Applications of three-dimensional graphenes for preconcentration, extraction, and sorption of chemical species: a review

Impact of nanotechnology on progress of flow methods in chemical analysis: A review

In evolution of instrumentation for analytical chemistry as crucial technological breakthroughs should be considered a common introduction of electronics with all its progress in integration, and then microprocessors which was followed by a widespread computerization. It is seems that a similar role can be attributed to the introduction of various elements of modern nanotechnology, observed with a fast progress since beginning of this century. It concerns all areas of the applications of analytical chemistry, including also progress in flow analysis, which are being developed since the middle of 20th century. Obviously, it should not be omitted the developed earlier and analytically applied planar structures like lipid membranes or self-assembled monolayers They had essential impact prior to discoveries of numerous extraordinary nanoparticles such as fullerenes, carbon nanotubes and graphene, or nanocrystalline semiconductors (quantum dots). Mostly, due to catalytic effects, significantly developed surface and the possibility of easy functionalization, their application in various stages of flow analytical procedures can significantly improve them. The application of new nanomaterials may be used for the development of new detection methods for flow analytical systems in macro-flow setups as well as in microfluidics and lateral flow immunoassay tests. It is also advantageous that quick flow conditions of measurements may be helpful in preventing unfavorable agglomeration of nanoparticles. A vast literature published already on this subject (e.g. almost 1000 papers about carbon nanotubes and flow-injection analytical systems) implies that for this reviews it was necessary to make an arbitrary selection of reported examples of this trend, focused mainly on achievements reported in the recent decade.

Development of a green miniaturized quick, easy, cheap, effective, rugged and safe approach in tandem with temperature-assisted solidification of floating menthol droplet for analysis of multiclass pesticide residues in milk

A new green miniaturized quick, easy, cheap, effective, rugged, and safe approach was developed and used for the extraction of multiclass 16 pesticides in milk before GC analysis. The miniaturization of method reduced the consumption of chemical reagents and samples. Magnetic three-dimensional graphene was used as sorbent in the clean-up step. Choline chloride:lactic acid (1:2) natural deep eutectic solvent was used as desorption solvent. Temperature-assisted solidification of floating menthol drop was executed for preconcentration of analytes. The method parameters including sorbent, desorption solvent, sorption and desorption times, menthol amount, pH, and ionic strength were optimized. The limit of quantification and linear range were 0.03-0.38 μg kg^-1 and 0.03-250 μg kg^-1 , respectively. The accuracy was assessed by recovery evaluation at the spike levels of 50 and 100 μg kg^-1 , in the range of 61-119%, with relative standard deviations within 2.1-18.2%. The method was applied to the analysis of pasteurized low and high-fat bovine milk, and various pesticide residues were detected in the concentrations range of 1.24-4.68 μg kg^-1 . Finally, the greenness of the procedure was evaluated using the Analytical Eco-Scale. This work represents the first application of hybrid miniaturized extraction/preconcentration using a natural deep eutectic solvent and menthol to analyze pesticides. This article is protected by copyright. All rights reserved.

Bi, Fe, and Ti ternary co-doped ZrO2 nanocomposites as a mass spectrometry matrix for the determination of bisphenol A and tetrabromobisphenol A in tea

Bi, Fe, and Ti ternary co-doped ZrO₂ (BFT-ZrO₂) nanocomposites have been prepared by a sol-gel process and used as both adsorbent and matrix for the enrichment and determination of small molecules by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS). The BFT-ZrO₂ nanocomposites not only can selectively enrich a wide variety of low-mass toxic pollutants but can also be used as an excellent matrix to enhance the laser desorption/ionization efficiency with low background noise and uniform co-crystalline film. Low limits of detection (LODs) (0.1 pg mL^-1 for bisphenol A (BPA), 2 pg mL^-1 for tetrabromobisphenol A (TBBPA), 0.1 pg mL^-1 for alizarin (AZ), 0.001 pg mL^-1for bisphenol S (BPS), 0.01 pg mL^-1 for indigo blue (ID), 0.01 pg mL^-1 for pentachlorophenol (PCP), 100 pg mL^-1 for estradiol (E2), 0.001 pg mL^-1 for cetyltrimethylammonium bromide (CTAB), 0.1 pg mL^-1 for crystal violet (CV), 1 pg mL^-1 for malachite green (MG), 0.01 pg mL^-1 for rhodamine B (RhB), and 0.01 pg mL^-1 for perfluorooctane sulfonate (PFOS) were achieved. The relative standard deviations (RSDs) of shot-to-shot are 9.4-24% and of sample-to-sample 5.2-17%. The BFT-ZrO₂ matrix was successfully applied to the determination of TBBPA and BPA in tea samples. This method shows a new strategy for determination of toxic compounds in tea. Graphical abstract.

