at the tip of the tube pulls positive charge towards the liquid front, when electrostatic repulsion becomes stronger than the surface tension, a small electrically charged droplet leaves the surface and travels through the surrounding gas to the counter-electrode.

TL;DR: The study reveals a pattern of distinct oil composition changes due to biodegradation, which is significantly different from the pattern due to physical or short-term weathering, confirming that patterns of oil biodegradability do exist.

TL;DR: In this article, the authors identify and quantify nine new BDE congener in the technical flame-retardant, Bromkal 70-5DE, using relative retention versus dechlorane and standard additions on four different high-resolution gas chromatography capillary columns with low-polar to very polar properties.

TL;DR: Seasonal variations of pesticide residues in surface waters and ground waters of the Imathia area of Central Mecedonia (N. Greece) were determined, showing that many of these compounds are transported significant distances from their application sites.

TL;DR: In this article, the authors studied quantitative and qualitative aspects of polypeptide extraction using micro-tip elution and found that partial fractionation, obtained by two-step microtip elutions, generally results in more and better signals during subsequent mass analysis.

TL;DR: This paper reviews instrumental developments in the field of combined liquid chromatography-mass spectrometry (LC-MS) with reference to currently available commercial LC-MS systems, and low and high flow-rate electrospray on quadrupole instrument is discussed.

TL;DR: In this article, a high-performance liquid chromatography (HPLC) method for the identification of its constituents using a wide pore RP-18 column and a water-methanol-acetonitrile-phosphoric acid mobile phase system was developed.

TL;DR: This paper gives a review of chromatographic methods used for the determination of ochratoxin A (OA) in animal and human tissues and fluids, and emphasis was given to HPLC methods.

TL;DR: Comparison of reversed-phase columns indicates that deactivated stationary phases, which utilize ultrapure silica and maximize coverage of the silica support, provide significantly improved separation and chromatographic efficiencies for catechin analyses using LC, compared to conventional monomeric or polymeric C18 columns.

TL;DR: A new form of protein chromatography, hydrophobic charge induction, is described, which could be carried out within the pH 5-9 range and matched to protein requirements by ligand choice and density.

TL;DR: It is shown that modern analytical chemistry can be successfully applied to perform identification in the broad field of analytes ranging from chemical to biological warfare agents.

TL;DR: High-performance liquid Chromatographic methods for the analysis of fluoroquinolones in biological fluids are reviewed and sample preparation and handling procedures, chromatographic conditions, and detection methods are discussed.

TL;DR: The influence of several experimental factors related to the enhanced gas chromatographic responses yielding apparent recoveries of pesticide residues greater than 100% was investigated in this article, where an increase of relative detector response (100% = response of analyte in pure solvent solution) was evidenced to be dependent both on the concentration of the analyte and the character of the matrix.

TL;DR: The use of Q-Sepharose columns (1, 10 and 40 ml) for the preparative purification of plasmid pUC18 enabled the isolation of supercoiled plasmids from low-M(r) RNA, cDNA and plasmID variants and anion-exchange HPLC on a Poros QE 20 column was used to quantifyplasmid yield.

TL;DR: In this paper, modern instruments for countercurrent chromatography and centrifugal partition chromatography are reviewed, and a description of biphasic solvent systems is provided, together with some simple rules for finding the best system for a given purification.

TL;DR: The mechanical strength and stability of the monolithic column were significantly greater than those of conventional columns packed with particulate stationary phase and the plate efficiency was similar to that of columns freshly packed with the same particles and was always higher in the CEC than in the mu-HPLC under otherwise identical conditions.

TL;DR: The present study demonstrates the capability of the solvophobic theory in describing the energetics of processes involving hydrophobic interactions, and exposes the difficulties in distinguishing between partition and adsorption mechanisms in RPC by using partition models based on the lattice approach.

TL;DR: LC-MS is found to play an important role in the determination and confirmation of sulphonamides, beta-lactam antibiotics, (fluoro) quinolone antibiotics, as well as various other groups including aminoglycosides, chloramphenicol, ionophore antibiotics, 5-nitrofuran derived compounds and macrolide antibiotics.

TL;DR: In this article, a monolithic silica gel with continuous gel skeletons and through-pores together with open mesopores has been developed and the principle and procedure of designing the built-in pore structure is explained.

TL;DR: In this paper, the intermolecular interactions between organic solutes and sorbent matrices under subcritical water conditions have been investigated at a pressure of 50 bar and temperatures ranging from 50 to 250°C.

TL;DR: In this article, multivariate statistical quality control principles, including control charting of calibration parameters and control samples, are applied to multilevel ion chromatography (IC) calibrations to determine instrument response stability and minimum calibration frequency.

TL;DR: In this paper, a new high-performance liquid chromatography chiral stationary phase (CSP) was prepared by bonding (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid to silica gel.

TL;DR: Differentiation of orange juice varieties and mixtures containing tangor juice using polyphenolic profiles and flavonoid content has been achieved and the determination of flavonoids compounds in grapefruit- and orange juice is applied.

TL;DR: Data relating to the chromatographic behaviour of some macrolide antibiotics as well as the various detection methods used, such as bioautography, UV spectrophotometry, fluorometry, electrochemical detection, chemiluminescence and mass spectrometry techniques are also included.

TL;DR: This review focuses on phosphorylation of serine, threonine and tyrosine, the most commonly phosphorylated amino acids in eukaryotes, and considers the speed, simplicity and sensitivity of tools for detection and identification, as well as quantitation and site characterisation.