Tese
Determinação de resíduos de compostos orgânicos em água por microextração líquido-líquido dispersiva (DLLME) E GC-(TQ)MS/MS
Fecha
2010-11-29Registro en:
MARTINS, Manoel Leonardo. Simultaneous determination of organic compound
residues in water samples by dispersive liquidliquid
microextraction (DLLME) AND GC-(TQ)MS/MS. 2010. 161 f. Tese (Doutorado em Química) - Universidade Federal de Santa Maria, Santa Maria, 2010.
Autor
Martins, Manoel Leonardo
Institución
Resumen
The use of chemicals, which generates a lot off benefits, is responsible for the contamination of soil, water and foods. The concern about contamination of surface
and ground water systems by pesticides has grown in scientific circles, especially by the presence of pesticides and other compounds in water sources. Thus, rapid analytical methods, sensitive and efficient must be developed in order to verify the concentration levels of pesticides and other organic compounds in water samples
agree with those established by law to protect human health and the environment media. This study aimed to optimize, validate and implement an extraction method to
determine residues of mononitro, ketones, trifluralin, oxirane, lindane, 2,4-D ester, chlorpyrifos, bromoketal, α-endosulfan, β-endosulfan and endosulfan sulfate in
samples of tap water, industrial wastewater and groundwater by Dispersive Liquid-Liquid Microextraction (DLLME) modified and Gas Chromatography with Mass
Spectrometry Tandem using Triple Quadrupole type (GC-(TQ)MS/MS). The method is based on the rapid injection, with a syringe, of a mixture of an extractor solvent (50
μL of carbon tetrachloride) and an dispersor solvent (2.0 mL acetone) previously cooled (ice batch, 0 - 4 °C) in an aqueous sample (5.0 mL), contained in a 10 mL
graduated glass tube with conical bottom, with no pH correction and cooled (ice batch, 0 - 4 °C). It is not necessary to stir the sample in this step. Remove 25 μL of
the sedimented phase separated by simple sedimentation for 10 min. from the bottom of conical tube with a microsyringe and transferred to a vial of 200 μL for GC-
(TQ)MS/MS determination. The preconcentration factor obtained was 100 times. The method was validated by determining the limits of detection and quantification limits (LOD and LOQ), linearity, precision and accuracy. The calibration curves showed adequate linearity between 0.05 e 10 μg L-1 with coefficients of determination higher
than 0.993. The method showed good recovery values between 70 and 115%, RSD(%) ranged from 10.9 to 17.2%, LOQs between 0.02 and 0.09 μg L-1, and was considered adequate for the analysis of pesticide residues and other organic
compounds evaluated in water samples. After validation, the method was applied to samples of drinking water, industrial wastewater and groundwater. No pesticide
residues and other organic compounds evaluated were found in the water samples tested.