Browsing by Author "Cuero Olaya, Laura Camila"
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Item Determinación de organoclorados en residuos sólidos mediante la lixiviación en disco rotativo y microextracción en fase solida simultáneos por cromatografía de gases(Universidad Santiago de Cali, 2019) Cuero Olaya, Laura Camila; Castro Bonilla, Duván André; Ríos Acevedo, Jhon Jairo (Director)A new methodology was developed that overcomes certain limitations in the analysis of conventional solid samples, applying an ecological approach. An experimental configuration based on microextraction in solid phase coupled to a rotating disc device for the determination of ten organochlorine pesticides in sludge samples (Benzene Hexachloride, Lindane, Heptachlor, Aldrin, Heptachlor Epoxide, Dieldrin, Endrin, Endrin Aldehyde, β-Endosulfan and Dichlorophenyldichloroethane) is proposed. In this innovative procedure, a sample of sludge is placed in the cavity of the rotating disc device and then immersed in an aqueous solution followed by high-speed agitation. In this case, the water is used as a green solvent to leach the analytes from the sample matrix. Simultaneously, a solid-phase microextraction fibre composed of carboxene/polydimethylsiloxane was immersed in the aqueous solution to extract the analytes from the aqueous matrix with subsequent thermal desorption in the injector of a gas chromatograph with electron capture detector. Optimum extraction conditions were obtained using an extraction temperature of 60°C for 60 minutes, with 50 mg of sludge inserted into the rotating disc. Using previously optimized extraction conditions, analytical performance was satisfactory with correlation coefficients greater than 0.9946 for all analytes, detection limits ranging from 1.67 to 4.34 ng g-1, quantification limits ranging from 5.50 to 14.46 ng g-1, recoveries from 75.3 to 93.3%, intraday precision (n = 3) from 4.2 to 16.3%, and interday precision (n = 9) from 3.2 to 14.6%. The evaluation of the bioavailable faction carried out at 25°C showed values of 42.3 to 60.2% of the analytes that pass into the aquatic medium. In the study of a sludge sample from a wastewater treatment plant, Benzene hexachloride 29.2 μg g-1, Heptachlor epoxide 30.7 μg g-1, Dieldrin 41.1 μg g-1, Endrin 37.9 μg g-1 were found; for Lindane, Heptachlor, Aldrin, β-Endosulfan and Endrin aldehyde concentrations below the limit of quantification were found. No dichlorophenyldichloroethane is reported in the sample. The proposed method represents a promising alternative for the analysis of complex samples in solid matrices