Eluent Solution Research Articles

A Green Analytical Method for Pre-concentration of Uranium in Water Samples Using Minicolumn with Sugarcane Bagasse

This study proposes a method based on solid-phase extraction using a minicolumn with sugarcane bagasse for pre-concentration uranium in water samples. The first optimization step was used factorial design in two levels (25) for the preliminary assessment of factors: elution flow, sample flow, pH, buffer concentration, and eluent concentration. From this design, it was found that all variables showed significant influence. In the second stage, using the Doehlert design with 5 variables, the optimal conditions were determined: pH 8.3, flow elution 5.5 mL min−1, buffer concentration 0.045 mol L−1, sample flow 5.5 mL L−1, and eluent solution (ascorbic acid 0.6% w/v in medium of hydrochloric acid at a final concentration of 0.06 mol L−1). The method was applied to the determination of uranium with a detection limit (LD) of 0.41 μg L−1 and quantification (LOQ) of 1.40 μg L−1, Relative standard deviation (RSD) 2.5 and 1.3% uranium concentration of 20 and 60 μg L−1, respectively. The factor of pre-concentration for the system is 46 for a sample volume of 50 mL. The accuracy was confirmed by the spike test. The procedure was applied for the determination of uranium in tap water, well water, and human consumption; the samples were collected in the municipalities of Caetite, Cruz das Almas, Itabuna, Aramari-BA, and seawater samples from Todos os Santos Bay. Uranium concentrations were found in the analyzed samples varying from 7.0 to 16.5 μg L−1.

Accurate and Sensitive Analytical Method for the Determination of Cyclanilide in Cotton and Cosmetic Pads at Trace Levels Using the Combination of Vortex Assisted Iron(II,III)/Reduced Graphene Oxide Nanocomposite Based Dispersive Solid Phase Extraction and High Performance Liquid Chromatography (HPLC)

A novel, accurate and sensitive analytical method was developed to determine cyclanilide using vortex assisted Fe3O4/reduced graphene oxide nanocomposite based dispersive solid phase extraction by high performance liquid chromatography (HPLC). An iron (II,III)/reduced graphene oxide nanocomposite (Fe3O4/rGO) was employed to extract and separate cyclanilide from aqueous solution. After the optimization of HPLC system, important parameters for the extraction method including mass of Fe3O4/rGO, pH, volume of buffer solution, nature/volume of eluent solution and vortex period were examined to obtain the highest extraction yields. Under the optimum conditions, the enhancement in the detection power was found to be 35-fold by the developed method. The limits of detection and quantification of the proposed method were 2.6 and 8.7 ng g−1, respectively. In order to characterize the accuracy and applicability of developed method, recovery studies were performed upon cotton and cosmetic pads. High percent recovery results between 90 and 104% were obtained for cotton and cosmetic pad samples. Therefore; this method may be easily applied to cotton samples with excellent precision and accuracy.

Biosorptive removal of acid orange 74 dye by HCl-pretreated Lemna sp.

Acid orange 74 (AO74) is a chromium-complex monoazo acid dye widely used in the textile industry. Due to being highly toxic and non-biodegradable, it must be removed from polluted water to protect the health of people and the environment. The aim of this study was two-fold: to evaluate the biosorption of AO74 from an aqueous solution by utilizing HCl-pretreated Lemna sp. (HPL), and to examine dye desorption from the plant material. The maximum capacity of AO74 biosorption (64.24 mg g-1) was reached after 4 h at the most adequate pH, which was 2. The biosorption capacity decreased 25% (to 48.18 mg g-1) during the second biosorption/desorption cycle and remained essentially unchanged during the third cycle. The pseudo-second-order kinetics model concurred well with the experimental results of assays involving various levels of pH in the eluent solution and distinct initial concentrations of AO74. NaOH (0.01 M) was the best eluent solution. The Toth isotherm model best described AO74 biosorption equilibrium data. FTIR analysis confirmed the crucial role of HPL proteins in AO74 biosorption. SEM-EDX and CLSM techniques verified the effective biosorption/desorption of the dye during the three cycles. Therefore, HPL has potential for the removal of AO74 dye from wastewaters.

