Preparation of a mixed stir bar for sorptive extraction based on monolithic material for the extraction of quinolones from wastewater

High performance enrichment and analysis of fluoroquinolones residues in environmental water using cobalt ion mediated paper-based molecularly imprinted polymer chips

BACKGROUND

Fluoroquinolones (FQs) are widely used for their excellent antimicrobial properties, yet their release into aquatic environments pose risks to ecosystems and public health. The accurate monitoring and analysis of FQs present challenges due to their low concentrations and the complex matrices found in actual environmental samples. To address the need for auto-pretreatment and on-line instrumental analysis, developing new microextraction materials and protocols is crucial. Such advancements will provide better analytical assurance for the effective extraction and determination of FQs at trace levels, which is of great significance to environmental protection and human health.

RESULTS

In this work, we presented a Co2+ mediated paper-based molecularly imprinted polymer chip (CMC@Co-MIP), combined with UPLC analysis, to develop an effective analytical method for identifying and quantifying trace amounts of ciprofloxacin (CIP) and enrofloxacin (ENR) in water samples. Notably, the addition of Co2+ in CMC@Co-MIP helped to capture the template molecule CIP through coordination before imprinting, which significantly improved the ordering of the imprinted cavities. CMC@Co-MIP exhibited a maximum adsorption capacity up to 500.20 mg g-1 with an imprinting factor of 4.12, surpassing previous reports by a significant margin. Furthermore, the enrichment mechanism was extensively analyzed by various characterization techniques. The developed method showed excellent repeatability and reproducibility (RSD < 13.0 %) with detection limits ranging from 0.15 to 0.21 μg L-1 and recoveries ranging from 64.9 % to 102.3 % in real spiked water samples.

SIGNIFICANCE

We developed a novel microextraction paper-based chip based on Co2+ mediation, which effectively improved the selectivity and convenience of extracting FQs. This breakthrough allowed the chip to have a high enrichment efficiency as well as provide a robust on-line instrumental program. It also confirms that the imprinting scheme based on metal ion coordination is a high-performance strategy.

Method Validation and Measurement Uncertainty (MU) Evaluation on Enrofloxacin and Ciprofloxacin in the Aquatic Products

This study aimed to investigate a detection method of enrofloxacin and ciprofloxacin to be avail for strictly supervising the quality and safety of aquatic products. The results displayed that the optimal extraction conditions for enrofloxacin and ciprofloxacin were the following five aspects: 15 g dosages of Na2SO4 to dehydrate, 8‰ of acetonitrile and 50% hydrochloric acid to deproteinization, 2 mL dosages of n-hexane to degrease, 10 min of ultrasonic time, and 20 min of extraction (stand) time. Meanwhile, it was also obtained for the optimal detection performance indexes of the recovery, precision, and accuracy from the tests of shrimp, grass carp, and tilapia. In particular, the expanded uncertainties were 2.8601 and 0.8613, and the factors of both the calibration curves (Urel(C)) and the analysis of the experiment (Urel(E)) were the two MU main contributors for enrofloxacin and ciprofloxacin together with the results above 40%. Consequently, the developed novel method was suited for the determination of the enrofloxacin and ciprofloxacin residues in aquatic products and would contribute to reinforce in supervision and inspection of the quality and safety of aquatic products.

Occurrence, transport and environmental risk assessment of pharmaceuticals and personal care products (PPCPs) at the mouth of Jiaozhou Bay, China based on stir bar sorptive extraction

In recent years, research on pharmaceuticals and personal care products (PPCPs) in the marine environment has attracted increasing attention worldwide. However, more work is needed to improve PPCPs detection methods, specifically for seawater environments. An analytical method based on stir bar sorptive extraction (SBSE) had been developed and fully optimized for the pretreatment and detection of ten widely used PPCPs that are commonly found in seawater samples. By optimizing several variables including the material of the stir bars, extraction temperature, extraction time, ionic strength, desorption solvent, and desorption time, the optimized method has achieved excellent results in the detection and quantification of target PPCPs with detection limits ranging from 0.03 to 1 ng/L. The distribution of target PPCPs at the mouth of Jiaozhou Bay was successfully determined by this method, and the concentrations and detection frequencies of PPCPs varied greatly from N.D. to 449.36 ng/L and from 9.1 % to 100 %, respectively. Moreover, the distributions of PPCPs were explained by the Lagrangian particle-tracking model, and the results showed that the Tuandao sewage treatment plant had the most significant impact on the study area. The environmental risk assessment results showed that several target PPCPs might pose risks to aquatic organisms. In particular, triclocarban should receive more attention and the risk quotients of the mixtures (MRQ) should not be ignored.

