Korrosion in Carbonsäuren. Teil I: Anwendung von Radionuklidtechnik und Impedanzspektrometrie auf Korrosionsuntersuchungen metallischer Werkstoffe

Corrosion in Carboxylic Acids – Part I: The Application of Radionuclide Techniques and impedance Spectrometry in Corrosion Studies of Metallic Materials Within the ?Corrosion and Protection”? research and development program, studies have been conducted on the corrosion of metals in low carboxylic acids. A radionuclide method has been employed to measure corrosive abrasion, and the technique of impedance spectrometry has been used to trace the electrochemical corrosion reactions. In this first communication, these methods of measurement are described and their uses and the kinds of information to be obtained from them are discussed. The corrosion systems studied, i.e., some high-alloy steel grades and nickel base alloys in formic acid and acetic acid with a number of additives, are indicated.     

A system for the direct determination of the nonvolatile organic carbon,dissolved organic carbon,and inorganic carbon in water samples through inductively coupled plasma atomic emission spectrometry

A new system has been developed for the determination of total organic carbon (TOC) and inorganic carbon (IC) or total inorganic carbon (TIC) in waters. Only nonvolatile organic compounds can be detected through the present method. The system presented in this work is based on the measurement of the carbon atomic emission intensity in inductively coupled plasma atomic emission spectrometry (ICP-AES). This way, the organic matter does not undergo any preoxidation step. A semiautomatic accessory connected to the spectrometer separates the different carbon fractions (i.e., organic and inorganic). Because most of the solutions used in the present work did not contain suspended solid particles, the actual parameter that was determined was the dissolved organic carbon (DOC). The present system exhibits good sensitivities compared to those provided by conventional TOC and IC determination methods. The limits of detection obtained in the present work have been 0.07 and 0.0007 mg/L C in terms of TOC and IC, respectively. Furthermore, the system is able to handle high-salt-content solutions. This fact suggests that it would be possible to analyze seawater samples, avoiding some of the problems encountered with conventional methods, such as system blocking or interferences. The TOC and IC values found for natural samples are very close to those measured using conventional methods. The ICP-AES method has been successfully used in two interesting applications: (i) monitoring the efficiency of a water treatment plant and (ii) determining the contents of dissolved carbon dioxide, on one hand, and that of carbonate and bicarbonate, on the other, in the same sample.     

Heterogeneous catalytic wet air oxidation of refractory organic pollutants in industrial wastewaters: a review

Catalytic wet air oxidation (CWAO) is one of the most economical and environmental-friendly advanced oxidation process. It makes a promising technology for the treatment of refractory organic pollutants in industrial wastewaters. Various heterogeneous catalysts including noble metals and metal oxides have been extensively studied to enhance the efficiency of CWAO. The present review is concerned about the literatures published in this regard. Phenolics, carboxylic acids, and nitrogen-containing compounds were taken as model pollutants in most cases, and noble metals such as Ru, Rh, Pd, Ir, and Pt as well as oxides of Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, and Ce were applied as heterogeneous catalysts. Reports on their characterization and catalytic performances for the CWAO of aqueous pollutants are reviewed. Discussions are also made on the reaction mechanisms and kinetics proposed for heterogeneous CWAO and also on the typical catalyst deactivations in heterogeneous CWAO, i.e. carbonaceous deposits and metal leaching.     

Vapor generation by UV irradiation for sample introduction with atomic spectrometry

Volatile species of the conventional hydride-forming elements (As, Bi, Sb, Se, Sn, Pb, Cd, Te), Hg, transition metals (Ni, Co, Cu, Fe), noble metals (Ag, Au, Rh, Pd, Pt), and nonmetals (I, S) were generated following UV irradiation of their aqueous solutions to which low molecular weight carboxylic acids (formic, acetic, propionic) had been added. Free radicals arising from photodissociation of the latter provide a new and useful alternative to the common methods of chemical/electrochemical vapor generation techniques for the determination of these analytes by atomic spectrometry. Quantitative estimates of the efficiencies of these generation processes were not undertaken, although calculated signal-to-background ratios (>1500 for 5 ng/mL As, Sb, Bi, Se, and Te; 20 for 10 ng/mL Sn, Cu, Rh, Au, Pd, Pt, and Cd; 2400 for 1 ng/mL Hg; and 1000 for Co using ICP-TOF-MS detection) do provide clear evidence of the efficacy of this approach for sample introduction. In the case of Ni and Se, the tetracarbonyl and alkylated selenium compounds have been identified, respectively.     

