Dispersive Solid-phase Extraction Method Research Articles

Covalent organic frameworks as dispersive solid-phase extraction adsorbents for β-lactam detection in aquatic environments

Currently, antibiotic residues in the environment pose a serious public health risk; therefore, new sensitive approaches for detecting the presence of antibiotics are urgently needed. Ionic-type covalent organic frameworks (TAPB-(TFIT)+Cl−-COFs) were designed and prepared in this work, and these imine-linked COFs were characterized by several techniques, proving of porous structure and rich of nitrogen. The materials were applied to the extraction of β-lactams from aqueous samples, and the important parameters of the adsorption–desorption conditions were optimized. A dispersive solid-phase extraction method coupled with ultrahigh-performance liquid chromatography-tandem mass spectrometry (TAPB-(TFIT)+Cl−-COFs-d-SPE-UPLC-MS/MS) was proposed and utilized to determine the levels of 11 antibiotics in the β-lactams in the extracted samples. Good linearity (1.0–200.0 μg·L−1, r > 0.9999) was achieved together with limits of detection and quantification of 0.01–0.92 μg·L−1 and 0.05–2.78 μg·L−1, respectively; recoveries ranged from 75.57 to 114.20 %, conferring relative standard deviations < 8.99 % and negligible matrix effects (84.88–109.40 %). The synthesized TAPB-(TFIT)+Cl−-COFs were demonstrated to have good reusability and high stability. Furthermore, the proposed method was clearly shown to be sensitive and separable for the reliable simultaneous detection of 11 β-lactam residues in aquatic environments.

MOF@N–doped carbon dots–based dispersive solid phase extraction combined dispersive liquid–liquid microextraction of several aflatoxins from raw cow’s milk samples prior to HPLC–FLD

A dispersive solid-phase extraction method based on metal–organic framework and nitrogen–doped carbon dot nanocomposite combined with magnetic ionic liquid-based dispersive liquid–liquid microextraction was established for the extraction of aflatoxins from raw milk samples. For this purpose, the proteins in the sample were precipitated using a zinc sulfate solution. After vortexing (for 5 min) and centrifuging, 35 mg of the sorbent were added into the aqueous phase obtained from previous step, and the mixture was vortexed for five minutes. In the following, the sorbent particles were separated and eluted with methanol in the presence of vortex agitation (4 min). After centrifuging, the eluent phase was mixed with magnetic ionic liquid (1- octyl-3-methylimidazolium tetrachloroferrate) and rapidly injected into deionized water to perform the dispersive liquid–liquid microextraction procedure. Finally, the magnetic solvent was separated in the presence of a magnet and injected into a high-performance liquid chromatography-fluorescence detector after diluting with the mobile phase. Referring to the results, the limits of detection and quantification of the studied aflatoxins were in the range of 0.69–1.09 and 2.31–3.63 ng/L, respectively. Extraction recoveries were in the range of 61 to 73 %. At the end, the suggested approach was employed in the analysis of the aflatoxins in the raw cow’s milk samples collected from different regions of East Azarbaijan and AFM1 was found in several samples (34 out of 60 samples). Also, AFB1 was found in three samples.

Improved preconcentration workflow for organic explosive traces in aqueous samples using solvent-assisted dispersive solid-phase extraction

The present study deals with the development of a solvent-assisted dispersive solid phase extraction method for the extraction of HMX, RDX, and TNT from aqueous samples. Benzophenone and methanol were selected as explosives sorbent and dispersive solvent respectively. Extraction parameters like pH, extraction time, amount of sorbent, volume and type of the disperser solvent and centrifuge time were optimized. Dispersion of 0.5 mL dispersive solution (4% (w/v) benzophenone in methanol) was performed by injection into the 5 mL aqueous sample (pH=7) using a 1.0 mL syringe. After centrifuge, the extracted explosives were analyzed by high performance liquid chromatography with ultraviolet detection (HPLC-Uv). The results indicated that the linear ranges with the correlation coefficients of 0.99 ≤ R2 were 1.6–204.6 μg L−1, 1.4–213.7 μg L−1 and 1.3–225.9 μg L−1 for HMX, RDX and TNT respectively. The limit of detection and limit of quantification obtained for each explosive were: 0.3 μg L−1 and 0.8 μg L−1 for HMX, 0.3 μg L−1 and 0.9 μg L−1 for RDX and 0.2 μg L−1 and 0.7 μg L−1 for TNT. Finally, the practical applicability of the developed method was evaluated for the extraction of some organic explosives in water samples followed their determination by HPLC-Uv.