Magnetic Solid Phase Extraction as a Promising Technique for Fast Separation of Metallic Nanoparticles and Their Ionic Species: A Review of Recent Advances

The widespread use of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) in a wide variety of industrial as well as medical sectors is indisputable. This leads to a new concern about their presence in various environmental compartments. Since their negative effect and potential toxicity impact have been confirmed, analytical chemists focus on the development of different procedures for their reliable detection, identification, characterization, and quantification, not only in homogenous and simple matrices but also in complex environmental matrices. However, nanoparticles and their ionic species can coexist and their toxicity may differ; therefore, novel analytical approaches are necessary to monitor not only the nanoparticles but also their ionic species. The aim of this article is to bring a review of recent works where magnetic solid-phase extraction (MSPE) procedures in connection with spectrometric methods were used for separation/preconcentration and quantification of (1) silver and gold ions in various environmental samples, (2) AgNPs and AuNPs in real water samples in the presence of various coexisting ions, and (3) both species (it means Ag ions and AgNPs; Au ions and AuNPs) in real water samples. The results presented herein show the great analytical potential of MSPE procedures in connection with spectrometric methods used in these fields and can be helpful in guiding analytical chemists who aim to work on this subject.

Electrochemical sensors and biosensors using laser-derived graphene: A comprehensive review

Laser-derived graphene (LDG) technology is gaining attention as a promising material for the development of novel electrochemical sensors and biosensors. Compared to established methods for graphene synthesis, LDG provides many advantages such as cost-effectiveness, fast electron mobility, mask-free, green synthesis, good electrical conductivity, porosity, mechanical stability, and large surface area. This review discusses, in a critical way, recent advancements in this field. First, we focused on the fabrication and doping of LDG platforms using different strategies. Next, the techniques for the modification of LDG sensors using nanomaterials, conducting polymers, biological and artificial receptors are presented. We then discussed the advances achieved for various LDG sensing and biosensing schemes and their applications in the fields of environmental monitoring, food safety, and clinical diagnosis. Finally, the drawbacks and limitations of LDG based electrochemical biosensors are addressed, and future trends are also highlighted.

Deep eutectic solvent functionalized graphene oxide composite adsorbent for miniaturized pipette-tip solid-phase extraction of toluene and xylene exposure biomarkers in urine prior to their determination with HPLC-UV

A deep eutectic solvent functionalized graphene oxide composite adsorbent (DFG) was synthesized through reversible-addition fragmentation chain-transfer polymerization. The synthesized DFG had multiple adsorption interactions after covalent modification with a deep eutectic solvent (allyltriethylammonium bromide/ethylene glycol). Adsorption isotherms and kinetics studies of DFG indicate that the adsorption of hippuric acid (HA) and methylhippuric acid (MHA) was monolayer chemical adsorption. The comparison of DFG with commercial adsorbents demonstrates that the adsorption ability of DFG was superior. This was due to the multiple adsorption interactions of DFG for the three analytes (mainly π-interaction, hydrogen bonding, electrostatic adsorption, and hydrophobic interaction). The DFG adsorbent was applied to miniaturized pipette-tip solid-phase extraction (MPT-SPE), followed by high-performance liquid chromatography (HPLC) to determine biomarkers in urine for toluene and xylene exposure. The DFG-MPT-SPE-HPLC method required only 2.00 mg of DFG as adsorbent, 0.50 mL of washing solvent, and 0.40 mL of elution solvent to achieve a wide linear range (0.200-200 μg mL^-1), high recoveries (90.9-99.1%), and high precision (RSD ≤ 6.3%). The proposed method was applied to determine HA and MHA in urine samples from occupational workers. Graphical abstract Deep eutectic solvent functionalized graphene oxide composite adsorbent for miniaturized pipette-tip solid-phase extraction of toluene and xylene exposure biomarkers in urine prior to their determination with HPLC-UV.

