In situ growth of copper-based metal-organic framework on a helical shape copper wire as a sorbent in stir-bar sorptive extraction of fenthion followed by corona discharge ion mobility spectrometry

Preparation strategy of molecularly imprinted polymers adsorbent based on multifunctional carrier for precise identification and enrichment of fenthion

Due to the existence of organophosphorus pesticides (OPs) in the environment and their potential hazards to ecosystems and human health, this study aimed to develop a novel adsorbent of OPs using multifunctional carriers and surface molecular imprinting technology (SMIT). SiO2-COOH served as a carrier, and molecularly imprinted polymers (MIPs) constituted a shell, creating a core-shell structured adsorbent. SMIT facilitated rapid and efficient binding between the target molecules and the imprinted cavities. The multifunctional SiO2-COOH enhanced the adsorbent's adsorption capacity, improved its mechanical stability, and strengthened the binding with the MIPs. The adsorbent demonstrated excellent specificity and reusability, achieving an adsorption capacity of 54.4 mg/g and the imprinting factor of 2.94. The relative recovery rate in actual sample detection ranged from 95.1% to 108.7%. This study provides a simple and effective method for detecting hazardous factors in environment protection and food safety fields, with significant scientific value and practical application potential.

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.

Modification of cellulose substrate by in situ synthesis of metal-organic framework-5 for thin film microextraction of some non-steroidal anti-inflammatory drugs and their measurement by high-performance liquid chromatography-ultraviolet detector

This work, reports the successful preparation a thin film by a simple and inexpensive process for quantification of a model analytes in the urine sample using HPLC-UV. To this end, cellulose paper was employed as a substrate for the in-situ synthesis of MOF-5, to increase the resistance of the prepared film. The prepared film can be reused 26 times with no reduction in its performance. The thin film prepared by MOF-5 modified cellulose substrate was utilized in thin film microextraction (TFME) method for the extraction and preconcentration of naproxen, aspirin, tolmetin, and celecoxib. Under optimal conditions, the linear dynamic range of the target analytes was 2-500 µg L-1 with correlation coefficients (R2) ranging from 0.9961 to 0.9990. Also, the limits of detection (LODs), the limits of quantification (LOQs) and relative standard deviation (RSD%) of the proposed method for selected analytes ranged between 0.57 and 0.77 µg L-1, 1.7 to 2.3 and 3.5 % to 6.2 %, respectively. Moreover, relative recoveries varied from of 94 % to 108 %, indicating the absence of matrices effect in the proposed method. Eventually, the TFME was successfully used for the extraction of selected analytes from urine samples.

A Schiff base networks coated stir bar for sorptive extraction of pyrethroid pesticide residues in tobacco

Schiff base networks (SNWs) were introduced as a new stir bar coating, and a method of SNWs- coated stir bar sorptive extraction (SBSE) coupled to high performance liquid chromatography-ultraviolet detector (HPLC-UV) was developed for determination of pyrethroid pesticide residues in tobacco. The prepared amorphous SNWs polymer from melamine and 3,5-dihydroxybenzaldehyde riches in triazine rings, hydroxyl groups and amino groups, and the SNWs/polydimethylsiloxane (PDMS) stir bar prepared by sol-gel method can extract weakly polar pyrethroid pesticides through hydrophobic, π-π and hydrogen bonding. The SNWs/PDMS stir bar exhibited high extraction efficiency toward pyrethroid pesticides (70-76%) and good mechanical stability with reused time more than 50 times. Under the optimal experimental conditions, the limits of detection were 0.20 - 0.66 µg/L with relative standard deviation varying in the range of 2.3-8.2%, which meets the requirements of trace analysis of pesticide residues in the tobacco industry. The method was applied to the determination of six pyrethroid pesticides in cigarette samples, and the recovery for the spiked samples ranged from 82 to 117%, showing a great applicability for the analysis of pesticide residues in real samples with a complex sample matrix.

Recent progress in organic-inorganic hybrid materials as absorbents in sample pretreatment for pesticide detection

Sample pretreatment is essential for trace analysis of pesticides in complex food and environment matrices. Recently, organic-inorganic hybrid materials have gained increasing attention in pesticide extraction and preconcentration. This review highlighted the common organic-inorganic hybrid materials used as absorbents in sample pretreatment for pesticide detection. Furthermore, the preparation and characterization of organic-inorganic hybrid materials were summarized. To obtain a deep understanding of adsorption toward target analytes, the adsorption mechanism and absorption evaluation were discussed. Finally, the applications of organic-inorganic hybrid materials in sample pretreatment techniques and perspectives in the future are also discussed.

3D printed spinning cup-shaped device for immunoaffinity solid-phase extraction of diclofenac in wastewaters

This article reports current research efforts towards designing bespoke microscale extraction approaches exploiting the versatility of 3D printing for fast prototyping of novel geometries of sorptive devices. This is demonstrated via the so-called 3D printed spinning cup-based platform for immunoextraction of emerging contaminants using diclofenac as a model analyte. A new format of rotating cylindrical scaffold (containing a semispherical upper cavity) with enhanced coverage of biorecognition elements, and providing elevated enhancement factors with no need of eluate processing as compared with other microextraction stirring units is proposed. Two distinct synthetic routes capitalized upon modification of the acrylate surface of stereolithographic 3D printed parts with hexamethylenediamine or branched polyethyleneimine chemistries were assayed for covalent binding of monoclonal diclofenac antibody.

Under the optimized experimental conditions, a LOD of 108 ng L⁻¹ diclofenac, dynamic linear range of 0.4–1,500 µg L^–1, and enrichment factors > 83 (for near-exhaustive extraction) were obtained using liquid chromatography coupled with UV–Vis detection. The feasibility of the antibody-laden device for handling of complex samples was demonstrated with the analysis of raw influent wastewaters with relative recoveries ranging from 102 to 109%. By exploiting stereolithographic 3D printing, up to 36 midget devices were fabricated in a single run with an estimated cost of mere 0.68 euros per 3D print and up to 16 €/device after the incorporation of the monoclonal antibody.

Rapid screening of chemical warfare agents (nerve agents) using dimethyl methylphosphonate as simulant substances in beverages by hollow fiber membrane-protected solid phase microextraction followed by corona discharge ion mobility spectrometry

The following work presents a new, rapid, potential to be portable, convenient, and low-cost method using hollow fiber membrane-protected solid phase microextraction followed by corona discharge ion mobility spectrometry which was used for determining dimethyl methylphosphonate in beverages. Response surface methodology based on the design of Box-Behnken was implemented for optimizing the different factors influencing the proposed method for obtaining the best results. Optimal extractions were calculated with 65 µm polydimethylsiloxane-divinylbenzene fiber, fiber equilibration time of 10 min, stirring rate of the sample solution at 750 rpm, and extraction temperature of 50 °C. The proposed technique provided linear range (0.5-50 µg mL^-1), good linearity (>0.991), and repeatability (the relative standard deviations of 5.42% and 8.37% of intra- and inter-day analyses, respectively) under the optimized extraction conditions. Finally, the developed method was successfully used for determining dimethyl methylphosphonate in beverages such as coffee mix, fruit juice, tap water, milk, and tea.