Switchable hydrophilicity solvent membrane-based microextraction: HPLC-FLD determination of fluoroquinolones in shrimps

In-tube solid phase extraction with graphitic-based polyurethane sponge as a superhydrophobic sorbent and determination of drug residues in foodstuffs using high-performance liquid chromatography

Veterinary drugs used in animal husbandry raise public health concerns due to their residues in the bodies of animals. This study employs a simple and quick sample preparation technique, in-tube solid phase extraction, to extract drug residues from foodstuffs, including eggs, honey, and water. This technique utilizes the synergy of graphitic-based materials and polyurethane sponges (PU) combined through dip coating method to make reusable sorbents for extracting drugs, including amoxicillin, paracetamol, ciprofloxacin, and cefixime. These prepared sorbents were characterized using FTIR, SEM, and XRD. HPLC analysis assessed the extraction efficiency, considering various parameters such as analyte concentration, sample solution pH, extraction time, type of eluting solvent, and graphitic-based polyurethane sponge reusability and stability. The proposed method exhibited a linear response for all three sorbents in the range of 0.03-1000 µg mL-1, with LOD 0.03-1.60 µg mL-1 and LOQ 0.18-4.84 µg mL-1. The % RSD ranged from 1.3 to 9.3 %, with recoveries of up to 98.42 %.

Determination of trace fluoroquinolones in honey and milk based on cyclodextrin modified magnetic metal-organic frameworks solid phase extraction coupled with ultra-high performance liquid chromatography

Long-term intake of animal-derived foods with excessive fluoroquinolones (FQs) will cause damage to human health, so it is critical to establish a feasible approach for sensitive and rapid monitoring of FQs residues. In this study, a new cyclodextrin modified magnetic metal-organic frameworks (Fe3O4@UiO-66-CD) was successfully synthesized by amidation reaction and applied to magnetic solid phase extraction (MSPE) for FQs analysis. The adsorption behavior of Fe3O4@UiO-66-CD was consistent with the pseudo-second-order kinetics and Freundlich isothermal adsorption model, which indicated that the designed material had various interactions on FQs, such as host-guest interaction and π-π interaction. The parameters of MSPE were optimized and the determination method of norfloxacin, enrofloxacin, lomefloxacin and gatifloxacin was established by using MSPE combined with ultra-high performance liquid chromatography (UHPLC) and fluorescence detector (FLD). The method validation results displayed that the detection limits were 0.02-0.09 ng/mL, and the RSDs of intra-day and inter-day precision were less than 4.1 and 6.4 %, respectively. In the target FQs analysis of real honey and milk samples, the recoveries at different fortified concentrations were in the ranges of 88.4 % to 108.6 % with RSD ≤ 5.7 %. The results showed that the proposed method was sensitive, accurate and reliable for the determination of trace FQs in animal-derived foods.

Current analytical strategies for the determination of quinolone residues in milk

Quinolones are potent antibacterial drugs extensively utilized for treating bacterial infections in poultry. However, the presence of quinolone antibiotic residues in milk is a matter of concern due to potential health risks and adverse effects on milk quality. This review provides an overview of current analytical strategies for the determination of quinolone residues in milk. Various sample preparation techniques, such as liquid-phase extraction, solid-phase extraction and QuEChERS, are discussed, along with detection methods including instrument-based detection, immune-based detection, and microbial detection. The advantages and limitations of each method are highlighted, as well as their applicability in different stages of milk production. Additionally, recent advancements in sample preparation and detection methods are presented. This comprehensive review aims to contribute to the development of accurate and reliable methods for the detection of quinolone residues in milk, ensuring the safety and quality of dairy products.

A smartphone-integrated portable platform based on polychromatic ratiometric fluorescent paper sensors for visual quantitative determination of norfloxacin

The emergence of "superbugs" due to antibiotics overuse poses a significant threat to human health and security. The development of sensitive and effective antibiotics detection is undoubtedly a prerequisite for addressing antibiotics overuse-associated issues. However, current techniques for monitoring antibiotics typically require costly equipment and well-trained professionals. Hence, we developed herein a rapid, instrument-free, and on-site detection method for antibiotic residues such as norfloxacin (NOR) based on a ratiometric sensing platform utilizing "on-off-on" response properties of polychromatic fluorescence for direct visual quantitative NOR analysis. Specifically, this platform integrated iron ions (Fe3+)-chelated blue carbon dots (BCDs) for signal sensing and red carbon dots (RCDs) as an internal reference. The sensor mechanism is selective quenching of BCDs' blue fluorescence by Fe3+ via an inner filter effect with unaffected RCDs' red fluorescence. Further NOR addition led to competitive binding with BCDs due to Fe3+ shedding from the BCDs' surface for a recovered blue fluorescence signal. Notably, the ratiometric fluorescence sensor demonstrated rapid and highly sensitive NOR detection in a concentration range of 1-70 μM with an impressive detection limit of 6.84 nM. The ratiometric fluorescence sensing platform was constructed by integrating smartphone and paper-based strategies, which exhibited exceptional sensitivity, selectivity, and rapid response for portable, instrument-free, visual quantification of NOR in real samples.