Magnetic amino-functionalized hollow silica-titania microsphere as an efficient sorbent for extraction of pesticides in green and roasted coffee beans

This study describes the synthesis and application of a magnetic amino-functionalized hollow silica-titania microsphere as a new sorbent for magnetic dispersive micro-solid phase extraction of selected pesticides in coffee bean samples. The sorbent was fully characterized by Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, transition electron microscopy, energy-dispersive X-ray spectroscopy, and vibrating sample magnetometry techniques. Significant extraction parameters affecting the proposed method, such as extraction time, sorbent amount, sample solution pH, salt amount, and desorption conditions (desorption solvent and time) were investigated and optimized. All the figures of merits were validated in coffee bean samples under the matrix-matched calibration method. Linear dynamic ranges were 5-250 µg/kg with the determination coefficients (R² ) > 0.9980. The limits of detection for the pesticides of chlorpyrifos, malathion, hexaconazole, and atrazine were 1.42, 1.43, 1.35, and 1.33 µg/kg, respectively. Finally, the method was successfully applied for the determination of the pesticides in green and roasted coffee bean samples, and the obtained recoveries were in the range of 74-113% for spiked samples. The prepared sorbent could be used for the magnetic dispersive micro-solid phase extraction of pesticides in the plant-derived food matrix.

Integrated in-syringe magnetic sheet solid-phase extraction and dispersive liquid-liquid microextraction for determination of aflatoxins in fresh and moldy breads

BACKGROUND

Magnetic three-dimensional graphene-based nanoadsorbents have unique characteristics such as large surface area, good thermal and chemical stability, and high adsorption capacity that make them efficient materials in sorbent-based extraction techniques. In this study, four aflatoxins (AFs) were analyzed in bread samples using magnetic three-dimensional graphene as the adsorbent phase in dispersive micro solid-phase extraction.

RESULTS AND CONCLUSIONS

In-syringe magnetic sheet solid-phase extraction based on magnetic three-dimensional graphene in tandem with dispersive liquid-liquid microextraction was used for the extraction and preconcentration of the target AFs. The effect of significant parameters of the method was investigated and the optimum conditions were determined as follows: adsorbent dosage, 20 mg; desorption/disperser solvent (methanol) volume, 700 μL; desorption solvent flow rate, 0.7 mL min^-1 ; pH, neutral; salt (NaCl) concentration, 10% (w/v); extraction solvent (chloroform) volume, 250 μL; and centrifugation rate (and time), 4000 rpm (5 min). The limits of detection and quantification were in the ranges 0.043-0.083 and 0.14-0.28 μg kg^-1 , respectively. The extraction method was followed by the HPLC technique with fluorescence detection and applied to the determination of the AFs in four different Iranian fresh and moldy bread samples. The relative recoveries were in the range 84-107% with relative standard deviations of 3.9-8.6%. © 2019 Society of Chemical Industry.

In vitro and in vivo Biological Responses to Graphene and Graphene Oxide: A Murine Calvarial Animal Study

BACKGROUND

Graphene and its derivatives have recently gained popularity in the biomedical field. Previous studies have confirmed that both the mechanical strength and wear resistance of graphene-containing polyethylene have been greatly improved. Therefore, it is being considered as an alternative for artificial joint replacement liners. Based on the literature, the wear debris generated from the traditional polymers used for orthopedic liners could lead to particle-induced osteolysis and, consequently, failure of joint replacement. However, the biological response of this novel graphene-based polymer is still unclear. Therefore, the current study aimed to investigate the in vitro and in vivo biological effects of graphene and graphene oxide (GO) particles on bone.

