Separation of inorganic anions by reversed-phase ion-pair chromatography with direct UV detection

In this paper, a separation method of the inorganic anions including I^–, NO ₂ ^– , NO ₃ ^– , IO ₃ ^– and SCN^– on the reversed-phase ion-pair chromatography with direct UV detection has been developed, and the limits of detection of these inorganic anions were determined. The effects of the organic modifier volume fraction and concentration of the ion-pair reagent on the retention of inorganic anions were discussed.     

Organic/inorganic nanocomposite polymer electrolyte

The organic/inorganic nanocomposites polymer electrolytes were designed and synthesized. The organic/inorganic nanocom-posites membrane materials and their lithium salt complexes have been found thermally stable below 200℃. The conductivity of the organic/inorganic nanocomposites polymer electrolytes prepared at room temperature was at magnitude range of 10-6 S/cm.     

Acrylation of polyvinylsilazane with allyl bromide for an UV photosensitive inorganic polymer

A novel inorganic polymer resin with high photosensitivity was prepared by grafting acrylate functional groups onto the backbone of polyvinylsilazane through a reaction with methyl-2-(bromo-methyl)acrylate via the highly efficient electrophilic substitution of allyl bromide. The as-modified polymer was characterized by ¹H NMR and 2D-¹H-¹H NMR (COSY) methods to determine the reaction mechanism. Differential photocalorimetry, FT-IR spectroscopy and TGA were used to examine its properties. The modified polyvinylsilazane is a promising inorganic polymer photoresist with a high UV sensitivity and a 55% ceramic yield, which is useful for fabricating non-oxide ceramic microstructures using mold free photocuring shaping processes.     

Interactions of ionic liquids with polysaccharides 9. Hydroxyalkylation of cellulose without additional inorganic bases

Water-soluble hydroxyalkyl cellulose with a molar degree of substitution of up to 2.79 was prepared under completely homogeneous reaction conditions in various ionic liquids without addition of inorganic bases. In acetate containing solvents the IL acts as a catalyst. The substitution patterns of the cellulose ethers were analyzed by ¹³C NMR spectroscopy, ¹H NMR spectroscopy after peracetylation and GLC/MS after permethylation and depolymerization. A diminished tendency towards the formation of side chains compared to heterogeneously prepared hydroxyalkyl celluloses in the presence of inorganic bases was found.     

Preconcentration of phenlymercury,methylmercury and inorganic mercury from natural waters with diethylammonium diethyldithiocarbamate-loaded polyurethane foam

The percentage extraction of organomercurials and inorganic mercury on polyurethane foam loaded with diethylammonium diethyldithiocarbamate is high over a wide pH range, particularly when a plasticizer is added to the foam. Flow rates up to 120 ml min^-1 give quantitative extraction of inorganic mercury. Mercury(II), methylmercury and phenylmercury ions at 1 μg l^-1 levels can be almost quantitatively preconcentrated from tap and saline water, and eluted from the foam with acetone.     

Unique carrier properties of neutral lanthanide complex for inorganic anions

Lipophilic lanthanide tris(fluorinated β-diketonates) exhibited interesting carrier properties for inorganic anions. Negative FABMS and ¹³C NMR studies revealed that they bound small Cl⁻ anion with a large hydration energy more strongly than large Br⁻ and I⁻ anions with small hydration energies. The direct anion coordination features of lanthanide complexes offered unique carrier properties for inorganic anions in liquid membrane transport.     

Determination of inorganic anions in human saliva by zwitterionic micellar capillary electrophoresis

Capillary electrophoresis (CE) using sulfobetaine-type zwitterionic micelles as the background electrolyte (BGE) has been used to determine inorganic anions in human saliva. The zwitterionic micelles resulted in unique migration behavior for the separation of inorganic anions. They also prevented adsorption of proteins on the inner wall of the capillary. These properties of the zwitterionic micelles enabled the direct determination of inorganic anions in human saliva. Three species of inorganic anions, NO₂ ^–, NO₃ ^–, and SCN^–, were found in real samples and the analysis was achieved within 3 min. Direct UV-absorption was used as the detection method and the detection limits for these anions were 2.0, 1.0, and 5.0 μmol L^–1, respectively (0.09, 0.06, and 0.30 μg mL^–1).     

