Nanoparticles For Solid-phase Extraction Research Articles

Simultaneous Determination of 16 Kinds of Synthetic Cathinones in Human Urine Using a Magnetic Nanoparticle Solid-Phase Extraction Combined with Gas Chromatography-Mass Spectrometry

A specific and sensitive approach using magnetic nanoparticle solid-phase extraction combined with gas chromatography-mass spectrometry (GC-MS) was carried out and applied in the simultaneous determination of 16 kinds of synthetic cathinones in human urine. The functionalized extraction material (Fe3O4/NH2-MWCNTs) was synthesized and factors affecting the extraction efficiency were all tested. Under the optimized conditions of magnetic nanoparticle solid-phase extraction, the determination of synthetic cathinones in human urine was carried out with GC-MS. Good linear relationships of 16 kinds of synthetic cathinones were obtained in the range of 0.005–5.00 μg/mL with the correlation coefficients (r) ranging from 0.9901 to 0.9979, the limits of detection were in the range between 0.005 and 0.01 μg/mL, and the limits of quantitation were between 0.01 and 0.02 μg/mL. Furthermore, the average intra-day precisions were below 8.90%, the average inter-day precisions were less than 9.52%, and the average recoveries were between 87.03% and 99.13%, respectively. The results show the advantages of the approach in the determination of trace synthetic cathinones in complex matrixes, such as environmentally friendly, fast detection, high efficiency and sensitivity. The practical application indicated that this method could provide scientific basis for the determination of drugs of abuse in forensic laboratories.

Acetic acid modified zinc oxide nanoparticles for solid phase extraction of Cu(II) and Cr(III) in water

Water pollution due to toxic metals may pose a significant effect on the environment and the biota indicating necessity of careful management of their concentration in the system. On the other hand, a simplified and useable sample preparation technique is required for their trace analysis. In this report, a simple solid phase extraction procedure was developed for fast extraction and preconcentration of Cu(II) and Cr(III) from waters using acetic acid modified zinc oxide nanoparticles prior to flame atomic absorption spectrometry. The extraction procedure was optimized in respect to sample volume, pH, adsorbent dose, eluent, and extraction time. Ionic strength and co-existing ions did not exhibited any significant effect on the extraction. Under optimum conditions, with an enrichment factor of 40 and recoveries of over 95%, the limits of detection for both analytes were in the low µg L−1 range. Intra-day and inter-day precision were at about 3% to 4%. The method was applied for trace determination of the analytes in real water samples.

Speciation and preconcentration of chromium in real samples by magnetic polythiophene nanoparticle solid-phase extraction (SPE) coupled with microsampling injection – flame atomic absorption spectrometry (FAAS)

Magnetic solid-phase extraction was evaluated using polythiophene nanoparticles (Fe3O4@PTh) as the adsorbent for chromium speciation from water samples and total chromium preconcentration from food, biological, and soil samples. Chromium concentrations were determined by microsample injection system – flame atomic absorption spectrometry (MIS-FAAS). Chromium speciation was achieved with selective adsorption of Cr(III) in the presence of Cr(VI) by Fe3O4@PTh from pH 6.5 to 10.0. Total chromium was preconcentrated after the reduction of Cr(VI) to Cr(III). The linear range, detection limit, enrichment factor, and repeatability of the optimized method for Cr(III) in aqueous solution were 4-60 µg L−1, 1.3 µg L−1, 124.7, and 2.2%, respectively. The method was validated by analyzing SPS-WW2 Batch 114, NCS DC 78302 Tibet soil, and LGC7162 strawberry leaves as standard reference materials (SRMs). The results are in good agreement with the certified values. Good recovery, precision, and relative error values were obtained for chromium in real samples by the optimized method.

Preparation of deep eutectic solvent-based hexagonal boron nitride-molecularly imprinted polymer nanoparticles for solid phase extraction of flavonoids.

