Magnetic Solid Phase Extraction

Um novo adsorbente para a determinação de Pb e Cu por espectrometria de absorção atômica de chama (FAAS) foi sintetizado e caracterizado por diferentes técnicas. O efeito de vários parâmetros como pH, tipo e volume do eluente, quantidade de adsorbente, volume da amostra e íons interferentes foram otimizados. Nas condições otimizadas, um gráfico de calibração linear foi obtido para a determinação de Pb(II) e Cu(II). As faixas lineares foram 15-500 µg L -1 e 18-500 µg L -1 para chumbo e cobre, respectivamente. Os limites de detecção e quantificação foram 4,3 e 14,5 µg L -1 para chumbo e 5,0 e 16,7 µg L -1 para cobre, respectivamente. O desvio padrão relativo para determinações de oito replicatas de 80 e 200 µg L -1 de Pb(II) foram 2,9 e 1,4% e para Cu(II) foram 3,5 e 1,9%, respectivamente. A aplicabilidade do método foi avaliada ao analisar traços de chumbo e cobre em diferentes amostras de água. A new adsorbent for determination of Pb and Cu by flame atomic absorption spectrometry (FAAS) was synthesized and characterized with different techniques. The effect of various parameters such as the pH, the type and volume of eluent, amount of adsorbent, sample volume and interfering ions were optimized. Under the optimized conditions, a linear calibration graph was obtained for determination of Pb(II) and Cu(II). The linear ranges were found to be 15-500 µg L -1 and 18-500 µg L -1 for lead and copper, respectively. The limit of detection and limit of quantification were 4.3 and 14.5 µg L -1 for lead and 5.0 and 16.7 µg L -1 for copper, respectively. The relative standard deviation for eight replicate determinations of 80 and 200 µg L -1 of Pb(II) were 2.9 and 1.4% and for Cu(II) were 3.5 and 1.9%, respectively. Applicability of the method was evaluated by analyzing trace amounts of lead and copper in different water samples.

The present study was the first report in the needle-based SPE for quantitative analysis of paraquat herbicide, which is a very sensitive, economical, and small method that can be performed at the laboratory level. Boehmite nanoparticles (BN/SPE) coupled with high-performance liquid chromatography equipped with UV detector was developed for the rapid removal of paraquat herbicide from a natural water sample. Solid phase extraction is a widely employed technique in environmental science for pre-concentration and purification purposes. Nevertheless, conventional methods necessitate the use of electrically powered pumps, large amounts of solvent (especially when multiple samples are processed), and significant time investment to filter a sample. Moreover, if the cartridge is exposed to the atmosphere, there is a risk of volatile compounds being lost and compromising the integrity of the sample. In contrast, needle tip-based solid phase extraction offers several advantages. It can be manually completed in under 2 minutes, requires only microliters of solvent, and yields comparable concentration factors to established methods. Furthermore, it operates as an enclosed system, preventing the loss of volatile components. In this paper, a novel extraction technique termed needle tip-based solid phase nano extraction was developed that describes a rapid method for the quantitative analysis of paraquat from an environmental water sample. Under the optimum extraction conditions, the method showed good linearity in the range of 1–100 µg/mL, acceptable reproducibility (RSD: 0.9507, n =4), and limits of detection (0.1µg/mL).

The preparation of samples for instrumental analysis is the most essential and timeconsuming stage of the entire analytical process; it also has the greatest impact on the analysis results. Concentrating the sample, changing its matrix, and removing interferents are often necessary. Techniques for preparing samples for analysis are constantly being developed and modified to meet new challenges, facilitate work, and enable the determination of analytes in the most comprehensive concentration range possible. This paper focuses on using metal-organic frameworks (MOFs) as sorbents in the most popular techniques for preparing liquid samples for analysis, based on liquidsolid extraction. An increase in interest in MOFs-type materials has been observed for about 20 years, mainly due to their sorption properties, resulting, among others, from the high specific surface area, tunable pore size, and the theoretically wide possibility of their modification. This paper presents certain advantages and disadvantages of the most popular sample preparation techniques based on liquid-solid extraction, the newest trends in the application of MOFs as sorbents in those techniques, and, most importantly, presents the reader with a summary, which a specific technique and MOF for the desired application. To make a tailor-made and well-informed choice as to the extraction technique.

A novel imidazolium-dysprosium-based magnetic nanomaterial, i.e. [C 16 mim] 5 [Dy(SCN) 8 ] nanoGUMBOS (nanomaterials fabricated from a group of uniform material based on organic salts), was prepared using a facile method for selective hemoglobin (Hb) isolation. In this nanomaterial, the imidazolium cation serves as a selective Hb affinity group, while dysprosium contributes paramagnetic properties. Through a combination of the advantages of ionic liquids, magnetic adsorbent, and nanoscale solid phase extraction, [C 16 mim] 5 [Dy(SCN) 8 ] nanoGUMBOS exhibit great selectivity toward Hb and a favorable extraction efficiency of 95.4% when 1 mL of 100 μg/mL Hb solution is processed with 0.6 mg of [C 16 mim] 5 [Dy(SCN) 8 ] nanoGUMBOS. As the Hb concentration increased to 800 μg/mL, the adsorption capacity approached ∼840 μg/mg. The adsorbed protein is recovered with an elution efficiency of 87% by using 1% SDS solution. This novel nanoGUMBOS solid-phase extraction procedure was successfully applied to selective isolation of Hb from human whole blood and verified using SDS-PAGE. This simple strategy is a novel approach towards fabrication and use of a nanoadsorbent for selective isolation of proteins.