Weak anion-exchange mixed-mode materials to selectively extract acidic compounds by stir bar sorptive extraction from environmental waters

In this study, the first example of a polytetrafluoroethylene (PTFE)-based magnet coated with weak anion exchange (WAX) monolith as novel support for stir bar sorptive extraction (SBSE) is presented. Firstly, the PTFE magnets were properly modified and vinylized in order to immobilize polymer monoliths onto its surface. Then, a glycidyl methacrylate monolith was prepared and modified with ethylenediamine (EDA) to create weak anion exchanger via ring opening reaction of epoxy groups. The prepared covalently immobilized EDA-modified monoliths onto PTFE magnet exhibited good stability and reusability. Application of resulting material as stir bar for SBSE was investigated for a series of acidic compounds that includes acesulfame, saccharin, diclofenac or ibuprofen, among others as target compounds. Firstly, the SBSE conditions were optimized to promote the WAX interactions with the target compounds achieving recoveries from 37 to 75% and enable the selective extraction of these compounds as it provided values of% matrix effect from 17 to -13% when they were determined by SBSE followed by liquid chromatography - tandem mass spectrometry. The analytical methodology, was then validated and applied for the determination of the target solutes in environmental water samples, which were found at concentration up to 2500 ng L^-1 in river waters.

Determination of quinolones in environmental water and fish by magnetic metal organic frameworks based magnetic solid-phase extraction followed by high-performance liquid chromatography-tandem mass spectrometry

The widespread use of quinolones has become an increasing global public health threat. In this study, IRMOF-3 coated SiO₂/Fe₃O₄ were prepared via a facile room-temperature method. The prepared IRMOF-3 coated SiO₂/Fe₃O₄ was used as a sorbent for magnetic solid phase extraction, and then combined with high-performance liquid chromatography-tandem mass spectrometry for the determination of 10 quinolines. The extraction conditions of magnetic solid phase extraction were studied in detail, and the optimal conditions were established. Under the optimal experimental conditions, the limits of quantification of 10 quinolones were in the range of 0.005-0.01 μg L^-1, the relative standard deviations were 6.58-10.6% (n=7), the enrichment factors were 21.0-23.8 for water samples. The limits of quantification of 10 quinolones were in the range of 0.10-0.20 μg kg^-1, the relative standard deviations were 5.95-14.5% (n=7), the enrichment factors were 1.08-1.24 for fish samples. The proposed method was applied for the determination of 10 quinolones in river water, aquacultural water and a fish sample, and enrofloxacin and ciprofloxacin were found in the fish sample.

Three-dimensional hollow porous raspberry-like hierarchical Co/Ni@carbon microspheres for magnetic solid-phase extraction of pyrethroids

A three-dimensional magnetic hollow porous raspberry-like hierarchical Co/Ni@carbon microspheres (3D Co/Ni@carbon) were synthesized by using a bimetal-organic framework (Co/Ni-MOF) as a precursor and subsequent calcination under nitrogen. The 3D Co/Ni@carbon is a novel solid phase extractant that displays outstanding extraction capability and separation efficiency for the pyrethroid pesticides ethofenprox and bifenthrin. This is ascribed to the beneficial effects of facile analyte transport (due to the presence of free pores), the abundant number of adsorption sites (which warrant efficient extraction), and the excellent structural stability of the material. The 3D Co/Ni@carbon was applied to dispersive magnetic solid-phase extraction (d-MSPE), and the two pyrethroids were quantified by HPLC (UV detection wavelength: 220 nm). The method has a high preconcentration factor (937-1012) and give recoveries that range between 85.6-106.9%, with RSDs (for n = 5) of <6% in case of real samples. Graphical abstract The hierarchical porous Co/Ni@carbon microsphere as adsorbent was fabricated, and it showed high extraction efficiency for two pyrethroids.

Sensitive Monitoring of Fluoroquinolones in Milk and Honey Using Multiple Monolithic Fiber Solid-Phase Microextraction Coupled to Liquid Chromatography Tandem Mass Spectrometry

In the present study, a new multiple monolithic fiber solid-phase microextraction (MMF-SPME) based on poly(apronal-co-divinylbenzene/ethylenedimethacrylate) monolith (APDE) was synthesized. The effect of the preparation parameters of APED on extraction efficiency was studied thoroughly. The combination of APDE/MMF-SPME with high-performance liquid chromatography tandem mass spectrometry detection (HPLC/MS-MS) was developed for sensitive monitoring of ultratrace fluoroquinolones (FQs) in foodstuffs, including milk and honey samples. Under the optimized experimental conditions, the limits of detection (S/N = 3) for the targeted FQs ranged from 0.0019 to 0.018 μg/kg in milk and 0.0010 to 0.0028 μg/kg in honey. The relative standard deviations (RSDs) for method reproducibility were less than 9% in all samples. The established method was successfully applied for the monitoring of FQs residues in milk and honey samples with the recoveries between 74.5% and 116% (RSDs were in the range 0.9-9.5%). In comparison to previous methods, the developed APDE/MMF-SPME-HPLC/MS-MS showed some merits, including satisfactory sensitivity, simplicity, high cost-effectiveness, and low consumption of organic solvent.

