Rapid determination of seven synthetic dyes in casual snacks based on packed-fibers solid-phase extraction coupled with HPLC-DAD.

Based on packed-fiber solid-phase extraction and HPLC-DAD, a simple analytical method for the determination of seven synthetic dyes has been successfully developed. Polystyrene/polypyrrole (PS/PPy) fibers were obtained via electro-spinning of polystyrene skeletal nanofibers, followed by the oxidation with FeCl3 to trigger the polymerization of pyrrole and the deposition of polypyrrole coatings on PS fibrous skeleton fibers. The relationship between the extraction performance of the fibers and the electrospinning process at different humidities was investigated based on morphologic study and BET surface area. In the extraction process, purification, concentration, and desorption could be accomplished in one step. The established method exhibited good sensitivity, selectivity, reproducibility, and good efficiency for synthetic dyes in casual snacks (preserved fruit, flavored yogurt, and fruity hard candy) samples. With optimal conditions, the LODs (S/N = 3) were 2.4 to 21.09 ng mL-1, and linearities were acceptable in liquid matrix and solid matrices. The recoveries were 93.9-103.9%.

Removal of Orange II (OII) dye by simulated solar photoelectro-Fenton and stability of WO2.72/Vulcan XC72 gas diffusion electrode.

The objectives of this study were to determine the viability of removing Orange II (OII) dye by simulated solar photoelectro-Fenton (SSPEF) and to evaluate the stability of a WO2.72/Vulcan XC72 gas diffusion electrode (GDE) and thus determine its best operating parameters. The GDE cathode was combined with a BDD anode for decolorization and mineralization of 350 mL of 0.26 mM OII by anodic oxidation with electrogenerated H2O2 (AO-H2O2), electro-Fenton (EF) and photoelectro-Fenton (PEF) at 100, 150 and 200 mA cm-2 and SSPEF at 150 mA cm-2. The GDE showed successful operation for electrogeneration, good reproducibility and low leaching of W. Decolorization and OII decay were directly proportional to the current density (j). AO-H2O2 had a reduced performance that was only half of the SSPEF, PEF and EF treatments. The mineralization efficiency was in the following order: AO-H2O2 < EF < PEF ≈ SSPEF. This showed that the GDE, BDD anode and light radiation combination was advantageous and indicated that the SSPEF process is promising with both a lower cost than using UV lamps and simulating solar photoelectro-Fenton process. The PEF process with the lowest j (100 mA cm-2) showed the best performance-mineralization current efficiency.

Pre-magnetization for enhancing the iron-catalyzed activation of peroxymonosulfate via accelerating the corrosion of Fe0.

Our findings proved that micron-scale zero-valent iron (mZVI) particles with pre-magnetization combined with peroxymonosulfate (PMS) can markedly enhance the removal of acid orange 7 (AO7). Investigation into the mechanism showed that PMS accelerated the corrosion of ZVI to release Fe2+ under acidic conditions, and the in-situ generated Fe2+ further activated PMS to produce SO4•- and •OH, resulting in AO7 removal. Further, the Lorentz force strengthened the convection in the solution and the field gradient force tended to move Fe2+ from a higher to a lower field gradient at the pre-magnetized ZVI (Pre-ZVI) particle surfaces, thus indicating that pre-magnetization promoted the corrosion of ZVI to release Fe2+, which resulted in the enhancement of PMS activation. Nano-scale ZVI (nZVI) was more effective than mZVI in activating PMS to degrade AO7, but the pre-magnetization effect on mZVI was better than on nZVI. AO7 removal increased with higher ZVI and PMS dosage, lower AO7 concentration, and acidic conditions (pH = 2, 3). This study helps to understand the reactive radicals-based oxidation process with application of pre-magnetized ZVI in activating PMS.

Costs and effects of intra-operative fluorescence molecular imaging - A model-based, early assessment.

