Showing papers in "Analytica Chimica Acta in 2001"

TL;DR: In this article, the authors developed and tested a sequential extraction procedure (SEP) for As by choosing extraction reagents commonly used for sequential extraction of metals, Se and P, including NH 4 NO 3, NaOAc, NH 2 OH·HCl, EDTA, NH 4 OH and NH 4 F, were shown to either have only low extraction efficiency for As, or to be insufficiently selective or specific for the phases targeted.

TL;DR: In this article, a new approach to the error sources in the spectrophotometric determination of total phenols in foods has been performed and the choice of the suitable phenolic standard and the influence of sugars and proteins as interfering compounds were carefully studied.

TL;DR: In this paper, a cloud point extraction (CPE) was used for the simultaneous pre-concentration of cadmium, copper, lead and zinc after the formation of a complex with 1-(2-thiazolylazo)-2-naphthol (TAN), and later analysis by flame atomic absorption spectrometry (FAAS) using octylphenoxypolyethoxyethanol (Triton X-114) as surfactant.

TL;DR: In this paper, the bismuth-coated electrode is shown to be prone to errors caused by the formation of Cu-Zn intermetallic compound, that can be circumvented by the addition of gallium, in a manner analogous to mercury film electrodes.

TL;DR: In this article, the use of sensor arrays and pattern recognition applied to the obtained signal patterns for environmental monitoring is discussed in some detail, and different types of electronic tongues are described and evaluated for monitoring purposes.

TL;DR: In this paper, a survey of systems from the literature revealing that the Freundlich isotherm gives a good mathematical approximation of the binding characteristics for non-covalently imprinted polymers.

TL;DR: In this paper, a new scheme for the simultaneous separation of lead and strontium is described and applied to the determination of isotope ratios in silicate samples, based on the selectivity and high capacity of the extraction chromatographic material referred to as Sr. This method affords a straightforward separation of Sr and Pb on 150μl columns, with high Pb yield (>96%), good purity and satisfactory blank levels, using small volumes of mineral acids (HNO 3 and HCl) easy to purify by sub-boiling distillation.

TL;DR: In this article, the thermal and chemical stability of a theophylline imprinted methacrylic acid-ethylene glycol dimethacrylate co-polymer has been investigated.

TL;DR: In this article, a multivariate calibration procedure using partial least squares (PLS) regression was developed to establish a relationship between reflectance spectra in the visible-near-infrared (VNIR) region and spectrally active soil characteristics (organic matter and clay content) that are inter-correlated with concentration levels of Cd and Zn.

TL;DR: In this article, the decomposition of H 2 O 2 catalyzed by transition metal ion has been investigated by chemiluminescence (CL) using a heterogeneous catalyst, Co(II)-monoethanolamine complex immobilized on Dowex-50W resin.

TL;DR: A critical review of historical and current analytical methods for the determination of iron in seawater is presented and their capabilities evaluated in this article, where the need for standard protocols for the clean sampling and storage of low-level (<1 nM) iron seawater in order to maintain sample integrity is emphasised.

TL;DR: In this article, a specific set-up using a pulsed laser focussed with a tilted angle on the surface of the liquid is presented, which allows on-line quantitative measurements with good reliability and reproducibility.

TL;DR: In this paper, the authors used stirrers 10mm long coated with 55μl polydimethylsiloxane (PDMS) to determine polycyclic aromatic hydrocarbons (PAHs) from water samples.

TL;DR: A nonionic polymeric adsorbent styrene divinylbenzene, Amberlite XAD-4 was functionalized with o-vanillinsemicarbazone and its analytical properties have been studied as mentioned in this paper.

TL;DR: In this article, cloud point extraction has been used for the preconcentration of cobalt and nickel, after the formation of a complex with 1-(2-thiazolylazo)-2-naphthol (TAN), and later analysis by flame atomic absorption spectrometry using octylphenoxypolyethoxyethanol (Triton X-114) as surfactant.

TL;DR: In this paper, a two-step method for constructing cholesterol biosensors by entrapment of cholesterol oxidase (ChOx) within a composite poly(2-hydroxyethyl methacrylate) (p(HEMA))/polypyrrole (p pyrrole)) membrane has been developed.

TL;DR: In this article, three classical methods such as forward selection, backward elimination and stepwise regression; orthogonal descriptors; leaps-and-bounds regression and genetic algorithm were performed.

TL;DR: Low-cost, renewable graphite transducers provide an attractive alternative to conventional carbon electrodes used for transducing DNA hybridization and hold promise for decentralized genetic testing.

TL;DR: In this paper, a flow injection analysis of paracetamol was developed based on its inhibitory effect on a luminol-permanganate chemiluminescence system.

TL;DR: In this article, the puerarin extraction from Radix puerariae under different microwave processing conditions was compared and it was shown that the microwave irradiation did not destroy the structure or molecule of the Puerarin.

TL;DR: The experimental results reveal that the reduced form (H2N OM)red, of NOM is bound more strongly to DNA than the oxidised form (NOM)ox, and a slight change in chemical structure causes significant changes in the binding affinity to DNA and consequently in clinical properties.

TL;DR: In this article, the p K a values of 25 structurally diverse drug compounds including mono-, di-and tri-protic molecules were determined by a recently developed multi-wavelength spectrophotometric technique, called dip-probe absorption spectroscopy (D-PAS), and the traditional titration.

TL;DR: A review of the literature concerning the use of acidic solutions of potassium permanganate to generate chemiluminescence during the oxidation of both organic compounds and inorganic species is presented in this paper.

TL;DR: A glassy carbon electrode was modified with electropolymerized films of sulfosalicylic acid in pH 5.5 phosphate buffer solution (PBS) by cyclic voltammetry.

TL;DR: In this article, a maximum capacity of ca. 40μm-pH−1/ml−1 was found at pH 10.2 when [Mg2+] was 0.045m.

TL;DR: In this article, a new type of silica sol-gel/organic hybrid composite material was developed for the fabrication of an amperometric H2O2 biosensor, which was used to immobilize horseradish peroxidase on a carbon paste electrode.

TL;DR: The most common form of imprinted polymers is the irregularly shaped particle obtained by grinding the traditional, macroporous polymer monolith as mentioned in this paper, which has been used for many applications.

TL;DR: A disposable electrochemical DNA biosensor for the determination of toxic aromatic amines has been developed in this article, which relies on the intercalative or electrostatic collection of aromatic amine onto an immobilized dsDNA or ssDNA layer (obtained from several sources), followed by a chronopotentiometric analysis.

TL;DR: The nearly exponential growth in the molecular imprinting literature has to a large extent been fuelled by an increasing awareness of the potential of molecular imprintings based technologies as discussed by the authors. But despite the acceptance of the technique by cognate disciplines and the demonstration of its usefulness in a number of enabling technologies, relatively little is known about the molecular level events underlying the imprinting process.

TL;DR: In this article, a microcolumn packed with nanometer TiO 2 as solid phase extractant has been developed for the simultaneous preconcentration of trace amounts of Cu, Mn, Cr and Ni prior to their measurements by inductively coupled plasma atomic emission spectrometry (ICP-AES).