Showing papers in "Analytica Chimica Acta in 1988"

TL;DR: In this paper, a U-tube chromatographic column with 15% OV-3 on Chromosorb WAW-DMSC, held at −196°C in liquid nitrogen, was used to preconcentrate alkylmercury compounds.

TL;DR: In this paper, a simple opto-electronic device is described for measuring lifetimes of a long-lived fluorophore with a frequency-modulated LED as light source.

TL;DR: In this paper, the authors found that the maximum sensitivity is obtained for a silver layer about 55 nm thick in direct contact with the species to be quantified, corresponding to ca. 10−10 mol1−1 antibody.

TL;DR: In this article, an alternative substrate for enzyme immunosaasay with electrochemical detection was described, where p-aminophenyl phosphate was used as the enzyme substrate and a detection limit of 30 pg ml-1 for digoxin and a 5min incubationtime for the enzyme reaction were obtained.

TL;DR: In this paper, an enzyme electrode that operates in chloroform was described, which is used to detect p-cresol via electrochemical reduction of the product, 4-methyl-1,2-benzoquinone, at a graphite foil electode.

TL;DR: In this paper, the certification of a second-generation biological reference material (freeze-dried human serum) for trace element determinations is described, which was prepared under rigorously controlled conditions to avoid extraneous additions.

TL;DR: In this article, the copper (I)-DMP complex was determined directly by spectrophotometric measurement at 454 nm, at concentrations in the range 1−120×10−6 mol l−1.

TL;DR: In this article, a comparison of the oscillation behavior of a piezoelectric quartz crystal immersed in various liquid systems of analytical interest including organic liquids, water/organic mixed solvents and aqueous solutions of various electrolytes, with a transistorized oscillator was made.

TL;DR: In this paper, the performance of a sodium-selective electrode based on the ligand methyl p-t-butylcalix andaryl acetate, one of a new series of ionophores, is described.

TL;DR: In this article, the development of methods for finding the equivalence volume by using linear regression methods is reviewed, mainly those developed and used at the Department of Analytical Chemistry at the Royal Institute of Technology in Stockholm.

TL;DR: In this article, the catalytic effect of the formazone complex with platinum on the development of hydrogen at a mercury electrode is used to provide a very sensitive method of determining dissolved platinum in fresh and sea water by adsorptive cathodic stripping voltammetry.

TL;DR: In this paper, the role of surface cleanliness in glassy carbon electrode activation is discussed. But the authors focus on simple electron-transfer reactions, where removal of contaminants from the electrode surface is important.

TL;DR: In this article, the impact of analytical errors on the determination of metal complexation parameters of natural waters by metal titration procedures based on cathodic stripping (CSV) or anodic stripping voltammetry is investigated by means of computer simulation.

TL;DR: In this article, a chemically modified electrode is constructed by incorporating zeolites into a conventional carbon-paste mixture, and the surface is renewed by placing the electrode in a sodium carbonate solution.

TL;DR: In this article, the best approach for total rocks and minerals was found to be alkaline fusion, where boron in silicates was rendered chemically reactive by fusion with potassium carbonate, the fusion cake was extracted with water and borate was isolated by Amberlite XE-243 selective resin.

TL;DR: In this paper, a piezo-electric quartz crystal is used to monitor viscosity changes in a liquid, and the gelation time is computed by using an approximation to a polynomial equation from the resistance or the resonance frequency change.

TL;DR: The proceedings of the Sixth International Conference on Secondary Ion Mass Spectrometry (SIMS VI) held in Paris in 1987 are described in this article, covering basics, instrumentation, quantification, ion imaging, depth profiling, organics, combined techniques, surfaces, and several applications.

TL;DR: In this article, the chelating characteristics of Chelex-100 resin were studied for selected heavy metals in seawater medium, and the results of batch equilibrium and breakthrough experiments showed that the metal-chelating efficiency of the resin is lower in seawATER than in freshwater.

TL;DR: In this article, the authors present the reader with the points of view of both the creator and user of modern computer program tools available for the study of solution equilibria, and discuss a variety of programs, one at a time, including the parts of the program, the types of problems to which it was applied, and the program's limitations.

TL;DR: In this article, the effects of operating parameters on the ammonium concentration in the acceptor line of the gas-diffusion unit are discussed and experimentally verified on the basis of a simple diffusion model, and several flowinjection methods are examined critically for their suitability for determing submicromolar levels of ammonium ion on a routine basis.

TL;DR: The proposed simultaneous determination of thiols and disulfides requires 4- (aminosulfonyl)- 7-fluor-2,1,3,3,-benzoxadiazole-4-sulfonate (ABD-F) as the pre-column derivatization reagent for thiolS and ammonium7-fluoro-2-1, 3,3,.

TL;DR: In this article, the activation energy of a photon has been shown to be around 30'MeV with respect to analytical sensitivity and interfering reactions, respectively, and this energy is best achievable with bremsstrahlung sources like high-power linear accelerators or microtrons.

TL;DR: In this paper, the ion-exchanger located in the flow cell of an unsegmented flow system is applied to the determination of copper(II) based on the formation of a colored chelate with 1-(2-pyridylazo)-2-naphthol retained on Dowex 50W resin.

TL;DR: In this paper, the Chromatographic Process Detection in Quantitative Liquid Chromatography Quantitative Analysis by Quantitative Gas Chromatography and Quantitative Thin-Layer Chromatography Chromatography as a Quantitative Tool in Pharmaceutical Analysis Is Automation the Future of Quantitative Chromatography?

TL;DR: In this paper, the authors measured molar absorptivities at 11 wavelengths between 200 and 300 nm for H 2 O 2 (aq) with an average error of 8.5% (95% confidence limit), and at 10 wavelengths in the same range for HO 2 − (aq), from absorbance vs. concentration plots.

TL;DR: In this paper, various improvements in flow-injection systems involving on-line separation and preconcentration by gas diffusion, ion-exchange and liquid-liquid extraction are reviewed and their merits are discussed.