INTRODUCTION: Successful breast conserving cancer surgeries come along with tumor free resection margins and account for cosmetic outcome. Positive margins increase the likelihood of tumor recurrence. Intra-operative fluorescence molecular imaging (IFMI) aims to focus surgery on malignant tissue thus substantially lowering the presence of positive margins as compared with standard techniques of breast conservation (ST). A goal of this paper is to assess the incremental number of surgeries and costs of IFMI vs. ST. METHODS: We developed a decision analytical model and applied it for an early evaluation approach. Given uncertainty we considered that IFMI might reduce the proportion of positive margins found by ST from all to none and this proportion is assumed to be reduced to 10% for the base case. Inputs included data from the literature and a range of effect estimates. For the costs of IFMI, respective cost components were added to those of ST. RESULTS: The base case reduction lowered number of surgeries (mean [95% confidence interval]) by 0.22 [0.15; 0.30] and changed costs (mean [95% confidence interval]) by €-663 [€-1,584; €50]. A tornado diagram identified the Diagnosis Related Group (DRG) costs, the proportion of positive margins of ST, the staff time saving factor and the duration of frozen section analysis (FSA) as important determinants of this cost. CONCLUSIONS: These early results indicate that IFMI may be more effective than ST and through the reduction of positive margins it is possible to save follow-up surgeries-indicating further health risk-and to save costs through this margin reduction and the avoidance of FSA.

Nanostructured Co3O4 grown on nickel foam: An efficient and readily recyclable 3D catalyst for heterogeneous peroxymonosulfate activation.

Cobalt-based heterogeneous catalyst has been recognized as one of most efficient activators for peroxymonosulfate (PMS) decomposition, but usually suffers from the poor stability and difficulty to recover and reuse. Here easily recyclable cobalt oxide (Co3O4) nanowires and nanoflowers grown on nickel foam (NF) are fabricated by a hydrothermal and calcination method. The prepared 3D Co3O4/NF catalyst is characterized and applied as a heterogeneous catalyst for PMS activation to generate sulfate radicals for decomposition of Acid Orange 7 (AO7). The results show that the AO7 degradation rate increases with cobalt loading and PMS dosage, but decreases with the increase of solution pH. The Co3O4/NF catalyst using 2 mM Co(NO3)2·6H2O as cobalt source exhibits highest activity, and almost complete decolorization could be achieved within 30 min. The diverse effects of coexisting anions (SO42-, HCO3-, NO3- and Cl-) on AO7 degradation are observed and explained. After 10 consecutive runs, excellent catalytic reactivity of the catalyst remains while the level of leached cobalt during the catalyst usage is much lower than the maximum allowable concentration in drinking and natural water. More importantly, the macroscopic Co3O4/NF catalyst shows advantage of easy recycling after application compared to traditional catalysts. It is believed that the as-prepared Co3O4/NF is promising to be an effective and green heterogeneous catalyst for PMS activation to degrade organic pollutants for environmental application.

The Identification of Aluminum in Human Brain Tissue Using Lumogallion and Fluorescence Microscopy.

Aluminum in human brain tissue is implicated in the etiologies of neurodegenerative diseases including Alzheimer's disease. While methods for the accurate and precise measurement of aluminum in human brain tissue are widely acknowledged, the same cannot be said for the visualization of aluminum. Herein we have used transversely-heated graphite furnace atomic absorption spectrometry to measure aluminum in the brain of a donor with Alzheimer's disease, and we have developed and validated fluorescence microscopy and the fluor lumogallion to show the presence of aluminum in the same tissue. Aluminum is observed as characteristic orange fluorescence that is neither reproduced by other metals nor explained by autofluorescence. This new and relatively simple method to visualize aluminum in human brain tissue should enable more rigorous testing of the aluminum hypothesis of Alzheimer's disease (and other neurological conditions) in the future.

Toxicity removal assessments related to degradation pathways of azo dyes: Toward an optimization of Electro-Fenton treatment.