Um novo adsorbente para a determinação de Pb e Cu por espectrometria de absorção atômica de chama (FAAS) foi sintetizado e caracterizado por diferentes técnicas. O efeito de vários parâmetros como pH, tipo e volume do eluente, quantidade de adsorbente, volume da amostra e íons interferentes foram otimizados. Nas condições otimizadas, um gráfico de calibração linear foi obtido para a determinação de Pb(II) e Cu(II). As faixas lineares foram 15-500 µg L -1 e 18-500 µg L -1 para chumbo e cobre, respectivamente. Os limites de detecção e quantificação foram 4,3 e 14,5 µg L -1 para chumbo e 5,0 e 16,7 µg L -1 para cobre, respectivamente. O desvio padrão relativo para determinações de oito replicatas de 80 e 200 µg L -1 de Pb(II) foram 2,9 e 1,4% e para Cu(II) foram 3,5 e 1,9%, respectivamente. A aplicabilidade do método foi avaliada ao analisar traços de chumbo e cobre em diferentes amostras de água. A new adsorbent for determination of Pb and Cu by flame atomic absorption spectrometry (FAAS) was synthesized and characterized with different techniques. The effect of various parameters such as the pH, the type and volume of eluent, amount of adsorbent, sample volume and interfering ions were optimized. Under the optimized conditions, a linear calibration graph was obtained for determination of Pb(II) and Cu(II). The linear ranges were found to be 15-500 µg L -1 and 18-500 µg L -1 for lead and copper, respectively. The limit of detection and limit of quantification were 4.3 and 14.5 µg L -1 for lead and 5.0 and 16.7 µg L -1 for copper, respectively. The relative standard deviation for eight replicate determinations of 80 and 200 µg L -1 of Pb(II) were 2.9 and 1.4% and for Cu(II) were 3.5 and 1.9%, respectively. Applicability of the method was evaluated by analyzing trace amounts of lead and copper in different water samples.

, Y. (2017). Multi-walled carbon nanotubes-based magnetic solid-phase extraction for the determination of zearalenone and its derivatives in maize by ultra-high performance liquid chromatography-tandem mass spectrometry. Food Control, 79, 177-184.

Mesostructured iron oxide/ethylene glycol (FeOx/EG) nanosheets with an oval shape were created and employed as a magnetic solid-phase extraction (MSPE) sorbent to extract herbicide chloridazon. Iron oxide layers are intercalated with deprotonated ethylene glycol molecules to provide an interlayer gap of 10.6 A. Using scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and a vibrating sample magnetometer (VSM), the size, shape, content, and characteristics of the produced nanocomposite were determined. The key influencing factors for extracting chloridazon, such as the volume of the sample, the amount of sorbent, and the desorption solvent, were optimized. High-performance liquid chromatography with UV detection was the subject of analyses. The approach demonstrated strong linearity in the range of 0.01–100 µg.mL-1, reasonable repeatability (RSD 3.017%, n = 3), and limits of detection (0.001 µg.mL-1) under the ideal extraction conditions.

A fast, simple, economical, and environmentally friendly magnetic solid-phase extraction (MSPE) procedure has been developed to preconcentrate 2,4,6-trinitrotoluene (TNT) from water samples prior to determination by liquid chromatography-UV-Vis employing graphene oxide/Fe3O4 nanocomposite as sorbent. The nanocomposite synthesis was investigated, and the MSPE was optimized by a multivariate approach. The optimum MSPE conditions were 40 mg of nanocomposite, 10 min of vortex extraction, 1 mL of acetonitrile as eluent, and 6 min of desorption in an ultrasonic bath. Under the optimized experimental conditions, the method was evaluated to obtain a preconcentration factor of 153. The linearity of the method was studied from 1 to 100 μg L(-1) (N = 5), obtaining a correlation coefficient of 0.994. The relative standard deviation and limit of detection were found to be 12% (n = 6, 10 μg L(-1)) and 0.3 μg L(-1), respectively. The applicability of the method was investigated, analyzing three ty...

The development of highly selective and miniaturized chemisensors for liquid media can enable newer discoveries and empower a wide range of disciplines from biology to human health, marine ecology to climate change, and industrial process monitoring to food safety. While the two-terminal chemiresistor architecture has been remarkably successful in this regard, they rely on appropriate surface functionalization to achieve selectivity for a specific target analyte. Furthermore, sensor drift and sensor-to-sensor variation in a multiplexed chemisensors array can severely impact their reliability and obscure the response of individual sensors to the target analytes. In this article, we overcome these challenges by introducing a new sensing paradigm that integrates an array of threeterminal chemitransistors based on monolayer graphene with an ensemble of machine learning (ML) algorithms. The extraordinary transport properties of graphene combined with its electrochemically inert basal plane allow a wide range of chemical species to electrostatically control the channel conductivity in a liquid medium through voltage gating. This in turn expands the parameter space for the sensing elements which enables the integration of various unsupervised and supervised ML algorithms to eliminate the need for surface functionalization, eradicate the need for sensor calibration, and minimize the impact of sensor-to-sensor variation. Our ML-aided, non-functionalized, and reusable graphene chemitransistors were found to be highly selective to de-ionized (DI) water, multiple chloride salts including NaCl, LiCl, CaCl2, and MgCl2 that are relevant to biosensing, several weak acids including acetic, propionic, and citric acid that are used in the food industry, as well as more complex solutions and processes such as decaying juices extracted from different fruits (grape, orange, watermelon, and pineapple).