Methylation of inorganic tin by decaying spartina alterniflora in estuarine water and by estuarine water

Methyltin compounds (MeSn) which do not originate from man–made pollution are common in estuaries and particularly in salt marshes containing the marsh grass Spartina alterniflora. This study reports the results of experiments in which estuarine water containing S. alterniflora leaves is spiked with inorganic tin, and estuarine water alone is spiked with inorganic tin and MeSn. When decaying leaves are present, inorganic tin concentrations in the water decrease and there is a 10-fold increase in inorganic tin concentration in the leaves. This biosorption follows pseudo–first–order kinetics. MeSn³⁺ and Me₂Sn²⁺ occur occasionally in the water. The Me₂Sn²⁺ concentration decreases with time and the Me₃Sn²⁺ concentration increases with time in S. alterniflora leaves. The results of estuarine water amended with inorganic tin and MeSn in the absence of leaves are quite different. The overall inorganic tin concentration decreases significantly during the experiment, the MeSn³⁺ concentration is approximately constant, and concentrations of Me₂Sn²⁺ and Me₃Sn⁺ increase. This means that net methylation of inorganic tin has occurred. We conclude that decaying S. alterniflora is likely to be important in the cycling of tin in salt marshes.     

Determination of total and inorganic mercury in biological and environmental samples with on-line oxidation coupled to flow injection-cold vapor atomic absorption spectrometry

A method for determination of inorganic and total mercury by flow injection-cold vapor atomic absorption spectrometry (FI-CVAAS) with on-line oxidation was developed. Potassium peroxodisulphate and sulphuric acid were used as oxidizing agents so that decomposition of organomercury compounds could be achieved. Depending on the temperature selected, inorganic or total mercury could be determined with the same FI manifold. In order to assess the method performance, synthetic wastewater, wastewater, urine and saline water samples were spiked with inorganic mercury, methylmercury and phenylmercury. Quantitative recoveries were obtained for the three mercury species, except with the synthetic wastewater when the chemical oxygen demand value was higher than 1000 mg l⁻¹. In most cases, the standard addition method was usually needed for calibration. LODs calculated as 3 σ/m were 0.47 μg l⁻¹ for inorganic mercury and 0.45 μg l⁻¹ for total mercury. R.S.D. values corresponding to peak height measurements were 1.5 and 2.2% for inorganic mercury and total mercury, respectively. The accuracy of the method was tested by analyzing 5 mol l⁻¹ hydrochloric acid extracts of seven biological and environmental CRMs. LODs in the solid CRMs ranged from 0.032 to 0.074 μg g⁻¹.     

On‐site sampling of inorganic contamination on the metal surface and analysis with capillary electrophoresis

Pipes are the primary structural elements used for transporting fluid in various industries. The most common damage mechanism is corrosion, which occurs in pipes surface of turbine. The corrosive compounds for pipes are inorganic ion (Na⁺, Cl^?, NH₄⁺, NO₃^?, etc.) and grinding oil. For rapid and quantitative detection of inorganic ions on site, more reliable and reproducible analytical methods are demanded. A highly efficient solid–liquid sampling collection system is introduced in this work. Papering on the sample surface, inorganic cations and anions were simultaneously collected and analyzed by capillary electrophoresis with indirect ultraviolet detection. As a result, five cations (Na⁺, K⁺, NH₄⁺, Ca²⁺, Mg²⁺) and three anions (Cl^?, NO₃^?, SO₄^2?) were completely separated. The efficiency of the sampling and ability of capillary electrophoresis analysis were presented by the determination of trace‐level (mg/m²) contaminants. The recoveries of cations and anions on the paper from metal surface were between 86.6 and 107.2%, and the relative standard deviations were less than 12.85%.     

