Adsorption of Macrolide Antibiotics and a Metabolite onto Polyethylene Terephthalate and Polyethylene Microplastics in Aquatic Environments.

Microplastics (MPs) and antibiotics are emerging pollutants widely found in aquatic environments, potentially causing environmental harm. MPs may act as carriers for antibiotics, affecting their environmental distribution. This study investigates the adsorption of four macrolide antibiotics and a metabolite onto two types of MPs: polyethylene terephthalate (PET) and polyethylene (PE). Results revealed a linear isotherm adsorption model, with higher adsorption to PET than to PE (R2 > 0.936 for PE and R2 > 0.910 for PET). Hydrophobic interactions and hydrogen bonding could be the main adsorption mechanisms, with pore filling potentially involved. Reduced particle size enhances adsorption due to the increase of active adsorption sites. This increasement is more pronounced in PE than in PET, leading to an 11.6% increase in the average adsorption of all macrolides to PE, compared to only 5.1% to PET. Dissolved organic matter inhibits adsorption (azithromycin adsorption to PE was reduced from 12% to 5.1%), while salinity enhances it just until 1% salinity. pH slightly influences adsorption, with maximal adsorption at neutral pH. Results in real samples showed that complexity of the matrix decreased adsorption. Overall, these findings indicate that PE and PET MPs can be a vector of macrolides in aquatic environments.

Influence of microplastic contamination on the dissipation of endocrine disrupting chemicals in soil environment.

Microplastic (MP) contamination is in the spotlight today, yet knowledge of their interaction with other organic contaminants in the soil environment is limited. Concerns extend to endocrine disrupting chemicals (EDCs), known for their potential to interfere with the hormonal systems of organisms and for their persistence and widespread presence in the environment. In this study, the most frequently occurring EDCs were monitored both in alluvial soil and in soil contaminated with different MPs commonly found in soil media, polyethylene, polyamide, and polystyrene. Bisphenol A and parabens were the most rapidly dissipating compounds, followed by triclosan and triclocarban, with the latter showing poor degradation. Per- and polyfluoroalkyl substances (PFAS) showed high persistence as concentrations remained nearly constant throughout the experiment. Although they fitted well with first-order dissipation kinetics, most showed biphasic behavior. The co-occurrence of MPs in the soil influenced the kinetic behavior in most cases although the differences were not very marked. MPs could impact sorption-desorption processes, affecting contaminant mobility and bioavailability to organisms in soil. These findings strengthen evidence for the influence of MPs on the behavior of soil contaminants such as EDCs, not only as vectors or sources of contaminants but by affecting dissipation kinetics.

Development and validation of a multi-class analysis of pesticides in corn products by comprehensive two-dimensional liquid chromatography-tandem mass spectrometry.

Due to the growing trend of organic food, there is still concern over the use of chemicals and pesticides in agriculture. In recent years, several procedures have been validated for the control of pesticides in food. In the present research, a comprehensive two-dimensional liquid chromatography coupled with tandem mass spectrometry is proposed for the first time for a multi-class analysis of 112 pesticides in corn-based products. Notably, a "reduced" QuEChERS-based method as extraction and clean-up procedure prior to the analysis, was successfully employed. Limits of quantification values were lower than the ones fixed by the European legislation; intra-day and inter-day precision were lower than 12.9% and 15.1%, respectively (at the 500 µg/kg concentration levels). Over 70% of the analytes provided recoveries between 70% and 120% range (at 50, 500 and 1000 µg/kg concentration levels) with standard deviation values below 20%. In addition, matrix effect values were in the range between 13% to 161%. The method was applied to the analysis of real samples, and three pesticides were detected at trace levels in both samples. The findings of this work pave the way for the treatment of complex matrices such as corn products.

Analytical method for the determination of usually prescribed antibiotics in human nails using UHPLC-MS/MS. Comparison of the efficiency of two extraction techniques.

Antibiotics are a group of drugs used for the treatment of bacterial diseases. They are used in both human and veterinary medicine and, although they are not permitted, they are sometimes used as growth promoters. The present research compares two extraction techniques: ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) in order to evaluate their efficiency in the determination of 17 usually prescribed antibiotics in human nails. The extraction parameters were optimized using multivariate techniques. Once both techniques were compared, MAE was selected as optimal due to its greater experimental practicability together with the better extraction efficiencies it provides. Target analytes were detected and quantified by ultra-high performance liquid chromatography with tandem mass spectrometry detection (UHPLC-MS/MS). The run time was 20 min. The methodology was then successfully validated, obtaining acceptable analytical parameters according to the guide used. Limits of detection were between 0.3 and 3 ng g-1 and limits of quantification were in the range from 1.0 to 4.0 ng g-1. Recovery percentages ranged from 87.5% to 114.2%, and precision (in terms of standard deviation) was less than 15% in all cases. Finally, the optimized method was applied to nails taken from 10 volunteers and the results revealed the presence of one or more antibiotics in all the samples examined. The most commonly found antibiotic was sulfamethoxazole, followed by danofloxacin and levofloxacin. The results demonstrated, on the one hand, the presence of these compounds in the human body and, on the other hand, the suitability of nails as a non-invasive biomarker of exposure.

An Overview of Analytical Methods to Determine Pharmaceutical Active Compounds in Aquatic Organisms.

