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

• Published in: Clean : soil, air, water Vol. 42; no. 10; pp. 1441 - 1449
• Main Authors: Martins, Gisele L., Friggi, Caroline A., Prestes, Osmar D., Vicari, Michele C., Friggi, Daniela A., Adaime, Martha B., Zanella, Renato
• Format: Journal Article
• Language: English
• Published: Weinheim Blackwell Publishing Ltd 01-10-2014; Wiley Subscription Services, Inc
• Subjects: Fungicides; Insecticides; Irrigated rice production; LC-MS/MS; Oryza sativa; QuEChERS
• ISSN: 1863-0650; 1863-0669
• DOI: 10.1002/clen.201300140

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.
A fraction of the amount of pesticide used reaches the soil leading to contamination and potential interference in crops development in future cultivations. This work developed a LC–MS/MS method for the simultaneous determination of pesticide residues with different physicochemical properties in soil samples. The method is simple and fast and was successfully applied to the analysis of soil samples from rice paddies.