The degradation pathway of Acid Orange 7 (AO7) by Electro-Fenton process using carbon felt cathode was investigated via HPLC-UV and LC-MS, IC, TOC analysis and bioassays (Vibrio Fischeri 81.9% Microtox(®) screening tests). The TOC removal of AO7 reached 96.2% after 8 h treatment with the optimal applied current density at -8.3 mA cm(-2) and 0.2 mM catalyst concentration. The toxicity of treated solution increased rapidly to its highest value at the early stage of electrolysis (several minutes), corresponding to the formation of intermediate poisonous aromatic compounds such as 1,2-naphthaquinone (NAPQ) and 1,4-benzoquinone (BZQ). Then, the subsequent formation of aliphatic short-chain carboxylic acids like acetic acid, formic acid, before the complete mineralization, leaded to a non-toxic solution after 270 min for 500 mL of AO7 (1 mM). Moreover, a quantitative analysis of inorganic ions (i.e. ammonium, nitrate, sulfate) produced during the course of degradation could help to verify molar balance with regard to original nitrogen and sulfur elements. To conclude, a clear degradation pathway of AO7 was proposed, and could further be applied to other persistent pharmaceuticals in aquatic environment.

Iron in non-hydroxyl radical mediated photochemical processes for dye degradation: Catalyst or inhibitor?

The acetylacetone (AA) mediated photochemical process has been proven as an efficient approach for decoloration. For azo dyes, the UV/AA process was several to more than ten times more efficient than the UV/H2O2 process. Iron is one of the most common elements on the earth. It is well known that iron can improve the UV/H2O2 process through thermal Fenton and photo-Fenton reactions. What will be the role of iron in the UV/AA process? Could iron-AA complexes act as photocatalysts in environmental remediation? To answer these questions, the photo-degradation of an azo dye, Acid Orange 7 (AO7), was conducted under the variant combinations of AA with iron species in both ionic (Fe2+, Fe3+) and complex (Fe(AA)3) forms. The pseudo-first-order decoloration rate constants of AO7 in these photochemical processes followed such an order: UV/Fe(II)/AA

One-step enrichment and chemiluminescence detection of sodium dodecyl benzene sulfonate in river water using Mg-Al-carbonate layered double hydroxides.

In this work, Mg-Al CO3-layered double hydroxides (LDHs) were used as adsorbent materials for sodium dodecyl benzene sulfonate (SDBS) in aqueous solutions, the enriched SDBS can be directly detected by IO4(-)-H2O2 chemiluminescence (CL) system. The commonly existing cations cannot be enriched by Mg-Al CO3-LDHs due to the structurally positively charged layers of LDHs, while other adsorbed anionic interferents had no effect on the IO4(-)-H2O2 CL reaction. The corresponding linear regression equation was established in the range of 0.1-10 µM for SDBS. The detection limit at a signal-to-noise (S/N) ratio of 3 for SDBS was 0.08 µM. The relative standard deviation (RSD) for nine repeated measurements of 0.5 µM SDBS was 2.6%. This proposed method has been successfully applied to the determination of SDBS in river water samples. To the best of our knowledge, we have first time coupled the high enrichment capacity of LDHs towards anions with CL detection for analytes.

Investigation of spin-trapping artifacts formed by the Forrester-Hepburn mechanism.

Free radical detection with ESR spin trapping relies on the specific addition of the radical to nitrone/nitroso compounds. It also has been proposed that spin traps can react in biological systems to give false-positive results. For nitrone spin traps, the reaction with nucleophiles, first described by Forrester and Hepburn, has been discussed as the most critical source of artifacts. For artifact identification, the ESR preincubation method may be used, which employs isotopically marked spin traps. Here we investigated the influence of fast sulfite-hydroxylamine equilibrium chemistry on the validity of this assay. Using the (faster) aspiration technique, we found that the Forrester-Hepburn mechanism also contributes to DMPO/(•)SO3(-) adduct formation during ferricyanide-mediated sulfite oxidation, but no evidence for artifactual DMPO/(•)SO3(-) formation was found if the more potent horseradish peroxidase was used. This is ESR evidence that the Forrester-Hepburn mechanism can occur under mild conditions, depending on the experimental details. This technique can also be used to test for other artifact mechanisms. We investigated the known ene reaction of DBNBS and tryptophan in more detail. We found that a strong artifact signal is induced by light; however, with atypically long incubations, we found that the artifact is also formed thermally.

