Solid-phase Extraction Technique Research Articles

Liquid chromatography-tandem mass spectrometry method for determination of rivaroxaban in human plasma and its application to a pharmacokinetic study.

A high-performance liquid chromatography tandem mass spectrometric method for the determination of Rivaroxaban in human plasma has been developed and validated using Rivaroxaban D4 as an internal standard. The extraction of analyte and internal standard was accomplished by solid phase extraction technique. The method has been validated over a concentration range of 5.96-801 ng/mL. Chromatographic separations were achieved using Gemini C18, 150 mm × 4.6 mm, 5 µm, column eluted at flow rate of 1.5 mL/min with mobile phase (acetonitrile: ammonium acetate buffer (80:20 v/v)). The overall run time of method was about 1.8 min with elution times of Rivaroxaban and its internal standard Rivaroxaban D4 at around 1.18 min. The multiple reaction monitoring transitions were set at 436/145 (m/z) and 440/145 (m/z) for Rivaroxaban and Rivaroxaban D4, respectively. The calibration curves were linear (r2 ≥ 0.99) over the range of 5.96-801 ng/mL with lower limit of quantitation validated at 5.96 ng/mL. Extraction recoveries were >88% for both rivaroxaban and its stable labeled internal standard rivaroxaban D4. The inter-day/between run precisions were ranged from 1.08% to 3.75%, while accuracy ranged from 96.3% to 102%. The presented method was used in pharmacokinetic study in healthy volunteers. Results of incurred sample reanalysis were within the acceptance range of ±20% of original value, for 98.3% of samples reanalyzed. This indicated good assay precision of target analytes in their real matrix at the employed experimental conditions. The applicability of the assay for the determination of the pharmacokinetic parameters was demonstrated.

Proficiency testing by the National Metrology Institute of Japan for quantification of pesticide residues in grain samples from 2012 to 2018.

From 2012 to 2018, proficiency testings (PTs) were carried out to support the analytical skill development of participants. Grains were sprayed with various target pesticides and used as material samples for PTs. It was found that 27-56% and 10-43% of participants used the Japanese official multiresidue method and a solid-phase extraction technique with the Quick, Easy, Cheap, Effective, Rugged, and Safe (modified QuEChERS, known as "STQ" in Japan) method, respectively. Reported results were evaluated using two types of z-scores: one was based on consensus values calculated from the analytical results reported by the participants, and the other was based on values obtained by the National Metrology Institute of Japan (NMIJ). Acceptable z-scores based on the consensus values and NMIJ reference values were achieved by 78-95% and 67-94% of the participants, respectively. Many laboratories improved their z-scores by continuing participation in our PT.

Combination of solid-phase extraction with microextraction techniques followed by HPLC for simultaneous determination of 2-methylimidazole and 4-methylimidazole in beverages

A sensitive analytical method for the monitoring 2-methylimidazole and 4-methylimidazole (2-MI and 4-MI) is desirable due to their carcinogenic property. Here, we propose a highly sensitive method basing on the combination of solid-phase extraction and dispersive liquid-liquid microextraction techniques followed by high-performance liquid chromatography to simultaneously determine 2-MI and 4-MI in beverages. Dansyl chloride was used as a derivatizing reagent. Microextraction parameters were optimized by Plackett-Burman design and response surface methodology. Results show that derivatization led to significant improvements in chromatographic behavior for 2-MI and 4-MI due to increased hydrophobicity. The method shows good linearity (R2 ≥ 0.9985), satisfactory precision (%RSD ≤ 8.3%) and low limit of quantification (20 ng/mL), and was successfully applied to determine 2-MI and 4-MI in carbonated drinks, beers and energy drinks, achieving satisfactory recoveries (85–101%). This method provides a potential for routine analysis of 2-MI and 4-MI at the nanogram per milliliter level in beverages.

Supported ionic liquid phases for the separation of samarium and europium in nitrate media: Towards purification of medical samarium-153

Samarium-153 is a medical radionuclide that serves in nuclear medicine for bone pain palliation or imaging of the skeleton, and is produced in a nuclear research reactor by irradiation of an enriched samarium-152 target with a high flux of thermal neutrons. However, long-lived europium-154 impurities are formed concurrently, which restricts the use of the samarium-153 radiopharmaceutical. Previous research already showed the possibility to separate samarium and europium efficiently by solvent extraction with the undiluted ionic liquid [A336][NO3]. Current research efforts investigated the feasibility to convert the separation method to an extraction chromatography application, taking advantage of solid phase extraction techniques. TEVA particles, where the ionic liquid is immobilized onto a solid support, served as the stationary phase in the column. Eu3+ was reduced to Eu2+ in a concentrated nitrate salt solution prior to the separation step. After loading onto the extraction chromatography column, Eu2+ was not retained by the TEVA particles upon elution with a concentrated nitrate salt solution, whereas Sm3+ was extracted to the ionic liquid layer. Sm3+ could be efficiently removed from the column by elution with water, hence yielding a simple, yet efficient separation method.