Magnetic Poly(Amidoamine) Dendrimer for the Dispersive Solid Phase Extraction of Nitrophenols from Environmental Water Samples.

A fast and simple dispersive solid phase extraction method is described for nitrophenols determination in water samples by using gas chromatography-nitrogen phosphorous detector. Firstly, the Poly(amidoamine) grafted Fe3O4 magnetic nanoparticles were synthesized in different generations by successive addition of butyl acrylate and ethylenediamine. After characterization, the prepared dendrimer was utilized as an adsorbent for magnetic solid phase extraction of 2-nitrophenol, 3-nitrophenol, and 4-nitrophenol to benefit large number of surface amine interaction sites. The effects of the different parameters influencing the sample preparation efficiency were investigated. The proposed method showed linearity in the ranges of 0.04-700 and 0.05-700µg/dm3 for nitrophenols. The obtained limits of detection and quantification under optimized conditions were 0.01-0.02 and 0.04-0.05µg/dm3, respectively. The relative standard deviations (n = 5) were less than 3.8% (at 10µg/dm3). Moreover, the calculated enrichment factors were above 200. In addition, the relative recoveries for a spiked river water sample were satisfactory.

Application of cobalt-cerium-iron ternary layered double hydroxide for extraction of perfluorooctane sulfonate followed by HPLC-MS/MS analysis

Herein, Ce-doped CoFe layered double hydroxide (LDH), noted as CoCeFe ternary LDH, was prepared using the co-precipitation route. Prosperous synthesis of CoFe LDH and successful partial replacement of iron cations with cerium cations in CoCeFe ternary LDH were confirmed by X-ray diffraction patterns, energy-dispersive X-ray spectroscopy, and elemental dot-mapping images. Nanosheet morphology was recognized for both CoFe LDH and CoCeFe ternary LDH from scanning electron microscopy and transmission electron microscopy micrographs. In the following, a dispersive solid phase extraction (DSPE) method was developed using the synthesized CoCeFe ternary LDH as a sorbent for extracting perfluorooctanesulfonic acid (PFOS) from wastewater samples. For the selective analysis of PFOS, high-performance liquid chromatography-tandem mass spectroscopy (HPLC-MS/MS) in multiple reaction monitoring mode was used. Analytical parameters such as the limit of detection equal to 0.02 μg/L, with a linear range of 0.05–300 μg/L, the limit of quantification equal to 0.05 μg/L, and an enrichment factor equal to 23.3 were achieved for PFOS at the optimized condition (sorbent: 5 mg of CoCeFe ternary LDH, eluent type and volume: 150 μL mobile phase, pH: 3, adsorption time: 3 min, and desorption time: 5 min). The developed strategy for the analysis of PFOS was tested in real wastewater samples, including copper mine and petrochemical wastewater. The amount of analytes in real samples was calculated using the standard addition method, and good relative recovery in the range of 86%–105% was obtained. The main novelty of this research is the application of CoCeFe ternary LDH to extract the PFOS from wastewater using the DSPE method for determination by HPLC-MS/MS.

Development of a dispersive micro solid phase extraction-HPLC method for the simultaneous quantification of antiepileptic drugs in various matrices

Due to the widespread utilization of antiepileptic drugs for seizure control and patient well-being, it is crucial to determine their presence in biological and water samples. This is essential for optimizing therapy, comprehending drug behavior, identifying drug interactions, monitoring environmental contamination, and safeguarding public health and ecology. Hence, a novel method that combines dispersive micro solid phase extraction with HPLC-DAD was developed to simultaneously determine the presence of Lacosamide, Levetiracetam, and Phenytoin. To achieve this, a new sorbent was synthesized using the hydrothermal and sol–gel methods, which consisted of bimetallic MIL-100 (Fe, Ni) on MIL-100 (Mn), SiO2, and Fe3O4 nanoparticles. We compared the extraction capabilities of several sorbents in order to select the most effective one. The optimal ratio of components for the chosen sorbent was determined through the simplex lattice design to enhance its efficiency. The optimized values for SiO2, Fe3O4, and MIL-100 (Fe, Ni) on MIL-100 (Mn) were found to be 0.1, 0.34, and 0.56, respectively. The parameters that affected the dispersive micro solid phase extraction method were optimized using both experimental design and one factor at a time. Under the optimal conditions, the linear range for the detection of Lacosamide, Levetiracetam, and Phenytoin was determined to be 0.1–363.0, 0.3–372.0, and 0.4–435.0 ng mL−1, respectively, with low LODs below 0.13 ng mL−1. Additionally, a preconcentration factor of 492.6, 487.1, and 469.5 was achieved for measuring Lacosamide, Levetiracetam, and Phenytoin, respectively. The intra-day and inter-day relative standard deviations (RSDs) ranged from 3.8 % to 4.6 % and 4.2 % to 5.2 %, respectively. The recoveries and RSDs for analyzing real water, human urine, and serum samples were found to be between 89.6–97.0 % and 4.53–6.44 %, respectively.

