Desenvolvimento de método por micro dispersão da matriz em fase sólida para determinação de resíduos de pesticidas em goiaba (Psidium guajava L.)

Abstract

Guava (Psidium guajava L.) is widely consumed in Brazil due to its pleasant aroma, characteristic flavor and high nutritional value. However, guava crops are subject to various pests and diseases and use pesticides as the main form of control. However, this can lead to residues remaining in the fruit, making it necessary to investigate and monitor the presence of these residues. In this work, we propose to develop a method for determining pesticide residues of different chemical classes in guava, using the solid-phase matrix dispersion technique as the extraction procedure and liquid chromatography/mass spectrometry as the instrumental analysis technique. The residues of acetamiprid, alachlor, aldicarb, ametryn, atrazine, azoxystrobin, bromuconazole, carbaryl, carbofuran, cypermethrin, chlorpyrifos, clothianidin, deltamethrin, difenoconazole, dimethoate, diuron, flutriafol, imidacloprid, lufenuron, malathion, methomyl, pendimethalin, pyraclostrobin, pirimicarb, simazine, teflubenzuron, thiacloprid, thiamethoxam and triadimefon were evaluated. The best extraction conditions were obtained with 0.085 g of water hyacinth biochar, 0.085 g of lyophilized guava and elution with 5 mL of methanol. Analytical validation was performed based on the following parameters: linearity and sensitivity, showing linearity with coefficients of determination higher than 0.99 and sensitive in the range of 0.25-100 μg L-1; selectivity (with matrix effect between 1.2–88%); accuracy and precision, with recovery values in the range of 38–116% with coefficients of variation lower than 16% for the concentration levels 0.01; 0.05; and 0.1 μg g-1(n=5); detection limit between 0.001-0.009 μg g-1 and quantification limit in the range of 0.002-0.028 μg g-1.