[Determination of copper, magnesium and zinc in mononuclear leukocytes by flame atomic absorption spectrometry]. / Determinación de cobre, magnesio y zinc en leucocitos mononucleares mediante espectrometría de absorción atómica con llama.

In this paper we evaluated a new micro-flow injector for the determination of the concentrations of Cu, Mg and Zn in mononuclear blood cells. This device analyzed sample volumes in the order of microliters by flame atomic absorption spectrometry; it is inexpensive, and easy to build and to adapt to the conventional injector of the atomic absorption spectrophotometer. Detection limits of 106, 65 and 37 microg L(-1) for Cu, Mg and Zn were obtained, respectively. The percentages of recovery tests were found between 98 and 110%.

Determination of selenium and iodine in human thyroids.

This study focuses on the determination of selenium and iodine in human thyroids. The glands were digested using nitric acid in a microwave oven. Selenium was determined by inductively coupled plasma optical emission spectrometry (ICP-OES) using a new sample introduction system consisting of a reduction system coupled to a hydride generation nebulizer (DHGN). Iodine was determined by using the Sandell-Kolthoff procedure. The detections limits were 0.2 ng/mL and 0.3 ng/mL for the determination method of selenium and iodine, respectively. The amount of iodine in the whole gland was 3.44 +/- 1.11 microg/g. The lowest iodine level was 2.34 microg/g and the highest 5.21 microg/g. The lowest selenium concentration for a single sample was 505 +/- 51 ng/g and the highest 1495 +/- 204 ng/g depending on the fraction of the gland selected.

Determination of normal human intrathyroidal iodine in Caracas population.

This study focuses on the determination of iodine content in healthy thyroid samples on male population from Caracas, Venezuela. Contribution to establish a baseline of iodine content in thyroid glands and hence to compare the iodine thyroid concentration of the Venezuelan population with other countries is also our objective. Male post-mortem individual samples were analyzed using a spectrophotometric flow injection method, based on the Sandell-Kolthoff reaction. The median intrathyroidal iodine concentration was 1443+/-677 microg/g (wet weight), ranging from 419 to 3430 microg/g, which corresponds to a median of total iodine content of 15+/-8 mg (ranging from 4 to 37). These results were higher than those values reported in the literature. No correlation of iodine content with age or weight of the healthy gland was found.

Determinación de cobre, magnesio y zinc en leucocitos mononucleares mediante espectrometría de absorción atómica con llama / Determination of copper, magnesium and zinc in mononuclear leukocytes by flame atomic absorption spectrometry

En este trabajo se evaluó un nuevo microinyector de inyección en flujo para la determinación de Cu, Mg y Zn en células mononucleares de la sangre. Este dispositivo permitió analizar muestras en el orden de microlitros mediante espectrometría de absorción atómica con llama, es fácil de construir y adaptar al inyector convencional del espectrofotómetro de absorción atómica. En la determinación de Cu, Mg y Zn se obtuvieron límites de detección de 106, 65 y 37 µg L-1,respectivamente. En las pruebas de recuperación de estos elementos en leucocitos mononucleares se encontraron porcentajes de recuperación entre 98 y 110%.

In this paper we evaluated a new micro-flow injector for the determination of the concentrations of Cu, Mg and Zn in mononuclear blood cells. This device analyzed sample volumes in the order of microliters by flame atomic absorption spectrometry; it is inexpensive, and easy to build and to adapt to the conventional injector of the atomic absorption spectrophotometer. Detection limits of 106, 65 and 37 µg L-1 for Cu, Mg and Zn were obtained, respectively. The percentages of recovery tests were found between 98 and 110%.

Investigation of the direct hydride generation nebulizer for the determination of arsenic, antimony and selenium in inductively coupled plasma optical emission spectrometry.

A direct hydride generation nebulizer (DHGN) was explored for introduction of the sample in inductively coupled plasma-optical emission spectrometry (ICP-OES) using radially viewed mode. This simple hydride generation system was constructed in our laboratory and requires similar plasma operating conditions to conventional nebulizer-spray-chamber arrangements. This work was focused on the optimization of the operating conditions for hydride generation and evaluation of the main analytical figures of merit for the determination of As, Sb and Se. The excitation conditions of the ICP-OES instrument operated with the DHGN were also explored. Results showed that the analytical performance of the new system for the determination of As, Sb and Se was superior to that of conventional nebulization systems. The DHGN also enabled the determination of elements that do not form volatile hydrides, but with less sensitivity than conventional nebulization systems. Evaluation of the plasma robustness showed that gases generated in hydride generation do not significantly affects the plasma discharge. Similar to conventional hydride generation techniques, analysis with DHGN was susceptible to non-spectroscopic interferences produced by transition metals. Finally, the utility of the DHGN in practical ICP-OES studies was demonstrated in the determination of trace elements in an oyster tissue standard reference material.

