Hydrophilic carboxyl supported immobilization of UiO-66 for novel bar sorptive extraction of non-steroidal anti-inflammatory drugs in food samples

In situ immobilization of covalent organic frameworks on diatomaceous earth for pipette-tip solid-phase microextraction

Solid-phase microextraction (SPME) is essential for analyzing ultra-low concentration samples, such as trace drugs and environmental pollutants. Among various formats, pipette tip-based SPME (PT-SPME) stands out for its advantages in efficiency, automation, and flexibility. However, PT-SPME faces challenges such as material loss, high synthesis costs, and environmental impact. To address these issues, we developed a novel PT-SPME device by synthesizing Schiff-base covalent organic frameworks (COFs) in situ on diatomaceous earth (DE), which served as both a matrix and support. This approach significantly improved stability and reduced COFs consumption by 93.7 %. The DE@COFs were packed into pipette tips with a sandwich-like structure and used to extract polycyclic aromatic hydrocarbons (PAHs), with detection achieved through high-performance liquid chromatography coupled with fluorescence detection (HPLC-FLD). The method exhibited excellent sensitivity, with limits of detection (LODs) ranging from 2.05 to 52.5 pg/mL and limits of quantification (LOQs) from 15.0 to 159 pg/mL. It also demonstrated high accuracy, with recoveries between 87.05 % and 115.86 %, and strong repeatability, making it suitable for trace pollutant analysis in complex matrices This cost-effective and environmentally friendly PT-SPME system enhances extraction efficiency while reducing material usage, providing a practical and innovative solution for trace pollutant analysis in pharmaceutical and environmental applications.

Development of novel bis(2-ethylhexyl) phosphate-based magnetic deep eutectic solvent for the highly efficient enrichment of non-steroidal anti-inflammatory drugs from environmental water and milk samples

In this study, a new type of magnetic deep eutectic solvent (MDES) based on a novel non-ionic hydrogen bond acceptor of bis(2-ethylhexyl) phosphate, as well as heptanol and CoCl2, was synthesized with low viscosity, certain magnetism, and hydrophobicity. Subsequently, a vortex-assisted dispersive liquid-liquid microextraction method based on the MDES was developed to analyze five non-steroidal anti-inflammatory drugs (NSAIDs) followed by HPLC-UV. Due to the unique properties of MDES, it can spontaneously float onto surface of the sample solution and gather together after extraction, thereby omitting the time-consuming centrifugation process. Under the optimal extraction conditions, this method showed good linearity, low limit of detection, high precision, and high enrichment factor. Satisfactory spiked recoveries in the range of 85.2 %-115.2 % were obtained from two environmental water and two milk samples. Taken together, this simple, convenient, fast, safe, highly efficient, and reliable method can be applied to the analysis of NSAIDs from aqueous samples.

Development of a lateral flow immunoassay for the rapid detection of diclofenac in milk and milk tea

Diclofenac (DCF) is widely used in veterinary medicine, but its milk residues may pose risks to human health. This study designed DCF haptens using computer modeling and developed an anti-DCF monoclonal antibody (mAb) with milk samples, achieving a semi-inhibitory concentration of 0.379 ng/mL. A lateral flow immunoassay (LFIA) was created to detect DCF residues in milk and milk tea, with calculated limits of detection (cLOD) of 0.083 ng/mL for milk and 0.055 ng/mL for milk tea. The results obtained from the LFIA assay for real samples, as well as the recovery rates, were consistent with those obtained from instrumental methods. Notably, the LOD for milk using this method was at least one order of magnitude higher than that of other methods. The method shows promise for detecting DCF in real milk and milk tea.

Modified vermiculite as a sorbent phase for stir-bar sorptive extraction

BACKGROUND

The presence of emerging contaminants (ECs) is a cause of great concern nowadays, and they are present at very low concentrations in surface waters, requiring a preconcentration process for their reliable quantification. The technique of Stir-Bar Sorptive Extraction (SBSE) is a valuable tool for achieving this purpose, and different sorbents have been developed to produce the bars. In this sense, we propose the use of the clay mineral vermiculite (Vt), modified with alkylammonium salts, aiming the determination of the ECs: bisphenol A, diclofenac, ibuprofen and triclosan in surface water samples.

RESULTS

The best conditions for sorption and desorption were: 50.0 mL of sample at pH 4.0, under stirring at 600 rpm (120 min), being the desorption carried out under sonication for 20 min using 500 μL of methanol, and the analytes were determined using LC-DAD. A linear range from 0.50 to 2.50 μg L-1 or from 0.50 to 5.00 μg L-1 and R2 higher than 0.9480 were observed, and attractive real enrichment factors between 116 and 177 times, affording a LOD between 0.11 and 0.33 μg L-1. The method was applied to determine the four ECs in samples of tap, river, and lake waters, presenting recovery results between 42.0 and 128.0 %, and RSD from 0.4 to 19.6 %. The bars prepared using Vt presented good chemical and mechanical resistance, even modified using the alkylammonium salts, permitting them to be employed at least 30 times, without memory effects.

SIGNIFICANCE

The modified Vt, afforded a simple, low-cost, and attractive alternative to work as a sorbent phase for SBSE technique, presenting very appropriate analytical parameters, even employing LC-DAD. Although the sorbent was applied to a limited number of contaminants, it is probable that other analytes could be successfully determined. It is important to notice that this is the first study reported, employing modified Vt for SBSE application.

