Pesticides in seaweed: optimization of pressurized liquid extraction and in-cell clean-up and analysis by liquid chromatography–mass spectrometry

Abstract

Chemical residues, such as insecticides and anthelmintics, are frequently redistributed from the aquatic environment to marine species. This work reports on a fast validated protocol for the analysis of azamethiphos, three avermectins, two carbamates and two benzoylurea pesticides and chemotherapeutic agents in seaweeds based on pressurized liquid extraction and separation of analytes by liquid chromatography coupled with tandem mass spectrometry. The variables affecting the efficiency of pressurized liquid extraction, including temperature, number of extraction cycles, static extraction time and percent acetonitrile flush volume, were studied using a Doehlert design. The optimum parameters were 100 °C and one cycle of 3 min with 70 % acetonitrile. Adequate in-cell clean-up of the seaweeds was achieved using 0.8 g of Florisil over 0.1 g of graphitized carbon black on the bottom of the cell. The optimized method was validated using an analyte-free seaweed sample fortified at different concentrations. The limits of quantification ranged from 3.6 μg kg(-1) (azamethiphos) to 31.5 μg kg(-1) (abamectin). The recovery was from 87 to 120 % in most cases at different spiking levels. Finally, the reproducibility of the method expressed as the relative standard deviation and evaluated at concentrations of 10 and 50 μg kg(-1) was in the range 9-14.3 % and 6.1-12.3 %, respectively. The applicability of the method was evaluated with five commercial and 12 wild edible seaweeds, and four target compounds were detected in two wild seaweeds at a concentration below the quantification limit.

Food safety hazards in the European seaweed chain

“…Lorenzo et al. () detected pesticides such as azamethiphos, diflubenzuron, teflubenzuron, and propoxur in wild seaweed ( U. rigida ), although at concentrations below the LOQ. Authors concluded that additional research on the use of chemotherapeutic agents is required given the lack of data on currently used compounds and to clarify transformation and biodegradation processes (Lorenzo et al., ).…”

Safety of Novel Protein Sources (Insects, Microalgae, Seaweed, Duckweed, and Rapeseed) and Legislative Aspects for Their Application in Food and Feed Production

“…Seaweeds were contaminated by polychlorinated dibenzo‐p‐dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) of industrial origin, such as combustion source (Hashimoto and Morita ). Pesticides that could be present in seaweeds are, for example, azametiphos, diflubenzuron, teflubenzuron, propoxur (Lorenzo and others ), and organic micropollutants (polychlorinated biphenyls (PCBs), chlorinated pesticides, polycyclic aromatic hydrocarbons (PAHs)) (Pavoni and others ). Further studies regarding the presence of chemotherapeutic agents in seaweeds are required, because of the lack of data on some currently used compounds, and to elucidate the transformation and biodegradation processes (Lorenzo and others ).…”

Sample Preparation Methods for Pesticide Analysis in Food Commodities, Biological and Environment Matrices

“…Solid matrices including soil, sediment, food commodities, and air sampling solid sorbent materials (filter, polyurethane foam, solid sorbents (XAD-2, XAD-4, Tenax-TA)) are extracted prior to an SPE (or dSPE) cleanup step with a variety of approaches including microwave extraction, pressurized liquid extraction (as referred commonly as pressurized solvent extraction), ultrasonic extraction, and traditional solid-liquid extractions [41,45,57,61,66,[78][79][80][81][82][83][84][85][86][87][88][89][90][91][92][93][94][95][96]. These approaches are not selective and the polarity of the organic solvents and choices of additives in these extraction procedures will impact the co-extractive matrix, which necessitate the subsequent SPE or dSPE cleanup choices.…”

“…In addition, for SPE, aqueous extracts are easier to optimize SPE loading, washing, and elution steps as extracts of organic solvents need careful consideration to ensure adequate retention of target analytes on sorbent materials to prevent washout. The most common solvent choices for pressurized liquid extraction and microwave extraction of solid matrices were acetonitrile, ethyl acetate, acetone, hexane, or combinations of these solvents [81][82][83][84][85][86][87][88][89][90][91][92][93][94][95][96]. With microwave extraction, acetone has been added to hexane (2:1) to improve the recoveries for polar OPs, while use of hexane can reduce matrix co-extractives [81].…”

“…Reduction in coextracts has also been reported with acetonitrile rather than methanol or acetone (with microwave extraction) and good recoveries have been reported for OCs and neonicotinoids [83,84]. Hexane, dichloromethane, ethyl acetate, acetone, and acetonitrile have also been commonly used for pressurized solvent extraction of a large range of polarity of pesticides [41,57,65,66,[85][86][87][88][89][90][91][92][93][94][95][96].…”