Simultaneous extraction of polycyclic aromatic hydrocarbons and tetracycline antibiotics from honey samples using dispersive solid phase extraction combined with dispersive liquid-liquid microextraction before their determination with HPLC-DAD

A dispersive solid-phase extraction method combined with dispersive liquid-liquid microextraction was offered for the extraction of four polycyclic aromatic hydrocarbons (anthracene, fluorene, phenanthrene, and pyrene) and tetracycline antibiotics (tetracycline, oxytetracycline, and chlortetracycline) from honey samples, simultaneously. In this work, cobalt-gallic acid bio-metal organic framework was synthesized and 20 mg of it was added into of 10 mL the diluted honey solution to efficiently adsorb the analytes. After vortexing (3 min) and centrifuging, the sorbent particles were eluted with 0.75 mL acetonitrile under vortexing for 3 min. In the following, this phase was mixed with 55 µL [Ch: 4-chlorophenol]+[FeCl4]- magnetic deep eutectic solvent and rapidly injected into deionized water. After separating the extractant phase in the presence of an external magnet and diluting it with the mobile phase, it was injected into a high-performance liquid chromatography-diode array detector. Under optimum extraction conditions, extraction recoveries were in the range of 63–84%. The limits of detection of the opted polycyclic aromatic hydrocarbons and tetracyclines were in the ranges of 0.18–0.26 and 0.25–0.29 ng g−1, respectively. Also, good repeatability (relative standard deviations ≤ 7.5 and 8.3% for intra– (n=6) and inter-day (n=4) precisions, respectively) was obtained. In summary, the validated method was successfully recommended for the determination of polycyclic aromatic hydrocarbons and tetracyclines in various honey samples and pyrene was found in two samples at 5.5 and 12.9 ng g−1. The used bio-metal organic framework has sufficient ability in extraction of different classes of compounds (polycyclic aromatic hydrocarbons and antibiotics) from honey. Performing the microextraction step has direct effect in analysis of the analytes in low concentrations and the use of magnetic solvents, eliminate the use of centrifugation in this step.

Zn-doped MoO3 nanorods for dispersive solid phase extraction of trace Pb(II) from water and food samples

A rapid, and environmentally friendly dispersive solid phase extraction method based on Zn-doped MoO3 nanorods for efficient extraction of trace level of Pb(II) from water and food samples was established before high-resolution continuum source flame atomic absorption spectrometric detection. The sorbent characterization studies were carried out using BET, FE-SEM, XRD, and FT-IR techniques. To achieve effective phase separation and accurate analytical data, the adsorption and desorption procedures have been precisely adjusted. The presented approach demonstrated a wide working range (9.3–500 µg L−1), a relatively low detection limit (3.1 µg L−1), and very good extraction recoveries (90–104%) under optimum conditions. The matrix effect was investigated by the addition of interference ions. The presence of many different anions and cations in the environment did not lead to negative results and selectivity towards the analyte was observed. The method was validated by the analysis of certified reference materials (TMDA - 64.3 and INCT-OBTL-5). The enhancement factor has been determined as 10.9. The suggested method worked efficiently to extract and determine Pb(II) from water, tea, and oil samples.

