F Bermejo Martínez

Spectrophotometric determination of molybdenum with thiocyanate and pyrogallol

Abstract A new extraction-spectrophotometric method for Mo determination with thiocyanate and pyrogallol in MIBK is reported. The mixed ligand complex obeys Beers law between 0.04 and 1 μg of Mo/ml and molar absorptivity is 100,000 liters · mol −1 · cm −1 . The absortion spectra and the effects of acidity, amount of reagents, time, and temperature are also studied, together with the stoichiometry of the complex, the reproducibility and precision of the method, and the susceptibility to interference of the common ions.

Determination of cesium in mineral and thermal waters by electrothermal atomic absorption spectrophotometry

Abstract A new procedure for the determination of cesium in mineral and thermal waters using electrothermal-atomic absorption spectrophotometry is described. The cesium is atomized at 2500 °C in 0.2% nitric acid medium. Cesium can be determined in the presence of SO42−, CO32−, F−, S2−, Mg2+, Li+, Ca2+, Sr2+, Rb+, Al3+, Co3+, and Fe3+ at levels higher than those of these ions in water. The precision and accuracy of the method were also investigated. In 163 mineral and thermal waters analyzed the cesium concentration range is between 4.5 and 148 μg liter−1.

Extractive Spectrophotometric Determination of Cobalt (II) as Ion Association Complex with Thiocyanate and Ephedrine

Abstract A new spectrophotometric method to determine cobalt(II), based on extraction into methyl-isobutyl—ketone at pH 4.0 of its Ephedrine-Co (II)-SCN− association ionic compound, is proposed. the organic extract shows an absorption band at 620 nm, having a molar absortivity coefficient of 4.3. 103 L. mol−1. cm−1. Beers law is obeyed in the 0.5–19.5 μg Co (II)/mL concentration range. the variation coefficient is 0.32 % for ten determinations at the concentration level of 8.8 ppm of cobalt (II).

Spectrophotometric determination of bismuth with N,N′-bis(2-hydroxyethyl)glycine

Abstract Bismuth(III) can be determined with N,N′-bis(2-hydroxyethyl)glycine as complexometric agent in the pH range 7–8.5. Beers law is obeyed from 1 to 70 μg ml−1 of bismuth with a minimum photometric error of 2.7%; the molar absortivity is 4.4 × 103 liters mol−1 cm−1. The stoichiometric ratio of bismuth(III) to N,N′-bis(2-hydroxyethyl)glycine is 1:2. The proposed method has been applied to the determination of bismuth in pharmaceutical formulations, with good results.

Direct determination of molybdenum in mineral waters by atomic absorption spectrometry with electrothermal atomization

A new method for the direct determination of molybdenum by ETA-AAS in mineral waters without prior separation or concentration is proposed. With careful control of the graphite furnace conditions selective volatilization of the salt matrix is successfully attained. The possible spectroscopic interference due to common metals as well as the reproducibility, precision and repeatability of the method has been studied and the molybdenum content of 21 mineral waters measured.

Spectrophotometric determination of iron with EDDHA (ethylenediamine N N bis o-hydroxyphenilacetic acid) by derivative spectroscopy

Abstract Derivative spectrometry is applied to a spectrophotometric determination of iron with EDDHA. the effect of amount of reagent, acidity, time and temperature have also been studied. the interval of application of the method is increased to 0.16–15.36 μg Fe(III) mL−1. the reproducibility, precision and potential interferents have been investigated. the interferences due to chlorate, wolframate, molybdate, permanganate, cyanide, cromate, Cu(II), Be(II), Ce(III), Al(III), Hg(II), Sn(II) and Zn(II) are reduced in this new procedure.

Rubidium determination in mineral and thermal waters by atomic-absorption spectrometry

Abstract A new procedure for rubidium determination in mineral and thermal waters using flame atomic-absorption spectrometry is described. to supress ionisation interference potassium solution was added. Rubidium can be determined in presence of Ca, Mg, Sr, Li, Cs, Fe, Al, CO2 3, F− and S2− at higher levels that levels of these elements in waters. the precision and accuracy of the method were also investigated. In 163 mineral and thermal waters analysed, the rubidium concentration range is between 0.08 to 0.84 μg mL−1.