Development and validation of a multi-residue analytical methodology to determine the presence of selected pesticides in water through liquid chromatography

Abstract

No presente trabalho uma metodologia analítica é descrita para determinar a presença de multiresiduos de pesticidas utilizados na cultura da cana de açúcar (tebuthiuron, hexazinona, diuron, 2,4-D e ametrina), em fontes de água de abastecimento. Os analitos foram isolados da matriz água, através das seguintes técnicas: extração liquido-liquido (LLE), utilizando diclorometano como solvente; extração em fase sólida (SPE), utilizando C18 como suporte sólido e acetonitrila como solvente para condicionamento da fase e eluição dos analitos; e extração com fluido supercrítico (SFE), utilizando C18 como suporte sólido e CO 2 no estado supercrítico como solvente de extração. Análise cromatográfica foi feita por cromatografia liquida de alta eficiência (HPLC) com detector ultravioleta, utilizando acetonitrila/água como fase móvel. Dentre as três técnicas de extração avaliadas, os melhores resultados foram obtidos com extração liquido-liquido e extração em fase sólida.In the present work an analytical methodology is described to determine the presence of multiresidues of selected pesticides used in sugar-cane cultures (tebuthiuron, hexazinone, diuron, 2,4-D and ametrine), in source of drinking water. The analytes were isolated from the water matrix through the following techniques: liquid-liquid extraction (LLE) using dichloromethane as solvent; solid phase extraction (SPE) using C 18 as solid support and acetonitrile as solvent to condition the solid phase and elution of the analytes; and supercritical fluid extraction (SFE) using C18 as solid support and CO 2 in supercritical state as extractant solvent. The chromatographic analysis was done by high performance liquid chromatography (HPLC) with an ultraviolet detector and using acetonitrile/ water as mobile phase. Among the three evaluated extraction techniques, the best results were obtained with both liquid-liquid extraction and solid phase extraction.

Validation of a liquid chromatography ultraviolet method for determination of herbicide diuron and its metabolites in soil samples

“…Due to analyte low concentration levels comprising interfering diversity, pesticides in water determined by HPLC usually requires the use of very sensitive detectors (such as mass spec's) and involves preconcentration steps which can take over half of the total analysis time (Stork et al 2008, Brondi and Lanças 2005, Azevedo et al 2001, Gallitzendorfer et al 2011. However, diuron and its by-products can be monitored in soil from cropping areas by using sensitivity and reasonable cost equipment as ultraviolet detectors (UV).…”

Principais técnicas de preparo de amostra para a determinação de resíduos de agrotóxicos em água por cromatografia líquida com detecção por arranjo de diodos e por espectrometria de massas

“…2 Os agrotóxicos geralmente são tóxicos e causam problemas de poluição ambiental e de saúde. 3 Uma parcela considerável do total aplicado para fins agrícolas atinge rios, lagos, aquíferos e oceanos por meio do transporte por correntes atmosféricas, eliminação incorreta de restos de formulações, limpeza de acessórios e recipientes empregados na aplicação desses produtos e também pelo carreamento do material aplicado no solo pela ação erosiva da chuva. Devido aos mecanismos de transporte característicos dos meios aquáticos, alguns desses compostos têm sido detectados até na região Antártica.…”

Validation of a method using solid phase extraction and liquid chromatography for the determination of pesticide residues in groundwaters

“…18 However, in order to reach the low concentration levels permitted in potable water, a preliminary concentration step is required before the chromatographic analysis. 14 Pesticide in water samples are usually enriched by liquid-liquid extraction (LLE) 19,20 or solid phase extraction (SPE). 10,21 The conventional liquid-liquid extraction often needs large amounts of toxic solvent and a time-consuming procedure, 22 while SPE is simple, fast and consumes very small volumes of high purity solvents.…”

“…10,21 The conventional liquid-liquid extraction often needs large amounts of toxic solvent and a time-consuming procedure, 22 while SPE is simple, fast and consumes very small volumes of high purity solvents. 20 Nowadays, SPE is the most appropriate method for the enrichment of pesticides in aqueous matrices. 18,23 Gas chromatography (GC) and high performance liquid chromatography (HPLC) coupled with various detection systems are the most powerful tools for the analysis of pesticides in water.…”

“…Therefore, diverse analytical methods for determination of pesticide residues have been developed and validated; 20,33,35 they describe definitions, procedures, parameters and strategies for validation. The analytical parameters normally found for validation of separation methods are: selectivity, linearity and range, precision, accuracy, limit of detection, limit of quantification and robustness.…”