Water-induced coacervation of alkyl carboxylic acid reverse micelles: phenomenon description and potential for the extraction of organic compounds

Coacervates made up of alkanoic (C8-C16) and alkenoic (C18) acid reverse micelles were described for the first time, and their potential for the extraction of organic compounds prior to liquid chromatography was examined. The coacervation process occurred in miscible binary mixtures of water and a variety of protic and aprotic solvents. The phase behavior of alkyl carboxylic acids was found to be a function of both the Hildebrand solubility parameter, delta, and the hydrogen-bonding capability of the solvent. The best solvents for analytical extractions were those featuring the lowest delta values. The phase behavior of alkyl carboxylic acid/water/tetrahydrofuran (THF) ternary systems as a function of component concentration, pH, ionic strength, and temperature was investigated. The efficiency and the time required for phase separation depended on the experimental procedure used (i.e., standing, centrifugation, stirring, and sonication). The formation of alkyl carboxylic acid reverse micelles in THF was proven using both hydrophilic fluorescent probes and scattered light measurements. The structure of the coacervates consisted of spherical droplets dispersed in a continuous phase. Phase volume ratios were a function of both alkyl carboxylic acid and THF concentration. The low volume obtained (e.g., 1.5 microL per mg of decanoic) compared to that obtained by other coacervates (e.g., 5.1 microL per mg of dodecane sulfonic acid and 11.3 microL per mg of Triton X-114) greatly improved the concentration factors reached by coacervation-based extractions. Parameters affecting the extraction efficiency were assessed. Analytes in a wide range of polarity were efficiently extracted on the basis of the hydrophobic (e.g., PAHs) and hydrogen bond (e.g., chlorophenols, bisphenols, pesticides, phthalates, nonionic surfactants, dyes, and photographic developers) interactions that reverse micelles can establish. The coacervates were compatible with the chromatographic determination of analytes following UV or MS detection. They were successfully applied to the extraction of alkylphenol ethoxylates (octyl and nonyl) and alcohol ethoxylates (C12-C16) from influent and effluent wastewater and river water samples. Nonionic surfactants in the coacervate were directly separated and quantified by liquid chromatography-ion trap mass spectrometry. Concentration factors were around 160. The recovery of nonionics in the environmental water samples ranged from 90 to 104%.     

Powering up the Future: Radical Polymers for Battery Applications

Our society's dependency on portable electric energy, i.e., rechargeable batteries, which permit power consumption at any place and in any time, will eventually culminate in resource wars on limited commodities like lithium, cobalt, and rare earth metals. The substitution of conventional metals as means of electric charge storage by organic and polymeric materials, which may ultimately be derived from renewable resources, appears to be the only feasible way out. In this context, the novel class of organic radical batteries (ORBs) excelling in rate capability (i.e., charging speed) and cycling stability (>1000 cycles) sets new standards in battery research. This review examines stable nitroxide radical bearing polymers, their processing to battery systems, and their promising performance.     

Tetrabutylammonium-induced coacervation in vesicular solutions of alkyl carboxylic acids for the extraction of organic compounds

The potential of the tetrabutylammonium-induced liquid-liquid-phase separation in alkyl carboxylic acid vesicular solutions for the extraction of organic compounds prior to liquid chromatography was examined for the first time. The behavior of the coacervates yielded from octanoic to oleic acids as a function of the pH and salts was investigated. The time required for phase separation depended on the length of the carboxylic acid alkyl chain and the experimental procedure (i.e., standing, sonication, centrifugation, stirring, etc.). Theoretical preconcentration factors were a function of both surfactant concentration and the length of the alkyl chain, and they greatly surpassed those obtained with other surfactant-mediated separations (e.g., surfactant-rich phases from dodecanesulfonic acid or Triton X-114). Parameters affecting the extraction efficiency were assessed. Analytes in a wide polarity/charge range, (e.g., PAHs, surfactants, chlorophenols, bisphenols, phthalates, herbicides, amines, dyes, and photographic developers) were extracted with high efficiencies on the basis of the different types of interactions that the vesicular coacervates can establish (i.e., hydrophobic and ionic interactions, hydrogen bonds, and formation of mixed aggregates). The coacervates were compatible with the chromatographic determination of analytes following UV or MS detection. Their suitability for working under real conditions was checked by applying them to the extraction of nonionic surfactants [alkylphenol ethoxylates (octyl and nonyl) and alcohol ethoxylates (C12-C16)] from raw and treated sewage and to river water samples. Analytes in the coacervate were separated and quantified by liquid chromatography-ion trap mass spectrometry. No cleanup steps were necessary. Recoveries of the target compounds in the environmental water samples ranged from 89 to 103%.     

