Nanoparticles Based Extraction Strategies for Accurate and Sensitive Determination of Different Pesticides

Synthesis and utilization of mixed-metal (Zn/Cd) metal-organic frameworks for ultra-trace determination of diazinon and ethion via ion mobility spectrometry

A novel mixed-metal (Zn/Cd) metal-organic framework-based dispersive solid-phase microextraction (MM-MOFs-DSPME) method was developed for the efficient extraction of organophosphorus pesticides, diazinon and ethion, from various environmental matrices. The detection of the extracted analytes was performed using ion mobility spectrometry. The synthesized mixed-metal (Zn/Cd) MOF was characterized using a comprehensive array of analytical techniques: Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), Brunauer-Emmett-Teller (BET) surface area analysis, X-ray photoelectron spectroscopy (XPS), and zeta potential measurement. This comprehensive characterization provided an in-depth understanding of the material's structural and functional properties. Key parameters influencing the efficiency of the dispersive solid-phase microextraction (DSPME) method were optimized, including pH, type of desorption solvent, buffer type and volume, sorbent amount, and adsorption and desorption time. Under these optimal conditions, the linear dynamic ranges obtained were 0.5 to 300 ng mL-1 for diazinon and 1.0 to 300 ng mL-1 for ethion, with limits of detection of 0.15 ng mL-1 and 0.29 ng mL-1, respectively. Preconcentration factors of 74% and 78%, with extraction recoveries of 98.4-104.2% and 96.6-103.4%, were achieved for diazinon and ethion, respectively. The relative standard deviations, calculated based on ten replicate measurements, yielded values of 3.8% for diazinon and 3.9% for ethion at a concentration of 10 ng mL-1, and 2.2% for diazinon, and 1.6% for ethion at a concentration of 150 ng mL-1, respectively. The developed method was successfully applied to the quantification of the target pesticides in soil, water, and apple samples.

Simultaneous determination of nineteen azo dyes in water samples by gas chromatography-mass spectrometry after Fe3O4@COF based dispersive solid phase extraction

This study was performed for the determination of nineteen azo dyes at trace levels in stream water sample by gas chromatography-mass spectrometry (GC-MS). The selected analytes were preconcentrated with the help of dispersive solid phase extraction (DSPE). Fe3O4 magnetic nanoparticle was modified with covalent organic framework (COF) and the synthesized Fe3O4@COF nanocomposite was used as adsorbent for the separation of the analytes from aqueous solution. The synthesized Fe3O4@COF was introduced to the literature for the first time in this study. Five different parameters (pH, volume of buffer solution, volume of desorption solvent, mixing period and amount of adsorbent) were univariately optimized to acquire high extraction outputs for each analyte. Under the optimum Fe3O4@COF-DSPE-GC-MS conditions, limit of detection (LOD), limit of quantitation (LOQ), linear range (LR), coefficient of determination (R2) and percent relative standard deviation (%RSD) were calculated using external calibration plots belonging to each analyte. LOD values were found between 2.8 and 70.7 μg/kg with corresponding LOQ values ranging between 9.5 and 235.7 μg/kg. In addition, %RSD values were lower than 12.8%. Matrix matching calibration method was used in spiking experiments. Percent recovery results obtained for spiked stream water samples were between 83.1 and 122.4%, with %RSD ≤ 17.5. The high percent recoveries confirmed the accuracy and applicability of the developed Fe3O4@COF-DSPE-GC-MS method for stream water samples.

Dispersive micro-solid phase extraction (D-μSPE) of nickel on activated nanodiamonds@Bi2WO6 nanocomposite from water and food samples

This study presents an original nano-sorbent using activated nanodiamonds@Bi2WO6 to separate and enrich nickel ions from water and food samples. FTIR, XRD, FE-SEM, FE-SEM-EDX, EDS-TEAM, TGA, and BET were used to characterize the nanocomposite. It has a large surface area, active functional groups, and better reactivity. Ni(II) ions were determined as Ni(II)-PADAP chelates using UV-VIS spectroscopy. The parameters were studied and optimized, including pH (6), eluent type and volume (1 mL), ligand quantity (10 μg), sorbent dosage (20 mg), and contact time (1 min). The method has a low limit of detection (LOD) of 1.6 μg L-1, a limit of quantification (LOQ) of 5.3 μg L-1, a relative standard deviation of 4.5%, and a preconcentration factor of 10. The method was validated by applying to certified reference materials (BCR estuarine water 505 and 1573a NIST). The method was successfully applied to tap waters, industrial waste waters, and vegetables.