The development of highly selective and miniaturized chemisensors for liquid media can enable newer discoveries and empower a wide range of disciplines from biology to human health, marine ecology to climate change, and industrial process monitoring to food safety. While the two-terminal chemiresistor architecture has been remarkably successful in this regard, they rely on appropriate surface functionalization to achieve selectivity for a specific target analyte. Furthermore, sensor drift and sensor-to-sensor variation in a multiplexed chemisensors array can severely impact their reliability and obscure the response of individual sensors to the target analytes. In this article, we overcome these challenges by introducing a new sensing paradigm that integrates an array of three-terminal chemitransistors based on monolayer graphene with an ensemble of machine learning (ML) algorithms. The extraordinary transport properties of graphene combined with its electrochemically inert basal pl...

This review aimed to inform about the magnetic nanoparticle functionalization and solid magnetic phase extraction application to separate analytes in various types of samples. The review was conducted by analyzing several articles published in 2010 until 2021 obtained through search engines, such as Science Direct, Google Scholar and PubMed, using the keyword “magnetic phase extraction” and “magnetic nanoparticle”. The magnetic nanoparticle can be functionalized with organic, inorganic, and metal-organic framework compounds to obtain good selectivity and extraction capability. The Magnetic Solid Phase Extraction (MSPE) can be applied to separate analytes in biological, food, environmental samples. The MSPE can be used in various biological, food, and environmental samples resulting in high enrichment factor value, good recovery, and the magnetic adsorbent has excellent reusability.

Currently, the challenges that analytical chemistry has to face are ever greater and more complex both from the point of view of the selectivity of analytical methods and their sensitivity. This is especially true in quantitative analysis, where various methods must include the development and validation of new materials, strategies, and procedures to meet the growing need for rapid, sensitive, selective, and green methods. In this context, given the International Guidelines, which over time, are updated and which set up increasingly stringent “limits”, constant innovation is required both in the pre-treatment procedures and in the instrumental configurations to obtain reliable, accurate, and reproducible information. In addition, the environmental field certainly represents the greatest challenge, as analytes are often present at trace and ultra-trace levels. These samples containing analytes at ultra-low concentration levels, therefore, require very labor-intensive sample preparat...

Sudan dyes are often illegally added as colorants into a variety of foodstuffs and have been tied to many food safety issues. In this study, surface-enhanced Raman spectroscopy (SERS) coupled with Au-Ag coreshell nanospheres (Au@Ag) was applied to analyze standard solutions of Sudan I-IV and Sudan dyes in chili flakes. With the use of 90 ± 5 nm Au@Ag (Au seed 20 ± 2 nm) as SERS substrate, the lowest detectible concentrations for Sudan I and II were 0.10 mg/L, for Sudan III was 0.08 mg/L, and for Sudan IV was 0.2 mg/L. The use of principal component analysis (PCA) could successfully classify different Sudan dyes based upon the SERS spectra of their standard solutions. For chili flakes, the use of acetonitrile as extraction solvent led to an overall higher sensitivity for analysis of Sudan dyes with SERS method compared to that of methanol, ethanol, and n-hexane. The lowest detectible concentrations for Sudan I-III in chili flakes were 1 mg/kg and for Sudan IV was 2 mg/kg, which were about ten times as much as that for their standard solutions due to the interference of non-target compounds from sample matrices. Partial least squares (PLS) models developed for quantitative analyses showed relatively high linear correlation between the actual and predicted amounts of Sudan dyes in chili flakes (R 2 cv = 0.869-0.959). The results showed great potential of applying Au@Ag as SERS substrate for qualitative and quantitative analysis of Sudan I-IV with simplified sample preparation method.

Um novo adsorbente para a determinação de Pb e Cu por espectrometria de absorção atômica de chama (FAAS) foi sintetizado e caracterizado por diferentes técnicas. O efeito de vários parâmetros como pH, tipo e volume do eluente, quantidade de adsorbente, volume da amostra e íons interferentes foram otimizados. Nas condições otimizadas, um gráfico de calibração linear foi obtido para a determinação de Pb(II) e Cu(II). As faixas lineares foram 15-500 µg L −1 e 18-500 µg L −1 para chumbo e cobre, respectivamente. Os limites de detecção e quantificação foram 4,3 e 14,5 µg L −1 para chumbo e 5,0 e 16,7 µg L −1 para cobre, respectivamente. O desvio padrão relativo para determinações de oito replicatas de 80 e 200 µg L −1 de Pb(II) foram 2,9 e 1,4% e para Cu(II) foram 3,5 e 1,9%, respectivamente. A aplicabilidade do método foi avaliada ao analisar traços de chumbo e cobre em diferentes amostras de água. A new adsorbent for determination of Pb and Cu by flame atomic absorption spectrometry (FAAS) was synthesized and characterized with different techniques. The effect of various parameters such as the pH, the type and volume of eluent, amount of adsorbent, sample volume and interfering ions were optimized. Under the optimized conditions, a linear calibration graph was obtained for determination of Pb(II) and Cu(II). The linear ranges were found to be 15-500 µg L −1 and 18-500 µg L −1 for lead and copper, respectively. The limit of detection and limit of quantification were 4.3 and 14.5 µg L −1 for lead and 5.0 and 16.7 µg L −1 for copper, respectively. The relative standard deviation for eight replicate determinations of 80 and 200 µg L −1 of Pb(II) were 2.9 and 1.4% and for Cu(II) were 3.5 and 1.9%, respectively. Applicability of the method was evaluated by analyzing trace amounts of lead and copper in different water samples.