Antioxidant and Potentially Anti-Inflammatory Activity of Anthocyanin Fractions from Pomace Obtained from Enzymatically Treated Raspberries.

Raspberry pomace was obtained from raspberries subjected to enzymatic maceration using three commercial pectinolytic preparations (Pectinex Ultra SP-L, Pectinex Yield Mash, and Ultrazym AFP-L). Phenolic compounds were extracted and anthocyanin fractions were isolated using the SPE solid phase extraction technique. In the separated anthocyanin fractions, the content of individual compounds was determined by the HPLC technique and the antioxidant activity was assessed with four complementary methods (DPPH and ABTS radical scavenging activity, chelating Fe(II) power, and ferric reducing power). Potential anti-inflammatory properties were also identified as the ability to inhibit the activity of lipoxygenase and cyclooxygenase 2. For these enzymes, the type of inhibition was determined based on the Lineweaver–Burke plot.

Ultrastable nitrogen-doped carbon nanotube encapsulated cobalt nanoparticles for magnetic solid-phase extraction of okadaic acid from aquatic samples

An easy-prepared adsorbent with high stable and good dispersibility is especially valuable for the development of magnetic solid-phase extraction (MSPE) techniques. In this study, magnetic nitrogen-doped carbon nanotube cages (N-CNTCs) were synthesized via direct carbonization of cobalt (II)-containing metal-organic frameworks. During carbonization, cobalt ions inside the MOFs were converted into magnetic functional nanoparticles of N-CNTCs. Simultaneously, large amounts of nitrogen, originating from the organic ligands, were doped into the carbon framework. This unique structure gave the N-CNTCs excellent chemical stability, high affinity, and good dispersibility. The synthesized magnetic N-CNTCs were then used for MSPE of okadaic acid (OA) from aquatic samples. A simple, efficient, and sensitive method for detecting and quantitating OA was developed by combining the above sample pretreatment technique with high-performance liquid chromatography -tandem mass spectrometry (HPLC-MS/MS). The resulting method boasts a linear dynamic range of 3.0–1000.0 pg mL−1 with good linearity (R2 ≥ 0.9994). The limit of detection (LOD) and limit of quantification (LOQ) were 1.3 pg mL−1 and 3.0 pg mL−1, respectively. Several shellfish and seafood samples were analyzed using the developed method, showing satisfactory recoveries (82.0–107.0%) and relative standard deviations (<4.5%). The developed method was also used to investigate the OA distribution in crab tissues. Our results demonstrate that magnetic N-CNTCs are promising adsorbents for providing reliable support for the early warning and tracing to the source of algae toxins.

Pectic acid–graphene oxide nanocomposite as an adsorbent in vortex-assisted dispersive solid-phase extraction for preconcentration of copper ion followed by flame atomic absorption spectrometry

An efficient, green, novel and rapid vortex-assisted dispersive solid-phase extraction (VADSPE) technique was used for the preconcentration and determination of trace levels of Cu2+ followed by flame atomic absorption spectrometry. Graphene oxide (GO) was synthesized from graphite and then modified by pectic acid (poly-d-galacturonic acid, PA) to synthesize the pectic acid–graphene oxide (PA-GO) nanocomposite. The Fourier transform infrared spectrophotometry, field emission scanning electron microcopy, energy-dispersive X-ray spectroscopy and X-ray diffraction analysis were used to characterize the synthesized GO-PA nanocomposite. By using VADSPE technique, PA-GO was used as an adsorbent for preconcentration of Cu2+. The main parameters affecting the extraction recovery, including pH of the sample solution, amounts of adsorbent, extraction time, type and concentration of desorbent solvent and desorption time were completely investigated and optimized. Under the optimum conditions, the results show that the proposed method has the linearity range of 10–300 µg L−1 with a correlation coefficient of 0.9950. The limit of detection based on six replicate analyses of the blank sample was 2.22 µg L−1, and the relative standard deviation was 2.7% for the five replicate analysis of 50 µg L−1 Cu2+. The validity of the proposed method was checked by the analysis of two certified reference materials including CRM-TMDW and GBW07605 tea samples, and then, the proposed method was successfully applied for the determination of trace levels of Cu2+ in different water and food samples.

