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W Faubel

Publications and source records attributed to W Faubel.

10 recordsLinked to original sources
PubMed2000

Capillary electrophoretic determination of dithiocarbamates and ethyl xanthate.

A simple and sensitive capillary electrophoretic method was developed for the separation and determination of sodium methyldithiocarbamate (metham), manganese ethylenebisdithiocarbamate (maneb) and ethyl xanthate in boric acid buffer by direct UV absorbance detection at lambda = 254 nm. The separation is dependent on pH and nature of the buffer. The detection limits (S/N = 3) are 1.7 x 10(-6) mol/L for ethyl xanthate, 1.3 x 10(-6) mol/L for metham and 2.1 x 10(-6) mol/L for maneb. The method has been successfully applied to the analysis of wheat samples spiked with maneb and in a commercial sample.

Anti-Infective Agents↗
PubMed1999

Capillary electrophoretic determination of ferric dimethyldithiocarbamate as iron(III) chelate of EDTA.

A simple and sensitive capillary electrophoretic method with UV detection has been developed for the determination of Ferbam (ferric dimethyldithiocarbamate) in boric acid buffer after its acidic decomposition and complexation with EDTA as Fe-EDTA- complex. The determination is dependent on the pH and the nature of the buffer solutions. In this method the detection limit (S/N = 3) is 1.8 x 10(-6) mol/L (0.7 mg/kg) of Ferbam. The relative standard deviation for the analysis of 50 microg/ml was found to be 2.9%. The method was successfully applied for the analysis of wheat grain samples spiked with Ferbam. The applicability of capillary electrophoresis as a useful tool for the analysis of Ferbam is demonstrated.

Calibration↗
PubMed1996

Trace analysis of pollutants in water using the photothermal interferometry as HPLC detector.

A new procedure including high performance liquid chromatography in combination with photothermal interference spectroscopy as detection device (HPLC/PIS) has been proposed, optimized and its figures of merit for pesticide residue analysis are shown. The flowing sample under study is set in one arm of a Mach-Zehnder interferometer, and its refractive index is modulated by a periodically chopped continuous wave argon ion laser. As chopper, an acousto optical modulator has been introduced to switch the excitation laser beam between different lines (457 nm, 488 nm, 514 nm) simultaneously. Thus a multi component analysis can be realized either by using an HPLC-system in front of the PIS device or by a multi line Ar(+)-laser, directly. The limit of detection of the HPLC/PIS system reached 71 microg/l of the pesticide di-nitro-ortho-cresol (DNOC).

Journal Article↗
PubMedDate not supplied

Miniaturized thermal lens device for capillary electrophoresis.

In this paper we will report on the combination of a miniaturized fiber optic modified photothermal sensor (size 2 x 2 x 2 cm) to capillary electrophoresis (CE) as detection device. The properties and the performances of the thermal lens detector, based on a double beam absorption scheme, were studied in a capillary electrophoresis system with different types of toxic pollutants, e.g. pesticides. A tunable Argon ion laser, which emits between 364 and 514 nm, was adapted to a commercial injection and high voltage CE system. The miniaturization of the thermal lens detector head with optical waveguides allows the combination with typical CE systems, therefore pesticides in microliter volumes can be treated. The detector performance is demonstrated with the monitoring of pesticides in capillaries with various diameter. The limit of detection is one of two orders of magnitude better than conventional absorption detector.

Electrophoresis, Capillary↗
PubMedDate not supplied

A review of capillary electrophoretic separations and their studies by nuclear magnetic resonance.

Capillary electrophoresis as a microvolume separation technique is receiving increased recognition for its use in the separation of inorganic and organic compounds due to its short analysis time and small sample volume in the nanoliter and picoliter ranges. The combination of capillary electrophoresis, one of the most-often employed chromatographic separation techniques, and studies by nuclear magnetic resonance (NMR) spectroscopy is finding an increased number of applications in pharmaceutical, biomedical, and polymer research. This paper discusses the applications of capillary electrophoresis for the separation of various analytes and their studies by NMR.

Carbohydrates↗