Jesús de Mingo Sanz

Simultaneous determination of inorganic arsenic(III) and arsenic(V) by arsine generation and gas-phase molecular absorption spectrometry

Abstract A method of simultaneous determination of inorganic As(III) and As(V) is described, which involves arsine generation, measurement of the molecular absorption of arsine in the gas phase at 190 nm and quantification of As(III) and As(V) based on different heights and areas of absorbance versus time profiles of arsine generated from both inorganic species. The limits of detection were 0.5 μg of As(III) and 3 μg of As(V) in a sample volume of 1 ml. An interference study for both species was made and the method was applied to the determination of As2O3 and As2O5 in a standard glass sample.

Determination of selenium by hydride generation ultraviolet-visible molecular absorption spectrometry with diode-array detection

A method for the determination of selenium is described that involves hydrogen selenide generation by reduction with sodium tetrahydroborate(III) and subsequent transfer, using nitrogen as carrier gas, into a flow cell placed in a UV-visible molecular absorption spectrometer with diode-array detection. Quantitative determination is performed at 220 nm, taking 8 s for total hydride generation and measurement. The time required for two determinations is 30 s. The limit of detection obtained was 1.8 µg of SeIV in a sample volume of 2 ml and the calibration graph is linear from 10 to 150 µg of selenium in a sample of the same volume. The method has been applied to the determination of selenium in a health-care product.

Some observations on the determination of germanium using hydride generation-ultraviolet-visible molecular absorption spectrometry with a diode-array detector

Abstract In this paper a method for determining germanium by hydride generation-uv-visible molecular absorption spectrometry with diode-array detection is described. The molecular absorption maximum of germanium hydride appears to be outside the instrumental possibilities of the spectrophotometer and for this reason the determination is performed at 190 nm. Hydride generation and determination procedures are optimized and a linear response up to 200 μg is obtained. The method is used to determine germanium in an organogermanium compound. The sample is first halogenated and germanium is then extracted into NaOH aqueous solution.

Direct lead determination in wine by hydride generation-atomic absorption spectrometry

In this work, a method for direct lead determination in wine, without wet or dry sample attack, by lead hydride generation-atomic absorption spectrometry, is proposed. To do this, ammonium persulphate is employed as the oxidizing agent, and sodium borohydride is used as the reducing agent. The pH value must be 1.0.Lead content in wine is determined by the analyte addition technique, and the result is compared with those obtained by three different methods.

Some observations on the use of a hydride generation flame-heated silica tube atomic absorption spectrophotometric system for the determination of lead in wine

Abstract This paper presents a method for directly determining lead in wine by hydride generation-atomic absorption spectrophotometry. Lead hydride is generated from the wine matrix, using ammonium persulfate as the oxidizing agent and sodium borohydride as the reducing agent. The sample is not subjected to prior oxidation or other sample treatment. Lead hydride is atomized in a flame-heated silica tube. Optimum conditions for hydride generation are studied. Lead concentrations found in wine using this method agree with those from three Other methods.

Antimony determination by hydride generation — UV-visible molecular absorption spectrophotometry with diode-array detection

SummaryA method for antimony determination is described comprising hydride generation and transport into a flow-cell placed in a UV-visible molecular absorption spectrophotometer with diode-array detection. Nitrogen is employed as carrier gas. The measurement is performed at 198 nm. The calibration curve is linear from 3 to 440 μg/ml of antimony. The method was successfully applied to the analysis of PVC.

Sulphide Determination in Water by Gas-Phase Molecular Absorption Spectrometry

Abstract In this paper a method for determining sulphide in water by gas-phase molecular absorption spectrometry, is presented. To do this, sulphide is quantitatively transformed into hydrogen sulphide, and the volatiles absorbance is measured at 196 nm, which is the wavelength of maximum absorbance of H2S. Volatile generation is slow. To get a quick and quantitative transformation of sulphide into hydrogen sulphide it is necessary to add NaBH4. Concentrated perchloric acid generates the highest yield with the lowest black signal. The effect of other parameters modifying H2S signal is also studied The method presents a linear response range from 4 to 550 μg of sulphide with an accuracy of 2.2%. The effects of other sulphide-content species and water matrix were also tested. Finally, the method was applied to sulphide determination in natural water. The results agreed with those obtained using the “methylene-blue” method.

Some observations on the determination of boron in wine by flame emission spectrometry after methyl borate generation in a heterogeneous phase

Abstract In this paper a method for the determination of boron in wine by flame emission spectrometry after methyl borate generation is proposed. The sample is evaporated to dryness and the determination is carried out by generation of the volatile boron compound from the solid phase. In order to perform the generation, 0.1 ml concentrated sulfuric acid is added to the solid phase, the mix at 90 °C is heated for 3 min, and then 5 ml methanol is injected. Boron concentration obtained in the wine sample was compared with that obtained using the 1,1′-dianthrimide spectrophotometric method.