Trace Determination of Phenanthrene and Fluorene in Beverages Using D-μ-SPE and Liquid Chromatography Analysis

Dispersive micro solid phase extraction (D-μ-SPE) method using Graphene Oxide (GO) for the extraction and pre-concentration of selected polycyclic aromatic hydrocarbons (PAHs) from beverage samples prior to high-performance liquid chromatography - diode array detector (HPLC - DAD) is reported. Selected PAHs Fluorene (FLU) and Phenanthrene (PHE) were used as targeted analytes. An experimental design using Response Surface Methodology (RSM) and Box–Box–Behnken design (BBD) was performed to evaluate the interactive effects of three significant parameters: mass of sorbent, sample volume and extraction time. Under the optimum conditions, the method revealed good linearity (R2 = 0.9995 – 0.9998) over a concentration range of 0.5 – 5.0 mg L-1. The limit of detection (LOD) was in the range of 0.03 – 0.24 mg L-1 with satisfactory relative recoveries (81 – 99 %) and good relative standard deviation (RSD) of ≤ 3.80 % (n = 3). The method was successfully applied to tea, coffee, and milk samples and proved to be a simple, rapid, and reliable method with good extraction efficiencies for the detection of PAHs in beverage samples.

A new methodology to reveal potential nucleic acid modifications associated with the risk of endometrial cancer through dispersive solid-phase extraction coupled with UHPLC-QE-Orbitrap-MS/MS and HPLC-UV.

Nucleic acid modifications have attracted increasing attention in recent years since they have been found to be related to a number of diseases including cancer. Previous studies have shown that the early development of endometrial cancer (EC) is often accompanied by changes in methylation levels of related genes, and the expression of related proteins that regulate reactive oxygen species (ROS) shows significant differences in EC cells and tissues. However, it has not been reported whether nucleic acid modifications related to methylation or ROS can serve as biomarkers for EC. Accurate quantification of these nucleic acid modifications still has challenges because their amounts in urine are very low and the interferences in urine are complicated. In this study, a novel dispersive solid-phase extraction (DSPE) method based on chitosan-carbon nanotube-Al2O3 (CS-CNT-Al2O3) has been established for the analysis of 5-hydroxymethyluracil (5mU), 5-methyl-2'-deoxycytidine (5-mdC), 5-hydroxymethyl-2'-deoxycytidine (5-hmdC), 5-formyl-2'-deoxycytidine (5-fdC), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in EC patient urine samples coupled with UHPLC-QE-Orbitrap-MS/MS and HPLC-UV. Firstly, the synthesis of the CS-CNT-Al2O3 nanocomposite was conducted by a sono-coprecipitation method and was characterized by scanning electron microscope (SEM), energy dispersive spectrometer (EDS), and Fourier transform infrared (FTIR). Under the optimal extraction conditions of DSPE, we successfully quantified 5mU, 5-mdC, 5-hmdC, 5-fdC, and 8-OHdG in urine samples from 37 EC patients and 39 healthy controls. The results showed that there were significant differences in the levels of 5-mdC, 5-hmdC, 5-fdC, and 8-OHdG in EC patients compared to the healthy control group. The receiver operator characteristic (ROC) curve analysis was carried out to evaluate the potential of 5-mdC, 5-hmdC, 5-fdC, and 8-OHdG to distinguish EC patients from healthy volunteers. The area under the curve (AUC) for 5-mdC, 5-hmdC, 5-fdC, and 8-OHdG was 0.7412, 0.667, 0.8438, and 0.7981, respectively. It indicated that 5-mdC, 5-hmdC, 5-fdC, and 8-OHdG had certain potential in distinguishing between EC patients and healthy volunteers and they could act as potential non-invasive biomarkers for early diagnosis of EC. Moreover, the present study would stimulate investigations of the effects of nucleic acid modifications on the initiation and progression of EC.

Development of a continuous magnetic dispersive solid phase extraction method for the extraction of seven widely used pesticides from fruit juices

Generally, food safety monitoring is vital issue to preserve human health and guarantee a longer lifespan. In present study, a continuous mode of magnetic dispersive solid phase extraction method based on using magnetic covalent organic framework@metal organic framework nanocomposite as sorbent has been proposed. The developed method has been tested for the extraction of some pesticides (pirimicarb, terbutryn, fenthion, triticonazole, hexaconazole, diniconazole, and haloxyfop-R-methyl) from commercial fruit juices prior to their analysis by high performance liquid chromatography–tandem mass spectrometry. In the current research, the properties of nanocomposite were characterized by scanning electron microscopy, Fourier–transform infrared spectrophotometry and X–ray diffraction techniques. In the next step, the synthesized nanocomposite was employed as an efficient sorbent in the developed extraction procedure that was done in a narrow bore tube. Under optimum extraction conditions, extraction recoveries were in the ranges of 67–83 %. Moreover, the limits of detection and quantification of the selected analytes were in the ranges of 17–43 and 56–143 ng L−1, respectively. Finally, the proposed method was successfully applied in the analysis of the opted pesticides in sixty fruit juice samples.

