Simultaneous Determination of Pesticides in Fruits by Using Second-Order Fluorescence Data Resolved by Unfolded Partial Least-Squares Coupled to Residual Bilinearization

Mercedes Villar Navarro,Miguel Angel Cabezón,Patricia C Damiani

doi:10.1155/2018/3217465

Abstract

In the present work, a chemometric-assisted spectrofluorimetric method has been developed for the simultaneous determination of natural fluorescent pesticides, carbaryl, carbendazim, and thiabendazole, in orange and banana. Only a simple extraction with methanol was required as sample pretreatment. Emission-excitation fluorescence matrices were obtained and resolved by using a second-order multivariate calibration method based on unfolded partial least-squares combined with residual bilinearization (U-PLS/RBL) for achieving “second-order advantage.” In this way, pesticides were determined in fruits even in the presence of inner filter effects, background interactions, strong spectral overlapping, and unexpected components. U-PLS can cope with effects that cause trilinearity loss such as, inner filter effects, including background in the calibration set; meanwhile, RBL allows to resolve the presence of unexpected components. The extraction technique was validated against a commonly applied technique based on the use of ethyl acetate and sodium sulfate. Besides, results obtained for real samples were statistically compared with those obtained by using HPLC. LODs of 0.038, 0.054, and 0.018 mg·kg−1 and 0.044, 0.072, and 0.020 mg·kg−1 were obtained for carbaryl, carbendazim, and thiabendazole in banana and orange samples, respectively; values were in accordance with the MRLs (Maximum Residue Limits) established by different official control organizations such as National Food Safety and Quality Service (SENASA), Codex Alimentarius (based on Food and Agriculture Organization (FAO) of the United Nations and World Health Organization (WHO), and Environmental Protection Agency (EPA).

Highlights

Pesticides are chemical compounds used to kill, repel, or control certain forms of plants or animal life that are considered to be pests. ey can be classified in accordance with their function in insecticides for controlling different varieties of insects, fungicides for preventing the growth of mildew and mushrooms, herbicides for destroying weeds, and disinfectants for avoiding the spread of bacteria and compounds used to control mice and rats
Thiabendazole shows a considerable excitation at the spectral range 280–320 nm, partially coincident to the excitation and emission ranges of carbendazim (Figure 1). is fact allows the reader to conclude that an inner filter effect is caused from thiabendazole over carbendazim when both pesticides are simultaneously present in samples
Calibration in Presence of Matrix: Analysis of Validation Samples and Test Samples—Evaluation of the Method Determination Stage. All these peculiar characteristics of the present systems that have been discussed above preclude the use of an external calibration and suggest that orange and banana matrices must be included in the calibration set. As it has been described in Experimental, calibration was performed including fruit backgrounds. en, a set of validation samples were prepared, using the same fruit pool samples applied in the calibration sets, maintaining the same background matrices

Summary

Introduction

Pesticides are chemical compounds used to kill, repel, or control certain forms of plants or animal life that are considered to be pests. ey can be classified in accordance with their function in insecticides for controlling different varieties of insects, fungicides for preventing the growth of mildew and mushrooms, herbicides for destroying weeds, and disinfectants for avoiding the spread of bacteria and compounds used to control mice and rats. Ey can be classified in accordance with their function in insecticides for controlling different varieties of insects, fungicides for preventing the growth of mildew and mushrooms, herbicides for destroying weeds, and disinfectants for avoiding the spread of bacteria and compounds used to control mice and rats. They are used in public health to kill vectors of diseases, such as mosquitoes, and in agriculture, to kill pests that damage crops. The United States Environmental Protection Agency (EPA) has classified carbendazim as Group C pesticide: Possible Human Carcinogen [4,5,6]

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