Ultrasound assisted-dispersive-modification solid-phase extraction using task-specific ionic liquid immobilized on multiwall carbon nanotubes for speciation and determination mercury in water samples

An efficient method based on 1-(3-aminopropyl)-3-methylimidazolium hexafluorophosphate (TSIL) immobilized on multiwall carbon nanotubes (MWCNTs@ [Apmim][PF6]) was used for speciation of inorganic/organic mercury (Hg2+, R-Hg or O-Hg) by ultrasound assisted-dispersive modification solid-phase extraction (UAS-DM-SPE) which was combined with cold vapor atomic absorption spectrometry (CV-AAS). The mixture of MWCNTs @ [Apmim][PF6] in acetone was injected to water samples in polypropylene syringe filters (PSF) which was already adjusted pH up to 8.5. After shaking, the Hg(II) and O-Hg were simply extracted on amine group of [Apmim][PF6] as TSIL and then, separated from the liquid phase by pushing plunger of PSF. The Hg(II) and O-Hg loaded in MWCNTs @ [Apmim][PF6] were back-extracted based on the eluent solution (HNO3, 0.5 mL, 0.2 mol L−1) with/without microwave system (UV radiation at 165 °C). Finally, the concentration of mercury was determined by CV-AAS. By microwave, organic mercury species in remained solution were changed to Hg (II) and the total amount of mercury (T-Hg) was determined. Finally, O-Hg concentration was computed by subtracting the Hg (II) concentration from T-Hg. Under the optimized conditions, the linear range, LOD and enrichment factor for Hg (II) and O-Hg were achieved (0.02–3.6 μg L−1; 0.02–3.4 μg L−1), (5.2 ng L−1; 5.8 ng L−1) and (19.9; 19.7), respectively (Mean of RSD<1.91%). Also, the capacity absorption based on MWCNTs and MWCNTs@ [Apmim][PF6] for O-Hg and Hg(II) ions were achieved 23.6/27.3 mg g−1 and 174.3/186.2 mg g−1, respectively. The proposed method validated for speciation of mercury by ICP-MS and standard reference material (SRM).

Developing a novel packed in-tube solid-phase extraction method for determination ∆ 9-tetrahydrocannabinol in biological samples and cannabis leaves.

A novel plate-like nano-sorbent based on copper/cobalt/chromium layered double hydroxide was synthesized by a simple coprecipitation method. The synthesized nanoparticels were introduced into a stainless steel cartridge using a dry packing method. Then, the packed cartridge was introduced as a novel on-line "packed in-tube" configuration and followed by high performance liquid chromatography for the determination of trace amounts of ∆ 9-tetrahydrocannabinol from biological samples and cannabis leaves. The as-prepared sorbent exhibited long lifetime, good chemical stability, and high anion-exchange capacity. Several important factors affecting the extraction efficiency, such as extraction and desorption times, pH of the sample solution and flow rates of the sample and eluent solutions, were investigated and optimized. Under optimized conditions, this method showed good linearity for ∆ 9-tetrahydrocannabinol in the ranges of 0.09-500, 0.3-500, and 0.4-500µg/L with coefficients of determination of 0.9999, 0.9991, and 0.9994 in water, serum and plasma samples, respectively. The inter- and intra-assay precisions (n=3) were respectively in the ranges of 1.8-4.6% and 1.9-4.0% at three concentration levels of 10, 50, and 100µg/L. The limits of detection were also in the range of 0.02-0.1µg/L.

Tri-n-octylamine impregnated Seplite LX-16 resin for extraction of U(VI) from sulfate medium

Impregnation of tri-n-octylamine (TOA) into Siplite LX-16 resin, by two commonly used methods namely; wet and dry impregnation method, was studied and applied for uranium extraction from sulfate medium. The resin beads were characterized using FT-IR and FE-SEM analysis. The influence of different parameters such as effect of TOA concentration, pH, aqueous sample and eluant flow rates were investigated. Maximum sorption of U(VI) was obtained using 30% TOA/Siplite LX-16 prepared by the dry method at a pH range of 1.4–1.6. Flow rate of 1.0 mL/min for the pregnant sample was favorable for quantitative sorption of uranium during the extraction step while the flow rate of 0.5 mL/min for eluant solution was effective for the elution step. TOA-impregnated Siplite LX-16 resin has been properly prepared and applied for U(VI) extraction from sulfuric acid medium.