Solid Phase Extraction is a method used for extraction, purification of compounds contained in complex matrices and purification of samples in the fields of industry, pharmacy, and toxicology analysis. This review represents the recent advances of solid phase extraction from different mode of separation which are the most commonly used in recent days such as molecular imprinting solid phase extraction (MISPE), magnetic solid phase extraction (MSPE) and matrix solid phase dispersion (MSPD). In this review, the applications of MISPE in the analysis of agrochemicals such as herbicides, fungicides and insecticides are summarized. This review also states preparation of various magnetic composites (MSPE) based on graphene and its application as adsorbents in pre concentrating natural mixes, organic macromolecules. Besides this, this review summarizes the application of MSPD in biological, food, and environmental samples, including both organic and inorganic analyte.

In this present study, magnetic Fe3O4@SiO2 nanoparticles (MNPs) functionalized with octadecyl groups (Fe3O4@SiO2-C18 NPs) were synthesized, characterized and employed, for the first time, as powerful nanosorbent to extract endogenous volatile organic metabolites (EVOMs) namely, hexanal, heptanal, decanal, benzaldehyde, 4-heptanone, 5-methyl-2-furfural and phenol, described as potential biomarkers of cancer, from human urine. By using co-precipitation, surface modification methods, the carbon-ferromagnetic nanocomposite was synthesized and characterized by infrared spectrum (IR) and transmission electron microscopy (TEM). By coupling with gas chromatography-mass spectrometry (GC-qMS), a reliable, sensitive and cost-effective method was validated. To test the extraction efficiency of the carbon-ferromagnetic nanocomposite toward urinary EVOMs experimental variables affecting the extraction performance, including nanosorbent amount, adsorption time, elution time, and nature of elution ...

As adulteration of foodstuffs with Sudan dye, especially paprika- and chilli-containing products, has been reported with some frequency, this issue has become one focal point for addressing food safety. FTIR spectroscopy has been used extensively as an analytical method for quality control and safety determination for food products. Thus, the use of FTIR spectroscopy for rapid determination of Sudan dye in paprika powder was investigated in this study. A net analyte signal (NAS)-based methodology, named HLA/GO (hybrid linear analysis in the literature), was applied to FTIR spectral data to predict Sudan dye concentration. The calibration and validation sets were designed to evaluate the performance of the multivariate method. The obtained results had a high determination coefficient (R(2)) of 0.98 and low root mean square error (RMSE) of 0.026% for the calibration set, and an R(2) of 0.97 and RMSE of 0.05% for the validation set. The model was further validated using a second valida...

This review aimed to inform about the magnetic nanoparticle functionalization and solid magnetic phase extraction application to separate analytes in various types of samples. The review was conducted by analyzing several articles published in 2010 until 2021 obtained through search engines, such as Science Direct, Google Scholar and PubMed, using the keyword "magnetic phase extraction" and "magnetic nanoparticle". The magnetic nanoparticle can be functionalized with organic, inorganic, and metal-organic framework compounds to obtain good selectivity and extraction capability. The Magnetic Solid Phase Extraction (MSPE) can be applied to separate analytes in biological, food, environmental samples. The MSPE can be used in various biological, food, and environmental samples resulting in high enrichment factor value, good recovery, and the magnetic adsorbent has excellent reusability.

Um novo adsorbente para a determinação de Pb e Cu por espectrometria de absorção atômica de chama (FAAS) foi sintetizado e caracterizado por diferentes técnicas. O efeito de vários parâmetros como pH, tipo e volume do eluente, quantidade de adsorbente, volume da amostra e íons interferentes foram otimizados. Nas condições otimizadas, um gráfico de calibração linear foi obtido para a determinação de Pb(II) e Cu(II). As faixas lineares foram 15-500 µg L −1 e 18-500 µg L −1 para chumbo e cobre, respectivamente. Os limites de detecção e quantificação foram 4,3 e 14,5 µg L −1 para chumbo e 5,0 e 16,7 µg L −1 para cobre, respectivamente. O desvio padrão relativo para determinações de oito replicatas de 80 e 200 µg L −1 de Pb(II) foram 2,9 e 1,4% e para Cu(II) foram 3,5 e 1,9%, respectivamente. A aplicabilidade do método foi avaliada ao analisar traços de chumbo e cobre em diferentes amostras de água. A new adsorbent for determination of Pb and Cu by flame atomic absorption spectrometry (FAAS) was synthesized and characterized with different techniques. The effect of various parameters such as the pH, the type and volume of eluent, amount of adsorbent, sample volume and interfering ions were optimized. Under the optimized conditions, a linear calibration graph was obtained for determination of Pb(II) and Cu(II). The linear ranges were found to be 15-500 µg L −1 and 18-500 µg L −1 for lead and copper, respectively. The limit of detection and limit of quantification were 4.3 and 14.5 µg L −1 for lead and 5.0 and 16.7 µg L −1 for copper, respectively. The relative standard deviation for eight replicate determinations of 80 and 200 µg L −1 of Pb(II) were 2.9 and 1.4% and for Cu(II) were 3.5 and 1.9%, respectively. Applicability of the method was evaluated by analyzing trace amounts of lead and copper in different water samples.