Comparison of the Effects of Extraction Techniques on Mass Spectrometry Profiles of Dissolved Organic Compounds in Oil Sand Process-Affected Water

Recent advances in mass spectrometry have facilitated chemical characterization and profiling of complex environmental mixtures such as oil sand process-affected water (OSPW) and identification of previously unresolved chemicals. However, because OSPW is a complex mixture of salts, metals, suspended particulate matter, and dissolved organics, extraction techniques are required to reduce the effects of signal suppression/enhancement. In this work, Orbitrap, ultrahigh resolution mass spectrometry was used to perform a comprehensive comparison of solid phase extraction (SPE) and liquid–liquid extraction (LLE) techniques on profiling of dissolved organic chemicals in OSPW. When operated in negative ion mode, extraction of naphthenic acid (NAs–O2) was dependent on acidification of OSPW samples for C18 and LLE techniques. However, when applying a hydrophilic lipophilic balance (HLB) sorbent (ABN) SPE technique, the extractability of NAs was independent of pH. When operated in positive ion mode, for all extracti...

Synthesis of a polymeric imidazolium-embedded octadecyl ionic liquid-grafted silica sorbent for extraction of flavonoids

In this work, a polymeric imidazolium-embedded octadecyl ionic liquid (poly(1-vinyl-3-octadecylimidazolium naphthalene sulfonate))-grafted silica (poly(C18VIm+NapSO3−)@SiO2) sorbent was prepared and applied as a solid-phase extraction (SPE) sorbent in extraction of flavonoids. The synthesized poly(C18VIm+NapSO3−)@SiO2 sorbent was characterized by X-ray photoelectron spectrogram (XPS) and fourier transform infrared spectroscopy (FT-IR). The thermodynamic and kinetic adsorption models of the prepared poly(C18VIm+NapSO3−)@SiO2 sorbent towards flavonoids were discussed by nonlinear fitting adsorption curve and the results indicated the thermodynamic adsorption model in this work was tended to be Freundlich model rather than Langmuir one and the pseudo-second order model could be used to describe the dynamic adsorption process. In addition, the adsorption amounts indicated the sorbent has satisfactory extraction capabities towards flavonoids. For investigating the influence of independent variables and their interactions on the extraction efficiency, a Box-Behnken design was used for optimizing three greatly influential parameters after performing single-factor experiments. The interaction energies between flavonoids and two ionic liquids were calculated to understand the adsorption mechanism. Under the optimal conditions, a method used for determining flavonoids was developed by combining SPE technique with high performance liquid chromatography (HPLC), and the developed method exhibited low limits of detection (0.25–0.4 μg L-1), good linearities with correlation coefficients (R2) in the range of 0.9951–0.9996 and satisfactory recoveries ranging from 83.6% to 114.1%, which confirmed the proposed method could be successfully used to determine trace flavonoids in real samples.

Physicochemical Parameters of Real Wastewater Originating from a Plant Protection Products Factory and Modification of the QuEChERS Method for Determination of Captan.

The aim of this study was the modification and application of the QuEChERS method for the preparation and purification of samples in order to determine the level of captan in real wastewater originating from a plant protection products factory which was characterized by a significant content of organic substances [Chemical Oxygen Demand (COD) = 856 ± 128 mg O2/L and Total Organic Carbon (TOC) = 62 ± 9 mg/L]. The optimization of the method consisted of the selection of solvents used for the extraction of captan from wastewater and also sorbents used to purify the extracts by the dispersion of a solid phase extraction technique (dSPE). Two steps were used: extraction and clean-up. In the extraction step, acetonitrile was replaced by anacetonitrile:acetone mixture. In the clean-up step by the dSPE, five sorbents were tested: Florisil®, aluminum oxide (Al2O3), zirconium oxide (ZrO2), silicon oxide (SiO2) and PSA (primary and secondary amine). Concentrations of captan in wastewater extracts were determined by gas chromatography (GC) combined with electron capture detection (μECD). The best recovery parameters and precision of the method were obtained for samples purified using ZrO2 (recovery 98% and precision expressed as relative standard deviation RSD 8%) and Florisil® (recovery 96%, RSD 9%). Limits of detection (LOD) and quantification (LOQ) for determination of captan in diluted extract of wastewater were 0.003 and 0.01 mg/L, respectively. Matrix effects were in the range of −69% to −44% for samples purified by ZrO2 and Florisil®, respectively. The modified and optimized method was applied for fast and simple determination of captan levels in real industrial wastewater samples, in which the concentration of captan in diluted extract was determined to be 4.0 ± 0.3 mg/L.

