New magnetic graphene-based inorganic-organic sol-gel hybrid nanocomposite for simultaneous analysis of polar and non-polar organophosphorus pesticides from water samples using solid-phase extraction

A new graphene-based tetraethoxysilane-methyltrimethoxysilane sol-gel hybrid magnetic nanocomposite (Fe3O4@G-TEOS-MTMOS) was synthesised, characterized and successfully applied in magnetic solid-phase extraction (MSPE) for simultaneous analysis of polar and non-polar organophosphorus pesticides from several water samples. The Fe3O4@G-TEOS-MTMOS nanocomposite was characterized using Fourier transform-infrared spectroscopy, energy-dispersive X-ray spectroscopy, field emission scanning electron microscopy and X-ray diffraction. Separation, determination and quantification were achieved using gas chromatography coupled with micro electron capture detector. Adsorption capacity of the sorbent was calculated using Langmuir equation. MSPE was linear in the range 100–1000 pg mL−1 for phosphamidon and dimethoate, and 10–100 pg mL−1 for chlorpyrifos and diazinon, with limit of detection (S/N = 3) of 19.8, 23.7, 1.4 and 2.9 pg mL−1 for phosphamidon, dimethoate, diazinon and chlorpyrifos, respectively. The LODs obtained is well below the maximum residual level (100 pg mL−1) as set by European Union for pesticides in drinking water. Acceptable precision (%RSD) was achieved for intra-day (1.3–8.7%, n = 3) and inter-day (7.6–17.8%, n = 15) analyses. Fe3O4@G-TEOS-MTMOS showed high adsorption capacity (54.4–76.3 mg g−1) for the selected OPPs. No pesticide residues were detected in the water samples analysed. Excellent extraction recoveries (83–105%) were obtained for the spiked OPPs from tap, river, lake and sea water samples. The newly synthesised Fe3O4@G-TEOS-MTMOS showed high potential as adsorbent for OPPs analysis

Synthesis of Polyaniline-Coated Graphene Oxide@SrTiO3 Nanocube Nanocomposites for Enhanced Removal of Carcinogenic Dyes from Aqueous Solution

The present investigation highlights the synthesis of polyaniline (PANI)-coated graphene oxide doped with SrTiO3 nanocube nanocomposites through facile in situ oxidative polymerization method for the efficient removal of carcinogenic dyes, namely, the cationic dye methylene blue (MB) and the anionic dye methyl orange (MO). The presence of oxygenated functional groups comprised of hydroxyl and epoxy groups in graphene oxide (GO) and nitrogen-containing functionalities such as imine groups and amine groups in polyaniline work synergistically to impart cationic and anionic nature to the synthesised nanocomposite, whereas SrTiO3 nanocubes act as spacers aiding in segregation of GO sheets, thereby increasing the effective surface area of nanocomposite. The synthesised nanocomposites were characterised by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The adsorption efficiencies of graphene oxide (GO), PANI homopolymer, and SrTiO3 nanocubes-doped nanocomposites were assessed by monitoring the adsorption of methylene blue and methyl orange dyes from aqueous solution. The adsorption efficiency of nanocomposites doped with SrTiO3 nanocubes were found to be of higher magnitude as compared with undoped nanocomposite. Moreover, the nanocomposite with 2 wt % SrTiO3 with respect to graphene oxide demonstrated excellent adsorption behaviour with 99% and 91% removal of MB and MO, respectively, in a very short duration of time

Dispersive graphene-based silica coated magnetic nanoparticles as a new adsorbent for preconcentration of chlorinated pesticides from environmental water

The present study describes the synthesis, characterization and application of new graphene-based silica coated magnetic nanoparticles (Fe3O4@SiO2–G) for the simultaneous preconcentration of four chlorinated pesticides namely lindane, chlorpyrifos, hexaconazole and azaconazole from contaminated water. The newly synthesised adsorbent was characterized using FT-IR spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Chlorinated pesticide extraction efficiency of the Fe3O4@SiO2–G was evaluated through magnetic solid phase extraction (MSPE) using gas chromatography with a micro electron capture detector (GC-μECD). Experimental parameters, i.e., desorption solvent, solvent volume, extraction time, desorption time, sample volume, adsorbent dosage and solution pH were optimized. Compared to commercial C18 sorbent and Fe3O4@SiO2, the newly synthesized Fe3O4@SiO2–G adsorbent showed a linear response (1–100 pg mL−1), low limits of detection (0.12–0.28 pg mL−1) and high adsorption capacity (13.04–18.69 mg g−1) with a coefficient of determination (R2) of 0.999. Environmental water samples were used to assess the field applicability of the adsorbents. Excellent percent recovery (80.8–106.3%) was achieved for Fe3O4@SiO2–G at pH 6.5. The results showed that the newly synthesized Fe3O4@SiO2–G is an efficient adsorbent with good potential for the preconcentration of selected chlorinated pesticides from aqueous media