A highly sensitive and cost-effective HPTLC method was developed for the determination of rivastigmine hydrogen tartarate (RIV) in bulk and capsules. Moreover, magnetic solid phase extraction procedure (MSPE) was performed for analysis of RIV in human plasma to preconcentrate RIV and decrease interference from plasma constituents. The magnetic nanoparticles (MNPs) were prepared by co-precipitation process and characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), powdered X-ray diffraction (PXRD) and dynamic light scattering (DLS). These prepared MNPs have shown high extraction efficiency and all parameters affecting the adsorption of RIV on the MNPs were fully investigated. The method was validated according to FDA bio-analytical guidelines and was found to be linear over the range of 30.2-648 ng/spot. The LLOQ and LOD were 26.2 and 8.6 ng/spot, respectively.

A fast, simple, economical, and environmentally friendly magnetic solid-phase extraction (MSPE) procedure has been developed to preconcentrate 2,4,6-trinitrotoluene (TNT) from water samples prior to determination by liquid chromatography-UV-Vis employing graphene oxide/Fe3O4 nanocomposite as sorbent. The nanocomposite synthesis was investigated, and the MSPE was optimized by a multivariate approach. The optimum MSPE conditions were 40 mg of nanocomposite, 10 min of vortex extraction, 1 mL of acetonitrile as eluent, and 6 min of desorption in an ultrasonic bath. Under the optimized experimental conditions, the method was evaluated to obtain a preconcentration factor of 153. The linearity of the method was studied from 1 to 100 μg L(-1) (N = 5), obtaining a correlation coefficient of 0.994. The relative standard deviation and limit of detection were found to be 12% (n = 6, 10 μg L(-1)) and 0.3 μg L(-1), respectively. The applicability of the method was investigated, analyzing three ty...

Magnetic solid-phase extraction is one of the most promising new extraction methods for liquid samples before ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis. Several types of materials, including carbonaceous ones, have been prepared for this purpose. In this paper, for the first time, the preparation, characterization, and sorption capability of Fe 3 O 4-graphitized carbon black (mGCB) composite toward some compounds of environmental interest were investigated. The synthesized mGCB consisted of micrometric GCB particles with 55 m 2 g −1 surface area bearing some carbonyl and hydroxyl functionalities and the surface partially decorated by Fe 3 O 4 microparticles. The prepared mGCB was firstly tested as an adsorbent for the extraction from surface water of 50 pollutants, including estrogens, perfluoroalkyl compounds, UV filters, and quinolones. The material showed good affinity to many of the tested compounds, except carboxylates and glucoronates; however, some compounds were difficult to desorb. Ten UV filters belonging to the chemical classes of benzophenones and p-aminobenzoates were selected, and parameters were optimized for the extraction of these compounds from surface water before UHPLC-MS/MS determination. Then, the method was validated in terms of linearity, trueness, intra-laboratory precision, and detection and quantification limits. In summary, the method performance (trueness, expressed as analytical recovery, 85-114%; RSD 5-15%) appears suitable for the determination of the selected compounds at the level of 10-100 ng L −1 , with detection limits in the range of 1-5 ng L −1. Finally, the new method was compared with a published one, based on conventional solid-phase extraction with GCB, showing similar performance in real sample analysis.

Mycotoxins can contaminate various food commodities, including cereals. Moreover, mycotoxins of different classes can co-contaminate food, increasing human health risk. Several analytical methods have been published in the literature dealing with mycotoxins determination in cereals. Nevertheless, in the present work, the aim was to propose an easy and effective system for the extraction of six of the main mycotoxins from corn meal and durum wheat flour, i.e., the main four aflatoxins, ochratoxin A, and the mycoestrogen zearalenone. The developed method exploited magnetic solid phase extraction (SPE), a technique that is attracting an increasing interest as an alternative to classical SPE. Therefore, the use of magnetic graphitized carbon black as a suitable extracting material was tested. The same magnetic material proved to be effective in the extraction of mycoestrogens from milk, but has never been applied to complex matrices as cereals. Ultra high-performance liquid chromatography tandem mass spectrometry was used for detection. Recoveries were >60% in both cereals, even if the matrix effects were not negligible. The limits of quantification of the method results were comparable to those obtained by other two magnetic SPE-based methods applied to cereals, which were limited to one or two mycotoxins, whereas in this work the investigated mycotoxins belonged to three different chemical classes.

Currently, the challenges that analytical chemistry has to face are ever greater and more complex both from the point of view of the selectivity of analytical methods and their sensitivity. This is especially true in quantitative analysis, where various methods must include the development and validation of new materials, strategies, and procedures to meet the growing need for rapid, sensitive, selective, and green methods. In this context, given the International Guidelines, which over time, are updated and which set up increasingly stringent “limits”, constant innovation is required both in the pre-treatment procedures and in the instrumental configurations to obtain reliable, accurate, and reproducible information. In addition, the environmental field certainly represents the greatest challenge, as analytes are often present at trace and ultra-trace levels. These samples containing analytes at ultra-low concentration levels, therefore, require very labor-intensive sample preparat...