Low-molecular-weight carboxylic acids produced from hydrothermal treatment of organic wastes

This article reports production of low-molecular-weight carboxylic acids from the hydrothermal treatment of representative organic wastes and compounds (i.e. domestic sludge, proteinaceous, cellulosic and plastic wastes) with or without oxidant (H(2)O(2)). Organic acids such as acetic, formic, propionic, succinic and lactic acids were obtained in significant amounts. At 623 K (16.5 MPa), acetic acid of about 26 mg/g dry waste fish entrails was obtained. This increased to 42 mg/g dry waste fish entrails in the presence of H(2)O(2). Experiments on glucose to represent cellulosic wastes were also carried out, getting acetic acid of about 29 mg/g glucose. The study was extended to terephthalic acid and glyceraldehyde, reaction intermediates of hydrothermal treatment of polyethylene terephthalate (PET) plastic wastes and glucose, respectively. In addition, production of lactic acid, one of the interesting low-molecular-weight carboxylic acids, was discussed on the viewpoint of resources recovery.Studies on temperature dependence of formation of organic acids showed thermal stability of acetic acid, whereas, formic acid decomposed readily under hydrothermal conditions. In general, results demonstrated that the presence of oxidants favored formation of organic acids with acetic acid being the major product.     

Ion-pair RP-HPLC determination of sugars, amino sugars, and uronic acids after derivatization with p-aminobenzoic acid

A new, selective, and sensitive ion-pair RP-HPLC method for the simultaneous determination of three classes of natural organic compounds, i.e., carbohydrates, amino sugars, and uronic acids, in environmental samples is presented. p-Aminobenzoic acid is used for precolumn derivatization of the analytes, enabling fluorescence (lambda(ex) 313 nm, lambda(em) 358 nm) or photometric detection (303 nm). The dependence of the derivatization yield on the reaction conditions is examined. Derivatives of lactose, galactose, glucose, mannose, xylose, arabinose, galacturonic acid, glucuronic acid, N-acetylglucosamine, and glycerinealdehyde were separated on a RP-C18 column with hydrophilic end capping within 35 min, applying TBAHSO4 as the ion-pair reagent. The concentration detection limits range between 20 and 30 microg L(-1) ((1-2) x 10(-7) M) for fluorescence detection and between 30 and 75 microg L(-1) for UV detection. A good linearity is achieved in the concentration range from 50 microg L(-1) to 100 mg L(-1) (r2 > 0.99). The described method has been applied for the determination of mono-/disaccharides, uronic acids, and amino sugars in soil solutions and in landfill leachates.     

Hazardous organic compounds in urban municipal solid waste from a developing country

Fresh and partially decomposed municipal solid waste (MSW) collected from three places in Chennai city, viz., a residential collection point and two dumping grounds (Kodungaiyur and Perungudi) were screened for hazardous organic pollutants. Toxicity Characteristics Leaching Procedure (TCLP) using a Zero Headspace Extractor (ZHE) followed by further extraction by solvent separation using n-hexane containing 15% di-ethyl ether was performed and the organic extract obtained was qualitatively screened by GC-MS. 28 different types of higher alkanes and their derivatives, 7 types of C6-C8 fatty acids and their esters, 7 different phenolic compounds including alkylated phenols and degradation products and 5 phthalate compounds occurred in a majority of the analysed samples. 17 other organic compounds such as carboxylic acids, chloroform, phosphate, pharmaceutical chemicals etc. were also detected. Among these compounds, phenolics and phthalates are highly hazardous in nature and occurred in relatively higher concentrations. Hazardous compounds like p-cresol, di-butyl, mono butyl and di-ethyl pthalates were found in concentrations more than 200mg/kg in MSW.     