Peptide enrichment by ion–pair solid-phase extraction

The technique of Solid-Phase Extraction (SPE) is widely used in various fields to concentrate samples and the search for tools to improve recoveries remains of outmost importance. The use of polymer based cartridges has become prevailing in a broad range of fields to enrich peptides from biological matrices. However, the existing SPE protocols are characterized by disparity. Ion-pairing (IP) reagents are commonly used in chromatographic applications, but their combination with SPE is less known. The aim of this study was to evaluate various SPE loading conditions, including the use of IP reagents, to improve the recoveries of nine selected peptide molecules. Control of pH and the use of IP reagents were found to be crucial to improve the enrichment of the peptides, especially cationic peptides, for which an up to ten-fold increase was observed. The practical potential of the presented theoretical findings were verified by employing IP-SPE for the development of an efficient extraction method for the doping relevant peptide Synacthen. The general proof of principle was obtained by analysis of excretion study urine samples and validation was performed with focus on the limit of detection (20 pg/ml) and recovery (37%).

Magnetic polydopamine modified with deep eutectic solvent for the magnetic solid-phase extraction of sulfonylurea herbicides in water samples

A novel magnetic solid-phase extraction (MSPE) technique coupled with ultra performance liquid chromatography (UPLC) has been developed for the determination of four sulfonylurea herbicides (sulfosulfuron, bensulfuron-methyl, pyrazosulfuron-ethyl and halosulfuron-methyl) in aqueous samples. The key point of this method was the application of a novel magnetic nanomaterial (Fe3O4 @ PDA-DES). The functional groups, morphology, and magnetic properties of this magnetic nanomaterial were investigated through fourier transformed infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and X-ray diffraction (XRD) respectively. The main factors which could affect the experiment results were optimized. Under the optimum conditions, the linearity of this method ranged from 5.0–200 μg L−1 for all analytes, with correlation coefficients (r) ≥0.9901. The enrichment factors were between 495 and 630, and the relative standard deviations (RSDs) were less than 3.6%. The limits of detections (LODs) varied from 0.0098 to 0.0110 μg L-1. In the final experiment, the developed method has been successfully applied to the determination of sulfonylurea herbicides in environment and drinking water samples, and the obtained recoveries were between 61.3% and 108.6%.

Recent Advances and Trends in Applications of Solid-Phase Extraction Techniques in Food and Environmental Analysis

This paper presents an overview of the more recent applications of solid-phase extraction (SPE, from January 2015 to September 2018, which have been recorded in Web of Science) in preparation of food and environmental samples. First, the history, milestones, principles, and features of different formats of SPE are discussed. In addition, miniaturization of SPE techniques and comparison of classical SPE and miniaturized SPE—called dispersive micro solid-phase extraction (D-μ-SPE)—are covered. Next, the published applications in extraction and separation of diverse organic and inorganic analytes from a variety of food and environmental samples are classified on the basis of their sorbents including layered double hydroxide, metal organic frameworks, carbon nanotube-based sorbents, graphene-based sorbents, β-cyclodextrin-based sorbents, dendrimer-based sorbents, molecular or ion recognition sorbents, and restricted access materials. Finally, the future trends in this area are discussed.

Carbofuran: analytical methods and its determination in natural water samples by flow injection DPA(III)–H2SO4 chemiluminescence

ABSTRACTThis study proposes, a simple, rapid and sensitive chemiluminescent (CL) method for determination of carbofuran based on diperiodatoargentate(III) (DPA)-sulfuric acid (H2SO4) reaction coupled with flow injection (FI) methodology. Under optimum conditions, a linear standard curve is achieved in the range of 0.001–8.0 mg L–1 (R2= 0.9994 (n = 11) with relative standard deviation (RSD) of 1.4–3.7% (n = 4)), a limit of detection (LOD) 5.0 × 10–4 mg L–1 (S/N = 3) and injection throughput 180 h–1. The proposed method was applied satisfactorily for the analysis of carbofuran in freshwater samples using solid phase extraction (SPE) technique with the recoveries of 94–110% (% RSD = 1.7–3.8, n = 4). A possible CL reaction mechanism has also been discussed briefly.