Ethylene glycol bisthioglycolate modified gold nanoparticles grafted Mn doped Fe₃O₄ nanoparticles (Au@Mn-Fe₃O₄NPs) adsorbent was synthesized and applied for extraction and preconcentration of trace amounts of Ag⁺ and Pb²⁺ ions in artificial and natural saliva. The adsorbent was characterized by transmission electron microscopy (TEM), Brunauer–Emmett–Teller analysis (BET), X-ray diffraction spectroscopy (XRD) and vibrating-sample magnetometer  (VSM) [h1] techniques and Fusayama artificial saliva was prepared and used as a blank sample. Natural saliva samples were collected from nine volunteers who exposed to posterior decayed teeth amalgam filling, and short-term release of heavy metal ions was assessed in 24, 72 and 96 h after filling. The main factors affecting extraction and desorption efficiency of target ions have been investigated. In Optimum conditions, the detection limits of 0.23 and 0.11 ng mL^-1 with preconcentration factors of 94 and 95 were obtained for Ag⁺ and Pb²⁺ ions, respectively. The results revealed that the adsorbent has high  capacity and good reusability for extraction and preconcentration of target metal ions in relatively high saline solution like biological fluids.

This work illustrates the improvement in ultra-trace Hg(II) determination in water based on a novel flexible extraction and preconcentration technique (FEPT). This method focuses on the covalent functionalisation of carbon fibre (CF) based on (3-mercaptopropyl)trimethoxysilane. The functionalisation of CF is carried out in two steps: functionalising the surface of CF using acid treatment to obtain hydroxy and carboxyl groups on the surface, followed by a condensation reaction between the carboxyl or hydroxy groups on the carbon (CF-OH) and (3-mercaptopropyl)trimethoxysilane to form mercapto-CF (CF-SH). FTIR, EDX, SEM, XRD and UV-Vis were utilised to confirm the modification. ICP-MS is utilised to determine the Hg(II) and to assess the influence of the memory effect on the results using Au 3+ solution and suspended Au nanoparticles (Au-NPs). The result shows that the Au-NPs improve Hg(II) detection and eliminate the memory effect. This study also includes appropriate parameters for contact time, eluent solution, pH, and the foreign metal and ions preconcentration factor. As a result, thiol-CF shows high Hg(II) uptake, flexibility, and stability during the analysis process, with a recovery of 98.96% ± 0.41% for 10 preconcentration factors. These features make FEPT a valuable method for extracting pollutants and overcoming the problems associated with the analysis of such samples.

Analytical chemistry has experienced, as well as other areas of science, a big change due to the needs and opportunities provided by analytical nanoscience and nanotechnology. Now, nanotechnology is increasingly proving to be a powerful ally of analytical chemistry to achieve its objectives, and to simplify analytical processes. Moreover, the information needs arising from the growing nanotechnological activity are opening an exciting new field of action for analytical chemists. Magnetic nanoparticles have been used in various fields owing to their unique properties including large specific surface area and simple separation with magnetic fields. For Analytical applications, they have been used mainly for sample preparation techniques (magnetic solid phase extraction with different advanced functional groups (layered double hydroxide, β-cyclodextrin, carbon nanotube, graphen, polymer, octadecylsilane) and automation of it, microextraction techniques) enantioseparation and chemosensors. This review summarizes the basic principles and achievements of magnetic nanoparticles in sample preparation techniques, enantioseparation and chemosensors. Also, some selected articles recently published (2010-2016) have been reviewed and discussed.

Along of widespread application of anti-cancer drug Gefitinib (GEF), it appears in human body fluids as well as clinical wastewater. Consequently, a reliable and easy-to-adapt detection technique is of essential importance to quantify the drug in different media. The extraction and quantitative detection of anti-cancer drug Gefinitib (GEF) is demonstrated based on a straightforward and efficient magnetic nanoparticle-assisted preconcentration route from water and human plasma samples. Iron oxide magnetic nanoparticles (Fe3O4) have been prepared with an average particle size of 15 nm and utilized as extractible adsorbents for the magnetic solid-phase extraction (MSPE) of GEF in aqueous media. The method is based on MSPE and preconcentration of GEF followed by High-Performance Liquid Chromatography-Ultraviolet Detection (HPLC-UV). The yield of GEF extraction under the optimum MSPE conditions were 94% and 87% for water and plasma samples, respectively. The chromatographic separation wa...

In this study, we combine magnetic solid phase extraction (MSPE), with the screen-printed carbon electrode (SPCE) modified by a molecular imprinted polymer (MIP) for sensitive and selective extraction and electrochemical determination of Rhodamine B in food samples. A magnetic solid phase extraction (MSPE) was carried out using magnetic poly(styrene-co-divinylbenzene) (PS-DVB) and magnetic nanoparticles (MNPs) synthetized on the surface of multiwalled carbon nanotubes (MWCNTs). An MIP was prepared on the surface of MWCNTs in the presence of titanium oxide nanoparticles (TiO2NPs) modifying the SPCE for the rapid electrochemical detection of Rhodamine B. The MIPs synthesis was optimized by varying the activated titanium oxide (TiO2) and multiwalled carbon nanotubes (MWCNTs) amounts. The MSPE and electrochemical detection conditions were optimized as well. The present method exhibited good selectivity, high sensitivity, and good reproducibility towards the determination of Rhodamine B,...