The Concept of “Noble,Heteroatom‐Doped Carbons,” Their Directed Synthesis by Electronic Band Control of Carbonization,and Applications in Catalysis and Energy Materials

Carbonization of organic compounds with a highest occupied molecular orbital (HOMO) level more positive than 1.3 V practically automatically results in highly sp²‐conjugated, heteroatom‐doped carbons. Due to the stability of the starting compounds, carbon bond formation is restricted to result in morphologies with a surprisingly high local order which as such are noble, i.e., they are hard to oxidize and combust. The work function of electrons in these systems is so positive that the systems usually accept electrons, i.e., they oxidize other matter rather than being oxidized. Such noble, heteroatom‐doped carbons have been proven to be efficient, metal‐free electrocatalysts, but can be also beneficially used in the manufacturing of carbon nanomaterials for energy applications or as highly active, non‐innocent catalytic supports.     

Comparison of annular diffusion denuder and high volume air samplers for measuring per- and polyfluoroalkyl substances in the atmosphere

Overestimation of the particle phase concentration collected on glass-fiber filters (GFFs) has been reported for perfluoroalkyl carboxylic acids (PFCAs) using conventional high volume air samplers. In this study, per- and polyfluoroalkyl substances (PFASs) were determined in the gas and particulate phases using colocated annular diffusion denuder and high volume air samplers at a semiurban site in Toronto, Canada, in winter 2010. Samples were analyzed for 7 PFAS classes (i.e., PFCAs, perfluoro-alkane sulfonic acids (PFSAs), fluorotelomer alcohols (FTOHs), fluorotelomer methacrylates (FTMACs), fluorotelomer acrylates (FTACs), perfluorooctane sulfonamides (FOSAs), and perfluorooctane sulfonamidoethanols (FOSEs)). The gas diffusion coefficients for individual PFASs were calculated and the denuder performance was evaluated. Modeled subcooled liquid vapor pressures (p(L)) correlated well with the vapor phase breakthrough for the denuder and high volume air systems. Total air concentrations for PFASs measured using annular diffusion denuders and high volume samplers were in agreement within a factor of 4; however, much greater differences were observed for measurements of gas-particle partitioning. Vapor phase PFSAs and PFCAs can adsorb to the GFF using high volume air samplers, resulting in much higher particle-associated fractions for these chemicals compared to the annular diffusion denuder sampler. This effect was not observed for the FTOHs, FTMACs, FTACs, FOSAs, and FOSEs. Thus, for investigations of gas-particle partitioning of PFSAs and PFCAs, the diffusion denuder sampler is the preferred method. The results of this study improve our understanding of the gas-particle partitioning of PFASs, which is important for modeling their long-range transport in air.     

Analysis of a GC/MS thermal desorption system with simultaneous sniffing for determination of off-odor compounds and VOCs in fumes formed during extrusion coating of low-density polyethylene

A thermal desorption equipment introducing volatile organic compounds (VOCs) into the gas chromatographic/ mass spectrometric system (GC/MS) with simultaneous sniffing (SNIFF) is a suitable method for identifying the volatile organic off-odor compounds formed during the extrusion coating process of low-density polyethylene. Fumes emitted during the extrusion coating process of three different plastic materials were collected at two different temperatures (285 and 315 degrees C) from an outgoing pipe and near an extruder. The VOCs of fumes were analyzed by drawing a known volume of air through the adsorbent tube filled with a solid adsorbent (Tenax GR). The air samples were analyzed by using a special thermal desorption device and GC/MS determination. The simultaneous sniffing was carried out to detect off-odors and to assist in the identification of those compounds that contribute to tainting and smelling. The amounts of off-odor carbonyl compounds and the total content of the volatile organic compounds were determined. The most odorous compounds were identified as carboxylic acids while the majority of the volatile compounds were hydrocarbons. The detection and quantification of carboxylic acids were based on the characteristic ions of their mass spectra. The higher the extrusion temperature the more odors were detected. An important observation was that the total concentration of volatiles was dependent not only on the extrusion temperature but also on the plastic material.     

