Determination of Emerging Contaminants in Cereals by Gas Chromatography-Tandem Mass Spectrometry

Abstract

Cereals are staple foods for human consumption in both developed and developing countries. In order to improve agricultural outputs, resources like reclaimed water for irrigation and biosolids and manure as fertilizers are frequently used, although they may increase the input of contaminants that can potentially be absorbed by crops and enter the food chain. Emerging contaminants (human and veterinary pharmaceuticals, personal care products, surfactants, plasticizers, and industrial additives, among others) are continuously introduced in the environment from a variety sources and these contaminants may enter the food chain through plant uptake. In this study, an analytical method, based on ultrasound-assisted extraction and dispersive solid-phase cleanup, was developed for the determination of emerging contaminants from different classes in four highly consumed cereal grains (wheat, oat, barley, and rice). These analytes were selected considering the results of our previous studies carried out in soil and vegetables and those frequently detected in real samples were chosen. The target compounds selected were bisphenol A (BPA), bisphenol F (BPF), methyl paraben, propyl paraben, linear chain nonylphenol in position 4 (4-n-NP), mixture of ring and chain isomers of NP and six pharmaceutical compounds (allopurinol, mefenamic acid, carbamazepine, paracetamol, diclofenac and ibuprofen). Recoveries ranging from 68 to 119% with relative standard deviations (RSD) < 18% were obtained for all the compounds except for allopurinol, with recoveries that ranged from 30 to 66% with RSD ≤ 12% and the limits of detection achieved ranged from 0.03 to 4.9 ng/g. The method was applied to the analysis of 16 cereal samples, ten were purchased in local supermarkets and the rest were collected directly from agricultural fields, five of which were fertilized with organic amendments. Bisphenol A (BPA) was detected in all samples at levels that ranged from 1.6 to 1,742 ng/g. Bisphenol F, a substitute for BPA, was also found in six samples (up to 22 ng/g). Linear 4-n-NP was found in a reduced number of samples but the mixture of NP isomers was found in all the samples, being the mean concentrations in wheat, barley, oat and rice 49, 90, 142, and 184 ng/g, respectively.

Simultaneous Determination of 15 Mycotoxins in Aquaculture Feed by Liquid Chromatography–Tandem Mass Spectrometry

“…In a first approach, a method based on ultrasound-assisted matrix solid-phase dispersion (UA-MSPD) was assayed. This technique has been successfully applied in our laboratory for the multiresidue determination of emerging contaminants in vegetables and cereals [ 17 , 18 ]. In the selection of the extraction solvent, it was taken into account that polar toxins such as FBs require aqueous solutions, while organic solvents are necessary for the extraction of hydrophobic toxins such as aflatoxins.…”

Detection of Emerging Pollutants Using Aptamer-Based Biosensors: Recent Advances, Challenges, and Outlook

“…Another alternative to increase the affinity is through aptamers that present cooperative binding interactions. They are capable of simultaneously binding to different sites on the same target, which is achieved by using multiple aptamers that are ligated onto one strand of DNA [ 6 ]. The affinity of aptamers for their target can also be promoted under native conditions through the use of SELEX variants such as in vivo-SELEX or Cell-Selex.…”

“…The affinity of aptamers for their target can also be promoted under native conditions through the use of SELEX variants such as in vivo-SELEX or Cell-Selex. These types of protocols allow the selection of aptamers under real physiological or environmental conditions [ 6 , 7 ].…”

“…For example, it has been reported the degradation of nucleic acids by nucleases in real environments. New strategies to improve the stability of the aptamers through modified nucleotides, by including chemical groups (2′- O -methoxy or 2′-fluoro or motifs) to replace 2′OH moieties, or by the addition of hairpin structures to the 5′ or 3′ ends have been proposed [ 5 , 6 ]. In addition, the backbone of the aptamers, which are phosphodiester bonds, can be substituted by residues of phosphorothioate and boranophosphate or nucleic acid peptides [ 6 ].…”

“…The relevance of mitigating the contamination caused by EPs is based on their characteristics related to bioavailability, mobilization, transformation, and persistence in water, sediments, and soil [ 5 ]. Moreover, EPs can be introduced to the food chain through different pathways, such as irrigation with contaminated water and plant uptake [ 6 ]. In this manner, researchers have explored the adverse effects of many EPs in organisms.…”