Gustavo Antonio Peñuela Mesa

QuEChERS GC–MS validation and monitoring of pesticide residues in different foods in the tomato classification group

The objective of this study was to validate (SANCO/12495/2011 and NTC-ISO/IEC 17025) multi-residue multi-class methods using QuEChERS sample preparation and GC-MS for the analysis of regulated pesticides in tomatoes (Solanum lycopersicum), tamarillos (Solanum betaceum) and goldenberries (Physalis peruviana). These Latin American products are representative and widely produced in Antioquia (Colombia). Sample preparation followed the UNE-EN 15662 method (150 mg MgSO4, 25mg primary secondary amines and 25mg of octadecylsiloxane for cleanup; graphitized carbon black was added for tomatoes). Extracts were injected using a programmed temperature-vaporizing injector. The residues were validated over a range from 0.02 mg/kg to 0.20 mg/kg, with 24 analytes validated in tomatoes, 33 in tamarillos and 28 in goldenberries. An initial risk assessment was enabled by monitoring 24 samples in the municipalities of El Peñol, Marinilla and San Vicente Ferrer. Risks were found for tomatoes, but no significant risks were found for tamarillos or goldenberries.

GC–MS Applied to the Monitoring of Pesticides in Milk and Blackberries and PAHs in Processed Meats of Colombia

Abstract Colombia is an agricultural country where many pesticides are used. They are overused in most of the cases, leaving residues in water bodies, soils, and crops. Consequently, it is necessary to analyze the pesticide residues from crops that have been fumigated. Colombia is also an active cattle raiser, and producer of meat and milk. The Diagnosis and Control of Pollution Research Group (GDCON), as an active part of the University of Antioquia, has analyzed residues of several toxic substances in water, soil, and foods using state-of-the-art analytical methods. This chapter presents the results of the analysis obtained by programmed temperature vaporizer–gas chromatography–mass spectrometry (PTV–GC–MS) of organic toxic pollutants, using QuEChERS as the sample preparation method. The presence of pesticide residues in milk, blackberries, and processed meat was demonstrated.

Revisión de los métodos estadísticos multivariados usados en el análisis de calidad de aguas

En los ecosistemas acuaticos se monitorea el agua para determinar sus variaciones espacio-temporales, generando grandes y complejas matrices de datos que requieren herramientas que ayuden en la interpretacion de los mismos, para que los administradores de los recursos hidricos puedan informar a la sociedad el deterioro de estos y tomar medidas correctivas. El presente articulo es una revision de tema cuyo objetivo es el examen de tecnicas estadisticas multivariadas usadas para examinar la variabilidad espacio-temporal de la calidad del agua. En el se presentan diversas tecnicas como el analisis factorial, que se usa con el fin de disminuir la dimensionalidad de los datos y construir factores subyacentes o variables latentes que generen las variables observadas, estos factores pueden usarse e interpretarse como indices de calidad del agua construidos a partir de los datos recolectados; tambien se presenta en analisis de cluster y el analisis discriminante que se usan comunmente para estudiar la variabilidad espacial, estudiando similaridades entre periodos o estaciones de muestreo, estas tres tecnicas se usan comunmente con fines exploratorios; para objetivos mas complejos como el modelamiento y la prediccion, se presentan los modelos jerarquicos, de regresion multiple y de ecuaciones estructurales. Para todos los metodos se presenta su funcionalidad y aplicabilidad y se ilustran usando casos de estudio. Esta revision describe como estos metodos pueden utilizarse con miras a estudiar la calidad del agua con el fin de monitorear espacial y temporalmente la variabilidad de las medidas tomadas.