A fluorogenic reagent, 4-mercapto-7-methylthio-2,1,3-benzoxadiazole for carboxylic acids, designed by prediction of the fluorescence intensity

During the course of our studies of the development of fluorogenic reagents having a 4,7-disubstituted benzofurazan structure, we previously proposed 7-acetylamino-4-mercapto-2,1,3-benzoxadiazole (AABD-SH) as a fluorogenic reagent for carboxylic acids. Since then, progress has made it possible to estimate the fluorescence quantum yields of the 4,7-disubstituted benzofurazan compounds on the basis of the PM3 calculation of their S1-T2 energies. Subsequently, a new fluorogenic reagent, 4-mercapto-7-methylthio-2,1,3-benzoxadiazole (MTBDSH) was designed and synthesized. In the presence of condensation reagents, triphenylphosphine (TPP) and 2,2'-dipyridyl disulfide (DPDS), MTBD-SH readily reacted with n-caprylic acid within 1 min at room temperature. The derivatives of five carboxylic acids (n-caprylic acid, n-capric acid, lauric acid, myristic acid, and palmitic acid) were well-separated on a reversed-phase column and were fluorimetrically detected at 519 nm with excitation at 391 nm. The detection limits (S/N = 3) were 2.4-5.0 fmol. Thus, MTBD-SH had properties that were considered to be superior. For carboxylic acids, itwas superior not only to AABD-SH, but also to many other conventional reagents. The superiority was examined in terms of its reactivity and sensitivity and the avoidance of interfering peaks that were derived from the reagent itself or degradation products in the chromatogram.     

Dependence of kinetic variables in the short-term release of Hg<Superscript>2+</Superscript>, Cu<Superscript>2+</Superscript> and Zn<Superscript>2+ </Superscript>ions into synthetic saliva from an high-copper dental amalgam

The short term (up to 14 days after restoration) release of selected ions (i.e., Hg(2+), Cu(2+) and Zn(2+)) from Dispersalloy into artificial saliva has been evaluated in regards to the nature of the saliva (Fusayama and McCarty and Shklar's solutions), the amount of amalgam, the time of contact and the periodical renewal (every 48 h interval) of artificial saliva. The evaluation of the ionic fraction of such metals has been accomplished by using anodic stripping methods (i.e., Differential Pulse Anodic Stripping Voltammetry, DPASV) with a 7 microm graphite disk microelectrode as a working electrode. Data obtained in this work are almost unprecedented in the literature due the fact that such analytical method exclude metals in non-ionic forms (e.g., metals or organometallic compounds). The high concentrations measured in every experimental condition confirm the concern for the short-term release of metals from amalgam into saliva.     

An optoelectronic nose: "seeing" smells by means of colorimetric sensor arrays

A new approach to general sensors for odors and volatile organic compounds (VOCs) using thin films of chemically responsive dyes as a colorimetric sensor array is described. This optoelectronic "nose," by using an array of multiple dyes whose colors change based on the full range of intermolecular interactions, provides enormous discriminatory power among odorants in a simple device that can be easily digitally imaged. High sensitivities (ppb) have been demonstrated for the detection of biologically important analytes such as amines, carboxylic acids, and thiols. By the proper choice of dyes and substrate, the array can be made essentially nonresponsive to changes in humidity.     

Identification of weak and strong organic acids in atmospheric aerosols by capillary electrophoresis/mass spectrometry and ultra-high-resolution fourier transform ion cyclotron resonance mass spectrometry

