Ultraviolet spectrophotometric determination of phenols in natural and waste waters with iodine monobromide.
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Biomedical subjects
Publications and source records attributed to G Font.
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Characteristics of the binding of 3-carbethoxipsoralen (3CPS) to human serum albumin (HSA) and serum proteins have been studied. An electrophoretic study showed that the predominant binding protein fraction was albumin, with small binding to globulins. Binding to HSA, studied by equilibrium dialysis, is 75% and characterized by a small saturable number of binding sites (N = 0.27) with a moderate affinity constant (K = 8 X 10(4) M-1). Free fatty acids were shown to decrease 3CPS binding to HSA by a non competitive process.
We present the case of a pentasomy X (49,XXXXX) prenatally diagnosed. The fluorescent in situ hybridization technique assisted in making the diagnosis. The problems identified in this fetus include a Dandy-Walker malformation, hydrocephaly, ventricular septal defect, hypertelorism and polyhydramnios.
Residues of benzoylphenylurea insecticides (diflubenzuron, hexaflumuron, and flufenuxuron), carboxamide acaricides (hexythiazox), and carbamate insecticides (benfuracarb) were determined in 150 orange fruit samples from September 1998 to June 1999, to estimate exposure of the Valencian population to oranges contaminated with these newly developed pesticides. The method for monitoring these residues is based on matrix solid-phase dispersion and liquid chromatography with UV or atmospheric pressure chemical ionization/mass spectrometry (APCI/MS) detection. Orange samples representing 11 varieties were collected from an agricultural cooperative and examined for the 5 pesticides. In 74.6% of all analyzed samples, the pesticide residues were below detection limits, which ranged from 0.002 to 0.05 mg/kg. Residues were detected in 25.4% of the samples, with higher incidences of diflubenzuron, flufenuxuron, hexythiazox, and benfuracarb; hexaflumuron residues were detected only occasionally. Two different pesticides exceeded maximum residue limits (MRLs) in 4 (2.7%) of the orange samples. Diflubenzuron surpassed 1 mg/kg MRL in 3 samples and flufenuxuron exceeded the 0.3 mg/kg MRL in 3 samples. The estimated daily intake of the 5 pesticide residues during the period was 0.077 microg/kg body weight per day. This value is much lower than the total admissible daily intake proposed by the Food and Agricultural Organization and the World Health Organization.
A qualitative and quantitative study is made of the polycyclic aromatic hydrocarbons (PAH), nitrogen oxide, and sulfur dioxide in the atmosphere of the city of Valencia for the period 1988-1989; an analysis is made of their concentrations during the year in terms of season and noise levels. Eleven sampling points in the city were used to determine PAH composition by reverse-phase, high-resolution liquid chromatography with fluorimetric detection, employing an acetonitrile-water gradient; nitrogen oxides and sulfur dioxide were determined by the Valencia city government. Environmental noise levels were determined using a BK 2221 integrated precision sonometer, and temperature values were obtained from the city Meteorological Institute. Daily PAH values varied between 0.1769 and 2.0916 micrograms/m3, whereas the figures for nitrogen oxide were between 91.5 and 100.67 micrograms/m3 during 1982-1989 (only one value, 58.01 micrograms/m3, is available for 1988-1989, corresponding to the Mercadona sampling point), and between 17.33 and 129.36 micrograms/m3 for sulfur dioxide for a total of 9 sampling points; the highest concentrations were recorded in the winter and spring months, the association between PAH and temperature being statistically significant (p less than or equal to .05). The relation to noise was also significant (p less than or equal to .005), Fluoranthene was the predominant PAH in all samples analyzed.
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The lindane, methoxichlor, parathion and methylparathion content of water is measured in a gas-chromatography fitted with a capture electron detector. Prior extraction and concentration are done by using Sep-Pak C18 cartridges with ethyl acetate as eluent, which is offers certain advantages over hexane and methanol. With solutions of 0.5 ppb recovery values of 102.7% (lindane), 85% (methoxychlor), 94.7% (parathion) and 93.1% (methylparathion) are obtained. The method proposed is less time-consuming and less expensive than the usual consisting of extraction with dichloromethane: hexane (15:75 v/V) and concentration in a Kuderna-Danish.