Occurrence of common plastic additives and contaminants in raw, steamed and canned mussel samples from different harvesting areas using MSPD-HPLC methodology.

Microplastics are a complex mix of chemicals containing polymers and certain plastic additives such as bisphenols and phthalates. These particles are porous materials that can also sorb contaminants from their surroundings, and leach chemicals from the particle under certain circumstances. Aquatic animals can ingest microplastic particles, which mostly bioaccumulate in the gastrointestinal tract of animals. In terms of dietary exposure, small animals consumed whole such as mussels, contribute more to the dietary intake of microplastic particles. Plastic additives and contaminants are not chemically bound to the polymers, and certain processing methods or cooking processes result in the release of these chemicals that leach from the plastic particles, leaving them more available for absorption when ingested. Analytical methods are crucial for a better understanding of the occurrence of plastic additives and contaminants in aquatic products, and to know certain circumstances and treatments that influence human exposure. This study uses an MSPD-HPLC methodology for the simultaneous determination of 9 analytes (BPA, BPF, BPS, DEP, DBP, DEHP, DDD, DDT, and DDE) analyzing, for the first time, the occurrence of these chemicals in raw, steamed and canned mussels of two different harvesting areas (Atlantic and the Mediterranean), becoming one of the most efficient methodologies for determining the presence of these analytes in very complex food matrices, able to define the changes in cooking and processing activities. The results showed that the heat and pressure treatment could influence the migration of plastic additives from microplastic particles present in mussels to the cooking liquids.

Occurrence of common plastic additives and contaminants in mussel samples: Validation of analytical method based on matrix solid-phase dispersion.

A new matrix solid-phase dispersion (MSPD) extraction methodology, combined with high-performance liquid chromatography equipped with a diode-array detector, was developed and validated for the simultaneous determination of 10 compounds in mussels from Galician Rias (Spain). These pollutants are compounds commonly used for plastic production as additives, as well as common plastic contaminants. The compounds selected were bisphenol-A, bisphenol-F, bisphenol-S, nonylphenol-9, nonylphenol, diethyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, dichlorodiphenyltrichloroethane, dichlorodiphenyldichloroethane, and dichlorodiphenyldichloroethylene. The parameters affecting the MSPD extraction efficiency such as the type of sorbent, mass sample-sorbent ratio, and extraction solvent were optimised. The proposed method provided satisfactory quantitative recoveries (80-100%), with relative standard deviations lower than 7%. In all cases, the matrix-matched calibration curves were linear in the concentration range of 0.32-120.00 µg/kg, with quantification limits of 0.25-16.20 µg/kg. The novel developed MSPD-high-performance liquid chromatography methodology provided good sensitivity, accuracy, and repeatability for quality control analysis in mussels.

Effective determination of ampicillin in cow milk using a molecularly imprinted polymer as sorbent for sample preconcentration.

The aim of this study was to prepare molecularly imprinted polymers (MIPs) with ampicillin (AMP) and to evaluate the feasibility of these materials for being used as solid phase extraction sorbent for the selective preconcentration and determination of AMP in cow milk samples. MIPs were synthesized by bulk polymerization using methacrylic acid or methyl methacrylate as monomer and ethylene glycol dimethacrylate as cross-linker at different ratios. Characterization of the MIPs were carried out by Fourier-transform infrared spectrometry. The variables affecting the molecularly imprinted solid-phase extraction (MISPE) procedure were optimized. AMP recoveries were higher than 98%, and RSD less than 7%. A preconcentration factor of 20 was reached, which was sufficient to determine AMP at levels allowed by the EU (4µgkg-1) in cow milk. The selectivity of the AMP-MIP was evaluated in presence of other structurally related ß-lactam antibiotics (amoxicillin, oxacillin, penicillin G).

Synthesis and characterization of a molecularly imprinted polymer for the determination of spiramycin in sheep milk.

A series of molecularly imprinted polymers (MIPs) comprising reactionary sites which are complementary to macrolide antibiotic spiramycin (SPI) were synthetized by noncovalent bulk polymerization technique. MIPs were synthesized under different polymerization process and their recognition efficiency was evaluated in binding studies in comparison with non-imprinted polymers. The best MIP was morphologically characterized and equilibrium assays were carried out. The MIP was evaluated as a sorbent for extraction and preconcentration of SPI from aqueous and sheep milk samples, and an off-line MISPE method followed by high-performance liquid chromatography with UV diode-array detection was established. Good linearity were obtained for SPI in a range of 24-965µgkg-1 and the average recoveries at three spiked levels in milk samples were higher than 90% (RSD<5%). Limit of quantification was 24.1µgkg-1. Cross-reactivity studies from other macrolides with similar structure were tested. The optimum imprinted polymer showed a good selectivity and affinity for SPI, demonstrating the potential of the proposed MISPE for rapid, sensitive and effective sample pretreatment for selective determination of SPI in sheep milk samples.

Occurrence of erythromycin residues in sheep milk. Validation of an analytical method.

The paper describes a new and selective analytical sample treatment for quantitative extraction and preconcentration of erythromycin in presence of other macrolide antibiotics in sheep milk samples. The methodology is based on the use of a molecular imprinted polymer (MIP) employed as solid phase extraction sorbent (MISPE). The synthesized material by bulk polymerization using erythromycin (ERY) as template was evaluated as solid phase extraction sorbent, in a novel sample treatment technique that can be coupled to high-performance liquid chromatography with diode-array detector (HPLC-DAD). MIP selectivity was studied for other macrolide antibiotics with similar structures, such as tylosin (TYL), spiramycin (SPI), josamycin (JOS), roxithromycin (ROX) and ivermectin (IVER) getting recoveries for these interferents lower than 35%, for all cases except for ROX, which recoveries were around 85%. The variables affecting the molecularly imprinted solid-phase extraction (MISPE) procedure were optimized to select the best conditions of selectivity and sensitivity to determine ERY at concentration levels established by EU legislation in sheep milk. Under the selected experimental conditions, quantification limit was 24.1 µg kg(-1). Recoveries were higher than 98%, with RSDs between 0.7% and 2%. The proposed MISPE-HPLC method was validated and successfully applied to ERY analysis in sheep milk samples.

Characterization of Spanish honeys with protected designation of origin "Miel de Granada" according to their mineral content.

Honey attributes such as geographical origin or specified botanical sources often command a premium price due to their organoleptic or pharmacoactive properties. "Miel de Granada" is a highly quality product with protected designation of origin (PDO) which includes six monofloral honeys and two multifloral honeys. Our objective was the characterization of "Miel de Granada" according to their metal content. Metal content was specific enough and allowed discrimination from honeys of different botanical and geographical origins and confirmed the authenticity of PDO labelling as Granada product with the determination of only five elements (K, Na, Ca, Mg and Zn). Chemometric techniques as cluster analysis and ANOVA were used to classify honeys according to their botanical and geographical origin in the metal data. Metal content marks the differences in honey samples and can be used as a tool to assess the quality of honeys. ANOVA showed significant differences among rosemary honeys from different geographical areas despite the botanical factor weight. Our research contributes to the groundwork studies to determine the geographical origin of Spanish honeys.