Poly(styrene-co-divinylbenzene)-coated magnetic multiwalled carbon nanotube composite synthesized by in-situ high temperature combination and precipitation polymerization of styrene-co-divinylbenzene has been employed as a magnetic sorbent for the solid phase extraction of antidepressants in human urine samples. Fluoxetine, venlafaxine, citalopram and sertraline were, afterwards, separated and determined by capillary electrophoresis with diode array detection. The presence of magnetic multiwalled carbon nanotubes in native poly(styrene-co-divinylbenzene) not only simplified sample treatment but also enhanced the adsorption efficiencies, obtaining extraction recoveries higher than 89.5% for all analytes. Moreover, this composite can be re-used at least 10 times without loss of efficiency and limits of detection ranging from 0.014 to 0.041 μg mL were calculated. Additionally, precision values ranging from 0.08 to 7.50% and from 0.21 to 3.05% were obtained for the responses and for the...

h i g h l i g h t s Gelatin as co-template for Pluronic F127 produced uniform mesoporous carbon microspheres, MCMs. Increasing Pluronic F127:gelatin ratios controlled the size of MCMs. Ibuprofen removal is influenced by the surface area and the crystallite size of MCMs. The kinetic of adsorption fits pseudo second-order kinetic model.

Sudan dyes are often illegally added as colorants into a variety of foodstuffs and have been tied to many food safety issues. In this study, surface-enhanced Raman spectroscopy (SERS) coupled with Au-Ag coreshell nanospheres (Au@Ag) was applied to analyze standard solutions of Sudan I-IV and Sudan dyes in chili flakes. With the use of 90 ± 5 nm Au@Ag (Au seed 20 ± 2 nm) as SERS substrate, the lowest detectible concentrations for Sudan I and II were 0.10 mg/L, for Sudan III was 0.08 mg/L, and for Sudan IV was 0.2 mg/L. The use of principal component analysis (PCA) could successfully classify different Sudan dyes based upon the SERS spectra of their standard solutions. For chili flakes, the use of acetonitrile as extraction solvent led to an overall higher sensitivity for analysis of Sudan dyes with SERS method compared to that of methanol, ethanol, and n-hexane. The lowest detectible concentrations for Sudan I-III in chili flakes were 1 mg/kg and for Sudan IV was 2 mg/kg, which were about ten times as much as that for their standard solutions due to the interference of non-target compounds from sample matrices. Partial least squares (PLS) models developed for quantitative analyses showed relatively high linear correlation between the actual and predicted amounts of Sudan dyes in chili flakes (R 2 cv = 0.869-0.959). The results showed great potential of applying Au@Ag as SERS substrate for qualitative and quantitative analysis of Sudan I-IV with simplified sample preparation method.

Chromium is one of the hazardous pollutants in industrial effluents. In this study, a new nano-boehmite modified with sodium dodecyl sulphate is developed for preconcentration trace amounts of chromium ions as a prior step to its determination by flame atomic absorption spectrometry. We investigated the effect of various parameters on the recovery of the analyte ions, including pH of sample solution, amount of sorbent, sample volume on extraction efficiency of the chromium ions. Under the best experimental conditions, the calibration curve was linear in the range of 1.0-700.0 ng.mL-1 of chromium with R 2 = 0.997. Detection limit was 0.6 ng.mL-1 in the original solution (3Sb/m) and the relative standard deviation for seven replicate determination of 0.5 µg.mL-1 chromium was ±2.4%. The developed method was successfully applied to the extraction and determination of chromium in water and food samples with satisfactory results.

Poly(styrene-co-divinylbenzene)-coated magnetic multiwalled carbon nanotube composite synthesized by in-situ high temperature combination and precipitation polymerization of styrene-co-divinylbenzene has been employed as a magnetic sorbent for the solid phase extraction of antidepressants in human urine samples. Fluoxetine, venlafaxine, citalopram and sertraline were, afterwards, separated and determined by capillary electrophoresis with diode array detection. The presence of magnetic multiwalled carbon nanotubes in native poly(styrene-co-divinylbenzene) not only simplified sample treatment but also enhanced the adsorption efficiencies, obtaining extraction recoveries higher than 89.5% for all analytes. Moreover, this composite can be re-used at least 10 times without loss of efficiency and limits of detection ranging from 0.014 to 0.041 μg mL were calculated. Additionally, precision values ranging from 0.08 to 7.50% and from 0.21 to 3.05% were obtained for the responses and for the...

This review provides an overview of the most recent developments involving materials for solid-phase extraction applied to determine organic contaminants. It mainly concerns polymer-based sorbents that include high-capacity, as well as selective sorbents, inorganic-based sorbents that include those prepared using sol-gel technology along with structured porous materials based on inorganic species, and carbon nanomaterials, such as graphene and carbon nanotubes. Different types of magnetic nanoparticles coated with these materials are also reviewed. Such materials, together with their main morphological and chemical features, are described, as are some representative examples of their application as solid-phase extraction materials to extract organic compounds from different types of samples, including environmental water, biological fluids, and food.