There is increasing scientific evidence that some pharmaceuticals are present in the marine ecosystems at concentrations that may cause adverse effects on the organisms that inhabit them. At present, there is still very little scientific literature on the (bio)accumulation of these compounds in different species, let alone on the relationship between the presence of these compounds and the adverse effects they produce. However, attempts have been made to optimize and validate analytical methods for the determination of residues of pharmaceuticals in marine biota by studying the stages of sample treatment, sample clean-up and subsequent analysis. The proposed bibliographic review includes a summary of the most commonly techniques, and its analytical features, proposed to determine pharmaceutical compounds in aquatic organisms at different levels of the trophic chain in the last 10 years.

Analytical methods for the determination of endocrine disrupting chemicals in cosmetics and personal care products: A review.

Personal care products (PCPs) and cosmetics are indispensable product in our daily routine. Their widespread use makes them a potential route of exposure for certain contaminants to which human would not be normally exposed. One of these contaminants includes endocrine disrupting chemicals, molecules capable of mimicking the body's natural hormones and interfering with the endocrine system. Some of them are ingredients included in the product's formulation, such as UV-filters (sunscreens), phthalates (plasticizers and preservatives), synthetic musks (fragrances), parabens and other antimicrobial agents (antimicrobial preservatives). Others are non-intended added substances that may result from the manufacturing process or migration from the plastic packaging, as with bisphenols and perfluorinated compounds. Some of these endocrine disruptors have been restricted or even banned in cosmetics and PCPs given the high risk they pose to health. Thus, the development of fast, sensitive and precise methods for the identification and quantification of these compounds in cosmetics is a substantial need in order to ensure consumer safety and provide insight into the real risk of human exposure. The present work aims at reviewing the more recently developed analytical methods published in the literature for the determination of endocrine disrupting chemicals in cosmetics and PCPs using chromatographic techniques, with a focus on sample treatment and the quality of analytical parameters.

Determination of ultraviolet filters in human nails using an acid sample digestion followed by ultra-high performance liquid chromatography-mass spectrometry analysis.

Ultraviolet filters (UV-filters) are specific chemicals that absorb and reflect UVA and UVB radiation from the sun. They are regularly used in sunscreens and in other personal care products (PCPs), and in products like plastics, adhesives, toys, or furniture finishes. This work develops and validates a new method to determine concentrations of UV-filters (BP-1, BP-2, BP-3, BP-6, BP-8, 4-OH-BP, THB, AVB) in human nail samples. Nails are easily available and are considered to be suitable indicators of cumulative and continued exposure to harmful chemicals. The treatment of nail samples includes microwave assisted digestion/extraction (MAE) in a methanolic solution of o-phosphoric acid (0.05 mol L-1) followed by analyte determination using ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS/MS) in multiple reaction monitoring mode. The analytes were separated in less than 10 min. The digestion procedure was optimized using multivariate techniques. Matrix-matched calibration with a pig hoof matrix was used for validating the method. A study of accuracy with spiked blank samples was also conducted. The calculated detection limits varied between 0.2 and 1.5 ng g-1, and quantification limits between 1.0 and 5.0 ng g-1. The trueness of the method was an estimation of the recovery, which was between 90.2% and 112.2%; with an estimated precision (relative standard deviation, % RSD) lower than 12.3% for all UV-filters. Nail samples were obtained from 22 volunteers (male and female). The results showed that BP-1 and BP-3 mainly bioaccumulate in human nails.

Determination of endocrine disrupting chemicals in human nails using an alkaline digestion prior to ultra-high performance liquid chromatography-tandem mass spectrometry.

Rapid industrialization has resulted in a progressive increase in human exposure to hazardous chemicals. The present work develops and validates a new method to determinate 18 endocrine disrupting chemicals (EDCs) in human nail samples. In contrast to other common biological samples, nail sampling is non-invasive and since they take several months to grow out, they are well suited for measuring and reflecting the cumulative exposure to harmful substances in the long term. A digestion of samples with a 0.04 M solution of sodium hydroxide is carried out followed by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), working in multiple-reaction-monitoring (MRM) mode. The compounds were separated in 8 min. Multivariate optimization strategies were used for the optimization of the parameters that affects the digestion procedure. The validation was developed using a matrix-matched calibration and a recovery assay with spiked samples. The limits of detection and quantification ranged from 0.3 to 1.2 ng g-1 and from 1 to 5 ng g-1, respectively. Recovery rates for spiked samples were between 88% and 113% and the relative standard deviation (% RSD) was lower than 12.7% for all studied EDCs. The method was applied for the analysis of these compounds in human nail samples from volunteers. All samples tested positive for several of the analyzed EDCs.

Analytical methods for the determination of emerging contaminants in sewage sludge samples. A review.

Emerging contaminants are a heterogeneous group of chemicals that includes daily personal care products and pharmaceuticals (PPCPs), flame retardants, endocrine disrupting chemicals (EDCs) and nanoparticles (NPs). The present work is an overview focused in the research published in the scientific literature for the determination of this type of pollutants in sewage sludge samples in the last 5 years. Instrumental and sample preparation methods for the detection and quantification of the analytes of interest are reviewed, with an emphasis on the sample treatment techniques. Liquid chromatography (LC) and gas chromatography (GC) coupled to mass spectrometry are generally employed as the analytical technique of preference. Sample preparation techniques include conventional methods such as Soxhlet, solid-phase extraction (SPE), pressurized liquid extraction (PLE) or ultrasound-assisted extraction (UAE), but also other recent techniques, including novel microextraction techniques such as microextraction by packed sorbent (MEPS) or solid-phase microextraction (SPME).