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Optimization of Analytical Conditions to Determine Steroids and Pharmaceuticals Drugs in Water Samples Using Solid Phase-Extraction and HPLC
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作者 Ramiro Vallejo-Rodriguez Alberto Lopez-Lopez +2 位作者 Hugo Saldarriaga-Norena Mario Murillo-Tovar leonel hernandez-mena 《American Journal of Analytical Chemistry》 2011年第8期863-870,共8页
Two reliable methods were optimized to determine two steroids (17?-Estradiol and 17?-Ethinylestradiol) and two pharmaceutical drugs (ibuprofen and naproxen) using Solid-Phase Extraction (SPE) for sample preparation an... Two reliable methods were optimized to determine two steroids (17?-Estradiol and 17?-Ethinylestradiol) and two pharmaceutical drugs (ibuprofen and naproxen) using Solid-Phase Extraction (SPE) for sample preparation and High Performance Liquid Chromatography (HPLC) for analysis. SPE (C18) conditions were evaluated varying elution solvent volume, pH conditions and sample mass in the cartridge and reduction techniques of the extract. The efficiency of the analytical methods was evaluated by spiking ultrapure water samples with compounds at three and four levels of concentration for steroids and pharmaceutical drugs, re- spectively. The recoveries were independent (P > 0.05) of added mass of target analytes with a repeatability lower than 6.5% for steroids and 12.1% for pharmaceutical compounds. The recovery factor (coefficient of variation, CV) was higher than 83% for steroids (CV 93% for pharmaceuticals (CV < 5.2%). The optimized analytical method was applied for the evaluation of a steroid degradation test using ozone, finding that the estimated limit of detection is sufficient to determine the residual mass (μg?L–1) of 17β-Estradiol after the experiment. 展开更多
关键词 STEROIDS Pharmaceuticals Drugs Solid-Phase Extraction HPLC-DAD
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Ionic Composition in Aqueous Extracts from PM2.5 in Ambient Air at the City of Cuernavaca,Mexico
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作者 Hugo Saldarriaga-Norena leonel hernandez-mena +5 位作者 Enrique Sanchez-Salinas Fernando Ramos-Quintana Laura Ortiz-Hernandez Rodrigo Morales-Cueto Vanesa Alarcon-Gonzalez Sandra Ramirez-Jimenez 《Journal of Environmental Protection》 2014年第13期1305-1315,共11页
The present study was carried out between May and June 2012 in the city of Cuernavaca, Mexico. During this time the average ambient temperatures were about 25°C, suggesting the formation of secondary aerosols, co... The present study was carried out between May and June 2012 in the city of Cuernavaca, Mexico. During this time the average ambient temperatures were about 25°C, suggesting the formation of secondary aerosols, consisting mainly of ammonium and sulfate. The average PM2.5 concentration was 37 μg·m-3 for the entire urban area and there were only two days which exceeded the limit established by the official standards for periods of 24 h. The most abundant ionic species associated with PM2.5 were sulfates (3634.82 ng·m-3, average) and ammonium (1709.53 ng·m-3, average). The ratio estimated between total anions and total cations indicated that the concentration of total anions was 1.94 times total cations. The contribution percentage of the ionic species associated with PM2.5 revealed that 76% of the PM2.5 is sulfates and ammonium. The ion balance made for the urban area of Cuernavaca indicated that during the study period, the aerosols showed alkaline characteristics;that is to say the concentration of anions was not sufficient to neutralize the cations, specifically ammonia (m = 0.060). Finally, wind fields showed that during the study the winds came in 50% from the south west, followed by 25% from east and 12.5% of the south east, which in part allowed transport of contaminants into the portion of the city, where the AUSM campus site was located. 展开更多
关键词 Ionic species Cuernavaca Ion Balance
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