MATERIALS AND METHODS

The biological responses of graphene and GO particles were tested via in vitro and murine calvarial in vivo models. In the in vitro model, murine macrophage cells were mixed with particles and hydrogel and printed into two differently designed scaffolds; the induced proinflammatory cytokines were then tested. In the murine in vivo model, the particle size distribution was measured via SEM, and these particles were then administrated in the calvarial area, referring to our established model. A micro-CT and histological analysis were performed to examine the biological effects of the particles on bone health. The data were analyzed via the one-way analysis of variance to determine the differences between the groups.

RESULTS

Both graphene and GO induced significantly higher TNF-α and IL-6 secretion compared with the control in the three-dimensional in vitro model. In the murine calvarial in vivo test, the graphene and GO particles increased the bone mass compared with the sham groups in the micro-CT analysis. Bone formation was also observed in the histological analysis.

CONCLUSION

In these in vivo and in vitro studies, the graphene and GO wear debris did not seem to induce harmful biological response effect to bone. Bone formation around the skull was observed in the calvarial model instead. Graphene-containing biomaterials could be a suitable new material for application in orthopedic prostheses due to their benefit of eliminating the risk of particle-induce osteolysis.

An integrated microfluidic device for solid-phase extraction and spectrophotometric detection of opium alkaloids in urine samples

A novel lab-on-chip integrated microfluidic device for solid-phase extraction (SPE) and spectrophotometric detection of morphine (MOR), codeine (COD), and papaverine (PAP) was developed. The extracted analytes were analyzed with a miniature UV-Vis spectrophotometer. The SPE adsorptive phase composed of polyurethane/polyaniline (PU/PANI) nanofibers was fabricated by electrospinning and in situ oxidative polymerization techniques. The sorbent was characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The main factors of extraction such as desorption conditions, pH, salt effect, and extraction time were investigated. The partial least square (PLS) regression was applied to improve the quantification of analytes. The linear dynamic ranges (LDRs) for MOR, COD, and PAP were 4-240, 4-210, and 1-150 ng mL^-1, respectively. Finally, the proposed method was successfully applied for the determination of MOR, COD, and PAP in human urine samples and the extraction recoveries were obtained in the range of 66.7-85.0% with RSDs < 8.3%.

A review on recent advancements in electrochemical biosensing using carbonaceous nanomaterials

This review, with 201 references, describes the recent advancement in the application of carbonaceous nanomaterials as highly conductive platforms in electrochemical biosensing. The electrochemical biosensing is described in introduction by classifying biosensors into catalytic-based and affinity-based biosensors and statistically demonstrates the most recent published works in each category. The introduction is followed by sections on electrochemical biosensors configurations and common carbonaceous nanomaterials applied in electrochemical biosensing, including graphene and its derivatives, carbon nanotubes, mesoporous carbon, carbon nanofibers and carbon nanospheres. In the following sections, carbonaceous catalytic-based and affinity-based biosensors are discussed in detail. In the category of catalytic-based biosensors, a comparison between enzymatic biosensors and non-enzymatic electrochemical sensors is carried out. Regarding the affinity-based biosensors, scholarly articles related to biological elements such as antibodies, deoxyribonucleic acids (DNAs) and aptamers are discussed in separate sections. The last section discusses recent advancements in carbonaceous screen-printed electrodes as a growing field in electrochemical biosensing. Tables are presented that give an overview on the diversity of analytes, type of materials and the sensors performance. Ultimately, general considerations, challenges and future perspectives in this field of science are discussed. Recent findings suggest that interests towards 2D nanostructured electrodes based on graphene and its derivatives are still growing in the field of electrochemical biosensing. That is because of their exceptional electrical conductivity, active surface area and more convenient production methods compared to carbon nanotubes. Graphical abstract Schematic representation of carbonaceous nanomaterials used in electrochemical biosensing. The content is classified into non-enzymatic sensors and affinity/ catalytic biosensors. Recent publications are tabulated and compared, considering materials, target, limit of detection and linear range of detection.