Activation of natural coal for selective preconcentration of Pb(II) ions prior to its trace determination in aqueous samples by flame atomic absorption spectrometer

Abstract Natural coal was collected from Thar coal field, block IX in Province Sindh, Pakistan. The Thar coal was modified to Activated Thar Coal Adsorbent (ATCA) by reacting with concentrated H2SO4, which enhanced its porosity by dehydration as concentrated H2SO4 is strongly dehydration agent. The surface oxidation of coal was carried out by refluxing in concentrated HNO3. The ATCA was subjected to FT-IR spectrometer for characterization, which revealed the presence of C O and COOH moieties onto its surface. The ATCA was packed in column for adsorption of Pb(II) ions and recovered ≥95.6% with relative error ≤4.4% and RSD ≤3.7% at pH 7.0, ATCA dosage 400 mg, sample volume 400 mL (flow rate of 2.0 mL min−1) and eluent solution 5.0 mL of 0.5 mol L−1 HCl (flow rate of 1.0 mL min−1). LOD (0.03 μg L−1) and LOQ (0.11 μg L−1) of method were calculated followed by blank recording (n = 15) with preconcentration factor (PF) of 80. A linear response was observed with regression equation of y = 0.0934x + 0.0411 and R2 = 0.99 for concentration range of 0.5–5.0 mg L−1 (before preconcentration). Similarly, a linear response was also observed with regression equation of y = 7.4358x + 0.0429 and R2 = 0.99 for concentration range of 0.005–0.050 mg L−1 (after preconcentration). Breakthrough curve was plotted for obtaining total saturation capacity (152.5 mg g−1) of ATCA for adsorption of Pb(II) ions. The method worked well on real water samples with recovery ≥92 ± 4.5% of Pb(II) ions.

Pipette-tip solid-phase extraction using cetyltrimethylammonium bromide enhanced molybdenum disulfide nanosheets as an efficient adsorbent for the extraction of sulfonamides in environmental water samples.

Surfactant cetyltrimethylammonium bromide enhanced molybdenum disulfide was used as an adsorbent in pipette-tip solid-phase extraction for the pretreatment of sulfonamides in environmental water samples. The factors affecting the extraction recoveries of the analytes, including the sample pH value, amount of sorbent, type and volume of eluent solution, and salt concentration were optimized. This pipette-tip solid-phase extraction method demonstrated good linearity (0.05-10.0 µg/L) with a coefficient of determination of 0.9984-0.9996, limit of detection (0.2-0.4 ng/L) and limit of quantitation (0.5-1.0 ng/L), good analyte recoveries (76-91), and acceptable limit of quantitation (<10%) under the optimized conditions. These results indicated that the proposed method was a good tool for monitoring sulfonamides in environmental water samples.

Preparation sulfhydryl functionalized paramagnetic Ni0.25Zn0.75Fe2O4 microspheres for separating Pb(II) and Hg(II) ions from aqueous solution

A novel sulfhydryl-functional paramagnetic solid-phase adsorbent (HS-M) is constructed based on Ni0.25Zn0.75Fe2O4 microsphere, modified by amino-functional coupling silane (KH-550), cyanuric chloride (TCT) and ethanedithiol (EDT) in turn. The HS-M samples are characterized via a vibration sample magnetism (VSM), an X-ray diffraction instrument (XRD), a scanning electron microscopy (SEM), a transmission electron microscopy (TEM), an energy dispersive spectrometer (EDS), and a Fourier-transform infrared spectroscopy instrument (FT-IR). Some parameters of absorbent properties are investigated, including pH value, adsorption time, ion concentrations, variety of ions, as well as a variety of eluant solutions and desorption time. The HS-M adsorbent presents excellent absorbability on Pb(II) and Hg(II) with the maximum adsorption capacity at 52.78 and 51.32 mg g-1, respectively. The HCl solution (1 mol L−1) is the best suitable eluant solution to regenerate the adsorbent. The as-prepared adsorbent demonstrates excellent reusability whose desorption efficiency remains beyond 92% after five-time recycles. The HS-M adsorbent reaches 58.1% and 47.7% Pb(II) and Hg(II) ions (50 ppm) in a real-water sample, respectively. The HS-M adsorbent is proper in the adsorption of Pb(II) and Hg(II) ions in the various aqueous setting.