Slice-layer COFs-aerogel: a regenerative dispersive solid-phase extraction adsorbent for determination of ultra-trace quinolone antibiotics

A novel type of three-dimensional network structure, covalent organic frameworks (COFs) aerogel, was fabricated and applied to dispersive solid-phase extraction (dSPE) of quinolone antibiotics (QAs). Density functional theory (DFT) was applied to investigate the possible interaction mechanism and results confirmed that the strong adsorption affinity is attributed to the intralayer hydrogen bonds and π-π interaction. Furthermore, a sensitive analytical method based on COFs-aerogel for determining quinolone antibiotics residues in water and honey samples was developed and HPLC-MS/MS was used for sample detection and quantification. Under the optimal conditions, COFs-aerogel exhibited a wide linearity (0.1-500 ng∙L-1), low limits of detection (0.02-0.06 ng∙L-1), and good precision (RSD ˂ 10%) for selected QAs. A preliminary practical application of the developed method was proved by the efficient detection of quinolone antibiotics in water and food samples with good recoveries (68.2-104% and 64.0-100% for water and honey samples, respectively). Combining the experimental data with theoretical calculation, results illustrated that COFs-aerogel holds a great potential to capture contaminants and address environmental and food safety issues.

Determination of quinolone antibiotics in honey by pH-induced natural deep eutectic solvent combined with vortex-assisted dispersive liquid-liquid microextraction

A green, fast, and efficient pH-induced natural deep eutectic solvent combined with vortex-assisted dispersive liquid-liquid microextraction method (pH-NADES-VA-DLLME) followed by HPLC was established for determination of ofloxacin (OFL), ciprofloxacin (CIP) and enrofloxacin (ENR) in honey. In this method, NaOH, as an emulsifier, can increase the contact area between the NADES and the sample solution, which can efficiently improve the extraction efficiency of the analytes. Moreover, HCl acts as the phase separation agent without centrifugation in the process, which can greatly enhance the efficiency of the sample analysis process. In addition, the main factors affecting the extraction effect were optimized by single factor experiments. Under the optimal conditions, the limits of detection (LODs), the limits of quantification (LOQs) and recoveries were in the range of 0.004-0.015 μg mL^-1, 0.012-0.050 μg mL^-1, and 98.0-112.5%, respectively. The RSD values of intra-day and inter-day precisions were no more than 5.5% and 6.0%, respectively. The developed method was successfully applied to determine the three quinolone antibiotics in honey.

An effervescence-assisted dispersive liquid-liquid microextraction based on three-component deep eutectic solvent for the determination of fluoroquinolones in foods

An effervescence-assisted dispersive liquid-liquid microextraction approach using three-component deep eutectic solvent based on short-chain and medium-chain carboxylic acids and terpenoid was developed for the first time. The microextraction procedure was applied to the determination of fluoroquinolone antibiotics in foods (milk and shrimp samples) by high-performance liquid chromatography with fluorometric detection. In this microextraction procedure three-component deep eutectic solvent acted as a proton donor agent and an extractant. The carbon dioxide bubbles caused by the fast reaction between precursor of deep eutectic solvent (short-chain carboxylic acid) and effervescent agent (sodium carbonate) promoted the dispersion of the extractant in an aqueous sample phase. Various carboxylic acids were studied as hydrogen bond donors for the formation of deep eutectic solvents and proton donor agents for the generation of CO₂ bubbles. Two natural terpenoids (menthol and thymol) were studied as the hydrogen bond acceptors for the formation of three-component solvent. The extraction system based on heptanoic acid and thymol (1:2, mol/mol) containing formic acid (proton donor for generating CO₂ bubbles) provided maximum extraction recovery (86-99%) and a higher extraction efficiency of analytes compared to their extraction into individual hydrophobic precursors of the system. The LODs, calculated from the blank tests based on 3σ, were varied from 0.03 to 0.06 μg L^-1 and from 0.3 to 0.6 μg kg^-1 for fluoroquinolone antibiotics in milk and shrimp samples, respectively. The proposed approach provided effective dispersion of extractant speeding up the extraction process and fast separation of phases without any external energy assistance.

