Biomedical subjects

B Cancho-Grande

Publications and source records attributed to B Cancho-Grande.

4 recordsLinked to original sources

PubMed2003

Application of single-drop microextraction and comparison with solid-phase microextraction and solid-phase extraction for the determination of alpha- and beta-endosulfan in water samples by gas chromatography-electron-capture detection.

Water contamination due to the wide variety of pesticides used in agriculture practices is a global environmental pollution problem. The 98/83 European Directive requires the measurement of pesticides residues at a target concentration of 1.0 microg/l in surface water and 0.1 microg/l in drinking water. In order to reach the level of detection required, efficient extraction techniques are necessary. The application of a new extraction technique: single-drop microextraction (SDME), followed by gas chromatography with electron-capture detection, was assessed for determining alpha-endosulfan and beta-endosulfan in water samples. Experimental parameters which control the performance of SDME, such as selection of microextraction solvent and internal standard, optimization of organic drop volume, effects of sample stirring, temperature and salt addition, and sorption time profiles were studied. Once SDME was optimized, analytical parameters such as linearity, precision, detection and quantitation limits, plus matrix effects were evaluated. The SDME method was compared with solid-phase microextraction and solid-phase extraction with the aim of selecting the most appropriate method for a certain application.

Chromatography, Gas↗

PubMed2003

HPLC method for determining ethylenediamine migration from epoxy-amine food packaging coatings into EU food simulants.

A simple, rapid, sensitive and inexpensive method has been developed for the determination of ethylenediamine (EDA) in European Union food simulants. The method involves precolumn derivatization with ortho-phthaldehyde (OPA) and 2-mercaptoethanol (ME) to obtain a fluorescent derivative. Liquid chromatographic (HPLC) elution was achieved with methanol-ultrapure water (65:35) as mobile phase with a Waters Spherisorb 5 microm ODS 2 column. Fluorescence detection (FD) was performed at 330 nm (excitation wavelength) and 450 nm (emission). Total chromatographic analysis time was < 10 min. The proposed method was validated by checking linearity, detection and quantification limits, and precision. Relative recovery rates were of about 100% because samples and standard-spiked blanks were processed in the same way. Method precision (RSD < 6%) was satisfactory and the quantification limit (0.25 mg x (-1)) indicated that specific migration limit for EDA in EU food simulants (12 mg x kg(-1)) can be easily controlled. When the validated method was applied to epoxy-amine formulations used for can coatings under different curing conditions, EDA migration was < 1.4 mg x l(-1).

Acetic Acid↗

PubMed2002

Optimization of solid-phase extraction and solid-phase microextraction for the determination of alpha- and beta-endosulfan in water by gas chromatography-electron-capture detection.

Water contamination due to the wide variety of pesticides used in agriculture practices is a global environmental pollution problem. The 98/83/European Directive requires to measure residues of pesticides at a target concentration of 1.0 microg/l in surface water and 0.1 microg/l in drinking water. In order to reach the level of detection required, efficient extraction techniques are required. Although solid-phase extraction (SPE) is the most common technique for isolation and concentration of pesticides from water, solid-phase microextraction (SPME) is being increasingly applied for this purpose. In this study, a direct-SPME procedure has been developed for the determination of alpha-endosulfan and beta-endosulfan in waters; experimental parameters such as selection of SPME coating, effect of temperature, effect of salt addition, optimization of the sample volume, adsorption and desorption profiles and desorption temperature were studied and optimized. Analytical parameters such as linearity, precision, detection and quantitation limits, and matrix effects for SPE and SPME methods were evaluated for comparison purposes with the aim of selecting the most appropriate for a certain application. Both extraction techniques, SPE and SPME, were followed by gas chromatography with electron-capture detector.

Chromatography, Gas↗

PubMed2002

Comparison of solid-phase extraction and solid-phase microextraction for carbofuran in water analyzed by high-performance liquid chromatography-photodiode-array detection.

In this study a direct solid-phase microextraction (SPME) procedure has been developed for the determination of carbofuran in water. Experimental parameters such as selection of SPME coating, effect of temperature, effect of salt addition and solvent desorption were studied and optimized. Analytical parameters such as linearity, precision, detection and quantitation limits, and matrix effects for solid-phase extraction (SPE) and SPME methods were evaluated for comparison purposes with the aim of selecting the most appropriate depending on the detection capabilities required. SPE and SPME were followed by high-performance liquid chromatography with diode-array detection, using a 50 x 4.6 mm I.D. guard column and a 150 x 4.6 mm I.D. analytical column, both packed with C18 silica. Both methods can be applied to real samples and give the same results, but SPE allows the detection of lower carbofuran concentrations (0.06 microg/L) as compared to

Carbofuran↗