Application of magnetic dispersive solid phase extraction combined with solidification of floating organic droplet-based dispersive liquid–liquid microextraction and GC-MS in the extraction and determination of polycyclic aromatic hydrocarbons in honey

A magnetic dispersive solid phase extraction method combined with solidification of floating organic droplet-based dispersive liquid–liquid microextraction has been validated for the extraction of polycyclic aromatic hydrocarbons from honey samples. For this purpose, a carbonised cellulose–ferromagnetic nanocomposite was used as a sorbent through the magnetic dispersive solid phase extraction. For preparation of the sorbent, first, carbonised cellulose nanoparticles were created by treating cellulose filter paper with concentrated solution of sulfuric acid. Then, the prepared nanoparticles were loaded onto Fe3O4 nanoparticles through coprecipitation. In the extraction process, first, a few mg of the sorbent was added to the diluted honey solution and dispersed in it using vortex agitation. The particles were then separated and the adsorbed analytes were eluted with an organic solvent. The eluent was taken and after mixing with a water–immiscible extraction solvent was used in the following solidification of floating organic droplet-based dispersive liquid–liquid microextraction procedure. By performing the extraction process under the obtained optimum conditions, low limits of detection (0.08–0.17 ng g−1) and quantification (0.27–0.57 ng g−1), satisfactory precision (relative standard deviations ≤ 5.0%), and wide linear range (0.57–500 ng g−1) with great coefficients of determination (r2≥ 0.9986) were obtained.

A novel removal of Ni2+ ions from water solutions using dispersive solid-phase extraction method with nano Fe3O4/chitosan-acrylamide hydrogel.

The effluent release containing heavy metals as Ni2+ ions has drastic risks to both the natural environment and human health. In this research, the nano Fe3O4/chitosan-acrylamide hydrogel was prepared as a novel nano sorbent for dispersive solid-phase extraction of Ni2+ ions and applied to the water sample solution. The pH, amount and type of elution solvent, the extraction time, etc. were optimized to improve the efficiency of the proposed method. Analytical parameters such as concentration factor and relative standard deviation (%) were achieved as 33.3 and 1.8%, respectively. The capacity in equilibrium sorption was calculated at 22.54 mg g-1. Furthermore, to estimate the adsorption mode, Freundlich, Langmuir, and Temkin models were fitted with experimental isotherm data. Besides, to check the basic process of the metal adsorption mechanism, pseudo-first-order, pseudo-second-order, and Roginsky-Zeldovich models were investigated and the results were fitted with the pseudo-second-order model. The value of change in entropy (⊿S) obtained is -65.24 (J(mol K)-1). Negative values of change in enthalpy, ⊿H in (kJ mol-1) is -24.45 (kJ mol-1) which indicates both physical and chemical adsorptions involved in the process of adsorption. Finally, the nano Fe3O4/chitosan-acrylamide hydrogel exhibited high performance to remove the Ni2+ ions from water sample solution.

Synthesis of novel MOF-on-MOF composite as a magnetic sorbent to dispersive micro solid phase extraction of benzodiazepine drugs prior to determination with HPLC-UV

Diazepam and lorazepam are two benzodiazepine drugs widely prescribed as antidepressants and antiepileptics. A straightforward and time-save dispersive micro solid phase extraction method as a sample preparation strategy was developed to extract these drugs in human urine and real water samples prior to their determination by HPLC-UV. A novel sorbent based on growing Co-MOF on Fe-MOF was synthesized and then magnetized using magnetic Fe3O4 nanoparticles and a sol–gel strategy. The sorbent (Fe3O4@SiO2@Co-MOF@Fe-MOF composite) showed the highest extraction efficiency toward diazepam and lorazepam compared to Fe-MOF and Co-MOF@Fe-MOF as sorbents. The effects of various factors on diazepam and lorazepam determination were studied by experimental design, in which a Plackett-Burman design and Box-Behnken design were used for screening the factors and optimizing the significant factors, respectively. Under optimum conditions, the method linearity for the diazepam and lorazepam determination was 0.3–450 and 0.2–400 ng mL−1 with an R2 of 0.9926 and 0.9943, respectively. Proper detection limits of 0.09 and 0.06 ng mL−1 were obtained for the diazepam and lorazepam determination. Also, intra-day and inter-day RSDs (n = 3) were in the range of 3.42–3.75 % and 4.76–5.39 % for the diazepam and lorazepam determination, respectively. The method exhibits a high preconcentration factor of 654.3 and 719.1 for the diazepam and lorazepam determination. Besides, the recoveries and RSDs were evaluated by analysis of tap, river, and well water, and two human urine samples using the method. RSDs were in the range of 3.09–6.80 %, with recoveries between 88.2 and 97.5 % for analysis of spiked real water and urine samples.