Hexagonal boron nitride (h-BN) is introduced as a 2D scaffold during the preparation of molecularly imprinted polymers (MIPs). The MIPs were prepared from deep eutectic solvents (DES) or fromDES containing h-BN, crosslinking agent (ethylene glycoldimethacrylate), initiator (AIBN), porogen (methanol), and template (quercetin). The recognition site of the monomer is protected by the hydrogen bond of the DES before the MIP is polymerized. The formation of the final MIP was analyzed theoretically using density-functional theory. The nanoparticles were characterized by scanning electron microscopy, nitrogen sorption analysis, thermogravimetry and Fourier transform infrared spectroscopy. The introduction of h-BN resulted in an increase in the surface area of the nanoparticles. They were applied as a solid phase extraction sorbent for the extraction of flavonoids (specifically of quercetin, isorhamnetin and kaempferol) from Ginkgo biloba leaves. Following extraction with ethanol, they were quantified by HPLC. The new sorbent has distinctly improved recognition capability for flavonoids compared to conventional MIP nanoparticles. Graphical abstractDeep eutectic solvent (DES)-based molecularly imprinted polymer (MIP) was polymerized on the surface of hexagonal boron nitride (h-BN). The h-BN-MIP nanoparticles were applied as a solid phase extraction sorbent for the specific recognition of flavonoids.

Metal-organic framework-1210(zirconium/cuprum) modified magnetic nanoparticles for solid phase extraction of benzophenones in soil samples

MOF-1210(Zr/Cu) is a new heterometallic cluster-based metal-organic framework material as well as a promising solid phase extraction coating material with ordered spatial structure, permanent high porosity and large specific surface area. In this work, a novel MOF-1210(Zr/Cu) modified magnetic nanoparticles (MNPs) was successfully prepared for magnetic solid phase extraction (MSPE) of benzophenones, including 2,4-dihydroxybenzophenone (BP-1), 2-hydroxy-4-methoxybenzophenone (BP-3) and 2,2′,4,4′-tetrehydroxybenzophenone (BP-6). The MOF-1210(Zr/Cu)-MNPs were synthesized in one step by a simple solvothermal method and showed high extraction efficiency towards analytes (with enrichment factors of 91–122). The extraction mechanism studies showed that the hydrogen bond interaction and coordination interaction between MOF-1210(Zr/Cu) and BPs played important roles during the extraction process. By coupling with HPLC, the MOF-1210(Zr/Cu)-MNPs-based MSPE-HPLC method showed wide linear range (0.1–300.0 ng·mL−1), good linearity (R ≥ 0.9982), excellent reproducibility (RSD ≤ 3.60%) and remarkable sensitivity (LODs in the range of 0.01–0.02 ng·mL−1). This method was also successfully applied to the extraction and detection of benzophenones in soil samples. Good recoveries were obtained (87.6%–113.8%) with RSDs less than 11.12%, which demonstrated the practicality of the proposed method.

Ionic liquid-based dispersive liquid-liquid microextraction combined with functionalized magnetic nanoparticle solid-phase extraction for determination of industrial dyes in water

N-butyl pyridinium bis((trifluoromethyl)sulfonyl)imide ([Hpy]NTf2) functionalized core/shell magnetic nanoparticles (MNPs, Fe3O4@SiO2@[Hpy]NTf2)) were prepared and applied as an adsorbent for magnetic solid phase extraction (MSPE) of three commonly used industrial dyes including malachite green, crystal violet and methylene blue. Extraction solution was mixed with 100 mg extraction material of Fe3O4@SiO2@[Hpy]NTf2, and 1 mL of acetonitrile was used to elute target analytes for further extraction and purification. [Hpy]NTf2 was used as extraction solution, and 500 μL methanol was selected as dispersive solvent in ionic liquid (IL) dispersive liquid–liquid microextraction (DLLME) method. After sonication for 5 min and centrifugation at 447 g for 10 min, 20 μL of sedimented phase was injected into HPLC-UV system. The limit of detection (LOD) and limit of quantification (LOQ) of current method were 0.03 and 0.16 μg·L−1, respectively, which indicated the sensitivity was comparable or even superior to other reported methods. The relative recoveries of the target analytes ranged from 86.1% to 100.3% with relative standard deviations between 0.3% and 4.5%. The developed method has been successfully applied to determine the level of three industrial dyes in different water samples.

