Simultaneous LC–MS/MS Determination of Imidazolinone Herbicides Together with Other Multiclass Pesticide Residues in Soil

Abstract

An effective method based on a modified quick, easy, cheap, effective, rugged, and safe sample preparation step and determination by LC with MS/MS has been developed and validated for the simultaneous determination of pesticides with different characteristics in soil samples. Several parameters that affect the extraction and analysis were studied and the proposed method was validated using spiked blank soil samples. Recoveries for the herbicides clomazone, imazapic and imazethapyr, the insecticides fipronil and thiamethoxam, and the fungicides propiconazole and trifloxystrobin from blank samples spiked at levels between 2 and 100 µg kg−1 were in the acceptable range of 72.5–119.3% with relative standard deviation below 18.2%. Method limit of detection ranged between 0.12 and 0.6 µg kg−1. The method was successfully applied to the analysis of soil samples from rice paddies were thiamethoxam (103.4–770.8 µg kg−1), imazethapyr (2.4–293.5 µg kg−1), and fipronil (2.1–170.0 µg kg−1) were found in all samples. Imazapic, clomazone, trifloxystrobin presented low concentrations and propiconazole was not detected. The main advantages of the method lie in the fact that is simple and quick to perform, demand small amount of solvent and permit the analysis of multiclass pesticides at trace levels in soil samples with good trueness and precision.

Contaminantes emergentes em matrizes aquáticas do Brasil: cenário atual e aspectos analíticos, ecotoxicológicos e regulatórios

“…28,188,189 Além da SPE, outras técnicas de preparo de amostras também são utilizadas para a determinação de micropoluentes no ambiente, por exemplo, a microextração em fase sólida (SPME), que faz uso de uma fibra de material sorvente para a extração dos compostos por imersão ou por headspace; a QuECheRS (do inglês, Quick, Easy, Cheap, Effective, Ruged and Safe), que utiliza como etapa inicial a extração por um solvente (originalmente acetonitrila), em seguida adição de sais e separação de fase, etapa de limpeza (clean up) e adição de padrão interno para posterior determinação dos analitos; dentre outras técnicas. [190][191][192][193] Concomitantemente com a otimização das técnicas analíticas, foram desenvolvidos e aprimorados diferentes bioensaios (os quais utilizam organismos vivos para avaliar um efeito de uma substância ao qual foram expostos por um período conhecido de tempo) como ferramentas capazes de fornecer informações adicionais aos ensaios ecotoxicológicos, sobre os efeitos estrogênicos, androgênicos, de sinergismo ou influências antiestrogênicas relacionadas à presença de inúmeros contaminantes em uma amostra complexa.…”

Richness and density of aquatic benthic macroinvertebrates after exposure to fungicides and insecticides in rice paddy fields

“…The extract was cleaned with anhydrous magnesium sulfate and PSA, with agitation and centrifugation. Pesticide determination was performed with ultrahigh-performance liquid chromatography and serial mass spectrometry (UHPLC-MS/MS) with electrospray ionization (ESI) sources (Prestes et al 2009, Martins et al 2014.…”

Introduction of imidazolinone herbicide and Clearfield® rice between weedy rice—control efficiency and environmental concerns

“…To understand this, the water solubility of IMI is generally relatively high (Sondhia et al, 2015), but the PKa for each is relatively low. This solubility of IMI-herbicides in water helps to determine the leaching potential at different depths, where the pKa values of the IMIherbicides are 1.3-3.9 (Martins et al 2014). However, its persistence in the soil is linked to the pH value of the soil (Marcia 2014;Neto et al 2017).…”