Published 2019 | Version v1
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Development and validation of an analytical method for the quantitative determination of pesticides in water by solid phase extraction and liquid chromatography with diode array detector

Creators

Description

The development and validation of a method for the quantitative determination of pesticides in water by solid phase extraction was carried out, using liquid chromatography with a diode array detector of pesticides belonging to the following different families: carbamates (carbofuran and carbaryl), triazines (ametrine and hexazinone), uracil (bromacil) and urea (diuron). The method was optimized from the Procedure for the General Screening of Cholinesterase Inhibitory Pesticides in Biological Matrices by Quechers Extraction and Detection With Gas Chromatography (GC) / Nitrogen Detector (NPD) / NPD, High Efficiency Liquid Chromatography (HPLC) /Diode Array Detector (DAD) and the methodology for the Determination of pesticides in surface water samples by solid phase extraction and liquid chromatography (EFS + LC) of the Regional Institute for Studies on Toxic Substances IRET of the Universidad Nacional de Costa Rica. In the extraction, 500mL of water enriched with pesticides was eluted and the extraction was carried out in solid phase with Envi-Chrom P cartridges and 10 mL with ethyl acetate, which were concentrated in 1 mL of mobile phase to inject 15 μl into the HPLC-DAD. Envi-Chrom P cartridges were previously compared for drying time and recovery efficiency against Isolute ENV + cartridges. The equipment's optimized experimental conditions were in a C8 column at 0.6 mL min-1, at 24 ° C, mobile phase of sodium phosphate buffer at pH 4.5 (B) and acetonitrile (C), at wavelengths of 234, 254, 280, 210 nm, with a gradient of 70% B / 30% C in 0 min and 50% B / 50% C from 0 to 14 min. The method was validated where heteroscedasticity was demonstrated at levels close to the detection limit of 1.0 μg/L and the quantification limit of 3.3 μg/L. The recoveries in all the analytes were between 85% and 114%, with the exception of carbaryl, with a recovery of 129% above the acceptance criterion (80% - 120%) and acceptable coefficients of variation were obtained in a range of 1 % and 18%. It was demonstrated that above the administrative limit of 1.0 μg/L, there were no interferences of the internal standard on the analytes or of the pesticides on the internal standard. In addition, the stability of the samples in the autoinjector was evaluated, obtaining that the responses of the analytes did not vary more than the percentage of bias allowed for the methodology (CV±20%) and that carbofuran can be injected up to 48 hours after its preparation, while ametrin must be injected the same day it is prepared. The method met the parameters in the validation tests, with the exception of the carbaryl that had a recovery above the acceptance criteria, which shows that it is suitable for use, but the test must be repeated at the low level to give the method by validated. The uncertainty that the component that has the greatest influence on its estimation is the signal from the equipment

Availability note (English)

Available from Biblioteca Luis Demetrio Tinoco, Universidad de Costa Rica

Abstract (Spanish)

Se realizo el desarrollo y validacion de metodo para la determinacion cuantitativa de plaguicidas en aguas mediante extraccion en fase solida, utilizando cromatografia liquida con detector de arreglo de diodos de plaguicidas pertenecientes a las siguientes familias diferentes: carbamatos (carbofuran y carbarilo), triazinas (ametrina y hexazinona), uracilo (bromacil) y urea (diuron). El metodo se optimizo a partir del Procedimiento para el Escrutinio General de Plaguicidas Inhibidoras de Colinesterasa en Matrices Biologicas por Extraccion Quechers y Deteccion Con Cromatografia de Gases (GC)/Detector de Nitrogeno (NPD)/NPD, Cromatografia Liquida de Alta Eficiencia(HPLC)/Detector de Arreglo de Diodos(DAD) y de la metodologia para la Determinacion de plaguicidas en muestras de agua superficial mediante extraccion con fase solida y cromatografia liquida (EFS + LC) del Instituto Regional de Estudios en Sustancias Toxicas IRET de la Universidad Nacional de Costa Rica . En la extraccion se eluyo 500mL de agua enriquecida con los plaguicidas y se realizo la extraccion en fase solida con cartuchos Envi-Chrom P y 10 mL con acetato de etilo, los cuales se concentraron en 1 mL de fase movil para inyectar 15 μl en el HPLC-DAD. Los cartuchos Envi-Chrom P fueron previamente comparados en tiempo de secado y eficiencia de recuperacion contra cartuchos Isolute ENV+. Las condiciones experimentales optimizadas del equipo fueron en columna C8 a 0.6 mL min-1, a 24 °C, fase movil de buffer de fosfato de sodio a pH 4.5 (B) y acetonitrilo (C), en las longitudes de onda de 234, 254, 280, 210 nm, con gradiente 70 %B / 30 % C en 0 min y 50 % B / 50 % C de 0 a 14 min. Se realizo la validacion del metodo donde se demostro heterocedasticidad en niveles cercanos al limite de deteccion de 1.0 μg/L y al limite de cuantificacion de 3.3 μg/L. Las recuperaciones en todos los analitos estuvieron entre 85% y 114%, con excepcion del carbarilo, con una recuperacion del 129% por encima del criterio de aceptacion (80% - 120%) y se obtuvieron coeficientes de variacion aceptables en un rango de 1% y 18%. Se demostro que por encima del limite administrativo de 1.0 μg/L, no existieron interferencias del estandar interno sobre los analitos ni de los plaguicidas sobre el estandar interno. Ademas, se evaluo la estabilidad de la muestras en el autoinyector obteniendo que las respuestas de los analitos no variaron mas del porcentaje de sesgo permitido para la metodologia (CV±20%) y que el carbofuran se puede inyectar hasta 48 horas despues de su preparacion, miestras que, la ametrina se debe inyectar el mismo dia en que se prepara. El metodo cumplio con los parametros en las pruebas de validacion, a excepcion del carbarilo que tuvo u na recuperacion por encima del criterio de aceptacion, lo cual muestra que es apto para uso, pero se debe repetir la prueba en el nivel bajo para dar el metodo por validado. La incertidumbre que el componente que tiene mayor influencia en su estimacion es la senal del equipo. (autor)

Additional details

Additional titles

Original title (Spanish)
Desarrollo y validacion de un metodo analitico para la determinacion cuantitativa de plaguicidas en agua mediante extraccion en fase solida y cromatografia liquida con detector de arreglo de diodos

Publishing Information

Imprint Place
Grecia (Costa Rica)
Imprint Pagination
106 p.

INIS

Country of Publication
Costa Rica
Country of Input or Organization
Costa Rica
INIS RN
52062653
Subject category
S54: ENVIRONMENTAL SCIENCES;
Resource subtype / Literary indicator
Numerical Data, Thesis, Non-conventional Literature
Descriptors DEI
CHROMATOGRAPHY; EVALUATED DATA; HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY; PESTICIDES; WATER POLLUTION
Descriptors DEC
CHROMATOGRAPHY; DATA; INFORMATION; LIQUID COLUMN CHROMATOGRAPHY; NUMERICAL DATA; POLLUTION; SEPARATION PROCESSES

Optional Information

Notes
Figs.,tabs., charts, ills., refs.