Automatic determination of inorganic carbon in surface waters

An automated colorimetric procedure was developed for the determination of inorganic carbon in the range 0.3–40.0 mg l^-1, and then modified to handle concentrations in the range 0.01–2.00 mg l^-1. The procedure entailed conversion of carbon dioxide equilibria products to carbon dioxide. By gas dialysis, a portion of this gas was dissolved in a weakly buffered alkaline phenolphthalein solution, and inorganic carbon was determined by measuring the loss in color of the indicator. Calibrations were linear within 1% full scale. When surface water samples were processed by the subject and by alternative methods, the colorimetric carbon results were lower by approximately 1% full scale.     

Temperature dependence of the rate constants for reactions of the carbonate radical with organic and inorganic reductants

Rate constants have been measured by pulse radiolysis for the reactions of the carbonate radical, CO₃^·?, with a number of organic and inorganic reactants as a function of temperature, generally over the range 5 to 80°C. The reactants include the substitution-inert cyano complexes of Fe^II, Mo^IV, and W^IV, the simple inorganic anions SO₃^2?, ClO₂^?, NO₂^?, I^?, and SCN^?, several phenolates, ascorbate, tryptophan, cysteine, cystine, methionine, triethylamine, and allyl alcohol. The measured rate constants ranged from less than 10⁵ to 3 × 10⁹ M^?1 s^?1, the activation energies ranged from ?11.4 to 18.8 kJ mol^?1, and the pre-exponential factors ranged from log A = 6.4 to 10.7. The activation energies for the metal complexes and inorganic anions generally decrease with increasing driving force for the reaction, as expected for an outer sphere electron transfer. For highly exothermic reactions, however, the activation energy appears to increase, probably reflecting the temperature dependence of diffusion. For many of the organic reactants, the activation energies were low and independent of driving force, suggesting that the oxidation is via an inner sphere mechanism.     

Preparation and characters of hyperbranched polyester‐based organic‐inorganic hybrid material compared with linear polyester

To compare the properties of hyperbranched polymers with linear oligomers for preparing organic‐inorganic hybrids, hyperbranched aliphatic polyester (Boltorn^TM H20) and linear polyester hexa‐acrylate (EB830) were selected as organic components for preparing UV‐curable transparent hybrid materials using 3‐(trimethoxysilyl) propylmethacrylate as a coupling agent via a sol‐gel process. The prehydrolyzed product of tetraethoxysilane was used as an inorganic component. The effects of inorganic content on the morphologies, thermal behaviors, photopolymerizaiton kinetics and mechanical properties of the hybrids were investigated. The results show that for hyperbranched polyester‐based hybrids, the organic phase shows much better compatibility with inorganic phase even at high inorganic component content due to its special spheral shape and plenty of functional end groups, compared with linear EB830‐based hybrids. Copyright © 2004 John Wiley & Sons, Ltd.     

Rate constants for some reactions of inorganic radicals with inorganic ions. Temperature and solvent dependence

Rate constants for several reactions of inorganic radicals with inorganic anions in aqueous and aqueous/acetonitrile solutions have been measured as a function of temperature by laser flash photolysis. The reactions studied were (1) Cl₂^? + N₃^?, (2) Br₂^? + N₃^?, (3) Cl₂^? + SCN^?, (4) Br₂^? + SCN^?, (5) SO₄^? + Cl^?, (6) SO₄^? + CO₃^2?, and (7) N₃? + I^?. The rate constants were corrected for ionic strength and ranged from 10⁶ to 10⁹ L mol^?1 s^?1. The Arrhenius activation energies varied from 2 to 12 kJ mol^?1 for the first 4 reactions, were higher for reaction 6, and negative for reaction 5. The pre-exponential factors also varied considerably with log A ranging from 5 to 14. The values of k₂₉₈ decreased in most cases by more than an order of magnitude upon increasing the acetonitrile (ACN) fraction from 0 to 70%. For most reactions, this decrease in k₂₉₈ was due to changes in log A with little regularity in the small changes observed in E_a. For reaction 7, k₂₉₈ was practically unchanged due to compensating effects of the changes in E_a and log A with ACN mol fraction, giving an isokinetic relationship. An isokinetic relationship was also observed in the case of reaction 6; E_a and log A change in parallel while changing ACN mol fraction. Reaction 3 (Cl₂^? + SCN^?) was also studied in water/t-butanol and water/acetic acid mixtures. Linear correlation was found between log k and the dielectric constant of the medium for water/ACN and water/t-BuOH but the lines for the two solvent mixtures had different slopes, suggesting specific solvation effects in addition to the primary solvent polarity effects. With water/acetic acid, k decreased and then increased upon addition of acetic acid. © 1993 John Wiley & Sons, Inc.     

