Quantification of Thiamethoxam in Rhizomes and Leaves of the &amp;lt;i&amp;gt;Hedychium coronarium&amp;lt;/i&amp;gt; and Water and Soil by High-Pressure Liquid Chromatography

Claudine Gonçalves Da Rocha,Francis Henrique Ramos França,Claudia Andrea Lima Cardoso

doi:10.4236/ajac.2012.33032

Abstract

The linearity, stability, accuracy and inter-day precisions of the assay method were evaluated in water, soil and rhizomes and leaves of Hedychium coronarium of the Zingiberaceae family. Mato Grosso do Sul is a predominantly agricultural state in Brazil and has many rivers and permanent and seasonal lakes, in which the Hedychium coronarium, an aquatic plant, is found the swampy environments. The prepared samples were analyzed quantitatively by High Performance Liquid Chromatography with PDA and UV detection for the presence of thiamethoxam. The thiamethoxam was recovered from these samples at rates ranging from 81.16% - 99.93%. The coefficient of variation in the quantitative analysis of the thiamethoxam was under 5%. The linearity of the method was determined by linear regression. The analysis of the samples spiked with known amounts of analyte demonstrated that the response was proportional to the concentrations of the samples with determination coefficients of r2 = 0.9992 (water and soil) and r2 = 0.9990 (leaves and rhizomes) for the linear range of the analytical calibration curves of the samples. The detection limit was 0.36 ug.L-1 and quantification limit was 1.2 ug.L-1 for thiamethoxam. The method was considered sensitive for quantification of the thiamethoxam in water, soil and rhizomes and leaves of Hedychium coronarium.

Highlights

Pesticides are usually studied in terms of their effectiveness in controlling pests and diseases, but recently synthesized molecules have caused physiological effects on plants, capable of modifying their metabolism and morphology, thereby influencing their growth and production [1,2].The introduction of Thiamethoxam® (Novartis, Switzerland) took place in 1998
The present study developed and validated a methodology to analyze thiametohxam in samples of soil, water and rhizomes and leaves of H. coronarium
Identification of the thiamethoxam with the aid of photodiode array detector (PDA) detector scanning in the spectral range of 200 - 800 nm did not reveal interferences in retention time of the extracts of water, soil rhizomes and leaves of H. coronarium in LC by the developed elution method

Summary

Introduction

Pesticides are usually studied in terms of their effectiveness in controlling pests and diseases, but recently synthesized molecules have caused physiological effects on plants, capable of modifying their metabolism and morphology, thereby influencing their growth and production [1,2].The introduction of Thiamethoxam® (Novartis, Switzerland) took place in 1998. Pesticides are usually studied in terms of their effectiveness in controlling pests and diseases, but recently synthesized molecules have caused physiological effects on plants, capable of modifying their metabolism and morphology, thereby influencing their growth and production [1,2]. Thiamethoxam, 3-[(2chloro-5-thiazoly)methyl]tetrahydro-5-methyl-N-nitro4H-1,3,5-oxadiozin-4-imine, belongs to a relatively new class of insecticides known as neonicotinoids, which act as agonists of the post-synaptic nicotinic acetylcholine receptors [1]. Their physicochemical properties make them useful for a wide range of application techniques, including foliar, seed treatment, soil drench, and stem application. Neonicotinoids show good activity against pest insects resistant to other classes of insecticides such as organophosphates, carbamates, pyrethroids, chlorinated hydrocarbons, and several other classes of compounds [3].

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