Enantiomeric resolution of ephedrine racemic mixture using molecularly imprinted carboxylic acid functionalized resin

In the current work, we prepared an enantio-selective imprinted resin adsorbent ((+)-EMIP) with remarkable affinity for (+)-ephedrine ((+)-Eph) enantiomer. The phenolic amide derived from 4-hydroxybenzoic acid (HBA) and (+)-Eph ((+)-Eph-HBA) was first synthesized via N,N′-diisopropylcarbodiimide (DIC) activation and then copolymerized with resorcinol and formalin. The template (+)-Eph was then expelled from the resin by alkaline degradation of the amide linkage and the finally obtained (+)-EMIP resin particles exhibited a considerable selectivity toward the (+)-Eph with a capacity reached 220 ± 1 mg/g. Also, the selectivity studies indicated a higher affinity toward the imprinted (+)-Eph enantiomer as a result of the formation of configuration-matching receptor sites that were able to fit the targeted enantiomer better than its mirror-image. Moreover, the prepared resin was successfully employed in the chiral resolution of (±)-Eph racemate using batch technique with (+)-Eph 87.1% enantiomeric excess in the loading supernatant solution and (−)-Eph 44.6% excess in the recovery eluant solution.

Reversed-phase stepwise gradient thin-layer chromatography of test dye mixtures with controlled developing solvent velocity

The new approach to the development of planar chromatogram with controlled developing solvent velocity was implemented for gradient reversed-phase chromatography of a test mixture of dyes. The developing solvent components were directly delivered onto the surface of the C18 type of silica adsorbent layer with controlled velocity by moving pipette combined with two syringe pumps. The eluent components were mixed onto the adsorbent layer, so in this way, there was no dwell volume of the developing solvent during gradient chromatogram development. The delivery of the developing solvent solution to the adsorbent layer was adjusted to its absorption rate by the adsorbent layer. Under such conditions, there was no excess of the eluent solution on the surface of the adsorbent layer, so the high performance of the chromatographic system could be obtained. In the paper, the results of the repeatability and reproducibility test of migration distances of selected separated solute zones are presented.

Indirect electrochemical determination of sulfates in mineral water by a flow-through system

The paper describes the indirect determination of sulfates by in-electrode coulometric indication method. The principle of the determination of sulfates consists in the on-line coupling of the exchange column filled with barium chromate and the flow-through coulometric analyser. In the column BaCrO4(s) converts to BaSO4(s) according to the equation: BaCrO4(s)+SO42−(aq)→BaSO4(s)+CrO42−(aq). This conversion is caused by the lower solubility of BaSO4(s) compared to the solubility of BaCrO4(s). Subsequently, the concentration of the chromate in the eluate solution was determined by the in-electrode coulometric indication method in the electrode made of reticulated vitreous carbon. The solution flowing out of the column was mixed in the flow-through analyser with 0.4 mol L−1 hydrochloric acid and the concentration of chromates was determined by direct reduction of Cr(VI) to Cr(III) with a constant current. The determination was evaluated by the calibration curve method. The linear range of the calibration curve was 3.9–100 mg L−1. The detection limit and the accuracy were 1.3 mg L−1 and 3.2%, respectively. The interference of the bicarbonate was eliminated through a conversion to insoluble carbonate by boiling the sample. The procedure was validated by analyses of certified reference material and bottled mineral water samples. A good agreement with the ion chromatography was achieved for all samples.