Low-cost gas sensors produced by the graphite line-patterning technique applied to monitoring banana ripeness.

A low-cost sensor array system for banana ripeness monitoring is presented. The sensors are constructed by employing a graphite line-patterning technique (LPT) to print interdigitated graphite electrodes on tracing paper and then coating the printed area with a thin film of polyaniline (PANI) by in-situ polymerization as the gas-sensitive layer. The PANI layers were used for the detection of volatile organic compounds (VOCs), including ethylene, emitted during ripening. The influence of the various acid dopants, hydrochloric acid (HCl), methanesulfonic acid (MSA), p-toluenesulfonic acid (TSA) and camphorsulfonic acid (CSA), on the electrical properties of the thin film of PANI adsorbed on the electrodes was also studied. The extent of doping of the films was investigated by UV-Vis absorption spectroscopy and tests showed that the type of dopant plays an important role in the performance of these low-cost sensors. The array of three sensors, without the PANI-HCl sensor, was able to produce a distinct pattern of signals, taken as a signature (fingerprint) that can be used to characterize bananas ripeness.

A rapid and reversible colorimetric assay for the characterization of aminated solid surfaces.

The covalent immobilization of synthetic or natural macromolecular compounds containing amino groups onto polystyrene (PS) solid surfaces is of great interest in diagnostic applications. A sensitive assay allowing the determination of reactive end groups is therefore a powerful tool for predicting the performance of the active surface. Recently, we reported the use of the Coomassie brilliant blue (CBB) colorimetric reagent to quantify protonated groups (N(+)) in linear and dendritic structures in solution (Coussot et al., Polym Int 58(5):511-518, 2009). In this work, a simple method using CBB dye for the characterization of PS aminated solid surfaces is developed. The proposed amino density estimation by colorimetric assay (ADECA) method is based on the reversible complexation of the dye with the N(+) groups on solid surfaces. The assay measures the released dye thanks to the use of a unique sodium carbonate-methanol buffer. Thereby, for the first time, the same surface can be used for characterization and for further coupling applications. A surface density of four N(+) groups per square nanometer can be measured in PS microwell format, the whole characterization being done within 30 min. Performances of this new colorimetric-based method are detailed. The ADECA method is further demonstrated to be useful for the characterization of aminated polypropylene and glass materials with various sizes and shapes.

The determination of the linear alkylbenzene sulfonate isomers in water samples by gas-chromatography/mass spectrometry.

A number of 20 compounds of linear alkylbenzene sulfonates (LASs) family were identified by electron impact mass spectrometry (EI-MS) in water samples collected from wastewater treatment plants (WWTP). This paper presents the mass spectra of 20 compounds, the proposed mechanism of formation of the diagnostic ions obtained by EI-MS and the distribution of individual isomers in water samples collected from compartments of WWTP. The individual isomers from four homolog series C(10)-, C(11)-, C(12)- and C(13)-LAS were analyzed as methyl derivatives.

Cadmium transport mediated by soil colloid and dissolved organic matter: a field study.

This study investigated the potential role of soil colloids and dissolved organic matter (DOM) in transporting Cd through in situ undisturbed paddy soil monoliths. Brilliant Blue was used as a tracer to assess the effect of preferential flow on Cd down migration. Experimental results showed that deep penetration of Cd and Brilliant Blue into the soil profile took place due to the preferential flow through macropores, mainly earthworm channels, with much of chemicals thus bypassing the soil matrix. Dye tracer and Cd distribution within the soil matrix was fairly restricted to several centimeters. Colloid restrained the migration of both dye and Cd in the matrix and preferential flow area. DOM facilitated the transport of Cd and Brilliant Blue in matrix and macropores by about 10 cm over that of the control. Pearson's is correlation analysis revealed strong associations between Brilliant Blue concentrations, exchangeable Cd and total Cd concentrations in three studied plots indicating that they had taken the same preferential flow pathway.

