Showing papers in "Analytica Chimica Acta in 1991"

TL;DR: In this article, a collision-activated dissociation (CAD) involving Fourier transform mass spectrometry (FTMS) is described, which can also be effected by application of a sustained (⩾ 500 ms) off-resonance (SORI) electric field pulse.

TL;DR: In this article, a review of neural networks in chemistry is presented, focusing on the back-propagation algorithm and its applications in spectroscopy, protein structure, process control and chemical reactivity.

TL;DR: In this article, a new method for peak purity control of liquid chromatography with photodiode array detection data is proposed, based on evolving factor analysis, which performs factor analysis on a moving window with a fixed number of spectra.

TL;DR: Amperometric biosensors based on two different reaction mechanisms are presented, each based on the combination of a selective enzymatic reaction with a selective mediated reaction that can be followed amperometrically at 0 mV vs. SCE and below.

TL;DR: The paper concentrates on the use of immobilized dehydrogenases, oxidases, peroxidases, and on electrodes on which these enzyme reactions can be selectively followed.

TL;DR: In this article, the Mg II 280.270-nm/Mg I 285.213-nm line intensity ratio is used to optimize the atomization and ionization processes in an inductively coupled plasma used as a source in atomic emission spectrometry.

TL;DR: In this article, a novel diffusion method was used for preparation of NH4+- and NO3−-N samples from soil extracts for 15N determination, where ammonium, and nitrate following reduction to ammonia, are allowed to diffuse to an acid-wetted glass filter enclosed in polytetrafluoroethylene tape.

TL;DR: In this paper, the cyclic voltammetric behavior exhibited by selected analytes (glucose, glycine, lactic acid, ethylamine and ethanol) at each of these electrodes was used to determine the optimum potentials suitable for flow detection so that the capabilities of the different metal electrodes could be evaluated and systematically compared.

TL;DR: There are three pH scales in general use and it is the aim of as discussed by the authors to make this fact recognized and to emphasize that the concept of pH is more complicated than might be thought (and to some extent also unsatisfactory).

TL;DR: In this article, the main advances in voltammetry are related to the deposition step which now normally utilizes deposition by adsorption rather than by plating, which suggests that equipment could now be usefully redesigned to provide fast wave-forms such as the high-frequency square-wave modulation as standard.

TL;DR: In this article, a method for the determination of total mercury in coal fly ash by gold amalgamation cold vapour atomic absorption spectrometry (CV-AAS) was optimized.

TL;DR: Enzyme heterobilayer-modified electrodes were fabricated by successively covalently binding to the surface of a tin(IV) oxide plate horseradish peroxidase (HRP), then an oxidase, which liberated hydrogen peroxide by reaction with the respective substrate.

TL;DR: In this paper, a procedure for the rapid, precise and accurate determination of CH3Hg+ in aqueous solutions is described, where in situ derivatization by NaB(C2H5)4 to CH3 hgC2 h5 and Hg(C 2 h5)2 results in easily chromatographed species, detected by quartz furnace atomic absorption spectrometry.

TL;DR: In this article, mixed monolayer films were prepared from ethanol solutions of ω-ferrocenylhexanethiol and simple C 4 C 10 n -alkanets.

TL;DR: An amperometric enzyme electrode for organic peroxides, based on the incorporation of horseradish peroxidase (HRP) into a carbon paste matrix, is reported in this paper.

TL;DR: In this paper, a critical but speculative review considers the detailed implications of operating enzyme electrodes in organic solvents and briefly examines the broader issues of optical, calorimetric and piezoelectric transduction coupled with both catalytic and affinity systems, such as nucleic acid probes and antibodies.

TL;DR: In this paper, the fluorescence enhancement reaction of terbium(III) with DNA or RNA in the presence and absence of phenanthroline (Phen) was studied.

TL;DR: In this article, the authors proposed to butylate the mercury species with a Grignard reagent to yield the non-polar dialkyl derivatives, and used a microwave-induced plasma emission detector to detect the methyl-and ethylmercury halides.

TL;DR: In this article, the molar absorptivity of the Fe(II)-ferrozine complex in methanol was 28.1 × 103 l mol−1 cm−1 at 562 nm.

TL;DR: An amperometric enzyme electrode incorporating horseradish peroxidase for the determination of hydrogen peroxide in organic solvents was described in this article, where the enzyme was co-adsorbed with an electron mediator, potassium hexacyanoferrate(II), on the surface of a graphite foil electrode.

TL;DR: In this article, the isotope distributions of polyisotopic elements are calculated by combining precalculated patterns of hypothetical atom clusters, which is a simple, easy-to-understand, highly accurate and extremely fast algorithm.

TL;DR: An amperometric biosensor for the detection and determination of organophosphate and carbamate pesticides is based on a cobalt phthalocyanine-modified carbon paste electrode covered with a cholinesterase enzyme membrane, which allows the repetitive use of an enzyme membrane.

TL;DR: In this paper, an optical sensor membrane for the determination of chloride was described, which incorporated trioctyltin chloride as an ionophore and a chromoinophore in a plasticized PVC matrix.

TL;DR: In this article, a linear correlation between the dissociation constants of polyaza and polyoxa-polyaza macrocyclic compounds was established between the acid forms obtained in deuterium oxide (p K D ) and in water ( p K H ).

TL;DR: In this paper, Electroanalysis of biologically important compounds, Electro analysis of biologically significant compounds, M.R.P., M.P.S., and M.M.S.

TL;DR: In this paper, the effects of concomitant variations in pH and organic modifier concentration on retention, efficiency and peak symmetry are considered for reversed-phase liquid chromatography (RPLC) on octadecyl-modified silica (ODS) columns.

TL;DR: In this article, a GC-MS with electron impact (EI), positive-ion chemical ionization (PCI) and negative-ION chemical ionisation (NCI) were applied as confirmatory techniques for residue analysis of chlorotriazine pesticides, their degradation products and organophosphorus pesticides in soil samples.

TL;DR: In this paper, an ion-sensitive field-effect transistor for sodium ions is described. Cahx[4]arene derivatives incorporated in a polyvinyl chloride-based membrane provide the selectivity.

TL;DR: In this paper, an electrosynthetic method for direct incorporation of antibodies into conducing polymeric coatings has been developed and the voltammetric behavior of an anti-human serum albumin (anti-HSA) containing electrode has been considered.