Showing papers in "Analytica Chimica Acta in 1997"

TL;DR: In this article, the number and weight-averaged molecular weights of different isolated humic fractions and organic matter from natural water samples were measured using high-performance size-exclusion chromatography (HPSEC).

TL;DR: In this article, a new method for the concomitant separation of the light rare-earth elements (LREEs), thorium and uranium is described, and applied to the determination of 143 Nd 144 Nd ratios, and concentrations of Sm, Nd, Th and U in silicate rocks, using isotope dilution and thermal ionization mass spectrometry.

TL;DR: How various voltammetric techniques such as large and small amplitude pulse voltammetry can generate information when combined with a multivariate analysis method is described.

TL;DR: This review describes recent efforts aimed at coupling nucleic acid recognition layers with electrochemical transducers, and considers DNA hybridization sensors for sequences related to microbial or viral pathogens, and DNA-modified carbon electrodes for monitoring low molecular weight priority pollutants interacting with the surfaceconfined DNA.

TL;DR: In this paper, the root-mean-square error of prediction (RMSEP) of a multiple linear regression (MLR) model and a partial least squares (PLS) model were compared.

TL;DR: A voltammetric study of the interaction of TMAP with DNA on Hg electrode in ammoniacal buffer solution is described in this paper, where the results of samples determination by electrochemical method are consistent with those by UV-spectroscopy.

TL;DR: In this article, an analytical procedure was developed for the direct determination of sugars in fruit juice samples, based on the partial least squares (PLS) treatment of first derivative near infrared (NIR) spectroscopic data obtained between 1200 and 2450 nm, using 1 mm pathlength cell and a multicomponent calibration set, including seven binary mixtures and 10 ternary mixtures of glucose, fructose and sucrose.

TL;DR: In this paper, two modifications of the unimodality constraint and a new constraint for chromatographic concentration profiles related to the prevention of fronting have been checked, and the parameters measured to assess the goodness of the constraints are related to recovery of the concentration profiles and the quality of the data fit.

TL;DR: A choline amperometric biosensor based on screen-printed electrodes was assembled and used to assess the inhibitory effect of organophosphorus and carbamic pesticides on acetylcholinesterase activi.

TL;DR: In this article, the authors used TMPP, sodium tetraphenylborate and a solvent mediator (dibutylphthalate) in polyvinyl chloride (PVC) based membrane sensors.

TL;DR: The synthesis and surface immobilization of oligonucleotides are described together with an evaluation of electrochemical, optical and acoustic wave structures that have been employed in genosensor development.

TL;DR: In this paper, the sequential extraction procedure recommended by the Bureau Commun de Reference (BCR) of the Commission of the European Communities is applied to a reference marine sediment (Standard Reference Material SRM 1646a) to test the reproducibility of a chemical method.

TL;DR: In this paper, a review of analytical and preparative chromatography of microcystins and nodularins, cyclic peptide liver toxins and tumor promoters from cyanobacteria is presented.

TL;DR: The PANI films have been characterized by absorption spectra which have maxima between 600 and 810 nm, except for halogenated or p-substituted anilines as mentioned in this paper.

TL;DR: In this paper, a simple method for rapid extraction and determination of ultra trace amounts of mercury(II) ions using octadecyl-bonded silica membrane disks modified with hexathia-18crown-6-tetraone and cold vapour atomic absorption spectrometry (CVAAS) is presented.

TL;DR: A Liquid Core Waveguide (LCW) can be used to extend the sensitivity of conventional absorbance spectroscopy by two or more orders of magnitude as discussed by the authors, and it has been shown that a 4.47m pathlength LCW made of Teflon AF-2400 provides a 0.2nmol−dm−3 detection limit and a linear response between 0.5 and 10nmol −m−m−3.

TL;DR: In this paper, the authors used capillary gas chromatography-mass spectrometry for the determination and detection of 50 substituted phenols with N -( t -butyldimethylsilyl)- N -methyltrifluoroacetamide (MTBSTFA) derivatives.

TL;DR: In this paper, a mixture of toluene and water is proposed for the microwave-assisted extraction of organic pollutants, hydrocarbons and pesticides from marine sediments, and the effect of experimental conditions, such as microwave power and irradiation time, on the extraction of linear, unresolved and polycyclic aromatic hydro-carbons as well as PCBs and DDTs has been evaluated using real marine sediment samples.

TL;DR: A novel method was developed based on interference with peroxidase activity, which caused a decrease of the rate of the coupling reaction of p-chlorophenol with 4-aminoantipyrine for spectrophotometric determinations of ascorbic acid, norepinephrine, epinephrine, dopamine and levodopa.

TL;DR: The analytical applicability of Schiff bases, 2-(3-pyridylmethyliminomethyl)phenol (compound 1), 2-(2-polycyclic diamine and enolimine) compounds, N,N′-bis(salicylidene)-2,3-polymorphic diamines (SDE), 2,6-polydimine (PPD), 2-amino-4-methox-ymethyl-6-methyl-3pyride methyl-3-methylinomet

TL;DR: In this paper, a sensitive, accurate and precise thermometric titration is described for the direct determination of ⩾75 mg of acetaminophen in pure form or in pharmaceutical formulations.

TL;DR: In this article, a multi-analyte imaging fiber sensor that allows pH, CO2 and O2 to be monitored simultaneously with rapid response is presented. But the sensor was used to monitor the pH and CO2 changes during a beer fermentation, and the working range is 0%-100% for O2 and 0%−10% for CO2 in the pH range 5.5-7.5.

TL;DR: In this paper, the authors proposed a method for the generation of recombinant Ab libraries, which will provide a huge repertoire, generated at the DNA level, for new Ab types with sufficiently different cross-reactivities.

TL;DR: In this paper, a waveguide surface plasmon resonance (WSPR) was used for the determination of simazine in water samples and the detection limit calculated as three standard deviations below the mean blank value was 0.2 μg l−1.

TL;DR: In this article, the self-quenching curve of dissolved organic carbon (DOC) was used to correct the inner filter effects caused by DOC, which complicate the interpretation of the partitioning coefficient of DOC to pyrene.

TL;DR: In this article, a new interface for coupling flow injection analysis (FIA) and capillary electrophoresis (CE) has been developed, which enables multiple injections so that a high sampling throughput can be achieved (up to 150 samples per hour).

TL;DR: Factors influencing the surface immobilization of the PNA probe, its hybridization to the p53 target sequence, and the chronopotentiometric detection step, are explored and optimized and hold promise for the diagnosis and management of cancer.

TL;DR: In this article, a Nafion®/ruthenium oxide pyrochlore chemically modified electrode was used for the simultaneous determination of caffeine and acetaminophen in drug formulations by square-wave voltammetry.

TL;DR: In this paper, thin layers of polyaniline are used to measure optically the pH in the range of 2-12 in the near infrared region and an absorbance drift lower than 1% per day (corresponding to about 30 titration) was observed.

TL;DR: In this article, an optical oxygen sensor was fabricated, based on the phosphorescence quenching of PtOEP, which responded in the range of 0.5 −100% O2.