Lack of association between excretion of sorafenib in sweat and hand-foot skin reaction.

STUDY OBJECTIVE: To determine if excretion of sorafenib in sweat is associated with hand-foot skin reaction in patients receiving sorafenib. DESIGN: Prospective pilot study. SETTING: Outpatient clinic of a cancer research institution. PATIENTS: Two patients who were receiving sorafenib and developed a hand-foot skin reaction of at least grade 1 and two healthy subjects (controls). INTERVENTION: Sweat production was stimulated in both the patients with hand-foot skin reaction and the healthy subjects by means of pilocarpine iontophoresis. MEASUREMENTS AND MAIN RESULTS: Sweat samples were collected from the patients with hand-foot skin reaction and from the healthy subjects. Using liquid chromatography-tandem mass spectrometry, sorafenib concentrations were measured in the sweat samples. Sweat samples from the healthy subjects were spiked with known concentrations of sorafenib to determine the lower limit of quantification of the assay, which was determined to be 5 ng/ml. Sorafenib concentrations in the samples from the patients with hand-foot skin reaction were undetectable based on the assay's sensitivity. CONCLUSION: Our results suggest that hand-foot skin reaction in patients receiving sorafenib is not associated with excretion of sorafenib in sweat. Further studies are needed to understand the mechanism of hand-foot skin reaction, a treatment-limiting adverse effect of multikinase inhibitors.

Liquid chromatography-tandem mass spectrometric assay for sorafenib and sorafenib-glucuronide in mouse plasma and liver homogenate and identification of the glucuronide metabolite.

The first bioanalytical assay for the simultaneous determination of sorafenib and sorafenib-glucuronide in mouse plasma and liver homogenate was developed and validated. In addition, the structure of the glucuronide metabolite was elucidated. The quantitative assay started with addition of isotopically labeled internal standards to a 20 microl sample volume and protein precipitation with acetonitrile, the supernatant was diluted with water and injected into the chromatographic system. A polar embedded reversed-phase column with gradient elution using formic acid in water-acetonitrile was used. The eluate was transferred into an electrospray interface with positive ionization and the analytes were detected and quantified using triple quadrupole mass spectrometry. The assay was validated in the ranges 10-5000 ng/ml for sorafenib and 1-500 ng/ml for sorafenib-glucuronide, the lowest levels of these ranges (10 and 1 ng/ml) being the lower limits of quantification (LLQ). Within day precisions were 2-8%, between day precisions 2-10% (both excluded the LLQ level of the glucuronide) and accuracies were between 89% and 106%. Both analytes were chemically stable under all relevant conditions. The assay was successfully applied in pilot in vivo pharmacokinetic studies with sorafenib in mice.

Direct, sensitive determination of trace amounts of dissolved ferric iron in natural water by light absorption ratio variation spectrometry.

The chromophore eriochrome cyanine R (ECR) was used to sensitively coordinate Al(II) and Fe(II) in the presence of cetylpyridinium chloride (CPC) at pH 4.8. Trace amounts of Fe(III) can displace Al(III) from the Al(ECR)(CPC) ternary complex to form the Fe(ECR)(CPC) complex. The composition of the complexes was determined by the break point approach. The competitive displacement complexation was sensitive and highly selective, even if no masking reagent was added. An ongoing novel spectrophotometry, named the light-absorption ratio variation approach, was applied to the direct determination of Fe(III) in natural water with recovery between 92.5 and 106%. The detection limit was only 9 ng/mL Fe(III).

