Development and validation of methodology for determination of pesticides in soybeans / Desenvolvimento e validação de metodo para determinação de agrotoxicos em grãos de soja

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

Soy is one of principal Brazilian exportation products of Brazil as it is much used as a foodstuff because of its functional properties: rich in vitamins, proteins and minerais. The increasing quantity and quality of soy demands a constant and even expressive application of pesticides during soy cultivation. On the other hand, for preservation of public heath, since most pesticides may be prejudicial to health, the main regulatory agencies impose the maximum residues limits of pesticides in food. Thus, in this work, a method to determine the main pesticides applied in soy cultivation (imazethapyr, imazaquin, metsulfuron-methyl, carboxin, chlorimurom-ethyl and tebuconazole) using matrix solid phase dispersion (MSPD) as the extraction technique, followed by a clean-up step and subsequent chromatographic analysis by high performance liquid chromatography - diode array detection (HPLC-DAD), was developed and validated. The results have shown that MSPD is a suitable extraction procedure for solid and complex matrices, as is the case of soy and is a rapid and simple technique. However, it requires the optimization of some variables during the process of methodology development. The clean-up step was necessary because of the amount of matrix impurities, but the majority was eliminated using a C8 co-column. Remaining im.purities with the same retention time as imazethapyr and metsulfuron do not invalidate the determination but prejudice the quantification of these compounds. The validated method has shown good -results of recuperation for ali pesticides (60 - 120 %) except for metsulfuron and tebuconazole at the lowest concentration levei, precision <15 % for ali compounds, except for imazethapyr and metsulfuron, good linearity and correlation coefficients >0.90 without visible bias. The quantification limit of the method allows determinations below the maximum residues limits for ali pesticides, except for the imazethapyr, due to the presence of an impurity. Soy samples from soy cultivation were analyzed and did not present contamination for the pesticides under study

ASSUNTO(S)

produtos quimicos agricolas hplc-dad cromatografia liquida de alta eficiencia method validation extração (quimica) soy pesticides mspd soja

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