New sporopollenin-based β-cyclodextrin functionalized magnetic hybrid adsorbent for magnetic solid-phase extraction of nonsteroidal anti-inflammatory drugs from water samples

A magnetic solid-phase extraction (MSPE)procedure on the newly synthesized magnetic β-cyclodextrin functionalized with toluene diisocyanate (TDI)as a linker and further modified with bio-polymeric spores of sporopollenin (MSp-TDI-βCD), was developed for the extraction of nonsteroidal anti-inflammatory drugs (NSAIDs), namely, indoprofen (INP), ketoprofen (KTP), ibuprofen (IBP)and fenoprofen (FNP)from water samples prior to their HPLC-DAD determination. The newly synthesized MSp-TDI-βCD was comprehensibly characterized using FT-IR, XRD, SEM-EDX, BET and VSM analyses. The separation of selected NSAIDs on MSp-TDI-βCD from aqueous solution was simply achieved by applying an external magnetic field via a permanent magnet. The MSPE parameters affecting extraction performance, i.e. sorbent dosage, sample volume, extraction and desorption time, type of organic eluent and volume and solution pH were investigated and optimized. The proposed method showed linear range between 0.5 and 500 ng ml-1, low limit of detection at S/N=3 (0.16-0.37 ng ml-1)and limit of quantification at S/N=10 (0.53-1.22 ng ml-1). The inter-day (n=15)and intra-day (n=5)precision for the proposed methods given by relative standard deviation (RSD%)was in the range of 2.5-4.0 and 2.1-5.5, respectively. The extraction recoveries of NSAIDs from environmental samples (tap, drinking and river water)ranged from 92.5% to 123.6%, with satisfactory precision (RSD% less than 12.4%)

Data from: New sporopollenin based β-cyclodextrin functionalized magnetic hybrid adsorbent for magnetic solid-phase extraction of NSAIDs from water samples

A magnetic solid-phase extraction (MSPE) procedure on the newly synthesized magnetic β-cyclodextrin functionalized with toluene diisocyanate (TDI) as a linker and was further modified with bio-polymeric spores of sporopollenin (MSp-TDI-βCD) was developed for the extraction of nonsteroidal anti-inflammatory drugs (NSAIDs) namely indoprofen (INP), ketoprofen (KTP), ibuprofen (IBP) and fenoprofen (FNP) from water samples prior to their HPLC-DAD determination. The newly synthesised MSp-TDI-βCD was comprehensibly characterized using FT-IR, XRD, SEM-EDX, BET and VSM analyses. The separation of selected NSAIDs on MSp-TDI-βCD from aqueous solution was simply achieved by applying an external magnetic field via a permanent magnet. The MSPE parameters affecting extraction performance i.e., sorbent dosage, sample volume, extraction and desorption time, type of organic eluent and volume and solution pH were investigated and optimized. The proposed method showed linear range between 0.5 - 500 ng/mL, low limit of detection at S/N = 3 (0.16 - 0.37 ng/mL) and limit of quantification at S/N = 10 (0.53 - 1.22 ng/mL). The interday (n = 15) and intraday (n = 5) precision for the proposed methods given by relative standard deviation (RSD%) in the range of 2.5 - 4.0 and 2.1 - 5.5 respectively. The extraction recoveries of NSAIDs from environmental samples (tap, drinking and river water) ranged from 92.5 - 123.6%, with satisfactory precision (RSD% less than 12.4%)

New magnetic silica-based hybrid organic-inorganic nanocomposite for the removal of lead(II) and nickel(II) ions from aqueous solutions

A novel magnetic sol-gel silica-based hybrid organic-inorganic adsorbent (MNPs@SiO 2 -TSD-TEOS) was synthesized by immobilizing silica (SiO 2 ) shell on Fe 3 O 4 magnetic nanoparticles (MNPs) prior to binding with hybrid organic-inorganic tetraethylorthosilicate (TEOS) and N-[3-(trimethoxysilyl)propyl]ethylenediamine (TSD)). The proposed material was characterized using Fourier transform infrared spectrometer (FTIR), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscope (EDS) and X-ray diffraction (XRD). MNPs@SiO 2 -TSD-TEOS was applied as an adsorbent for the simultaneous adsorption of Pb(II) and Ni(II) ions from aqueous solutions. The adsorption process, reusability test and field application of MNPs@SiO 2 -TSD-TEOS were performed using batch adsorption of metal ions at pH 5. The adsorption process was well-matched to type III isotherm model (multilayer sorption) set by IUPAC. The experimental adsorption data were well-fitted to the Freundlich adsorption isotherm since its coefficient of determination (R 2 = 0.997) is higher than that of the Langmuir isotherm (R 2 = 0.871). The adsorption kinetics were fitted well to pseudo-2 nd -order model as compared to pseudo-1 st -order. Furthermore, the results showed maximum adsorption capacities of 417 and 357 mg g −1 for Pb(II) and Ni(II), respectively. Isotherm model (type III), Freundlich isotherm and pseudo-2 nd -order model confirm a multilayer chemical/physical adsorption process. © 2019 Elsevier B.V