DETERMINACIÓN DE LA DISTRIBUCIÓN DE CONTAMINANTES EMERGENTES EN AGUA INTERSTICIAL EN SEDIMENTOS DE HUMEDAL MEDIANTE LA OPTIMIZACIÓN Y VALIDACIÓN DE UN MÉTODO ANALÍTICO

The present work shows the methodology (study of a method) for the analysis of four emerging pollutants. Each studied pollutant represents a family from emerging pollutants (an estrogenic compound, an antibacterial, a pharmaceutical and a fragrance). The method was optimized to be used in a complex environmental matrix such as sediment interstitial water of a wetland with high organic matter content. The extraction of the compounds was carried out by solid phase extraction technique and quantified by gas chromatography with mass spectrometry in single ion monitoring mode. The method was validated using the “Single Laboratory Method Validation Process” through the determination of the performance parameters of the method. The optimized method was applied to the analysis of sediment interstitial water from the canals of the periurban agricultural zone of Xochimilco, Mexico. This preliminary study showed that the sampling point close to the wastewater discharge area from the secondary treatment wastewater plant had the highest concentration of emerging pollutants. Also, an inversely proportional relationship was observed between the concentrations of ibuprofen and musk with the concentration of organic matter in the sediments. The optimization of the method and the ratification with sediment interstitial water samples from the wetland, showed the worthiness of the method for the evaluation of the presence and distribution of emerging pollutants.

Determination of naproxen, diclofenac and ibuprofen in Umgeni estuary and seawater: A case of northern Durban in KwaZulu–Natal Province of South Africa

In recent years, the occurrence of pharmaceuticals including non-steroidal anti-inflammatory drugs in Umgeni River water system in South Africa has been a concern to the scientific community. In this study; naproxen, diclofenac and ibuprofen were isolated from various water samples (river, estuarine and sea water) using the solid-phase extraction technique based on Oasis hydrophilic–lipophilic balance cartridges. The extracted compounds were identified and quantified using high performance liquid chromatography-photo diode array detector. Validation of the analytical method was performed by spiking seawater with a mixture of all the three pharmaceuticals at 0.025 μg/L. Percentage recoveries for naproxen, diclofenac and ibuprofen were 82.3, 65.5 and 79.5%, respectively. The analytical method quantitation limits for naproxen, diclofenac and ibuprofen were 0.025, 0.036 and 0.035 μg/L, respectively. Diclofenac was not detected in any of the analysed river, estuarine and seawater samples. Naproxen was quantified in all water samples and reached a maximum concentration of 0.36 μg/L in river water. In seawater, naproxen and ibuprofen were detected up to 0.16 and 0.17 μg/L respectively. The occurrence of these pharmaceuticals in water resources is a cause of concern due to potential impacts on the wellbeing of aquatic organisms and humans.

Residues of pesticides and some metabolites in dissolved and particulate phase in surface stream water of Cachapoal River basin, central Chile

In the last twenty years, pesticide use in Chile has increased more than 160%, generating a greater risk of water resources pollution. The objective of this study was to assess the presence of 22 pesticides and 12 degradation products in surface water samples from the Cachapoal River basin, Central Chile, an area characterized by intense agricultural activity. Pesticide concentrations in the dissolved phase (DP) and particulate phase (PP) in samples collected in the dry season and after precipitation events was assessed. The solid-phase extraction technique was used to preconcentrate the samples and GC/MS and LC/MS were used to detect pesticides. The results present spatio-temporal variations in the proportion and concentration of pesticides and their degradation products in both the DP and PP for each site and sampling period. The most ubiquitous compounds in the dissolved phase were atrazine, atrazine-2-hydroxy (HA), cyprodinil, pyrimethanil, and tebuconazole, while in the particulate phase HA, imidacloprid, diazinon and pyrimidinol were detected. The results presented in this study make up the first record of pesticides in the dissolved and particulate phases in surface water in Chile. They show that the problem of pesticide contamination undoubtedly affects the quality of bodies of water in agricultural areas in Chile and support the need for a proper assessment of the water quality of the Cachapoal River in the future.