Nano activated carbon from industrial mine coal as adsorbents for removal of dye from simulated textile wastewater: operational parameters and mechanism study

Feasibility studies were conducted in the preparation of an effective activated carbon (AC) using the new raw Egyptian coal source called Maghara coal. Using this is eco-friendly, economical and highly available since it is a local and a natural material; thus, it was inspected for the removal of methylene blue (MB) dye from aqueous solutions. A very simple technique known as impregnation activated carbon with NaOH by chemical activation process was used. The most proper nano-activated carbon (NAC) was produced from carbonization of average particle size coal of 0.478 mm at 550 °C for 90 min. with 50% NaOH and ratio 35. The equilibrium data of MB onto the most effective prepared material was simulated using Langmuir and Freundlich isotherm models. Moreover, the adsorption mechanism of MB onto the prepared nano-activated carbon was suggested to take place as mono-layers adsorption on the homogenous active sites. The maximum mono-layers adsorption capacity was recorded as 28.09 mg/g. The morphological, chemical, and textural properties of the prepared NaOH activated carbon was investigated using TEM, Raman spectroscopy, FT-IR, and BET. Results indicated that the material was prepared at spherical shape with average diameter of 38 nm with high total pore volume of 0.183 cm3/g. The adsorption stability and reuseability of NAC was established using HCl as an eluent solution. The findings revealed the versatility of Maghara coal as a good precursor for the preparation of high quality, efficient and economical NAC.

Synthesis and characterization of reduced graphene oxide-Fe3O4@polydopamine and application for adsorption of lead ions: Isotherm and kinetic studies

The functionalization of graphene causes many of its features to be altered, which can be used to better adsorption metal ions in aqueous solution. In this work, catecholamine, with a stable polymeric structure and as a safe material, was coated on graphene oxide by the self-polymerization and creates strong and toughness composite that exhibits high resistance to destruction due to stirring or sonication. Graphene oxide (GO) was reduced in the polymerization process and many functional groups including amine and hydroxyl groups are formed on the composite structure, which causes more interaction with Pb2+ ions. The surface area of the magnetic GO was increased after covering with polydopamine. The sorbent was characterized by Field emission scanning electron microscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, Vibrating-sample magnetometer and Energy-dispersive X-ray spectroscopy. To achieve the highest adsorption efficiency, various parameters including pH, sorbent amount, breakthrough volume, adsorption time, desorption time and volume and concentration of eluent solution were optimized. The sorbent capacity was achieved as about 35.2 mg g−1. The isotherm data fitted well with the Langmuir isotherm model. The experimental results proved that rGO/Fe3O4@PDA had higher stability than GO@Fe3O4 and can be reused many times after washing with eluent.

Effect of biomolecule chemical structure on the synthesis of surface magnetic molecularly imprinted polymer in aqueous solution using various monomers for high-capacity selective recognition of human insulin

Magnetic molecular imprinting technique was used for the detection of human insulin. The structure and binding sites of insulin determined by the use of Cn3D software were considered in the selection of functional monomers types and ratios. Methacrylic acid (MAA) was chosen as the electrostatic functional monomer and acrylamide (AAm) as the neutral monomer with a cross-linker of methylenebisacrylamide (MBAAm) for surface imprinting onto vinyl-functionalized Fe3O4 nanoparticles (MNPs). The effect of factors including the monomers' molar ratio, pH of the synthesis media, template concentration, type of eluent solution, and elution time was investigated on the characteristics and performance of molecularly imprinted polymers along with the molecular analysis of the system at the elution stage. The results revealed the importance of considering the template structure. The best result was obtained with an imprinting factor equal to 2.2 by magnetic molecularly imprinted polymers at the molar ratio of 20:100:5 for MAA:AAm:MBAAm (on the basis of 1 M of insulin), synthesized in phosphate buffer (pH = 6) and eluted with methanol/acetic acid (9/1, v/v) solution for 72 h. Its high selective recognition to insulin in the presence of a competitor demonstrated the separation ability of the imprinted polymer to the template molecule.