Magnetic nanoparticles were synthesised to extract Sudan dyes from chilli powders. The adsorbents used were magnetic ferroferric oxide nanoparticles coated with polystyrene. The extraction procedures for Sudan dyes comprised liquid-solid extraction and magnetic solid phase extraction. The conditions were optimised to achieve efficient magnetic solid phase extraction, including extraction and desorption time, type and volume of the desorption solvent, and the mass of the adsorbents. Repeatability tests showed satisfactory recovery rates of 80.2-115.8%, with a relative standard deviation < 3.8%. The results suggested that the proposed extraction method was effective and efficient to extract Sudan dyes from chilli powders. The extraction process was simpler compared with traditional approaches because the adsorbents can be rapidly removed from the sample matrix using a permanent magnet. The use of recyclable adsorbents decreased the cost greatly. Chilli powder samples collected from local markets in Singapore were tested using the proposed method under optimum conditions.

Poly(styrene-co-divinylbenzene)-coated magnetic multiwalled carbon nanotube composite synthesized by in-situ high temperature combination and precipitation polymerization of styrene-co-divinylbenzene has been employed as a magnetic sorbent for the solid phase extraction of antidepressants in human urine samples. Fluoxetine, venlafaxine, citalopram and sertraline were, afterwards, separated and determined by capillary electrophoresis with diode array detection. The presence of magnetic multiwalled carbon nanotubes in native poly(styrene-co-divinylbenzene) not only simplified sample treatment but also enhanced the adsorption efficiencies, obtaining extraction recoveries higher than 89.5% for all ana-lytes. Moreover, this composite can be re-used at least ten times without loss of efficiency and limits of detection ranging from 0.014 to 0.041 g/mL were calculated. Additionally, precision values ranging from 0.08 to 7.50% and from 0.21 to 3.05% were obtained for the responses and for the migration times of the analytes, respectively.

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 (3S b /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.

A new, simple, fast and reliable method has been developed for the separation/preconcentration of trace amounts of silver ions using 2-mercaptobenzothiazole/sodium dodecyl sulfate immobilized on alumina-coated magnetite nanoparticles (MBT/SDS-ACMNPs) and their determination by flame atomic absorption spectrometry (FAAS). Optimal experimental conditions, including pH, sample volume, eluent concentration and volume, and co-existing ions, have been studied and established. Under optimal experimental conditions, the enrichment factor, detection limit, linear range and relative standard deviation (RSD) of Ag(I) ions were 250 (for 500 mL of sample solution), 0.56 ng mL −1 , 2.0-100.0 ng mL −1 and 3.1% (for 5.0 µg mL −1 , n = 10), respectively. The presented procedure was successfully applied for determination of silver content in the different samples of water.

Um novo adsorbente para a determinação de Pb e Cu por espectrometria de absorção atômica de chama (FAAS) foi sintetizado e caracterizado por diferentes técnicas. O efeito de vários parâmetros como pH, tipo e volume do eluente, quantidade de adsorbente, volume da amostra e íons interferentes foram otimizados. Nas condições otimizadas, um gráfico de calibração linear foi obtido para a determinação de Pb(II) e Cu(II). As faixas lineares foram 15-500 µg L −1 e 18-500 µg L −1 para chumbo e cobre, respectivamente. Os limites de detecção e quantificação foram 4,3 e 14,5 µg L −1 para chumbo e 5,0 e 16,7 µg L −1 para cobre, respectivamente. O desvio padrão relativo para determinações de oito replicatas de 80 e 200 µg L −1 de Pb(II) foram 2,9 e 1,4% e para Cu(II) foram 3,5 e 1,9%, respectivamente. A aplicabilidade do método foi avaliada ao analisar traços de chumbo e cobre em diferentes amostras de água.

Um novo adsorbente para a determinação de Pb e Cu por espectrometria de absorção atômica de chama (FAAS) foi sintetizado e caracterizado por diferentes técnicas. O efeito de vários parâmetros como pH, tipo e volume do eluente, quantidade de adsorbente, volume da amostra e íons interferentes foram otimizados. Nas condições otimizadas, um gráfico de calibração linear foi obtido para a determinação de Pb(II) e Cu(II). As faixas lineares foram 15-500 µg L −1 e 18-500 µg L −1 para chumbo e cobre, respectivamente. Os limites de detecção e quantificação foram 4,3 e 14,5 µg L −1 para chumbo e 5,0 e 16,7 µg L −1 para cobre, respectivamente. O desvio padrão relativo para determinações de oito replicatas de 80 e 200 µg L −1 de Pb(II) foram 2,9 e 1,4% e para Cu(II) foram 3,5 e 1,9%, respectivamente. A aplicabilidade do método foi avaliada ao analisar traços de chumbo e cobre em diferentes amostras de água.

Um novo adsorbente para a determinação de Pb e Cu por espectrometria de absorção atômica de chama (FAAS) foi sintetizado e caracterizado por diferentes técnicas. O efeito de vários parâmetros como pH, tipo e volume do eluente, quantidade de adsorbente, volume da amostra e íons interferentes foram otimizados. Nas condições otimizadas, um gráfico de calibração linear foi obtido para a determinação de Pb(II) e Cu(II). As faixas lineares foram 15-500 µg L −1 e 18-500 µg L −1 para chumbo e cobre, respectivamente. Os limites de detecção e quantificação foram 4,3 e 14,5 µg L −1 para chumbo e 5,0 e 16,7 µg L −1 para cobre, respectivamente. O desvio padrão relativo para determinações de oito replicatas de 80 e 200 µg L −1 de Pb(II) foram 2,9 e 1,4% e para Cu(II) foram 3,5 e 1,9%, respectivamente. A aplicabilidade do método foi avaliada ao analisar traços de chumbo e cobre em diferentes amostras de água.