A. Sánchez Misiego

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.

Extract-photometric determination of iron with 2-indolehydroxamic acid

SummaryA new extract-photometric method is proposed for determining trace amounts of Fe3+ based on the formation of a coloured complex with 2-indolehydroxamic acid (2-IHA), that can be extracted into a solution of trioctylmethylammonium chloride solution in toluene. Beers law was obeyed between 0.06 μg/g and 1.25 μg/g (minimum error range) of iron in the aqueous phase, with a relative error (p=0.05) of ±0.86%. Molar absortivity at 455 nm was 6500 l mol−1 cm−1. The method was applied to the determination of iron in various samples: commercial pharmaceutical nutritional preparations, wine and standard samples of Portland cement and magnesite.

Determination of Mo(VI) with 2-benzylideneiminobenzohydroxamic acid (2-BIBH) in urine by cathodic stripping voltammetry

SummaryControlled adsorptive accumulation of Mo(VI)-2-BIBH at the hanging mercury drop electrode (HMDE) provides the basis for the direct stripping measurement of Mo(VI) in nanomolar concentration. The cathodic stripping response is evaluated with respect to experimental parameters such as preconcentration time, preconcentration potential and others. A differential pulse cathodic stripping voltammetric method for the determination of Mo(VI) with 2-BIBH in urine is proposed. The detection limit is 10−9 mol/l Mo(VI), standard deviation for 5×10−8 mol/l is ±1.58×10−9 mol/l.

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.

Rapid Spectrophotometric Determination of Chlorate with Dimedone Bisthiosemicarbazone Monohydrochloride

Dimedone bisthiosemicarbazone monohydrochloride has been examined to evaluate its usefulness as a reagent for rapid and sensitive Spectrophotometric determination of chlorate (0.5–5.0 ppm) by oxidation of the reagent in 70% perchloric acid medium and measurement of the yellow product. The molar absorptivity at 417 nm is 1.86×104 l·mole−1·cm−1. The relative standard deviation is 1.6% for 2.5 ppm of chlorate.

Extract-photometric determination of vanadium(V) with 3-indole-acetohydroxamic acid

SummaryA spectrophotometric study has been carried out of the violet complex 3-indole-acetohydroxamic acid-vanadium extracted into a solution of trioctylmethyl-ammonium chloride in toluene [λmax 525 nm; ε=5381 l mol−1 cm−1; stoichiometry 1:3 (metal:reagent)]. A new method for the extract-spectrophotometric determination of V5+ in the range of 2–7 μg/g is proposed and interferences by foreign ions were investigated. The method has been satisfactorily applied to the determination of vanadium(V) in fuel oil. The relative error is ±2.9%.

Electroanalytical study of the anodic wave of 5-nitroorotic acid

The electroanalytical behaviour of 5-nitroorotic acid has been studied at several pH values, using DC and differential pulse polarography and cyclic voltammetry techniques. 5-Nitroorotic acid undergoes one oxidation wave in the pH interval considered. The best conditions for determination of the acid are also studied.

Polarographic behaviour of orotic acid (vitamin B13). Cathodic processes

The electroanalytical behaviour of orotic acid in cathodic processes has been studied in HClO4, at several pH values in Britton-Robinson buffers, using DPP and CV techniques.Orotic acid undergoes three cathodic waves over the entire pH range considered. Optimum conditions for determination of orotic acid using the DPP technique are also studied.

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.