Showing papers in "Analytica Chimica Acta in 1978"

TL;DR: In this paper, a rapid carbamate extraction method with pyrrolidinedithiocarbamate (PDI) and diethyldithionic carbamate (DHC) was described for the simultaneous determination of Cd, Co, Cu, Fe, Ni, Pb and Zn in sea water by atomic absorption spectrometry with a graphite atomizer.

TL;DR: The dispersion of sample zones in Flow Injection systems is described by analogy with the mixing of fluids in large-scale chemical reactors as mentioned in this paper, which has resulted in a definition of the sample zone dispersion, its mathematical description, and the identification of the main parameters which can be used to effect the desired degree of mixing.

TL;DR: In this paper, a novel system of substructure codes is developed to characterize the spherical environment of single atoms and complete ring systems, which are automatically generated from topologically represented chemical structures and serve to describe structural entities corresponding to spectral parameters.

TL;DR: In this article, a method for the determination of chromium species has been developed and successfully applied to both fresh and sea water samples, which utilizes pre-concentration of total chromium, chromium(ni) and particulate chromium at natural pH with accurate and precise analysis by a single flameless atomic absorption procedure.

TL;DR: In this paper, a method for the determination in natural waters of selenite, selenate, dimethyl selenide, and dimethyl diselenide was described.

TL;DR: In this paper, an extraction system consisting of a pump, a rotary valve and a spectrophotometer is used to extract 12-25 µl of caffeine from a sample.

TL;DR: In this article, a nickel sulphide fire assay technique has been adapted to extract the noble metals from a large sample size (50 g) into a Nickel sulphide button, and then the fire assay button is dissolved in hydrochloric acid and the solution is filtered.

TL;DR: In this paper, the effects of various experimental conditions on the results obtained by using membrane filtration for the separation and fractionation of organic matter in fresh waters (mainly fulvic and humic substances) are described.

TL;DR: In this paper, the problem of pattern recognition in chemistry and other subjects can be divided conveniently into four different types depending on the level of scope of the problem: (1) classification into one of a number of defined classes.

TL;DR: In this paper, the authors developed a theory of error for target factor analysis, which predicts the magnitudes of these errors without requiring any a priori knowledge of the error in the data matrix or the target vector.

TL;DR: In this article, a phase-separation chamber and a proportional injector were used to determine molybdenum in plant ash solutions down to 0.05 ppm with good reproducibility and accuracy.

TL;DR: In this article, a simple expression relating the current at a rectangular channel-type flow-through electrode to the volume flow rate of solution, cell dimensions and physical constants is derived, valid for laminar flow with neglect of longitudinal depolarizer diffusion.

TL;DR: In this paper, the use of thiosemicarbazide and 1,10-phenanthroline as masking agents to minimize interferences from Cu, Ni, Pt, and Pd in the determination of arsenic by atomic absorption spectrometry in an argon-hydrogen flame by the hydride generation technique is reported.

TL;DR: The use of polyurethane foams for the separation and enrichment of inorganic and organic species in aqueous solution, and for the collection of pesticide vapours in air is discussed in this article.

TL;DR: In this article, a derivative potentiometric stripping analysis based on pre-concentration of metal analytes in a thin film of mercury on a glassy carbon electrode and subsequent measurement of the electrode potential subject to controlled transport of oxidant to the electrode surface is discussed.

TL;DR: The SLOWPOKE nuclear reactor as mentioned in this paper meets modern elemental analysis requirements; rapid multielement analysis of most types of samples is possible; the variable neutron flux (maximum 10 12 n cm -2 s -1 ) is stable, homogeneous and reproducible from day to day over a period of months.

TL;DR: In this article, the authors compared with conventional acid digestion procedures for the release of bound heavy metals in natural waters and in blood, before their determination by anodic stripping voltammetry.

TL;DR: In this article, a method for the selective determination of chromium( VI) and chromium (III) in sea water is described, where chromium is quantitatively extracted with Aliquat-336 from weakly acidic (pH 2) sample solutions.

TL;DR: In this article, reduced nicotinamide adenine dinucleotide (NADH) was oxidized coulometrically at a rotating platinum gauze electrode at 0.7 V vs. SCE at pH 9.

TL;DR: In this paper, the authors used a semipermeable membrane and a platinum electrode for determining alcohol, lactate, and glutamate sensitivity in the presence of phenazine methosulphate (PMS+) as intermediate.

TL;DR: In this article, the various arsenic species in a water sample are reduced to the corresponding hydrides, collected in a liquid nitrogen cold trap from which they are selectively vaporized and then swept directly through the sample port into a graphite furnace for detection.

TL;DR: In this article, the effect of room-temperature phosphorescence (r.t.p) on polynuclear aromatic hydrocarbons (PAH) was studied. But the results were limited to filter paper.

TL;DR: An automated precipitation sampler and an instrumental neutron activation analysis (i.n.a.) method for the determination of some major and trace elements in dry atmospheric fall-out and rain-water are presented in this paper.

TL;DR: In this article, an electrochemical double cell for the detection of cystine in aqueous liquid streams is described, where a column electrode of amalgamated silver powder is used to reduce cystines quantitatively to cysteine, which is detected amperometrically at a mercury electrode.

TL;DR: It is shown that in this application only two laboratory tests are necessary to obtain a sufficiently high diagnostic effectiveness when linear discriminant analysis is applied, and the optimal linear combination of laboratory tests obtained by means of linear discriminating analysis results in a better use of the information present in each test.

TL;DR: In this article, the construction and performance of an integrated on-chip reference field effect transistor (FET) was described, and it was shown that excellent temperature and noise compensation can be obtained with this arrangement.

TL;DR: In this paper, the construction and operation of ion-selective field effect transistors (ISFETs) with polymeric membranes are described, and their electrical and chemical performance are discussed.

TL;DR: In this article, aicotinic acid was determined by using immobilized Lactobacillus arabinosus and a combined glass electrode in agar-gel matrix.

TL;DR: SISCOM is especially suitable for detecting structural similarities like common substructures, even in cases where no similarity can be recognized by visual comparison of patterns or by human interpretation of the spectrum.