A Novel Dispersive Nanomagnetic Particle Solid-Phase Extraction Method to Determine Aflatoxins in Nut and Cereal Samples

The application of a simple, fast, and cheap sample pre-concentration technique based on the dispersive magnetic Fe3O4 nanoparticle solid-phase extraction has been developed for extraction and determination of aflatoxins B1, B2, G1, and G2 in nut and cereals. Aflatoxins were extracted from samples with a mixture of methanol–water 8:2 (v/v) and then by magnetic Fe3O4 nanoparticles and a 500 μL of chloroform; pre-concentration and cleanup of the analytes simultaneously were done. HPLC with fluorescence detector and electrochemical post-column derivatization has been used for aflatoxin determination. The main parameters affecting the extraction efficiency, such as type and volume of extraction solvent, the volume of water, and sample volume, were investigated and optimized to achieve the best extraction efficiency. The LODs and LOQs of the proposed method for the AFs were determined, which LODs were 0.35 and 0.06 μg/kg, and LOQs were 1 and 0.2 μg/kg, for aflatoxin groups B and G, respectively. Acceptable recoveries were achieved (76.0–112.7%), and the low limits of detection (LOD <0.35 and 0.06 μg/kg), with proper precision (RSD <15%), were obtained. Therefore, the validated method represents simple and low-cost substitute to the conventional method and is suitable for screening of contamination in food samples.

Simultaneous Determination of Trace Amounts of Anti-Hypertensive Drugs in Urine Using Mixed Hemimicelle Magnetic Nanoparticles Solid-Phase Extraction Combined with HPLC-UV

Simultaneous Determination of Trace Amounts of Anti-Hypertensive Drugs in Urine Using Mixed Hemimicelle Magnetic Nanoparticles Solid-Phase Extraction Combined with HPLC-UV

C18-Functionalized Magnetic Silica Nanoparticles for Solid Phase Extraction of Microcystin-LR in Reservoir Water Samples Followed by HPLC-DAD Determination

In this study, C18-functionalized magnetic silica nanoparticle (Fe3O4@SiO2@C18 MNPs) based magnetic solid phase extraction (MSPE) was successfully developed for the determination of microcystin-LR (MC-LR) in reservoir water samples followed by high performance liquid chromatography–diode array detection (HPLC–DAD). After the extraction, the adsorbent can be conveniently and rapidly separated from aqueous samples by an external magnet. The main factors influencing the extraction efficiency including the amount of the MNPs, the extraction time, the pH of sample solution, and desorption conditions were optimized to obtain high recoveries and extraction efficiency. High enrichment factor 500 was attained. Under the optimized experimental conditions, the calibration curve of MC-LR was linear in the range of 0.1–10.0 µg/L with correlation coefficients (r2) 0.9996. Limit of detection (LOD, S/N = 3) of the method was 0.056 µg/L. The developed method was successfully applied to the determination of MC-LR in reservoir water samples. The method recoveries were obtained ranging from 73.3–104% for three spiked concentrations, with the relative standard deviations (RSD) of 2.90–4.30%. The developed Fe3O4@SiO2@C18 MNPs-based MSPE coupled with HPLC–DAD demonstrated excellent sensitivity and repeatability, simplicity, rapidity, and ease of operation, as well as practical applicability.

Analysis of Steroid Hormones in Water Using Palmitate-Coated Magnetite Nanoparticles Solid-Phase Extraction and Gas Chromatography–Tandem Mass Spectrometry

A new extractive method based on magnetic solid–phase extraction using palmitate-coated magnetite nanoparticles coupled with gas chromatography-tandem mass spectrometry was developed for the extraction of estrone, androstenedione and progesterone hormones from water. The amount of nanoparticles and extraction time were optimized applying an experimental design to estimate simultaneously their influence on the recoveries. Results showed that the extraction efficiency was highly affected by the addition of salt and acetonitrile was the solvent used to elute the analytes from the nanoparticles. Derivatization via enolization of ketone group was carried out in the extract for the simultaneous derivatization of hydroxyl and ketone groups of steroid hormones previously to their chromatographic analysis. The extraction efficiencies of the nanoparticles were studied spiking at four concentration levels and recoveries from 94.6 to 109.7 % were obtained. The limits of detection ranged from 4 to 8 ng L−1. The developed method provided a preconcentration factor of 100. The present work shows that palmitate-coated magnetite nanoparticles have good applicability for the extraction of natural estrogenic hormones that could be pollutants in real water samples.