A simple microwave-assisted synthesis of cobalt ferrite nanoparticles and its application for the determination of lead ions in rooibos (Aspalathus linearis) tea.

In this study, a magnetic sorbent assisted dispersive solid phase extraction (DSPE) method was used to preconcentrate lead ions from rooibos tea samples for determination by slotted quartz tube-flame atomic absorption spectrometry (SQT-FAAS). Cobalt ferrite magnetic nanoparticles (CoFe2O4 MNPs) were synthesized by microwave assisted digestion. Limits of detection and quantification were calculated as 5.3 and 17.6µg/L, respectively, in a linear dynamic range of 20-800µg/L. The enhancement factor of the developed method was found to be 80-folds when compared to the detection limit of the regular FAAS system. The percent recoveries obtained for rooibos tea samples spiked at different concentrations were in the range of 77 - 125%, with high repeatability as indicated by low standard deviations. The findings of the study demonstrated that the CoFe2O4 MNPs-based extraction method is a straightforward, fast, affordable, safe, and eco-friendly approach to qualifying/quantifying lead with high precision in the selected beverage sample.

Extraction of Covid-19 drug (Favipiravir) from plasma samples by yolk-shell mesoporous silica before HPLC-MS/MS determination

In this work, a simple and inexpensive dispersive solid phase extraction method using SiO2 @MCM-41-Co3O4 yolk shell as a sorbent was developed for the extraction of favipiravir from plasma samples. The sorbent was synthesized with a simple and novel method. Optimization of the extraction procedure was performed using one parameter at a time strategy. For selective measurement of favipiravir in real samples, multiple reaction monitoring mode in high-performance liquid chromatography-tandem mass spectrometry was used. The synthesized sorbent presented a high adsorption capacity for favipiravir due to its mesoporous structure and different interactions. After optimization of effective parameters including the amount of sorbent, pH, and adsorption and desorption times, the analytical parameters of the method were evaluated. The developed method exhibited a wide linear range from 0.50 to 1000 μg/L. The detection limit and quantification limit of the method were 0.15 and 0.50 μg/L, respectively. The relative standard deviation of the method was obtained by using intra- and inter-day tests, and in both cases, it was less than 6.0%. Finally, the method was successfully used to measure favipiravir in plasma samples with relative recoveries in the range of 87–105%.

Carbonized aerogel/ZnO-based dispersive solid phase extraction of daclatasvir and sofosbuvir from biological samples prior to liquid chromatography–tandem mass spectrometry

Daclatasvir and sofosbuvir are antiviral medications utilized in the treatment of chronic hepatitis C virus (HCV) infection. Due to their low therapeutic index, careful monitoring is necessary to ensure that the optimal dose is administered. High-performance liquid chromatography-tandem mass spectrometry (HPLC–MS/MS) is an exceptionally sensitive and specific technique for quantifying these drugs within biological matrices. In this study, we developed a novel dispersive solid-phase extraction method employing a carbonized bio aerogel composite with ZnO for efficient extraction of daclatasvir and sofosbuvir from exhaled breath condensate, urine, and plasma samples. The extracted analytes were subsequently subjected to analysis using HPLC–MS/MS. Optimal parameters including pH adjustment, sorbent quantity variation, and elution solvent selection were fine-tuned to achieve maximum recovery efficiency while ensuring selectivity enhancements. The developed method demonstrated broad linearity ranging between 1.2 and 200 ng/mL along with good precision (relative standard deviations ≤6.2 %) and an acceptable coefficient of determination (r2 ≥0.994). These findings establish our proposed method as suitable for reliable drug quantification in clinical samples.