A facile colorimetric sensor for ketoprofen detection in milk: Integrating molecularly imprinted polymers with Cu-doped Fe3O4 nanozymes

A facile and efficient detection method is required to address the potential health risks of ketoprofen (KP) in animal-derived foods. Herein, we integrated molecularly imprinted polymers (MIPs) with Cu-doped Fe3O4 nanozymes (Fe3O4-Cu) to develop a selective colorimetric sensor for KP detection. Chitosan and glutaraldehyde were used as functional monomers and cross-linkers to fabricate proposed the MIPs@Fe3O4-Cu. On KP addition, it was specifically captured by the imprinted cavities, thereby blocking the channels between chromogenic substrates and Fe3O4-Cu. Based on this rationale, a selective colorimetric sensor utilizing MIPs@Fe3O4-Cu was established, exhibiting a linear range of 0.25-100 μM and a detection limit of 0.073 μM. The developed method was validated through its application in milk samples, yielding satisfactory recoveries with low relative standard deviations. This efficient and selective colorimetric sensor holds immense significance for KP detection in complex samples.

Overview of Liquid Sample Preparation Techniques for Analysis, Using Metal-Organic Frameworks as Sorbents

The preparation of samples for instrumental analysis is the most essential and time-consuming stage of the entire analytical process; it also has the greatest impact on the analysis results. Concentrating the sample, changing its matrix, and removing interferents are often necessary. Techniques for preparing samples for analysis are constantly being developed and modified to meet new challenges, facilitate work, and enable the determination of analytes in the most comprehensive concentration range possible. This paper focuses on using metal-organic frameworks (MOFs) as sorbents in the most popular techniques for preparing liquid samples for analysis, based on liquid-solid extraction. An increase in interest in MOFs-type materials has been observed for about 20 years, mainly due to their sorption properties, resulting, among others, from the high specific surface area, tunable pore size, and the theoretically wide possibility of their modification. This paper presents certain advantages and disadvantages of the most popular sample preparation techniques based on liquid-solid extraction, the newest trends in the application of MOFs as sorbents in those techniques, and, most importantly, presents the reader with a summary, which a specific technique and MOF for the desired application. To make a tailor-made and well-informed choice as to the extraction technique.

Targeted cancer treatment using folate-conjugated sponge-like ZIF-8 nanoparticles: a review

ZIF-8 (zeolitic imidazolate framework-8) is a potential drug delivery system because of its unique properties, which include a large surface area, a large pore capacity, a large loading capacity, and outstanding stability under physiological conditions. ZIF-8 nanoparticles may be readily functionalized with targeting ligands for the identification and absorption of particular cancer cells, enhancing the efficacy of chemotherapeutic medicines and reducing adverse effects. ZIF-8 is also pH-responsive, allowing medication release in the acidic milieu of cancer cells. Because of its tunable structure, it can be easily functionalized to design cancer-specific targeted medicines. The delivery of ZIF-8 to cancer cells can be facilitated by folic acid-conjugation. Hence, it can bind to overexpressed folate receptors on the surface of cancer cells, which holds the promise of reducing unwanted deliveries. As a result of its importance in cancer treatment, the folate-conjugated ZIF-8 was the major focus of this review.

A Carboxyl Group-Functionalized Ionic Liquid Hybrid Adsorbent for Solid-Phase Extraction and Determination of Trace Diclofenac Sodium in Milk Samples

A simple and efficient sample pretreatment technology is very important for the accurate determination of trace drug residues in foods to ensure food safety. Herein, we report a new carboxyl group-functionalized ionic liquid hybrid solid- phase adsorbent (PS-IL-COOH) for the highly efficient extraction and quantitative determination of diclofenac sodium (DS) residue in milk samples. It was found that the adsorption efficiency of PS-IL-COOH for the ppb level of DS was greater than 93.0%, the adsorption capacity was 934.1 mg/g, and the enrichment factor was 620.0, which surpass most of the previously reported values for DS adsorbents. The high concentration of salts did not interfere with the adsorption of DS. Importantly, the recovery of DS was above 90% after 16 adsorption--regeneration cycles. The synergistic effect of the multiple interactions was found to be the main factor for the high efficiency of DS adsorption. The proposed method was applied to the extraction and detection of DS in milk samples, with the relative recovery ranging from 88.2 to 103.0%.

Novel solid-phase extraction filter based on a zirconium meta-organic framework for determination of non-steroidal anti-inflammatory drugs residues

In this study, a zirconium-based metal-organic framework UiO-66-NH₂ modified cotton fiber (CF@UiO-66-NH₂) was fabricated for the extraction of five common NSAIDs, namely ketoprofen, naproxen, flurbiprofen, diclofenac sodium, and ibuprofen. UiO-66-NH₂ was synthesized and immobilized on the surface of cotton fiber using an environmentally friendly aqueous synthesis method. The prepared CF@UiO-66-NH₂ composite of 50 mg was loaded into a 13 mm recessed filter for use as a solid-phase extraction (SPE) adsorbent material. The filter was then used to enrich NSAIDs in fish and shrimp muscle tissues followed by ultra-high performance liquid chromatography (UPLC) detection. Several key parameters were evaluated and optimized, including adsorption flow rate, pH value of sample, desorption flow rate, and the formic acid content of the eluent. Under optimized conditions, linear ranges of ketoprofen, naproxen, flurbiprofen, diclofenac sodium, and ibuprofen were 2.0-300.0 ng/mL, 1.4-280.0 ng/mL, 3.0-400.0 ng/mL, 1.0-500.0 ng/mL, and 14.0-560.0 ng/mL, respectively. The detection limits ranged from 0.12 ng/mL to 3.50 ng/mL with recoveries in the range of 72.95-116.99%, RSDs < 9.90%. The results demonstrated that the homemade filters based on CF@UiO-66-NH₂ exhibited good reproducibility, stability and adsorption property for the determination of trace-level NSAIDs in complex matrix.