A ratiometric fluorescence platform based on carbon dots for visual and rapid detection of copper(II) and fluoroquinolones

A simple smartphone-integrated ratiometric fluorescent sensing system for visual determination of copper ions (Cu²⁺) and fluoroquinolones (FQs) was developed based on carbon dots (CDs) which were synthesized through the high-temperature pyrolysis of citric acid. In this system, with the fluorescence resonance energy transfer effect between CDs and 2,3-diaminophenazine (oxOPD), the detection of Cu²⁺ and ciprofloxacin (CIP, an example for FQs) was realized. Cu²⁺ catalyzes the oxidation of OPD to form oxOPD with yellow fluorescence, resulting in the quenching of CDs. In addition, CIP can inhibit the catalytic activity of Cu²⁺ and induce the recovery of CDs fluorescence. Under the excitation of 400 nm, the changes of CDs fluorescence at 472 nm and oxOPD fluorescence at 556 nm were monitored. The detection results showed that the sensing system exhibited good selectivity and sensitivity to Cu²⁺ and CIP with the limit of detection of 2.32 × 10^-8 mol L^-1 and 0.2 ng mL^-1, respectively. In addition, a smartphone was developed as a portable analyzer to capture the change of fluorescence color and quickly analyze the concentration of Cu²⁺ and CIP. The proposed smartphone-based sensing platform has satisfactory sensitivity, and it has application prospects for detecting Cu²⁺ and FQs in food safety monitoring.

Miniaturized green sample preparation approaches for pharmaceutical analysis

The development of green sample preparation procedures is an extremely important research field in which more and more applications are constantly being proposed in different areas, including pharmaceutical analysis. This review article is aimed at providing a general overview of the development of miniaturized green analytical sample preparation procedures in the pharmaceutical analysis field, with special focus on the works published between January 2017 and July 2021. Particular attention has been paid to the application of environmentally friendly solvents and sorbents as well as nanomaterials or high extraction capacity sorbents in which the solvent volumes and reagents amounts are drastically reduced, with their subsequent advantages from the sustainability point of view.

Simultaneous determination of 11 quinolone residues in freshwater fish samples by magnetic solid-extraction coupled to liquid chromatography-tandem mass spectrometry

In this study, well-defined core-shell ethylenediamine-functional magnetic ferroferric oxide polymers were prepared and were fully characterized by transmission electron microscopy, scanning electron microscopy, FTIR spectroscopy, and vibrating sample magnetometry. Then, it was used as a magnetic solid-phase extraction adsorbent for simultaneous determination of 11 trace quinolone residues in freshwater fish samples coupled to liquid chromatography-tandem mass spectrometry. The obtained results revealed that the adsorbent showed good extraction efficiency and the adsorption mechanisms referred to hydrogen bond and π-π stacking interaction. Moreover, the magnetic solid-phase extraction conditions were also carefully optimized. The limits of quantitation of 11 quinolones were in the range of 0.15-0.36 μg/kg, while spiking recoveries were in the range of 80.2-99.5% for the 11 quinolones in freshwater fish samples at four spiked levels including limits of quantitation, 1.0, 40.0, and 80.0 μg/kg with the relative standard deviations ranging from 0.8 to 9.1%. The proposed method was applied to analyze 45 freshwater fish samples, and enrofloxacin was detected in 91.1% samples with concentrations ranging from 0.659 to 333 μg/kg. It could be concluded that the proposed method is fast, simple, sensitive, and accurate for the routine monitor of freshwater fish.

Switchable-hydrophilicity solvent liquid-liquid microextraction versus dispersive liquid-liquid microextraction prior to HPLC-UV for the determination and isolation of piperine from Piper nigrum L

Switchable-hydrophilicity solvent liquid-liquid microextraction and dispersive liquid-liquid microextraction were compared for the extraction of piperine from Piper nigrum L. prior to its analysis by using high-performance liquid chromatography with UV detection. Under optimum conditions, limits of detection and quantitation were found as 0.2-0.6 and 0.7-2.0 μg/mg with the two methods, respectively. Calibration graphs showed good linearity with coefficients of determination (R² ) higher than 0.9962 and percentage relative standard deviations lower than 6.8%. Both methods were efficiently used for the extraction of piperine from black and white pepper samples from different origins and percentage relative recoveries ranged between 90.0 and 106.0%. The results showed that switchable-hydrophilicity solvent liquid-liquid microextraction is a better alternative to dispersive liquid-liquid microextraction for the routine analysis of piperine in food samples. A novel scaled-up dispersive liquid-liquid microextraction method was also proposed for the isolation of piperine providing a yield of 102.9 ± 4.9% and purity higher than 98.0% as revealed by NMR spectroscopy.

