Juan Mora - Academia.edu (original) (raw)

Papers by Juan Mora

Journal of Analytical Atomic Spectrometry, 1991

The variations of the droplet size distribution, transport efficiency and absorbance which arise ... more The variations of the droplet size distribution, transport efficiency and absorbance which arise as a consequence of the addition of long-chain surfactants to aqueous solutions of Mn II were studied. The results show that the drop size distribution of the primary aerosol does ...

Fresenius Journal of Analytical Chemistry, 2000

Four different spray chambers were evaluated in ICP-AES at very low liquid flow rates: a double-p... more Four different spray chambers were evaluated in ICP-AES at very low liquid flow rates: a double-pass (Scott type), a conventional cyclonic, and two low-volume cyclonic-type spray chambers (i.e., Cinnabar and Genie). A glass concentric pneumatic micro nebulizer (Atom Mist) was used in conjunction with all four chambers. The liquid flow rate was varied from 10 to 160 μL min–1. The conventional cyclonic spray chamber gave rise to coarser tertiary aerosols, higher analyte and solvent transport rates, higher sensitivity and lower limits of detection than the remaining ones. The low-volume spray chambers afforded analytical figures of merit similar to the double-pass one, despite their very different designs. However, these spray chambers exhibited shorter wash-out times. The matrix effects were significant only for the double-pass. This fact allowed the analysis of reference samples by employing aqueous standards at a minimum level of sample consumption. The recoveries obtained for the cyclonic spray chambers and several certified samples were close to 100%, being always lower in the case of the double-pass spray chamber.

Analytica Chimica Acta, 1998

In the present work, a new¯ow injection analysis (FIA) manifold for the rapid determination of ch... more In the present work, a new¯ow injection analysis (FIA) manifold for the rapid determination of chemical oxygen demand is presented and evaluated. The FIA manifold combines sample digestion by means of an oxidant solution (i.e., potassium dichromate and mercury sulfate) and an acid solution (sulfuric acid and silver sulfate) in a domestic microwave oven with the liquid±liquid extraction of Cr(VI) with tributyl phosphate (TBP). Finally, the remaining (non-reduced) Cr(VI) is determined in the organic phase by atomic absorption spectrometry. The digestion of the organic matter is carried out in the stopped-¯ow mode. Potassium hydrogenphthalate has been used for optimization of the method and as a standard to check its performance. The optimized conditions (oxidation) are: digestion time, 7 min; acid concentration, 67% (v/v). The optimized conditions for the extraction of the remaining Cr(VI) are: acid concentration, !30% (v/v); TBP, 1 ml. The proposed method has been successfully applied, with the exception of pyridine, to several organic compounds and waters. A semi-micro method has been used for comparison. The application range extends from 40 to 12 000 mg O 2 l À1 , whereas the lowest limits of detection and quanti®cation are 13.5 and 45 mg O 2 l À1 , respectively. Following this method, the interference of Cl À can be compensated for at least up to 10 000 mg l À1 Cl À . Up to nine samples per hour can be analyzed. #

Journal of Analytical Atomic Spectrometry, 1997

Five nebulizers for use in ICP-AES were compared. Two of them work at low pressure, a Meinhard an... more Five nebulizers for use in ICP-AES were compared. Two of them work at low pressure, a Meinhard and a V-groove nebulizer (VGN), and three at high pressure, a single-bore high-pressure pneumatic nebulizer (SBHPPN), a hydraulic high-pressure nebulizer and a ...

