Browsing by Author "Ruíz, M.A."

The aim of this study was to assess the degree of asthma control according to GINA criteria during two different seasons in Spain. An multicenter, longitudinal, epidemiological study with the participation of a sample of physicians in Spain was conducted. Consecutive asthma patients, 18 years of age and older, seeking primary and specialist care were included in the study. Patients were seen during the winter and spring 2004 and were asked about asthma control according to GINA control criteria (daytime and nighttime symptoms, asthma exacerbations, limitations of physical activity, and visits to the emergency department) during the 4 weeks prior to the visit. Control was defined according to daytime and nighttime symptoms. A total of 614 patients participated in the study. The proportion of patients reporting daytime symptoms ‘‘every day’’ or ‘‘most days’’ during the winter versus spring was 40.1% vs. 23% ðPo0:01Þ; 26.9% vs. 14.1% presented symptoms at night ðPo0:01Þ; 11.5% vs. 8.3% had severe exacerbations; 33.5% vs. 35.7% presented symptoms accompanying exercise, and 9.4% vs. 4.3% ðPo0:01Þ had required emergency visits. The number of patients with inadequate control was slightly higher in winter than in spring (74.4% vs. 71%) ðPo0:01Þ. The most commonly prescribed treatment was ICS plus LABAs for both periods.

The preparation of a peroxidase biosensor by immobilization of the enzyme during the electropolymerization of N-methylpyrrole and its use in the determination of organic peroxides in a predominantly nonaqueous medium, such as reversed micelles, is reported. Reversed micelles were formed with ethyl acetate as the continuous phase, 4% of 0.05 mol l−1 phosphate buffer solution of pH 7.4 as the dispersed phase, and 0.1 mol l−1 AOT as the emulsifying agent. Working variables affecting the polymer biosensor preparation, such as the polymerization potential, the constant accumulated charge to stop the polymerization process, the concentration of monomer and enzyme in the polymerization solution and the pH and concentration of the phosphate buffer solution, were optimized and discussed. Concerning the variables regarding the amperometric measurements in the reversed micellar medium, the potential value applied, the pH of the phosphate buffer solution, and the temperature were also optimized. Under the optimized conditions, the steady-state current for 2-butanone peroxide is reached in only 4 s. Linear calibration plots over the ranges 5–85 mol l−1, and 2–48 mmol l−1 were obtained for 2-butanone peroxide and tert-butylhydroperoxide, respectively. The limits of detection obtained were 0.086 mol l−1, and 0.03 mmol l−1, respectively. The poly-N-methylpyrrole-HRP amperometric biosensor was used for the determination of the organic peroxide content in body lotion samples, by employing 2-butanone peroxide as a standard. Optimization of the peroxide extraction step from the sample was carried out, and recoveries approximating 100% were obtained.

The suitability of nickel phthalocyanine polymer-coated glassy carbon electrodes for the amperometric detection of the phenolic antioxidants 1er1-butylhydroxytoluene (BHT), lert-butylhydroxyanisole (BHA), propyl gallate (PG) and /ert-butylhydroquinone (TBHQ). after their separation by HPLC under gradient elution conditions, is demonstrated. An applied potential of +0.70 V (vs. Ag/ AgC!) was used, which offers the best signal-to-noise ratio and is considerably lower than those reported in the literature with conventional electrodes. A good separation of the four antioxidants was obtained in 17 min. Furthermore. no fouling of the electrode surface was observed when using the polymer modified electrode during the whole working day. Using TBHQ ii!, internal standard, detection limits of 5.5 ng, 7.5 ng and 30 ng (for a 50-µL volwne injected) were obtained for BHA, PG and BHT, respectively. As an application, the determination of the antioxidants contained in commercial chewing gum samples was carried out by applying a simple extraction procedure. It was demonstrated that only BHT was present as antioxidant in the, samples, in a concentration of 51 ± 3 µg g- 1• Sample linearity and recovery studies, after adding a known amount of BHT to the analyzed samples, confirmed the sutability of the proposed method.

The preparation of a peroxidase biosensor by immobilization of the enzyme during the electropolymerization of N-methylpyrrole and its use in the determination of organic peroxides in a predominantly nonaqueous medium, such as reversed micelles, is reported. Reversed micelles were formed with ethyl acetate as the continuous phase, 4% of 0.05 mol l−1 phosphate buffer solution of pH 7.4 as the dispersed phase, and 0.1 mol l−1 AOT as the emulsifying agent. Working variables affecting the polymer biosensor preparation, such as the polymerization potential, the constant accumulated charge to stop the polymerization process, the concentration of monomer and enzyme in the polymerization solution and the pH and concentration of the phosphate buffer solution, were optimized and discussed. Concerning the variables regarding the amperometric measurements in the reversed micellar medium, the potential value applied, the pH of the phosphate buffer solution, and the temperature were also optimized. Under the optimized conditions, the steady-state current for 2-butanone peroxide is reached in only 4 s. Linear calibration plots over the ranges 5–85 mol l−1, and 2–48 mmol l−1 were obtained for 2-butanone peroxide and tert-butylhydroperoxide, respectively. The limits of detection obtained were 0.086 mol l−1, and 0.03 mmol l−1, respectively. The poly-N-methylpyrrole-HRP amperometric biosensor was used for the determination of the organic peroxide content in body lotion samples, by employing 2-butanone peroxide as a standard. Optimization of the peroxide extraction step from the sample was carried out, and recoveries approximating 100% were obtained.

Brassica napus var. oleifera and Helianth11s annus were grown in artificially contaminaled soils. Accumulation and translocation of 1he environmenlal pollutams zinc, cadmium, lead, and copper, was evaluated in different porlions of the plants at two harvesting times. The distributio n into the plants of these metal ions, as well as their capacity for contaminant phytoextraction and accumulation was assessed. For this purpose, an analytical method util izing focused ultrasound employed for extraction and stripping voltammetry for measurement has been optimized and validated for the simultaneous measurement of Zn, Cd, Pb, and Cu in plant extracts.