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

Abstract

Neste trabalho, um método para determinação dos agrotóxicos carbofurano, clomazona, 2,4-D e tebuconazol em águas subterrâneas é descrito. O método utiliza a Extração em Fase Sólida (EFS) com cartuchos de C18 e quantificação por Cromatografia Líquida de Alta eficiência com Detector de Arranjo de Diodos (CLAE-DAD). Após a otimização dos parâmetros de extração e separação dos compostos, o método foi validado avaliando-se curva analítica, linearidade, limites de detecção e quantificação, precisão e exatidão (recuperação). O método apresentou recuperações médias de 87,9% e 96,9%, para a repetibilidade e precisão intermediária, respectivamente, com RSD de 0,8 a 20,7% para todos os compostos. O método será empregado na determinação de agrotóxicos em águas subterrâneas com um limite de quantificação de 0,2 µg L -1 .A method is described for the determination of the pesticides carbofuran, clomazone, 2,4-D and tebuconazole in groundwaters. The method involves solid phase extraction (SPE) with C18 cartridges and quantification by high performance liquid chromatography with diode array detector (HPLC-DAD). After the optimization of the extraction and separation parameters, the method was validated by evaluating the analytical curve, linearity, limits of detection and quantification, precision and accuracy (recovery). The method presents an average recovery of 87.9% and 96.9%, in repeatability and intermediate precision conditions, respectively, with adequate precision (RSD from 0.8 to 20.7%), for all compounds. The method will be applied to determine pesticides in groundwater samples with limit of quantification of 0.2 µg L -1 . Keywords: pesticides, groundwater, HPLC-DAD, SPE, validation IntroductionA group of artificially synthesized substances, called pesticides, has been used in agriculture to control pests and to increase production. 1 These substances protect the agricultural crops, but overuse and incorrect use can pose risks to human health and the environment. 2,3 Brazil ranks eighth in pesticide use in the world, 4 and Rio Grande do Sul State is responsible for 10.4% of pesticide consumption in Brazil. 5 Many researchers have analyzed the residue of pesticides in water samples. [6][7][8] The pesticides 2,4-D, clomazone, tebuconazole and carbofuran are often used in the regional agriculture of Rio Grande do Sul.The increase in the amount and variety of products applied to agriculture makes it necessary to monitor residues in the environment; 9 therefore, the analysis of pesticides has received increasing attention in the last few decades.Groundwater represents an important source of drinking water supply in many countries, and the use of pesticides in agricultural areas may lead to its contamination by drift, runoff, drainage and leaching. 10 The groundwater contamination by pesticides has been documented in many papers around the world. [10][11][12][13][14] For many years, the pesticide analysis in environment samples has attracted the attention due to the wide use of such compounds, as well as its environmental i...

Resíduos de pesticidas em águas superficiais de área de nascente do Rio São Lourenço-MT: validação de método por extração em fase sólida e cromatografia líquida

“…Trabalhos análogos ao apresentado que visam o desenvolvimento de métodos analíticos adequados para a determinação simultânea de vários princípios ativos, [51][52][53][54] assim como sua posterior aplicação em amostras de água, 51,52,54 têm sido evidenciados com frequência na literatura.…”

Determination of carbamates in beverages by liquid-liquid extraction with low temperature partitioning and liquid chromatography

“…Generally, analytical methods utilized for determination of carbamates in these matrices involve laborious steps, consume analysis time and require derivatization procedures, 40 which are not suitable in emergency cases related to intentional intoxications. 17 They usually include a liquid-liquid extraction (LLE), 18,28 solid-phase extraction (SPE), 19,22,[41][42][43] solid-phase microextraction (SPME), 44,45 matrix solid-phase dispersion (MSPD), [46][47][48] liquid-liquid microextraction, 49 dispersive liquid-liquid microextraction (DLLME), 50,51 temperature controlled ionic liquid dispersive liquid phase microextraction, 52 carbon nanotube reinforced hollow fiber liquid-phase microextraction 53 or supercritical fluid extraction 54 followed by gas 20,50,[55][56][57][58][59][60] or liquid chromatography. 1,19,48,49,52,53,[61][62][63][64][65][66][67][68][69][70] The low volatility and the thermolability of these compounds and ...…”

Herbicides Persistence in Rice Paddy Water in Southern Brazil

“…In Brazil some studies has been done until now to investigate the behavior and destination of herbicides in the systems related to the rice paddy fields in an attempt to evaluate the risk to the environment. (Zanella et al 2002;Noldin et al, 1997: Bortoluzzi et al 2006Marchesan et al 2007;Resgalla et al, 2007;Bortoluzzi et al 2007;Grützmacher et al 2008;Caldas et al 2009;Silva et al, 2009;Caldas et al 2010;Demoliner et al 2010;Marchesan et al 2010;Reimche, 2010).…”