Atomic spectrometry updates: Review of advances in atomic spectrometry and related techniques

This review covers developments in ‘Atomic Spectrometry’. It covers atomic emission, absorption, fluorescence and mass spectrometry, but excludes material on speciation and coupled techniques which is included in a separate review. It should be read in conjunction with the other related reviews in the series.1–6 A critical approach to the selection of material has been adopted, with only novel developments in instrumentation, techniques and methodology being included. A number of themes have emerged from this year's review. Novel developments in sample preparation include the use of magnetic nanoparticles for solid phase extraction and an increase in the number of viable methods for use in quantitation of peptides, proteins and DNA by elemental tagging, particularly the development of multiplexed techniques. There were also some advances in electrochemical vapour generation, such as the use of reducing reagents immobilized on electrodes and development of electrolytic membrane diffusion cells. New instrumentation has been to the fore, with research into some novel and interesting miniaturized plasma sources being of particular interest, plus the development of a new distance of flight (DOF) mass spectrometer. There have been some insightful fundamental studies of particle atomization and ionization in ICP-MS, and subsequent space-charge effects after ion sampling, which should enable practical steps to solving some of these problems. One of the main drivers of research in isotope ratio analysis has been to increase detection power to enable smaller and smaller quantities of analyte to be measured, which yields advantages in geochronology and nuclear forensics. Laser ablation has played a large part in many types of analysis where high resolution is required, including analysis of single particles, small inclusions or elemental mapping of tissues, so the development of LA methods with extremely small spot sizes and efficient sample transport to the source has been key. In addition, several novel methods have been developed, such as laser ablation molecular isotopic spectrometry (LAMIS) for isotope ratio analysis, and stand-off LIBS techniques such as ‘underwater LIBS’. In contrast, very little research into the use of chemometrics has been reported, and fundamental studies are generally confined to characterization of new plasma sources.

Silica chemically bonded N-propyl kriptofix 21 and 22 with immobilized palladium nanoparticles for solid phase extraction and preconcentration of some metal ions

Silica gel chemically bonded N-propyl kriptofix 21 (SBNPK 21) and N-propyl kriptofix 22 (SBNPK 22) and subsequently immobilized with palladium nanoparticles (PNP-SBNPK 21 and PNP-SBNPK 22) to produce two new complexing lipophilic materials. Then these novel sorbents were applied for the enrichment of some metal ions and their subsequent determination by flame atomic absorption spectroscopy (FAAS). The influences of the variables including pH, amount of solid phase, sample flow rate, eluent conditions and sample volume on the metal ion recoveries were investigated. The detection limit of proposed method was in the interval 2.1–2.3 and 1.7–2.8ngmL−1 for PNP-SBNPK 21 and PNP-SBNPK 22 respectively, while the preconcentration factor was 80 for two sorbents. The relative standard deviations of recoveries were between 1.23–1.31 and 1.28–1.49 for PNP-SBNPK 21 and PNP-SBNPK 22 respectively. The method has high sorption-preconcentration efficiency even in the presence of various interfering ions. Due to the reasonable selectivity of proposed method, the relative standard deviation of recoveries of all understudied metal ions in some complicated matrices was less than 3.0%.

Light-induced pH change and its application to solid phase extraction of trace heavy metals by high-magnetization Fe3O4@SiO2@TiO2 nanoparticles followed by inductively coupled plasma mass spectrometry detection