The determination of organic and inorganic lead compounds in urban air by atomic-absorption spectrometry with electrothermal atomization

A method for the simultaneous determination of inorganic and organic lead compounds in air is described, together with some results from its application at different sampling sites. Air-borne particulate lead is collected on a cellulose filter. Organic lead vapours are trapped in an iodine monochloride solution, placed behind the filter. A fraction of the cellulose filter is subjected to low-temperature ashing, after which the lead content in the residue is measured by electrothermal atomic-absorption spectrometry. The organolead material absorbed in the iodine monochloride solution, is determined by solvent extraction and electrothermal atomic-absorption spectrometry. For a 6-h sampling period, detection limits of the order of 10 ng m^-3 for inorganic and 8 ng m^-3 for organic lead materials may be obtained.     

Monitoring inorganic mercury and methylmercury species with liquid chromatography-piezoelectric detection

A piezoelectric detection system coupled with a liquid chromatographic system is developed for the speciation of inorganic mercury(II) and methylmercury. Piezoelectric detection has been demonstrated to be a very sensitive detection system for total mercury determination when a gold-coated piezoelectric quartz crystal was used. The analytical features of this detection unit make it very suitable to be used as a detector coupled with a liquid chromatographic system for monitoring mercury species. After separation by a chromatography column (Spherisorb ODS-2, 5 μm,  mm i.d.), mercury species are liberated and reduced, by using stannous chloride, and are detected as an amalgam on the gold-coated piezoelectric quartz crystal, the sensor subsequently was regenerated by passing a peroxydisulfate solution. This detector exhibits good sensitivity, it allows the determination of mercury at sub-ppb concentration levels (0.30-1.20 μg l⁻¹). The precision, expressed as relative standard deviation, was ±2.7% (n=11) for a 0.5 μg l⁻¹ total mercury concentration. The proposed method is free of interferences and it allowed the determination of inorganic mercury and methylmercury species in natural waters.     

A tr esr study of the reactions of excited organic triplet molecules with inorganic sulfur oxoanions

The reactions of excited triplet ketones including benzophenone, 4,4′-dihydroxybenzophenone, and acetone with inorganic sulfur oxoanions: sulfite (SO₃ ⁼), metabisulfite (S₂O₅ ⁼), and dithionite (S₂O₄ ⁼) in solution were studied by TRESR. Observation of radical anion intermediates polarized by the Triplet Mechanism demonstrated the reactions of electron transfer from the sulfur dianions to the organic triplet states. Thus, electron transfer from SO₃ ⁼ to the triplet organic carbonyl compounds gave rise to the SO₃ ^? radical; reactions with metabisulfite and dithionite were more complex and may be interpreted as occurring via electron transfer to the carbonyl system followed by dissociation of the S-S bond in the resulting sulfur oxoanion radical. The initial radical ion pairs thus formed consist of pairs of anion radicals, one organic and one inorganic.     