Selective extraction and detection of norfloxacin from marine sediment and seawater samples using molecularly imprinted silica sorbents coupled with HPLC

A simple, sensitive and effective method was developed and validated for selective adsorption and quantitation of norfloxacin (NFX) from marine sediments and seawater samples using the novel molecularly imprinted silica polymers as sorbents followed by high-performance liquid chromatographic analysis with diode array detection (HPLC-DAD). The imprinted particles were characterized by different techniques and the molecular recognition for NFX was also investigated. Several parameters affecting the extraction efficiency of molecularly imprinted solid-phase extraction (MISPE) process were optimized. Three sediment and seawater samples from Weihai bay in China were analyzed and the results show that satisfactory recoveries (77.2-98.7%) were achieved in seawater samples with low relative standard deviation (RSD) values less than 6.89% (n = 3), and the recoveries in sediments were in the range of 75.5-91.7%. The limits of detection are respectivley 2 μg L^-1 in seawater samples and 5 μg kg^-1 in sediments.

Silver nanoparticles enhanced fluorescence for sensitive determination of fluoroquinolones in water solutions

A new type of silver nanoparticle (AgNPs) was prepared with simple and fast methods and low-toxic compounds. With the addition of different concentrations of AgNPs, the effects of AgNPs on the fluorescence properties of three different kinds of fluoroquinolones (enrofloxacin ENR, lomefloxacin LMF and norfloxacin NOR) in water solutions were studied, respectively. The experimental results demonstrated that the fluorescence intensity for each of the fluoroquinolones (FQ)was firstly enhanced and then quenched with the increased concentration of AgNPs in water solutions. The possible mechanisms about the AgNPs on the fluorescence behaviors of each FQ were also investigated, respectively. In addition, new silver enhanced nanoparticles materials fluorescence methods were established for the separate determination of ENR, LMF and NOR in water solutions. As compared with the identical control fluorimetric methods with no addition of AgNPs, the new enhanced fluorimetic methods were also investigated, respectively. The experimental results indicated that the new enhanced methods could detect lower concentrations of ENR, LMF and NOR in water solutions. Moreover, the newly enhanced fluorimetric methods were validated and successfully applied for the quantitative assay of ENR, LMF and NOR in different kinds of medicinal preparations, respectively.

An automated magnetic dispersive micro-solid phase extraction in a fluidized reactor for the determination of fluoroquinolones in baby food samples

An automated magnetic dispersive micro-solid phase extraction procedure in a fluidized reactor was developed for the determination of fluoroquinolone antimicrobial drugs (fleroxacin, norfloxacin and ofloxacin) in meat-based baby food samples. A stepwise injection system was successfully combined with afluidized reactorand applied for the magnetic dispersive micro-solid phase extraction procedure automation. The developed automated procedure involved injection of the sample solution into the fluidized reactor followed by the on-line separation of the analytes from the sample matrix based on fluidized beds strategy using magnetic nanoparticles, elution and determination of the analytes using a high performance liquid chromatography system with fluorescence detection. The floating of the magnetic nanoparticles in a liquid sample phase was accomplished by air-bubbling. In the developed method Zr-Fe-C magnetic nanoparticles were used as an efficient sorbent for the determination of fleroxacin, norfloxacin and ofloxacin. Under the optimal conditions, the calibration graphs were linear over the concentration ranges of 10-1000 μg L^-1 for fleroxacin (R² = 0.996), 5-1000 μg L^-1for norfloxacin (R² = 0.998) and ofloxacin (R² = 0.998). The limits of detection, calculated from the blank tests based on 3σ, were 3.0 μg L^-1forfleroxacin, 1.5 μg L^-1for norfloxacin and ofloxacin. The limits of quantification, calculated from the blank tests based on 10σ, were 10 μg L^-1 forfleroxacin, 5 μg L^-1for norfloxacin and ofloxacin. The method was applied for the determination of fluoroquinolonesin meat-based baby food samples and the results were compared with those obtained by the reference method. The recovery values for all analytes were within of 86-122% range.