Development of dispersive solid phase extraction method for the preconcentration of parathion ethyl as a simulant of nerve agent sarin from soil, plant and water samples prior to GC-MS determination

In the presented study, an efficient and fast analytical method was developed for the determination of parathion ethyl as sarin simulant by gas chromatography-mass spectrometry (GC-MS). Dispersive solid phase extraction (DSPE) was performed to concentrate parathion ethyl from soil, plant and water samples. Reduced graphene oxide-iron (II, III) oxide (rGO-Fe3O4) nanocomposite was used as an adsorbent to collect the target analyte from the aqueous sample solutions. After the optimization of extraction/preconcentration parameters, optimum conditions for adsorbent amount, eluent type, mixing type/period, eluent volume and initial sample volume were determined as 15 mg, acetonitrile, vortex/30 s, 100 µL and 10 mL, respectively. Under the optimum conditions, analytical performance of the developed DSPE-GC-MS method was evaluated in terms of limit of detection (LOD), limit of quantitation (LOQ) and dynamic range. Dynamic range, LOD and LOQ values were figured out to be 0.94-235.15 µg/kg, 0.41 µg/kg and 1.36 µg/kg (mass based), respectively. Satisfactory percent recovery results (90.3-125% for soil, 93.5-108.7% for plant, 88.5-112.9% for tap water) were achieved for soil, plant and tap water samples which proved the accuracy and applicability of the developed method. It is predicted that the DSPE-GC-MS method can be accurately used for the detection of sarin in soil, plant and water samples taken from war territories.

Development of Fe3O4/reduced graphene oxide nanocomposite-based dispersive solid-phase extraction for the quantification of five steroid hormones

Aim: An accurate and sensitive analytical method was proposed to detect some steroid hormones in biological samples. Materials & methods: An Fe₃O₄/reduced graphene oxide nanocomposite-based dispersive solid-phase extraction was developed for the effective and simple preconcentration of steroid hormones from human serum samples. Results & conclusion: The nanocomposite was firstly used as adsorbent to simultaneously extract the selected hormones. Limit of detection values for the selected hormones were calculated between 5.5 and 39.2 ng/kg (mass based). An artificial serum sample was used to test the applicability and accuracy of the developed method; percentage recovery results obtained from two different spiked concentrations were found to be in the range of 80.5-99.9%.

Gold Nanoparticles-Based Colorimetric Assays for Environmental Monitoring and Food Safety Evaluation

Recent years have witnessed an exponential increase in the research on gold nanoparticles (AuNPs)-based colorimetric sensors to revolutionize point-of-use sensing devices. Hence, this review is compiled focused on current progress in the design and performance parameters of AuNPs-based sensors. The review begins with the characteristics of AuNPs, followed by a brief explanation of synthesis and functionalization methods. Then, the mechanisms of AuNPs-based sensors are comprehensively explained in two broad categories based on the surface plasmon resonance (SPR) characteristics of AuNPs and their peroxidase-like catalytic properties (nanozyme). SPR-based colorimetric sensors further categorize into aggregation, anti-aggregation, etching, growth-mediated, and accumulation-based methods depending on their sensing mechanisms. On the other hand, peroxidase activity-based colorimetric sensors are divided into two methods based on the expression or inhibition of peroxidase-like activity. Next, the analytes in environmental and food samples are classified as inorganic, organic, and biological pollutants, and recent progress in detection of these analytes are reviewed in detail. Finally, conclusions are provided, and future directions are highlighted. Improving the sensitivity, reproducibility, multiplexing capabilities, and cost-effectiveness for colorimetric detection of various analytes in environment and food matrices will have significant impact on fast testing of hazardous substances, hence reducing the pollution load in environment as well as rendering food contamination to ensure food safety.