Mineralogical and geochemical constraints on chromium oxidation induced by birnessite

We have explored redox reactions between dissolved Cr and the phyllomanganate birnessite with high resolution through simultaneous synchrotron X-ray diffraction, X-ray spectroscopy, and fluid analysis at different concentrations of solution pH. Specifically, we collected time-resolved synchrotron X-ray diffraction patterns and X-ray absorption near edge structure (XANES) spectra from triclinic Na-birnessite every 15 min while passing pH controlled 1.0 mM Cr(III) nitrate solutions through a capillary cell. In addition, we quantified Cr(VI) concentrations of the eluate solution every 15 min using spectrophotometry.Consistent with previous studies, we observed an increased rate of Cr(VI) production with decreasing pH. We attribute the comparatively slow kinetics of Cr(III) oxidation at pH 5.0 and 4.0 to a transformation from triclinic to hexagonal birnessite. This solid-state transition reproducibly coincided with a ∼10-fold decline in the extent of oxidation of aqueous Cr(III). Control experiments without Cr(III) revealed no evidence for birnessite transformation within the same time frame, and experiments with hexagonal birnessite as the starting material generated solutions with low fractions (∼3 mol%) of dissolved Cr(VI) from start to finish. At pH 3.0 and 2.0, however, production of Cr(VI) was consistently higher than was observed at pH 5.0 and 4.0. Specifically, at pH 2.0, 80 mol% of the influent Cr(III) was oxidized to Cr(VI) during the experiment compared to 20 mol% at pH 5.0. XANES analyses showed evidence for both Cr(III) and Cr(VI) adsorbing onto the surface of birnessite at all pH values.We propose that Cr(III) is oxidized to Cr(VI) by an electron exchange that reduces Mn(III) in birnessite to Mn(II). At pH 3.5 and higher, the structure of birnessite consequently transforms to hexagonal birnessite. By this pathway, the birnessite crystal structure critically controls the oxidation of dissolved Cr(III) due to the accessibility of reactive Mn(III) in triclinic birnessite relative to hexagonal birnessite. Below pH 3.5, however, birnessite dissolution systematically exposes reactive sites that enable the continuous oxidation of Cr(III) to Cr(VI).

Study on oxygen pressure thiosulfate leaching of gold without the catalysis of copper and ammonia

There are several limitations of thiosulfate leaching methods in its industrial application. The main limitation is the addition of copper and ammonia which act as catalysts in the thiosulfate leaching process. The introduction of cupric ions can accelerate the rate of gold leaching but cause massive oxidation of thiosulfate, and cupric ions in the leachates are also adverse to gold recovery. Moreover, the presence of ammonia must be taken into account due to the increasing environment concerns. In this paper, a systematic investigation was carried out during oxygen pressure thiosulfate leaching (OPTL) without adding copper and ammonia at elevated temperature and oxygen pressure. Thermodynamic calculations showed that the improvement of temperature and pressure was favorable to gold leaching by thiosulfate. However, high temperature and pressure also caused high thiosulfate consumption (55.3 kg/t-ore of sodium thiosulfate) and relatively low gold extraction (87.6%) without additives. Addition of ammonium alcohol polyvinyl phosphate (AAPP) in the tests could reduce thiosulfate consumption to 45.7 kg/t-ore, whilst 90.2% of gold extraction can be achieved. XPS and SEM studies indicated that AAPP could also hinder the deposition of some passivation species including FeOOH, Fe2O3, Al2O3, S0, etc. on the ore surface. The gold recovery from oxygen pressure thiosulfate leach solution was conducted by the method of resin adsorption. Over 98% of gold can be loaded at 1 g/L strong base anion exchange resin of Tulsion A-21S and almost 100% of gold on the loaded resin can be stripped with a two component eluent solution comprising chloride and sulfite.

