Showing papers in "Analytica Chimica Acta in 1987"

TL;DR: The concept of Vibronic Interactions was introduced in this paper, where it was shown that VIBR can be used in Chemical Reactions and Catalysis, as well as in Spectroscopy.

TL;DR: In this article, a set of descriptors that code the shapes of molecules by calculating the areas of three orthogonal projections is developed, and applied to a series of tests of their applicability on diverse problems in studies of structure/activity and structure/property relationships.

TL;DR: A method is described for quantifying individual absorbing species in mixtures of unknown composition that can be applied to the resolution of chromatographic peaks, to the evaluation of spectrophotmetric titrations, and to related methods producing ordered, two-dimensional arrays of data.

TL;DR: In this paper, the enhanced luminescence of europium in a thenoyltrifluoroacetone/1,10-phenanthroline/Triton X-100 system in the presence of terbium is studied.

TL;DR: In this paper, an ion-selective optrode for continuous determination of electrolytes is presented, which is based on the ability of certain fluorescent dyes to respond to an electrical potential at the interface between a lipid phase and an aqueous phase.

TL;DR: The total fluorescence of human urine was measured at various excitation and emission wavelengths and presented in 3-dimensional form as mentioned in this paper, showing that 3-5 distinct fluorescence maxima can be observed.

TL;DR: A portable, automated spectrophotometric field monitor for the determination of total ammonia in river water was described in this article, which was designed to operate unattended for a minimum of one week, after which the reagent solutions (bromothymol blue and sodium hydroxide) and the standard solutions were renewed and the teflon gas-diffusion membrane replaced.

TL;DR: Chemistry for the protection of the environment 4, Chemistry for the preservation of the natural environment 4, 4, 4, 5, 6, 7, 8, 9, 10, 11, 12,

TL;DR: In this article, a double-beam photometric detector incorporating light-emitting diodes and photodiodes in enclosed in a 20-cm 3 box is described for the determination of phosphate in natural waters.

TL;DR: In this paper, the slope of the linear portion of the frequency shift/electrolyte concentration plot for a AT-cut quartz piezoelectric crystal immersed in a solution is dependent on the circuit capacitance, decreasing from positive to negative values with increasing capacitance.

TL;DR: In this article, the Fourier-transform ion-cyclotron resonance mass spectrometers were used for desorption of industrial polymers and carbohydrates, and the time-of-flight and Fourier transform ion-cycle resonance (FOTI-CRS) mass analyzer was used for de-noising polymers.

TL;DR: In this paper, a procedure for the on-line preconcentration of cobalt in water samples was developed under the guidelines presented, and an enrichment factor of 48 was achieved at a sampling frequency of 60 h−1 with good recoveries for all the water types studied.

TL;DR: In this article, size exclusion chromatography (SEC) is used as a clean-up procedure after extraction of pesticides with the compatible solvent ethyl acetate, achieving better than 90% recovery for oranochlorine and organophosphorus pesticides, fungicides and chlorobiphenyls.

TL;DR: In this paper, a bilayer electrode coating, with a cellulose acetate film over the Nafion layer, offers a bifunctional (selectivity, protection) capability.

TL;DR: Ion chromatography is used to determine the concentrations of organic (formate, acetate and methanesulphonate) and inorganic (fluoride and ammonium) ions present in Antarctic ice at less than 10−9 g g−1 levels as mentioned in this paper.

TL;DR: In this paper, an automated atomic absorption method involving high-performance liquid chromatographic separation of the arsenic species and continuous hydride generation is described for the determination of arsenite, arsenate, DMA and MMA at μg As l−1 levels.

TL;DR: In this paper, an automatic stopped-flow system featuring a mixing module and real-time data collection and treatment is presented, which is compatible with a number of spectrophotometers and spectrofluorimeters.

TL;DR: In this paper, several procedures for immobilization of pyruvate oxidase by chemical bonding are reported, including polyazetidine, a commercially available prepolymer and a new nylon membrane with surface carboxyl groups provided good longterm stability, up to 30 days in the case of the nylon membrane.

TL;DR: An automated flow-injection system with gas diffusion separation and preconcentration and spectrophotometric detection is described for the determination of total cyanide in waste waters in this paper, where an unstable red intermediate product of the reaction of cyanide with isonicotinic acid and 3-methyl-1-phenyl-2-pyrazolin-5-one is used instead of the conventional blue final product to improve the efficiency.

TL;DR: In this paper, a computerized conductometric procedure for the determination of stability constants of crown ethers with alkali metal salts in polar solvents is described, based on a microcomputer-controlled titration system.

TL;DR: In this article, carbon fiber flow electrodes suitable for use in connection with potentiometric and constant-current stripping are described, and the fibre electrodes are compared with a glassy carbon disc thin layer cell.