Monitoring and toxicity of sulfonated derivatives of benzene and naphthalene in municipal sewage treatment plants.

Monitoring benzenesulfonates (BS) and naphthalenesulfonates (NS) took place in five municipal sewage treatment plants (STP). A previously optimized method based on solid phase extraction with polymeric cartridges followed by ion-pair liquid chromatography-electrospray-mass spectrometry (SPE-IPC-ESI-MS) was used. This work confirmed the little or no effect of primary settlement on total organic carbon (TOC) and monosulfonated compounds removal, whereas the main reduction is obtained at the biological stage. However, the most polar compounds, such as naphthalenedisulfonates (NDS), were not effectively removed using the biological treatment. An aromatic sulfonated compound is suggested to be used as a tracer of the origin of industrial pollutants discharged into STPs. A bioluminescence inhibition test, Microtox assay, allowed toxicity determination of the most relevant aromatic sulfonated compounds detected and toxicity comparison between primary and secondary effluents.

Treatment of orange II azo-dye by electrocoagulation (EC) technique in a continuous flow cell using sacrificial iron electrodes.

This paper describes the EC treatment of orange II dye solution in a flow cell using sodium chloride as an internal electrolyte. In this technique dye solutions were passed through a flow-through EC apparatus consisting of a flow-through cell, the electrode assembly, the feed pump and the DC power supply unit. The cell contained five parallel iron electrodes, which form four parallel cells. Experiments were run at 25 degrees C under various electrolyte concentrations, dye concentrations, current density, flow rate of the solution, and pH at dc current range of 2-5A. Various number of recycles of the treated dye solution were also performed at the same dc current range. Optimum conditions to get high removal efficiency were experimentally determined. It was found that 98.5% of the dye was removed from the solution under the optimum conditions. The residue from a blank run (pH = 7.3) and a dye added run (pH = 8.5) were collected by vacuum filtration and analyzed by XRD after drying in a vacuum desiccator. The XRD data indicated the presence of mainly maghemite (gamma-Fe2O3) and magnetite (Fe3O4) in the residue. However, there is not much difference between the X-ray diffractograms of the blank sample and the dye-containing residue to warrant any conclusions therefrom with regard to the interactions between the oxides and the dye molecules.

Stability study and determination of benzene- and naphthalenesulfonates following an on-line solid-phase extraction method using the new programmable field extraction system.

Seven benzene- and naphthalenesulfonates (3-nitrobenzenesulfonate, 4-methylbenzenesulfonate, 1-hydroxy-4-naphthalenesulfonate, 1-amino-7-naphthalenesulfonate, 4-chlorobenzenesulfonate, 1-naphthalenesulfonate and 2-naphthalenesulfonate) were studied. A rapid method for quantifying aromatic sulfonated compounds from waste water samples was developed. This method consists in on-line in-field sampling and monitoring based on ion-pair solid-phase extraction with PLRP-S sorbent, using the new programmable field extraction system and ion-pair liquid chromatography with UV diode-array and electrospray mass spectrometry. Limits of detection for the studied compounds, using the SIM acquisition mode, ranged from 0.01 to 0.33 ng ml(-1). The influence of the aqueous matrix on the on-line SPE was checked by spiking ground and waste waters. Recoveries varied from 70 to 99% when 10 ml of water sample were enriched. The method was applied to the analysis of some environmental sewage samples. This study confirmed that high concentration levels of aromatic sulfonated compounds can be found in sewage samples. In addition, the stability of the seven studied sulfonated benzene and naphthalene compounds was investigated using on-line polymeric SPE pre-columns, based on the styrene-divinylbenzene polymer PLRP-S. Different storage conditions were tested to carry out the stability survey, which included storage at room temperature, at 4 degrees C and at -20 degrees C, during a period of up to 2 weeks. This study showed that the stability of aromatic sulfonic acids on disposable on-line SPE polymeric pre-columns is related to temperature and that the target compounds are more stable at lower temperatures.