Some features of hydrolysis of organic and inorganic substrates by Escherichia coli inorganic pyrophosphatase in the presence of various activator cations

The kinetics of hydrolysis of the inorganic (PP_i) and organic (ATP) substrates by Escherichia coli inorganic pyrophosphatase (PPase) and its mutant forms with Asp42 replaced by Ala, Asn, or Glu was studied. The Mn²⁺ or Zn²⁺ ions were used as activators of the enzymatic reaction. The kinetic parameters of hydrolysis were determined. The inhibitory effect of these cations on substrate hydrolysis was investigated. The dissociation constants were calculated for the Mn²⁺- and Zn²⁺-binding activator and inhibitor subsites of E. coli PPase. The observed hydrolysis rate of PP_i increases in the series Zn²⁺ < Mn²⁺ < Mg²⁺, whereas the potential efficiency of these cations decreases in this series. Hydrolysis of ATP by E. coli PPase occurs only in the presence of Mn²⁺. The reasons for the observed differences in the substrate specificity of the enzyme are discussed.     

Short-term bioconcentration and distribution of methylmercury,tributyltin and corresponding inorganic species in the starfish leptasterias polaris

Starfish, Leptasterias polaris, were exposed between 30 min and 48 h to seawater containing 0.25 nmol dm^?3 of radiolabelled methylmercury (Me²⁰³HgCI), tributyltin [(C₄H₉)₃¹¹³SnCI], and inorganic ²⁰³HgCI₂ and ¹¹³SnCI⁴, with the objectives of comparing the uptake and distribution kinetics of these metal species in organs and tissues of treated organisms. Some starfish exposed to metals for 48 h were allowed to depurate for 24 h in clean seawater. Whole-body autoradiography was used to locate radiotracers very precisely within starfish tissues. The total amount of methylmercury (MeHg) accumulated in the whole animal after 48 h reached 0.53 nmol compared with 0.09 nmol for inorganic mercury, while tributyltin (TBT) reached 0.72 nmol compared with 0.017 nmol for inorganic tin. No significant reduction of body burdens occurred during the depuration period. The first-order rate constant characterizing the uptake of metals by whole animals, k₁, ranged from 0.102 h^?1 for MeHg to 3.6 × 10^?3h^?1 for inorganic mercury(II) and to 8.4 × 10^?4 h^?1 for inorganic tin(IV). The first-order rate constant characterizing the translocation of metals from seawater-exposed tissues toward internal organs, k₃, was available for inorganic Hg and Sn and had values similar to k₁. Concentration ratios between external tissues and internal organs after a 48 h exposure were 11.5 and 25.4 for MeHg and TBT, respectively, and 2.1 and 6.1 for inorganic mercury and tin. Furthermore, autoradiograms showed that MeHg and TBT were accumulated only on the external surface of the body wall and podia. This finding indicates a much slower translocation process for organometallic species than inorganic species, a process which seems to be related to the binding mode of MeHg and TBT to the organic matrix of external tissues of starfish.     

Application of co-electroosmotic capillary electrophoresis for the determination of inorganic anions and carboxylic acids in soil and plant extract with direct UV detection

Summary Indirect UV detection in capillary zone electrophoresis (CZE) is frequently used for the determination of inorganic anions and carboxylic acids. However, there are few reports on direct UV detection of these solutes in real samples. This paper describes the use of direct UV detection of inorganic anions and organic acids in environmental samples using co-electroosmotic capillary zone electrophoresis (co-CZE) at 185 nm. The best separation and detection of the solutes was achieved using a fused silica capillary with an electrolyte containing 25 mM phosphate, 0.5 mM tetradecyltrimethylammonium bromide (TTAB) and 15% acetonitrile (v/v) at pH 6.0. Four common inorganic anions (Cl⁻, NO₂ ⁻, NO₃ ⁻ and SO₄ ²⁻) and 11 organic acids (oxalic, formic, fumaric, tartaric, malonic, malic, citric, succinic, maleic, acetic, and lactic acid), were determined simultaneously in 15 min. Linear calibration plots for the test solutes were obtained in the range 0.02–0.5 mM with detection limits ranging from 1–9 μM depending on the analyte. The proposed method was successfully used to determine inorganic anions and carboxylic acids in soil and plant tissue extracts with direct injection of the sample.