Showing papers in "Microchemical Journal in 1990"

TL;DR: Positron annihilation spectroscopy for chemical analysis (PASCA) has been developed to analyze the microstructure of polymers as discussed by the authors, where the positronium atom is trapped in the atomic-scale holes which have a size ranging from 1 to 10 A. Theoretical aspects, experimental developments, and examples in analyzing the microstructures of epoxy, PEEK, and PMMA polymers are presented.

TL;DR: In this paper, a series of electrochemical and Raman studies were undertaken to investigate the effects of orientation of electroactive species on their electrochemical behavior, and the experimental results indicated that the systems studied show varied behavior and a complex interaction of the important variables operative during electrochemical processes.

TL;DR: The binding of six tetracyclines to borosilicate glass or polypropylene test tubes was studied in vitro, and the binding was mostly due to surface area as mentioned in this paper.

TL;DR: The capacitor theory as mentioned in this paper emphasizes the importance of the electrode surface, the double layer, the adsorption of both cations and anions on the zwitterionic surfaces, the surface active sites, the charge density, the role of anions, etc.

TL;DR: Cerium (IV) in the forms (NH 4 ) 2 Ce(NO 3 ) 6 and Ce (IV)-Pd (II) has been evaluated as a chemical modifier for 24 and 17, respectively, analyte elements of high and moderate volatility.

TL;DR: In this paper, a spectrophotometric procedure is proposed for the determination of total free amino acids after reaction with o-phthalaldehyde and N-acetyl- l -cysteine, using isoleucine as the reference.

TL;DR: The ion-pair associates E-BTB and E-MTB were subsequently utilized for assaying erythromycin in two dosage forms and exhibited absorption maxima at 415, 430, and 550 nm, respectively.

TL;DR: In this paper, a spectrophotometric method for the determination of rutin was developed, based on the oxidative coupling of Rutin with 3-methylbenzthiazolinone-2-hydrazone using acidic ceric ammonium sulfate as the oxidizing agent.

TL;DR: In this article, the authors applied the oxidative coupling reaction of promethazine · HCl with primary aromatic amines to the determination of aniline and four of its substituents.

TL;DR: In this paper, a sensitive procedure for the determination of hydrazine in air is described, in which the air is absorbed in acidified vanillin solution which is coupled with water, forming a yellow aldazine dye, which exhibits a maximum absorbance at 400 nm.

TL;DR: Spectrophotometric quantitative determination of amines and sulfa drugs via interaction with p -benzoquinone was extended to determination of amino acids, whereby the colored products obtained display maximum absorption at λ = 490-500 nm, E 1 cm 1% in the range 160-480, and a concentration range of 1.5-34.0 μg/ml.

TL;DR: In this article, the interfacial and redox behavior of lorazepam at the hanging mercury drop electrode was studied by adsorptive stripping voltammetry, and linear and differential pulse scan modes were used to record the stripping curves.

TL;DR: An indirect method for the determination of iodine as iodide by continuous flow cold-vapor generation of mercury and atmospheric pressure helium microwave induced plasma atomic emission spectrometry (MIP-AES) is described in this article.

TL;DR: In this paper, an accurate and simple spectrophotometric method for the determination of novalgin has been developed, which is based on reduction of iron(III) with NOVG and subsequent complexation of IR with 1,10-phenanthroline.

TL;DR: In this paper, the use of derivative absorption spectrophotometry has been applied to the direct determination of carbaryl and carbofuran in water samples, and a limit of detection of 4 ppb and a variation coefficient of 0.1% have been obtained for carbaryl.

TL;DR: A method for the determination of Thiram in waters and formulations using HPLC with amperometric detection on a carbon paste electrode is reported in this article, which has a detection limit of 2.7 ng injected for an injection volume of 20 μl.

TL;DR: In this article, a simple method for the determination of N -penicillamine based on the formation of a yellow complex with Co(II) is proposed, which can be easily adapted for flow injection analysis, the peak height being proportional to the drug concentration over the 10 −4 −2 × 10 −3 M range.

TL;DR: In this article, a well-defined cathodic wave was produced over the entire pH range 5-10, and the wave was characterized as being diffusion-controlled, although adsorption phenomena played a limited role in the reduction process.

TL;DR: In this paper, the current potential response of a very small interface formed between two immiscible solutions of electrolytes is examined, and the diameter of the contact area between two solvents is 50 to 300 μm.

TL;DR: In this paper, a method for determining germanium by hydride generation-uv-visible molecular absorption spectrometry with diode-array detection is described, which is performed at 190 nm.

TL;DR: In this paper, a low capacity silica-based column was used for the separation with 5m M potassium hydrogen phthalate (pH 4.3) as the mobile phase.

TL;DR: In this article, a sensitive method for the determination of micro-amounts of cobalt by ion-exchanger spectrophotometry has been developed, where the chromogenic agent, Nitroso-R-Salt (NRS), was loaded on an anionic-exchange resin (Amberlite CG-400).

TL;DR: A new mapping and display technique, which depends upon high-resolution computer graphics for the presentation of results, was used to develop relationships between gas chromatograms of hexane soaks obtained from red carpenter ants.

TL;DR: In this article, a sample-introduction method for flame-atomic absorption spectrophotometry is described, where solutions of trifluoroacetyl acetonate complexes of chromium, cobalt, and iron are volatilized, and then atomized in a heated silica tube connected directly to the generation apparatus.

TL;DR: A new spectrophotometric determination of parathion-methyl using guaiacol as a new reagent is described in this article, which is based on the reduction of the nitro group present in p-methyl with zinc/HCl to form amino-parathionmethyl.

TL;DR: In this article, the Whatman No. 1 chromatography paper is wetted with 0.5 M CdCl 2 solution and then dried, and the intensity of luminescence can be correlated with hydrogen sulfide concentration.