Development of a sequential injection system with online photo-cleavage coupled to SPE for spectrophotometric determination of N-nitrosoglyphosate

The nitrosamine N-nitrosoglyphosate (NNG) is present as a minor impurity in technical-grade glyphosate (GLY), which is widely used in crops worldwide. Due to their high toxicity, regulatory agencies have established as 1.0 mg kg−1 (w/w) the maximum concentration of NNG allowed in the technical standard of glyphosate to produce commercial formulations. Considering the high similarity between the structural formulas of NNG and GLY, a flow system with online photo-cleavage coupled to solid phase extraction is proposed. The NO group of NNG was cleaved by UV radiation (254 nm) and sequentially isolated in the form of NO2− at the strong anionic exchange sorbent in a mini-column. Griess reagent was used as eluent solution for the spectrophotometric determination of NO2−, which was related to NNG concentration. The extraction procedure and photo-cleavage reaction were carried out in SIA system, resulting in a linear range from 0.05 to 1.25 mg kg−1 NNG (R2 = 0.9937) with sampling rate of 5.7 det h−1. The pre-concentration factor was twelve-fold and good repeatability for the 0.05 mg kg−1 solution of NNG was observed (r.s.d = 3.7%, n = 3) after 48 successive determinations, without significant changes in the analytical figures of merit. A limit of detection (LOD) of 3.1 × 10−3 mg kg−1 was estimated and good recoveries (96.5%, n = 3) in the presence of high amount of glyphosate was obtained.

Combination of ions promotes cell migration via extracellular signal‑regulated kinase 1/2 signaling pathway in human gingival fibroblasts.

Wound healing is a dynamic process that involves highly coordinated cellular events, including proliferation and migration. Oral gingival fibroblasts serve a central role in maintaining oral mucosa homeostasis, and their functions include the coordination of physiological tissue repair. Recently, surface pre‑reacted glass‑ionomer (S‑PRG) fillers have been widely applied in the field of dental materials for the prevention of dental caries, due to an excellent ability to release fluoride (F). In addition to F, S‑PRG fillers are known to release several types of ions, including aluminum (Al), boron (B), sodium (Na), silicon (Si) and strontium (Sr). However, the influence of these ions on gingival fibroblasts remains unknown. The aim of the present study was to examine the effect of various concentrations of an S‑PRG filler eluate on the growth and migration of gingival fibroblasts. The human gingival fibroblast cell line HGF‑1 was treated with various dilutions of an eluent solution of S‑PRG, which contained 32.0ppm Al, 1,488.6ppm B, 505.0ppm Na, 12.9ppm Si, 156.5ppm Sr and 136.5ppm F. Treatment with eluate at a dilution of 1:10,000 was observed to significantly promote the migration of HGF‑1 cells. In addition, the current study evaluated the mechanism underlying the mediated cell migration by the S‑PRG solution and revealed that it activated the phosphorylation of extracellular signal‑regulated kinase 1/2 (ERK1/2), but not of p38. Furthermore, treatment with a MEK inhibitor blocked the cell migration induced by the solution. Taken together, these results suggest that S‑PRG fillers can stimulate HGF‑1 cell migration via the ERK1/2 signaling pathway, indicating that a dental material containing this type of filler is useful for oral mucosa homeostasis and wound healing.

A sequential injection fluorimetric methodology with in-line solid phase extraction for biogenic amines screening in water

ABSTRACTA method for the screening of biogenic amines in waters, whose presence at some concentration levels potentially cause adverse effects on humans, was developed for the first time. A suitable and easy to operate system, with low reagent consumption was devised. The proposed flow-based system was divided into two analytical parts, preconcentration and derivatization of the biogenic amines. Solid phase extraction, using a Chelex 100 resin, was the newly chosen strategy for preconcentration of the analyte and also removal of possible matrix interferences. Fluorescamine was used as derivatization reagent for biogenic amines followed by fluorimetric detection. The influence of different sorbent materials for preconcentration and flow system parameters such as pH of standards and buffer, composition of the eluent solution, flow-rates, standard/sample volume, were studied. The interference of ammonia was assessed, and no interference was observed. The limits of detection and quantification were 1.7 and 5.6 µmol L−1, respectively. The developed system was applied to water samples and the recovery results were 98 ± 7%.