A novel approach using a combination of capillary electrophoresis/mass spectrometry (CE/MS) and off-line Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) revealed the structural details of acidic constituents of atmospheric organic aerosol. Both techniques utilized electrospray ionization (ESI), a soft ionization method, to facilitate the analysis of complex mixtures of organic compounds. CE/ESI-MS using an UltraTrol LN-precoated capillary and acidic background electrolytes at different pH values (2.5 and 4.7) was used to differentiate between weak (carboxylic) and strong (sulfonic) organic acids. On the basis of the electrophoretic mobility, m/z constraints from CE/ESI(-)-MS, and elemental composition information retrieved from off-line FTICR-MS, a variety of aliphatic and aromatic carboxylic acids (CHO-bearing molecules), nitrogen-containing carboxylic acids (CHON-bearing molecules), organosulfates (CHOS-bearing molecules), and (nitrooxy)organosulfates (CHONS-bearing molecules) were tentatively identified in the Oasis-HLB-extracted urban PM(2.5) (particulate matter with an aerodynamic diameter of <2.5 μm). The chemical known/unknown structures of detected compounds were confirmed by the semiempirical Offord model (effective mobility linearly correlated to Z/M(2/3)). The majorities of the identified compounds are products of atmospheric reactions and are known contributors to secondary organic aerosols.     

Flexural strength of ice grown from chemically impure melts

A series of experiments have been performed to measure the ultimate (flexural) strength of ice grown from impure melts containing one of a number of chemical dopants (chloride and sulfate salts, salts of the carboxylic acids, alcohols, amides and sugars). The results of these experiments indicate: (1) within a homologous series, the greatest strength reduction in the ice usually occurs for the lowest member of the series; (2) the overall reduction in strength of the ice to a limiting value is greater for the lower molecular weight dopants; and (3) of the chemical families tested, the most effective ice-strength reducing ones were the R-OH alcohols, the salts of the carboxylic acids and the amides. These results are discussed in terms of the structural features of the ice. An empirical relationship is presented for electrolytic dopants which predicts the optimum concentration of dopant necessary for reducing the strength of ice.     

Electrogenerated chemiluminescence derivatization reagent, 3-isobutyl-9,10-dimethoxy-1,3,4,6,7,11b-hexahydro-2H-pyrido[2,1-a]isoquinolin-2-ylamine,for carboxylic acid in high-performance liquid chromatography using tris(2,2'-bipyridine)ruthenium(II)

3-Isobutyl-9,10-dimethoxy-1,3,4,6,7,11b-hexahydro-2H-pyrido[2,1-a]isoquinolin-2-ylamine (IDHPIA) was found to be a selective and highly sensitive derivatization reagent for carboxylic acid by high-performance liquid chromatography (HPLC) with electrogenerated chemiluminescence detection using tris(2,2'-bipyridine)ruthenium(II). Free fatty acids and phenylbutylic acid were used as model compounds of carboxylic acids, and the derivatization conditions were optimized with myristic acid. Under the mild reaction conditions of room temperature for 45 min in acetonitrile containing 2-bromo-1-ethylpyridinium tetrafluoroborate and 9-methyl-3,4-dihydro-2H-pyridol1,2-a]pyrimidin-2-one, all the fatty acids tested were reacted with IDHPIA to produce highly sensitive derivatives. The chemiluminescence intensity was essentially the same for all fatty acids. The derivatives obtained from 10 free fatty acids were completely separated by reversed-phase chromatography under isocratic elution conditions. The on-column detection limit (signal-to-noise ratio of 3) with proposed HPLC separation and chemiluminescence detection was 0.5 and 0.6 fmol for myristic acid and phenylbutylic acid, respectively. IDHPIA was 100-fold more sensitive than previously developed reagents (Morita, H.; Konishi, M. AnaL Chem. 2002, 74, 1584-1589). The free fatty acids in human serum were successfully determined using the present method.     

Identification of organic acids in secondary organic aerosol and the corresponding gas phase from chamber experiments

Organic acids in the gas and aerosol phase from photooxidation of 1,3,5-trimethylbenzene in the presence of 300 ppb propene and 300 ppb NOx in smog chamber experiments were determined using a wet effluent diffusion denuder/aerosol collector coupled to ion chromatography (IC) with conductivity detection. Behind the IC, the samples were collected using a fraction collector, for identification of unresolved/unidentified organic acids with IC-mass spectrometry (MS). In total, 20 organic acids were found with MS of which 10 were identified. The organic acids identified offline by IC-MS were then further quantified based on the online IC data. The identification was additionally confirmed with gas chromatography-mass spectrometry. At the maximum aerosol concentration, organic acids comprised 20-45% of the total aerosol mass. The method has a detection limit of 10-100 ng/m3 for the identified carboxylic acids.