Studies on the extraction performance of phorate by aptamer-functionalized magnetic nanoparticles in plasma samples

Abstract Phorate, a highly toxic organophosphorus pesticide, poses significant risks due to its efficiency, versatility, and affordability. Therefore, studying pretreatment and detection methods for phorate in complex samples is crucial. In this study, we synthesized core-shell phorate aptamer-functionalized magnetic nanoparticles using solvothermal and self-assembly techniques. Subsequently, we developed a magnetic dispersive solid-phase extraction and detection method to identifying phorate in plasma samples. Under optimal conditions, we achieved quantitation of phorate within a range of 2–700 ng·mL−1 using gas chromatography-mass spectrometry. The detection limit (S/N = 3) was 0.46 ng·mL−1, and the intraday and interday relative standard deviation were 3.4% and 4.1%, respectively. In addition, the material exhibited excellent specificity, an enrichment capacity (EF = 416), and reusability (≥15). During phorate extraction from real plasma samples, spiked recoveries ranged from 86.1% to 101.7%. These results demonstrate that our method offers superior extraction efficiency and detection capability for phorate in plasma samples.

One-pot/one-step synthesis of Bi2O3/ZnO/Pd nanocomposite for preconcentration and determination of some heavy metal ions in different samples

ABSTRACT In this contribution, a new green eco-friendly synthesised nanocomposite (Bi2O3/ZnO/Pd) was fabricated by one-pot/one-step method, using ultrasonic waves. The nanocomposite was used for pre-concentration of some heavy metals, i.e. cadmium (II), lead (II), and copper (II), exploiting ultrasound-assisted dispersive micro solid phase extraction (UA-D-μ-SPE) method, before their determination by flame atomic absorption spectroscopy (FAAS). The adsorbent synthesis was confirmed by XRD, SEM, BET, TEM, EDS, and TGA analyses. The central composite design (CCD) method was employed to optimise various parameters affecting the extraction of heavy metals. The effective parameters in the adsorption process, viz. the amount of adsorbent (16 mg), pH of the sample solution (6.2), and adsorption time (4 min), were optimised. The type and the concentration of eluting agent (HCl solution) was investigated as one parameter at a time. Impressive parameters in the desorption stage such as the volume and concentration of eluting solution (400 μL of 0.8 mol L−1 HCl) and desorption time (2.5 min) were optimised. In the best extraction conditions for cadmium (II), lead (II), and copper (II), the limits of detection (LODs) were 0.75, 2.1, and 0.90 ng mL−1; the limits of quantification (LOQs) were 2.5, 7.0, and 3.0 ng mL−1; the linear dynamic ranges (LDRs) were 2.5–100, 7.0–600, and 3.0–250 ng mL−1; preconcentration factors (PF) were 24.10, 25.20, and 25.39; and the relative standard deviations (RSDs%) were 3.7, 4.1, and 3.8 (n = 5), respectively. Additionally, the adsorbent had the ability to extract metals up to 8 times without a significant decrease in the extraction percentages. The adsorbent was successfully used in the determination of cadmium (II), lead (II), and copper (II) ions in different food, biological, cosmetic, and water samples.

Facile synthesis of spherical covalent organic frameworks for enrichment and quantification of aryl organophosphate esters in mouse serum and tissues.

Here, an imine-linked-based spherical covalent organic framework (COF) was prepared at room temperature. The as-synthesized spherical COF served as an adsorbent in dispersive solid-phase extraction (dSPE), by its virtue of great surface area (1542.68 m2 /g), regular distribution of pore size (2.95nm), and excellent stability. Therefore, a simple and high-efficiency dispersive solid phase extraction method based on a spherical COF coupled with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was established to determine aryl organophosphate esters in biological samples. This approach displayed favorable linearity in the range of 10.0-1000.0ng/L (r>0.9989), a high signal enhancement factor (58.8-181.8 folds) with low limits of detection (0.3-3.3ng/L). Moreover, it could effectively eliminate complex matrix interference to accurately extract seven aryl organophosphate esters from mouse serum and tissue samples with spiked recoveries of 82.0%-117.4%. The as-synthesized spherical COF has been successfully applied in sample preparation. The dSPE-HPLC-MS/MS method based on a spherical COF has potential application to study the pollutants' metabolism in vivo.