R. M. García-Moncó Carra

Evaluation of the influence of physical activity on the plasma concentrations of several trace metals

Our study was carried out with the aim of evaluating the influence that the degree of physical activity may have on plasma concentrations of essential and toxic elements. Copper and zinc, elements of known importance in basic cellular processes, have been analysed as essential, and cadmium and lead as toxic for the body in abnormal doses. The study was performed on a total population of 50 healthy individuals, 34 of them professional sportsmen and the rest who undertook moderate physical activity (control group), all of them living in a polluted environment (Madrid, Spain). Sampling was conducted at the beginning of the season (October). Electro-analytical techniques of proved reliability and accuracy were used for the determination of the metals. The results were related to data obtained using graphite furnace atomic absorption spectrophotometry and by use of biological reference materials. We found significantly higher zinc plasma concentrations in the sportsmen involved in anaerobic-type training (judo, fencing) compared to those undertaking aerobic activities (endurance, cycling) (P < 0.05). The values in both cases were higher than those found in the control group. Our study showed an increase of plasma copper concentrations in professional sportsmen, especially in those performing anaerobic activities, compared to those subjects undertaking moderate activity (control group) (P < 0.05). In summary, our results showed that there were no deficiencies of copper and zinc in the athletes studied at the beginning of the season. The levels were higher than those of the control population. As for the toxic metals, cadmium and lead, we observed lower levels in the athletes than in the control group (cadmiumP < 0.005, leadP < 0.05). These results may indicate the existence of possible elimination systems for these metals in athletes, when they are training in a polluted environment.

Determination of oxytetracycline in urine and human serum by differential pulse polarography

SummaryA differential pulse polarographic method for the determination of oxytetracycline in urine and human serum in acid media (HClO4 of pH 2) is proposed. The effects of the amount of sample taken and the concentration of HClO4 present were investigated. The detection limit was 5.5×10−6 mol/l. The standard deviation of the determination of 5.5×10−5 mol/l of oxytetracycline in 2 ml of urine was 1.7×10−6 mol/l and that of the determination of 5.5×10−5 mol/l of oxytetracycline in 2 ml of human serum was 1.9×10−6 mol/l.

Trace-element analysis in biological fluids: evaluation of contamination in samples collected with metallic needles

The present study refers to the determination of trace elements in biological fluids, specially copper in cerebrospinal fluid (CSF) from animals and it assesses the possible contamination of the samples with copper originating from the systems (metallic needles) employed for their extraction from the animals. The results show that there is a significant incorporation of copper originating from the material (stainless steel) with which the needles have been manufactured. The influence of numerous variables on the quantity of the contamination has been evaluated; a very simple and practical procedure has been developed which minimises the contamination and introduces the necessary correction in the analytical results so that these can be used to diagnose certain diseases. The electroanalytical techniques employed were anodic stripping potentiometry with mercury film electrode and square wave voltammetry (SWV) with static mercury drop. The recommended procedure is valid for any other sample and any other metallic component present in the material used to manufacture the needle employed in the sample extraction.

Polarographic behaviour of alizarincomplexan, anodic wave and its analytical applications

Polarographic Behaviour of Alizarincomplexan, Anodic Wave and Its Analytical Applications The polarographic DPP and DC techniques have been utilized to carry out the study of the anodic wave of alizarincomplexan (AC) in aqueous medium. At pH>5.7 the anodic current is produced by the complex formed between the AC and Hg(II) proceeding from the dropping electrode. At pH=7.3 theE 1/2 of this anodic wave is 0.000 V vs. Ag/AgCl. The main characteristics of the wave have been studied, and the corresponding electrode mechanism process is proposed. Since Hg(II) forms a complex with AC, a method for the amperometric determination of Hg(II) is proposed. We have also studied the analytical possibilities for doubly charged ions which form complexes with the reagent, and an amperometric method for Co(II) determination is also proposed.