[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%.

Nanoemulsion stability: experimental evaluation of the flocculation rate from turbidity measurements.

The coalescence of liquid drops induces a higher level of complexity compared to the classical studies about the aggregation of solid spheres. Yet, it is commonly believed that most findings on solid dispersions are directly applicable to liquid mixtures. Here, the state of the art in the evaluation of the flocculation rate of these two systems is reviewed. Special emphasis is made on the differences between suspensions and emulsions. In the case of suspensions, the stability ratio is commonly evaluated from the initial slope of the absorbance as a function of time under diffusive and reactive conditions. Puertas and de las Nieves (1997) developed a theoretical approach that allows the determination of the flocculation rate from the variation of the turbidity of a sample as a function of time. Here, suitable modifications of the experimental procedure and the referred theoretical approach are implemented in order to calculate the values of the stability ratio and the flocculation rate corresponding to a dodecane-in-water nanoemulsion stabilized with sodium dodecyl sulfate. Four analytical expressions of the turbidity are tested, basically differing in the optical cross section of the aggregates formed. The first two models consider the processes of: a) aggregation (as described by Smoluchowski) and b) the instantaneous coalescence upon flocculation. The other two models account for the simultaneous occurrence of flocculation and coalescence. The latter reproduce the temporal variation of the turbidity in all cases studied (380≤[NaCl]≤600 mM), providing a method of appraisal of the flocculation rate in nanoemulsions.

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%.