Data from: New sporopollenin based β-cyclodextrin functionalized magnetic hybrid adsorbent for magnetic solid-phase extraction of NSAIDs from water samples

A magnetic solid-phase extraction (MSPE) procedure on the newly synthesized magnetic β-cyclodextrin functionalized with toluene diisocyanate (TDI) as a linker and was further modified with bio-polymeric spores of sporopollenin (MSp-TDI-βCD) was developed for the extraction of nonsteroidal anti-inflammatory drugs (NSAIDs) namely indoprofen (INP), ketoprofen (KTP), ibuprofen (IBP) and fenoprofen (FNP) from water samples prior to their HPLC-DAD determination. The newly synthesised MSp-TDI-βCD was comprehensibly characterized using FT-IR, XRD, SEM-EDX, BET and VSM analyses. The separation of selected NSAIDs on MSp-TDI-βCD from aqueous solution was simply achieved by applying an external magnetic field via a permanent magnet. The MSPE parameters affecting extraction performance i.e., sorbent dosage, sample volume, extraction and desorption time, type of organic eluent and volume and solution pH were investigated and optimized. The proposed method showed linear range between 0.5 - 500 ng/mL, low limit of detection at S/N = 3 (0.16 - 0.37 ng/mL) and limit of quantification at S/N = 10 (0.53 - 1.22 ng/mL). The interday (n = 15) and intraday (n = 5) precision for the proposed methods given by relative standard deviation (RSD%) in the range of 2.5 - 4.0 and 2.1 - 5.5 respectively. The extraction recoveries of NSAIDs from environmental samples (tap, drinking and river water) ranged from 92.5 - 123.6%, with satisfactory precision (RSD% less than 12.4%)

Capillary Gas Chromatographic Determination of Gamma Aminobutyric acid and Putrescine in Cerebrospinal Fluid using Trifluoroacetylacetone as Derivatizing Reagent

In present work, a new capillary gas chromatographic procedure was established and validated for the determination of gamma aminobutyric acid (GABA) and putrescine (Put) using trifluoroacetylacetone (FAA) as derivatizing reagent from Cerebrospinal Fluid (CSF) samples prior to their gas chromatographic- flame ionization detector (GC-FID) analysis. GABA, Put, cadaverine (Cad) and tyramine (TY) as imitative of FAA extracted from the column HP-5 (30 m x 0.32 mm i.d) at temperature 110 ºC for 1 min, tracked by heating rate 25 ºC to 260 ºC /min. The detection was carried out by FID with segregate ratio 10:1, v/v with whole run time 10 min. The proposed method showed linear calibration range between 2.5-50 µg/mL with low limit of detection 1.0 - 2.5 µg/mL analogous to 0.1 ng to 0.25 ng for selected Put, Cad, GABA, and TY. The method based on the pre-concentration was used for the determination of GABA and Put from CSF of human being and amounts found were 0.25- 0.56 µg/mL and 0.16 - 0.41 µg/mL with relative standard deviation (RSD) within 0.8 - 1.1 and 1.1 - 1.5 %, respectively. Many of amino-acids tested, separated completely and did not variate the determinations of GABA and Put

Nano-Size Biomass Derived from Pomegranate Peel for Enhanced Removal of Cefixime Antibiotic from Aqueous Media: Kinetic, Equilibrium and Thermodynamic Study

Nano-sized activated carbon was prepared from pomegranate peel (PG-AC) via NaOH chemical activation and was fully characterized using BET, FT-IR, FE-SEM, EDX, and XRD. The newly synthesized PG-AC was used for cefixime removal from the aqueous phase. The effective parameters on the adsorption process, including solution pH (2–11), salt effect (0–10%), adsorbent dosage (5–50 mg), contact time (5–300 min), and temperature (25–55 °C) were examined. The experimental adsorption equilibrium was in close agreement with the type IV isotherm model set by the International Union of Pure and Applied Chemistry (IUPAC). The adsorption process was evaluated with isotherm, kinetic, and thermodynamic models and it is were well fitted to the Freundlich isotherm (R2 = 0.992) and pseudo-second-order model (R2 = 0.999). The Langmuir isotherm provided a maximum adsorption capacity of 181.81 mg g−1 for cefixime uptake onto PG-AC after 60 min at pH 4. Hence, the isotherm, kinetic and thermodynamic models were indicated for the multilayer sorption followed by the exothermic physical adsorption mechanism