Surfactant functionalisation of magnetic nanoparticles: A greener method for parabens determination in water samples by using magnetic solid phase extraction

The present work highlights a new strategy through funtionalisation of Fe3O4 nanoparticles with green, effective and highly water soluble surfactant (DC193C) (MNP@DC193C) as an efficient adsorbent for the determination of parabens in water samples by using magnetic solid phase extraction (MSPE) technique. The newly prepared MNP@DC193C was analysed by using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometer (XRD), energy dispersive X-ray spectroscopy (EDX) and vibrating sample magnetometer (VSM) analysis. The obtained results confirmed that surfactant DC193C was successfully grafted onto Fe3O4 nanoparticles surface. The proposed MNP@DC193C-MSPE method was effectively applied for the selected paraben extractions (methyl, ethyl, propyl and benzyl parabens) from water samples prior to HPLC-UV analysis. Several parameters, such as the effect of pH, sample volume, sorbent mass, types of desorption solvent, volume of desorption solvent, desorption and extraction time of the sample matrix were optimised to obtain the optimum conditions for the paraben extractions. The proposed MNP@DC193C-MSPE method provided low detection limit (0.0024–0.0063 μg mL−1), good linearity of the detection method with correlation coefficients (R2) between 0.995 and 0.998 and satisfactory reproducibility with relative standard deviations (RSDs) of less than 10.1%. Under optimised conditions, the newly synthesised MNP@DC193C was successfully applied to water samples from the environment. This newly developed method has successfully enriched selected parabens from these complex matrices because good recoveries were obtained in the range of 86.0–118.0% with satisfactory RSD % (0.41–15.9%). This study demonstrated that MNP@DC193C was a promising MSPE adsorbent for the preconcentration of parabens from environmental samples.

Magnetic adsorbent based on mesoporous silica nanoparticles for magnetic solid phase extraction of pyrethroid pesticides in water samples

Mesoporous KIT-6-magnetite composite (Fe3O4@SiO2@KIT-6) was successfully prepared and characterized by transmission electron microscopy, scan electron microscopy, elemental mapping, energy dispersive X-ray spectrum, Fourier transform infrared spectroscopy, thermal gravimetric analysis, X-ray powder diffraction, Brunauer Emmett Teller analysis and magnetic property analysis. It was then applied as adsorbent for magnetic solid phase extraction of fenpropathrin, lambda-cyhalothrin, S-fenvalerate and bifenthrin from water samples before analyzed by high performance liquid chromatography-ultraviolet detector. A few factors impacting extraction were studied. The optimal results were acquired by using acetonitrile to eluent the targets adsorbed on 40 mg of Fe3O4@SiO2@KIT-6 adsorbent in 100 mL water samples at a pH of 7 at 25 ℃ within 10 min. The experimental limit of detections of fenpropathrin, cyhalothrin, S-fenvalerate and bifenthrin are 0.01 × 10−3, 0.006 × 10−3, 0.01 × 10−3 and 0.005 × 10−3 mg∙L-1, respectively. Good relative recoveries (86.58–98.80%) and reproducibility values are also obtained. The kinetic experiment shows that the adsorption follows pseudo-second order, while the isotherm experiment follows Langmuir isotherm model. Trace pyrethroid pesticides in water samples can be detected by the developed magnetic solid phase extraction technique followed by high performance liquid chromatography, which is simple, easy, environmental friendly and efficient.

Magnetic solid phase extraction with carbon-coated Fe3O4 nanoparticles coupled to HPLC-UV for the simultaneous determination of losartan, carvedilol, and amlodipine besylate in plasma samples

In this paper, a chemical coprecipitation method was used for the synthesis of Fe3O4 magnetic nanoparticles. The Fe3O4 magnetic nanoparticles were then modified by carbon via a simple hydrothermal method by using glucose. The synthesized Fe3O4 and carbon-coated Fe3O4 (C/Fe3O4) magnetic nanoparticles were characterized by diverse techniques such as XRD, FESEM, EDX, FTIR, and BET. The characterization results were confirmed the formation of the uniformly magnetic nanoparticles and a successful modification of them by carbon. The FTIR spectra confirmed the presence of functional groups on the C/Fe3O4 magnetic nanoparticles surface. The magnetic nanoparticles were used for extraction of losartan, carvedilol, and amlodipine besylate from plasma samples based on magnetic solid phase extraction (MSPE) technique. The effective parameters on extraction efficiency were optimized by multivariate optimization. Under the optimized experimental conditions the MSPE method showed wide linear ranges (1–7500 ng mL−1), low detection limits (0.09–0.69 ng mL−1), good extraction recoveries (56.35–66.43%), and low RSD values (1.6–5.8%). Despite high protein binding of the drugs, the analyses of them were done without protein precipitation. The accuracy was studied by analyses of the spiked plasma samples at different concentrations.