We report here the preparation of high-magnetization Fe3O4@SiO2@TiO2 nanoparticles for solid phase extraction of trace amounts of Cd(II), Cr(III), Mn(II) and Cu(II) from environmental waters. The prepared nanoparticles were characterized by scanning electron micrograph (SEM) and transmission electron microscopy (TEM). The high-magnetization nanoparticles carrying the target metals could be easily and fast separated from the aqueous solution simply by applying an external magnetic field while no filtration or centrifugation was necessary. A light-induced hydroxide ion emitter, molecular malachite green carbinol base (MGCB) was applied to adjust pH value of solution for quantitative adsorption instead of the conventional used buffer. In the presence of UV light, MGCB gives out OH− ions, and this leads to an increase in the pH value without the aid of buffer solution. Using high-magnetization Fe3O4@SiO2@TiO2 nanoparticles as the extraction material and the light-induced MGCB for pH adjustment, we developed an efficient and convenient two-step method for separation/preconcentration trace amounts of Cd(II), Cr(III), Mn(II) and Cu(II) in environmental water samples followed by inductively coupled plasma mass spectrometry (ICP-MS) detection. The parameters affecting the extraction such as MGCB concentration, exposal time, sample volume, eluent condition, and interfering ions have been investigated in detail. Under the optimized conditions, the limits of detection for Cd(II), Cr(III), Mn(II) and Cu(II) were 4.0, 2.6, 1.6 and 2.3ngL−1, respectively, and the relative standard deviations (RSDs, c=1μgL−1, n=7) were 3.6%, 4.5%, 4.0 and 4.1%, respectively. The proposed method has been validated using certified reference materials, and it has been successfully applied in the determination of trace Cd(II), Cr(III), Mn(II) and Cu(II) in environmental water samples.

Application of magnetic hydroxyapatite nanoparticles for solid phase extraction of plasmid DNA

We developed a facile method for plasmid DNA (pDNA) extraction from crude Escherichia coli lysate using magnetic hydroxyapatite nanoparticles (MHapNPs) in the presence of polyethylene glycol (PEG)/NaCl. DNA condensation induced by PEG/NaCl is a prerequisite for achieving pronounced DNA recovery. The quality and quantity of MHapNP-purified pDNA under optimal binding buffer conditions (0.5volume of 20% PEG 8000/2M NaCl) were comparable to those obtained using organic solvents or commercial kits. This MHapNP technique is rapid, simple, cost-effective, and environmentally friendly and has the potential to extract DNA from other cell lysates.

Salicylic acid functionalized silica-coated magnetite nanoparticles for solid phase extraction and preconcentration of some heavy metal ions from various real samples

A method for the preconcentration of trace heavy metal ions in environmental samples has been reported. The presented method is based on the sorption of Cu(II), Cd(II), Ni(II) and Cr(III) ions with salicylic acid as respective chelate on silica-coated magnetite nanoparticles. Prepared adsorbent was characterized by XRD, SEM, BET and FT-IR measurements. The metals content of the sorbed complexes are eluted using 4.0 mL of 1.0 mol L-1 nitric acid. The influences of the analytical parameters including pH, amount of solid phase and condition of eluting solution, the effects of matrix ions on the retention of the analytes were examined. The accuracy and precision of suggested method were tested by analyzing of certified reference materials. The detection limits (3Sb/m, N = 8) for Cu(II), Cd(II), Ni(II) and Cr(III) ions are 0.22, 0.11, 0.27 and 0.15 μg L-1, respectively, and the maximum preconcentration factor is 200. The method was successfully applied to the evaluation of these trace and toxic metals in various waters, foods and other samples.

Molecularly imprinted layer-coated silica nanoparticles for selective solid-phase extraction of bisphenol A from chemical cleansing and cosmetics samples

Highly selective molecularly imprinted layer-coated silica nanoparticles for bisphenol A (BPA) were synthesized by molecular imprinting technique with a sol–gel process on the supporter of silica nanoparticles. The BPA-imprinted silica nanoparticles were characterized by fourier transform infrared spectrometer, transmission electron microscope, dynamic adsorption and static adsorption tests. The equilibrium association constant, K a, and the apparent maximum number of binding sites, Q max, were estimated to be 1.25 × 10 5 mL μmol −1 and 16.4 μmol g −1, respectively. The BPA-imprinted silica nanoparticles solid-phase extraction (SPE) column had higher selectivity for BPA than the commercial C18-SPE column. The results of the study indicated that the prepared BPA-imprinted silica nanoparticles exhibited high adsorption capacity and selectivity, and offered a fast kinetics for the rebinding of BPA. The BPA-imprinted silica nanoparticles were successfully used in SPE to selectively enrich and determine BPA from shampoo, bath lotion and cosmetic cream samples.