Preparation of magnetic poly(vinylimidazole-co-divinylbenzene) nanoparticles and their application in the trace analysis of fluoroquinolones in environmental water samples

Nanosized spherical magnetic poly(vinylimidazole-co-divinylbenzene) particles were synthesized and used as a sorbent for the enrichment of trace fluoroquinolones (FQs) from environmental water samples. A suspension polymerization procedure was used to prepare the sorbent. The magnetic sorbent was characterized by SEM, transmission electron microscopy, elemental analysis, and FTIR spectroscopy. Analysis of enrofloxacin, marbofloxacin, fleroxacin, lomefloxacin, and sparfloxacin in environmental water samples by the combination of the magnetic sorbent and HPLC with diode array detection was selected as a paradigm for the practical application of the new adsorbent. Several extraction conditions, including desorption solvent, extraction and desorption time, pH value, and ionic strength in sample matrix, were optimized. Results showed that the new sorbent had high affinity for FQs and could be used to extract them effectively. Under the optimum conditions, low detection (S/N = 3) and quantification (S/N = 10) limits were achieved for the target analytes, within the ranges of 0.20-1.46 and 0.68-4.84 μg/L, respectively. Method repeatability was achieved in terms of intra- and interday precisions, indicated by the RSDs, which were both <10.0%. The method also showed good linearity, simplicity, practicality, and environmental friendliness for the extraction of FQs. Finally, the developed method was successfully applied to the determination of FQs in lake water, surface water, and reservoir water samples. Acceptable recoveries of spiked target compounds in these water samples were in the range of 52.1-104.5%.

Novel sorption-based methodologies for static microextraction analysis: A review on SBSE and related techniques

Stir bar sorptive extraction (SBSE) became a well-established analytical technique in the last years, for which hundreds of applications in almost all types of scientific fields can be found in the literature. In spite of the great enrichment capacity and outstanding performance to operate at the ultra-trace level, this remarkable static sorption-based method is already not quite effective for some complex systems, in particular to monitor the large group of polar organic compounds. This review aims to cover the state-of-the-art in SBSE, as well as supplying a discussion of the analytical potential of the novel adsorptive microextraction techniques, as complementary enrichment approaches, by explaining the main principles and providing technical know-how for the beginners.

Extraction and stirring integrated techniques: examples and recent advances

Extraction techniques, which focus on selectivity and sensitivity enhancement by isolation and preconcentration of target analytes, are essential in many analytical methods. Because many extraction techniques occur under diffusion-controlled conditions, stirring of the sample solution is required to accelerate the extraction by favoring diffusion of the analytes from the bulk solution to the extractant phase. This stirring may be performed by use of an external device or by integrating extraction and stirring in the same device. This review focuses on the latter techniques, which are promising methods for sample treatment. First, stir-bar-sorptive extraction, the most widely used method, is considered, paying special attention to the development of new coatings. Finally, a general overview of novel integrated techniques in both solid-phase and liquid-phase microextraction is presented; their main characteristics and marked trends are reported.

[Advance of stir bar sorptive extraction]

Stir bar sorptive extraction (SBSE) is an environmentally-friendly technology of sample preparation which combines extraction, cleanup and enrichment together, and it has been developed rapidly and widely applied to the trace enrichment of various target analytes in environmental, food and biological samples. Based on our research, the advance of SBSE, especially, the development of new coatings, are reviewed. At the same time, the possible development orientations of SBSE are discussed.

Chiral imprinted polymers as enantiospecific coatings of stir bar sorptive extraction devices

This paper reports the design of Molecularly Imprinted Polymers (MIP) with affinity towards (S)-citalopram using computational modeling for the selection of functional monomers and monomer:template ratio. Acrylamide was selected as functional monomer and the final complex functional monomer/template resulted in a 3:1 ratio. The polymer was synthesized by radical polymerization initiated by UV onto magnetic stir-bars in order to obtain a stir bar sorptive extraction (SBSE) device capable of selective enantiomeric recognition. After successful template removal, the parameters affecting the SBSE procedure (sample volume, ionic strength, extraction time and pH) were optimized for the effective rebinding of the target analyte. The resultant chirally imprinted polymer based stir-bar was able to selectively extract (S)-citalopram from a racemic mixture in an aqueous media with high specificity (specificity factor 4) between 25 and 500 μgL(-1). The MIP coated stir-bars can have significance for enantiospecific sample pre-concentration and subsequent analysis without the need for any chiral chromatographic separation.