High-sensitive determination of tetracycline antibiotics adsorbed on microplastics in mariculture water using pre-COF/monolith composite-based in-tube solid phase microextraction on-line coupled to HPLC-MS/MS

Microplastics (MPs) act as carriers for organic pollutants (e.g. antibiotics) and microorganisms (e.g. bacteria) in waters, leading to the proliferation of antibiotic resistance genes. Moreover, the antibiotics adsorbed on MPs may exacerbate this process. For further research, it is necessary to understand the types and amounts of antibiotics adsorbed on MPs. However, due to the heavy work of MPs collection and sample pretreatment, there is a lack of analytical methods and relevant data. In this study, an in-tube solid phase microextraction (IT-SPME) on-line coupled to HPLC-MS/MS method based on amorphous precursor polymer of three-dimensional covalent organic frameworks/monolith-based composite adsorbent was developed, which could efficiently capture, enrich and analyze tetracycline (TCs) antibiotics. Under the optimal extraction parameters, the developed method was capable of detecting TCs at levels as low as 0.48-1.76 pg. This method was applied to analyze the TCs adsorbed on MPs of different particle sizes in mariculture water for the first time, requiring a minimum amount of MPs of only 1 mg. Furthermore, it was observed that there could be an antagonistic relationship between algal biofilm and TCs loaded on MPs. This approach could open up new possibilities for analyzing pollutants on MPs and support deeper research on MPs.

MXene nanosheets woven in polyacrylonitrile nanofiber yarns aligned spider web as a highly efficient sorbent for in-tube solid phase microextraction of beta-blockers from biofluids

The use of electrospinning has received much attention in the production of nanofiber webs due to its advantages such as flexibility and simplicity. The direct electrospinning of nanofibers in an aligned or twisted form and the production of nanofiber yarns can turn nanofibers into woven fabrics, which leads to an increase in the diversity of nanofiber applications and improves their end-use possibilities. In this work, a victorious nanofiber yarn spinning system was used with the help of a rotating funnel. Yarn formation was studied using a composited polyacrylonitrile (PAN)/MXene polymer solution ejected from two oppositely charged nozzles. Finaly their application for packed-in-tube solid-phase microextraction of β-blocker drugs from biofluids was demonstrated. The separation and quantification of analytes were performed by HPLC-UV instrument. The 3D-yarn PAN/MXene sorbent exhibited high flexibility, porosity, sorbent loading, mechanical stability, and a long lifetime. The characterization of the final nanofiber was carried out utilizing Fourier-transform infrared spectroscopy, field emission scanning electron microscope, energy-dispersive X-ray mapping, transmission electron microscope and X-ray diffraction analysis. Various parameters that affect the extraction efficiency, such as extraction time, pH, ionic strength and flow rate of sample solution, and type, volume and flow rate of eluent, were investigated and optimized. Under optimized conditions, the limits of detection were obtained in the range of 1.5-3.0 μg L-1. This method demonstrated appropriate linearity for β-blockers in the range of 5.0-1000.0 μg L-1, with coefficients of determination greater than 0.990. The inter- and intra-assay precisions (RSDs, for n = 3) are in the range of 2.5-3.5%, and 4.5-5.2%, respectively. Finally, the validated method was put in an application for the analysis of atenolol, propranolol and betaxolol in human urine and saliva samples at different hours and acceptable relative recoveries were obtained in the range of 89.5% to 110.4%.

Development of on-line monolith-based in-tube solid phase microextraction for the sensitive determination of triazoles in environmental waters

In this work, a convenient and sensitive method for the determination of triazoles in environmental waters was developed by on-line combining in-tube solid phase microextraction (IT-SPME) and high performance liquid chromatography with diode array detector (HPLC-DAD). To extract triazoles effectively, poly (4-vinyl pyridine-co-ethylene dimethacrylate) monolith was in-situ fabricated and utilized as the extraction phase of IT-SPME. A series of key extraction parameters including desorption solvent, sample volume, adsorption and desorption flow rate, pH value and ionic strength in sample matrix were optimized thoroughly. Under the most favorable conditions (volume of sample, 6.0 mL; adsorption flow rate, 0.2 mL/min; desorption solvent, 80.0 µL mixture of ACN/water (70/30, v/v); desorption flow rate, 50.0 µL/min; sample pH value, 8.0; ionic strength did not be adjusted), the developed monolith-based IT-SPME could extract target analytes effectively and expected analytical merits were achieved. The limits of detection (S/N = 3) and limits of quantification (S/N = 10) were in the ranges of 0.014-0.031 µg/L and 0.11-0.074 µg/L, respectively. Satisfactory method reproducibility was obtained by intra-day and inter-day precisions, with relative standard deviations (RSDs) lower than 10%. The optimized IT-SPME-HPLC-DAD method was then applied to detect triadimenol, triazolone and hexaconazole in water samples including lake, river and sewage waters. The spiked recoveries were 78.9-106% and the RSDs were in the range of 0.2-7.2%. The results well evidence that the proposed method is convenient, accurate, sensitive, practical and environmentally friendly for the determination of triazoles in environmental waters.

A sustainable on-line CapLC method for quantifying antifouling agents like irgarol-1051 and diuron in water samples: Estimation of the carbon footprint

In this work, in-tube solid phase microextraction (in-tube SPME) coupled to capillary LC (CapLC) with diode array detection has been reported, for on-line extraction and enrichment of booster biocides (irgarol-1051 and diuron) included in Water Frame Directive 2013/39/UE (WFD). The analytical performance has been successfully demonstrated. Furthermore, in the present work, the environmental friendliness of the procedure has been quantified by means of the implementation of the carbon footprint calculation of the analytical procedure and the comparison with other methodologies previously reported. Under the optimum conditions, the method presents good linearity over the range assayed, 0.05-10μg/L for irgarol-1051 and 0.7-10μg/L for diuron. The LODs were 0.015μg/L and 0.2μg/L for irgarol-1051 and diuron, respectively. Precision was also satisfactory (relative standard deviation, RSD<3.5%). The proposed methodology was applied to monitor water samples, taking into account the EQS standards for these compounds. The carbon footprint values for the proposed procedure consolidate the operational efficiency (analytical and environmental performance) of in-tube SPME-CapLC-DAD, in general, and in particular for determining irgarol-1051 and diuron in water samples.