Trends in Analytical Chemistry, 2003

Journal of Analytical Atomic Spectrometry, 1998

Spectrochimica Acta Part B-atomic Spectroscopy, 1999

. The analytical behaviour of an electrothermal vaporization ETV device for the introduction of m... more . The analytical behaviour of an electrothermal vaporization ETV device for the introduction of mineral acid Ž . solutions in inductively coupled plasma mass spectrometry ICP-MS was evaluated. Water, nitric acid, hydrochloric acid, perchloric acid and sulphuric acid in concentrations within the 0.05᎐1.0 mol l y1 range were studied. For all the acids tested, increasing the acid concentration increases the ion signal and deteriorates the precision. The magnitude of the signal enhancement depends on the analyte and on the acid considered. Acid solutions give rise to ion signals that are between 2 and 10 times higher than those with water. Among the acids tested, sulphuric acid provides the highest signals. The addition of palladium reduces matrix effects due to the acids and increases the signal in ETV Ž . ICP-MS. In comparison with conventional sample nebulization CS , the ETV sample introduction system provides Ž . higher sensitivities between 2 and 20 times higher at the same acid concentration. The magnitude of this Ž . improvement is similar to that obtained with a microwave desolvation system MWDS . The ETV sample introduction system gives rise to the lowest background signals from matrix-induced species. Due to this fact, the limits of Ž . detection LODs obtained for the isotopes affected by any interference are lower for ETV sample introduction than those obtained with the CS and the MWDS. For the isotopes that do not suffer from matrix-induced spectral interferences, the ETV gives rise to LODs higher than those obtained with the CS. For these isotopes the lowest LODs are obtained with MWDS. ᮊ 0584-8547r99r$ -see front matter ᮊ 1999 Elsevier Science B.V. All rights reserved. Ž . PII: S 0 5 8 4 -8 5 4 7 9 9 0 0 0 2 9 -4 ( ) J. Mora et al. r Spectrochimica Acta Part B: Atomic Spectroscopy 54 1999 959᎐974 960

Spectrochimica Acta Part B-atomic Spectroscopy, 2002

Journal of Analytical Atomic Spectrometry, 2002

J. Anal. At. Spectrom., 2002, 17, 142-169 DOI:10.1039/B009570M (Review). Elemental matrix effects... more J. Anal. At. Spectrom., 2002, 17, 142-169 DOI:10.1039/B009570M (Review). Elemental matrix effects in ICP-AES. José Luis Todolí*, Luis Gras, Vicente Hernandis and Juan Mora. Department of Analytical Chemistry, University of Alicante, PO Box 99, Alicante 03080, Spain. ...

Journal of Analytical Atomic Spectrometry, 1999

Page 1. Evaluation of several commercially available spray chambers for use in inductively couple... more Page 1. Evaluation of several commercially available spray chambers for use in inductively coupled plasma atomic emission spectrometry Salvador Maestre, Juan Mora, José-Luis Todolı and Antonio Canals* Departamento ...

Spectrochimica Acta Part B-atomic Spectroscopy, 1997

Analyst, 2000

The behaviour of a single-bore high-pressure pneumatic nebulizer (SBHPPN) as a tool for the analy... more The behaviour of a single-bore high-pressure pneumatic nebulizer (SBHPPN) as a tool for the analysis of lubricating oils by flame atomic absorption spectrometry (FAAS) was investigated. The effects of the sample oil content [from 10% to 100% (w/w) oil in 4-methylpentan-2-one, IBMK] and the carrier nature (IBMK and methanol) on the characteristics of the aerosols generated, on the analyte transport efficiency and on the analytical figures of merit in FAAS were studied. A pneumatic concentric nebulizer (PCN) was used for comparison. Increasing the oil content increases the viscosity of the sample. With the PCN this gives rise to coarser aerosols, making it impossible to nebulize samples with an oil content higher than 70% (w/w). Using the SBHPPN, the viscosity of the sample scarcely affects the characteristics of the primary aerosols. Hence, the SBHPPN is able, by using the appropriate carrier, to nebulize pure lubricating oils. Among the carriers tested, IBMK is the most advisable because it is fully miscible with all the oil samples. The SBHPPN provides higher sensitivities and lower limits of detection than the PCN. Compared with a method based on organic dilution, the use of the SBHPPN for the direct analysis of lubricating oils by FAAS makes it possible, in addition to increasing the analysis throughput, to detect elements at lower concentrations. Moreover, the SBHPPN provides similar results to those obtained using a previous acid digestion step.

el crecimiento del Producto Bruto Interno (P.B.I.) en el primer trimestre del presente año fue de... more el crecimiento del Producto Bruto Interno (P.B.I.) en el primer trimestre del presente año fue de 4.8% para el período interanual (Marzo 2013 -Marzo 2014) -con lo que se sitúa en un nivel un poco menor a los pronósticos, que eran de 5 % por lo menos-debido a la debilidad que vienen presentando las exportaciones.