In this work, two analytical methods based on liquid chromatography coupled to electrospray time-of-flight mass spectrometry (LC/ESI-TOFMS) and tandem mass spectrometry (LC/ESI-MS/MS) are described for the identification, confirmation and quantitation of three insecticides non-authorized in the European Union (nitenpyram, isocarbophos and isofenphos-methyl) but detected in recent monitoring programmes in pepper samples. The proposed methodologies involved a sample extraction procedure using liquid-liquid partition with acetonitrile followed by a cleanup step based on dispersive solid-phase extraction. Recovery studies performed on peppers spiked at different fortification levels (10 and 50 microg kg(-1)) yielded average recoveries in the range 76-100% with relative standard deviation (RSD) (%) values below 10%. Identification, confirmation and quantitation were carried out by LC/TOFMS and LC/MS/MS using a hybrid triple quadrupole linear ion trap (QqLIT) instrument in multiple-reaction monitoring (MRM) mode. The obtained limits of quantitation (LOQs) were in the range 0.1-5 microg kg(-1), depending on each individual technique. Finally, the proposed methods were successfully applied to the analysis of suspected pepper samples.
The objective of this study is to describe and to analyze the pattern of utilization of benzodiazepines (Diazepam, Lorazepam and Clonazepam) at the Cartago Health Area (ASC), during the period from February, 2007 to January, 2008. The facts about the consumption of benzodiazepines were directly obtained from the prescriptions which were prescribed for the physicians of the ASC. The information is expressed in defined daily doses per thousand inhabitants and day (DHD). The results showed up that a significant majority of prescriptions of benzodiazepines belong to patients of the feminine sex. On the other hand, the degree of utilization of benzodiazepines was regular during the analysis period, resulting that Lorazepam was the most demanded. Nevertheless, in relation to the EBAIS of ascription of the patients, great variability exists in the utilization of the three benzodiazepines analyzed, which is demonstrated in the high consumptions of the medicaments in some EBAIS or very low in others. Such results pointed out that there is a necessity carry out other benzodiazepines utilization studies, and also the analysis of its facts, not only in ASC but in other Healthy Areas, in order to accomplish comparisons.
Palabras clave: tratamiento de aguas, ultrasonido, colorante azoico RESUMEN Se estudia la decoloración del anaranjado de metilo (AM), un colorante azoico con propiedades mutagénicas. Se analiza la acción del triclorometano (HCCl3) (TM) como agente sinérgico, utilizando un reactor ultrasónico por lotes y otro continuo. Se demuestra que la decoloración sonoquímica del AM es ampliamente favorecida por la adición de bajas concentraciones de HCCl3. En el caso del reactor por lotes, se obtuvieron decoloraciones del 17 y 98 % sin y con triclorometano, y las constantes cinéticas respectivas fueron estadísticamente diferentes. En el reactor continuo se alcanzaron decoloraciones del 7 % y superiores al 80 % sin y con TM, respectivamente, una vez que el reactor entró en estado estacionario.
Se analiza la degradación de soluciones acuosas del colorante azoico anaranjado de metilo en un reactor sonoquímico de flujo continuo. Las determinaciones de los tiempos de residencia en cada una de las cuatro unidades del reactor muestran que los mismos no difieren de los tiempos espaciales, por lo que el reactor puede considerarse un reactor continuo de mezcla completa sin volúmenes muertos ni cortocircuitos.
Mediante la simulación dinámica se desarrollan modelos de funcionamiento del reactor. Los resultados tanto en el estado transiente como en el estacionario no presentan diferencias estadísticamente significativas con los obtenidos analíticamente.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.