Simultaneous determination of lead, nickel, tin and copper in aluminium-base alloys using slurry sampling by electrical discharge and multielement ETAAS.

The simultaneous multielement determination of Pb, Sn, Ni and Cu in aluminium alloys by electrothermal atomic absorption spectrometry (ETAAS) was performed by a quick method using slurry sampling. The metallic colloidal slurries were obtained by an electrical discharge operated in liquid medium. In this work, the effects of aluminium were evaluated and the results show that it causes a strong retention of Pb, Ni and Cu at low pyrolysis temperatures which is overcome by employing high pyrolysis temperatures. Aluminium also significantly improves the thermal stabilisation of Pb and Sn, it being possible to reach pyrolysis temperatures of 1100 and 1300 degrees C, respectively. Such stabilisation indicates that the performance of aluminium as a matrix modifier for Pb is better than that obtained using phosphate and magnesium nitrate without substantial changes of the figures of merit. The effects of aluminium on the atomisation characteristics of the elements and those coming from the simultaneous multielement determination on the figures of merit of the elements are also discussed. In this work, a calibration procedure involving a matrix matching method with aqueous aluminium standards is proposed as a simple and efficient way to solve the inconveniences originated by the aluminium matrix. The proposed method was applied to the simultaneous multielement determination of several aluminium-base alloy standards giving results well within the recommended values.

Contenido de zinc, cobre, hierro, calcio, fósforo y magnesio en leche materna en los primeros días de lactanción / Zinc, copper, iron, calcium, phosphorous and magnesium content of maternal milk at early stage of lactation

Se determinó, el contenido de Zn, Cu, Fe, Ca, P y Mg en leche temprana en 72 madres de la ciudad de Caracas. Las muestras fueron colectadas durante tres etapas de lactación: calostro (3 días), transicional (7 días) madura (21 días). Los cambios más marcados en las concentraciones de los elementos estudiados se observan principalmente durante las primeras semanas de lactación, tendiendo a estabilizarse hacia la tercera semana de lactación. El contenido de Zn, Cu, Fe, Ca, P y Mg en leche calostro, fue de 7,1 ñ 2,5 µg/ml, 0,52 ñ 0.15 µg/ml, 0,49 ñ 0,14 µg/ml, 214 ñ 62 µg/ml, 107 ñ 27 µg/ml y 33,3 ñ 5,5 µg/ml. En leche transicional 4,0 ñ 1,0 µg/ml, 0,5 ñ 0,10 µg/ml, 0,38 ñ µg/ml, 292 ñ 62 µg/ml, 213 ñ 36 µg/ml y 30,4 ñ 5,2 µg/ml y en leche madura 2,8 ñ 2,7 µg/ml, 0,47 ñ 0,08 µg/ml, 0,36 ñ 0,09 µg/ml, 224 ñ 49 µg/ml, 175 ñ 35 µg/ml y 25,2 ñ 3,3 µg/ml. Las concentraciones de los elementos traza estudiados (Zn, Fe, Cu) se mantienen dentro de los niveles considerados normales. Los valores de los elementos mayoritarios (Ca, P, Mg) son comparables a los reportados en la bibliografía para otros países. Estos resultados sugieren que el estado nutricional de esta población de madres es adecuado, para satisfacer las demandas del lactante en las primeras etapas de su vida

Zinc y cobre en embarazadas venezolanas y sus recién nacidos / Cinc and copper in pregnant venezuelan women and their new borns

Se ha reportado distintos datos sobre oligoelementos, debido a diferencias geográficas, raciales y nutricionales, de allí la importancia de conocer los valores de cada país. En 91 gestantes de un Hospital de Caracas y sus recién nacidos en el momento del parto se les tomó sangre venosa y del cordón umbilical respectivamente. El zinc (Zn) y cobre (Cu) en plasma se obtuvo por espectrofotometría de absorción atómica (varían modelo AA-875) y los parámetros maternos del neonato se correlacionaron. Las madres pertenecían a los estratos III-IV-V de Graffar. El Zn materno fue: Parto: 93,12 ug/dl ñ 22,41 ug/dl y puerperio: 93,24 ug/dl ñ 16,13 ug/dl. Cu materno parto: 304,59 ug/dl ñ 66,25 ug/dl y puerperio: 290,06 ug/dl ñ 47,16 ug/dl. Zn en cordón 131,07 ug/dl ñ 8,00 ugdl y el puerperio fue más bajo Cu en el puerperio 82,88 ug/dl ñ 22,20 ug/dl y en el puerperio aumentó a 108,27 ug/dl. Dieciseis RN presentaron Cu bajo (< 70 ug/dl). La correlación fue negativa entre Zn materno y semanas de gestación (primer cuartil)y entre concentración de Cu (primer cuartil) en sangre del cordón, peso y talla de los neonatos