Removal Of ClO Research Articles

Chemosensor-Anchored Halloysite Nanotubes for Detection and Removal of Hypochlorite in Water

Preparation of a smart tool for simultaneous detection and removal of hypochlorite (ClO–) in water, a kind of serious persistent pollutant in industrial wastewater and even in tap water, is a puzzling issue in the chemosensing field. Here, halloysite nanotubes (HNTs), a natural product with excellent dispersibility in water, were employed as the scaffold to solve the urgent problem. The diaminomaleonitrile moiety, accompanying with the coumarin derivative as a chemosensor unit, was decorated on the surface of the HNTs. The diaminomaleonitrile group can be transferred into substituted imidazole formation and thereby triggers strong fluorescence emission upon ClO–, which triggers a dramatically “turn-on” fluorescence change and reduce ClO– into eco-friendly chloridion (Cl–). The detection and removal capacities show high selectivity over other commonly used ions. These results suggest that the smart nanocomposite can be used in the synchronous detection and removal of ClO– in water, which may pave a path in water quality monitoring and treatment.

Nucleotide profile of mouse liver: response to 2 ′- O-dibutyryl cytidene 3 ′,5 ′-cyclic monophosphate

The effect of 2 ′- O-dibutyryl cytidene 3 ′,5 ′-cyclic monophosphate (dibutyryl cCMP) on the nucleotide profile of mouse liver was examined. Dibutyryl cCMP caused an increase in the amount of CTP in mouse liver. Perchloric acid extracts of liver tissue were neutralized with tri- N-octylamine in trichlorotriflouroethene and, after removal of CLO 4 −, subjected to preliminary purification on a Cu 2+-loaded column of Chelex 100. A high-pressure liquid chromatographic anion-exchange procedure was used and gave good resolution of the free nucleotides on a single column.

Involvement of myosin light-chain kinase in chloride-sensitive Ca2+ influx in porcine aortic endothelial cells.

This study was designed to investigate the involvement of myosin light-chain kinase (MLCK) in bradykinin- and thapsigargin-induced changes in intracellular Cl- and Ca2+ concentrations ([Cl-]i; [Ca2+]i) in porcine aortic endothelial cells. Using the fluorescent probes N-ethoxycarbonylmethyl-6-methoxyquinolinium bromide (MQAE) and fura-2/AM, the effects of different MLCK inhibitors on bradykinin- and thapsigargin-induced changes in [Cl-]i and [Ca2+]i were assessed. Bradykinin and thapsigargin significantly decreased the MQAE fluorescence intensity, which indicates increased [Cl-]i; these changes were reversed by removal of extracellular chloride (Cl-o) and were significantly inhibited by Cl(-)-channel inhibitor N-phenylanthranilic acid but not by Na(+)-K(+)-Cl- cotransport inhibitor furosemide. Pretreatment with ML-9 and wortmannin, two different selective inhibitors of MLCK, significantly reduced these changes in a dose-dependent manner. The inhibitory effects of ML-9 and wortmannin on the Cl- responses were not significantly different and were not additive. Bradykinin and thapsigargin provoked large increases in [Ca2+]i, which were significantly diminished by removal of Cl-o and by pretreatment with the Cl(-)-channel inhibitor N-phenylanthranilic acid. The study shows that an increase in [Cl-]i may be involved in the Ca2+ influx in response to bradykinin and thapsigargin and that MLCK might be involved in the Cl- response. We suggest that MLCK might be involved in the Cl(-)-sensitive endothelial Ca2+ responses to bradykinin and thapsigargin.

Comparison of cryogenic and membrane desolvation for attenuation of oxide, hydride and hydroxide ions and ions containing chlorine in inductively coupled plasma mass spectrometry

Conventional, cryogenic and membrane desolvation methods were compared with respect to sensitivity, MO+/M+ signal ratios and the aerosol gas flow rate required to maximize M+ and MO+ signals. Thorium was used to represent the actinides, which form relatively strong hydrides and hydroxides. The LaO+/La+ ratio is reduced from 0.24% with conventional desolvation to 0.08% with membrane desolvation and 0.01% with cryogenic desolvation. Membrane desolvation reduces ThH+ and ThOH+ 2-fold compared with conventional desolvation. Cryogenic desolvation attenuates ThH+ 7-fold and ThOH+ 20-fold compared with conventional desolvation. The three desolvation methods were also evaluated for the removal of ClO+ and ArCl+ for the determination of vanadium and arsenic at trace levels in the presence of chloride. The density of oxygen atoms is reduced as water vapor is removed, and chloride is also removed, presumably as hydrogen chloride. The concentration of vanadium in a urine standard reference material was determined by standard additions to be 7 ppb with cryogenic desolvation and 5 ppb with membrane desolvation. Analysis of several nasal wash samples using cryogenic and membrane desolvation yielded results that agreed within 5% for the two methods in all cases except for the sample with the highest V+ concentration.

Potassium-chloride cotransport in cultured chick heart cells.

The polystrand preparation of cultured chick heart cells has a unidirectional transmembrane Cl- efflux that is twice K+ efflux. However, Cl- conductance of this heart cell membrane is low [regardless of extracellular K+ (K+o)], suggesting the existence of electroneutral Cl--dependent transport mechanisms. Furosemide (10(-3) M) decreases the 36Cl tracer efflux rate constant from a control value of 0.67 to 0.33 min-1. Extracellular Na+--free solution, which depletes intracellular Na+ within 1 min, has no significant effect on 36Cl efflux. K+o-free solution plus 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS; 10(-4) M) promotes the loss of Cl- against the Cl- electrochemical gradient; Cl- loss is furosemide sensitive in a dose-dependent manner. Incubating polystrands in 133 mM K+o, normal extracellular Cl- (Cl-o) solution causes net K+ and Cl- uptake in a 1:1 stoichiometry as well as a furosemide-sensitive volume increase; 130 mM extracellular choline or Li+ cannot mimic this high-K+o-induced volume increase. Removal of Cl-o from 133 mM K+o solution prevents K+ uptake and causes a Cl- loss as well as a furosemide-sensitive volume decrease. Adjusting Cl-o concentrations in high-K+o solution plus DIDS, so that the Cl- chemical gradient equally opposes the K+ chemical gradient, prevents high-K+o-induced volume changes. These data suggest that the cardiac cell membrane contains a furosemide-sensitive K+-Cl- cotransport mechanism.

Towards an estimate of chloride permeability in the smooth muscle of guinea-pig vas deferens.

Cl movements across the cell membranes of smooth muscle from the guinea-pig vas deferens were measured using Cl-sensitive micro-electrodes and 36Cl fluxes. The rate constants for the loss of Cl ions measured by both methods under a variety of conditions were used to calculate the apparent Cl permeability (PCl). If it is assumed that the initial rate of decline of the intracellular Cl activity (aiCl) on removal of extracellular Cl (Clo) represents net transmembrane Cl movement, the apparent PCl was 3-6 X 10(-8) cm s-1. This value is in good agreement with those calculated from the rate constant of 36Cl efflux into both normal Krebs solution (steady-state) and Cl-free solution. Such a value for PCl predicts a large depolarization on removal of Clo, but only a minimal change was recorded. It also predicts that changes in membrane potential (Em) would affect aiCl; furthermore that removal of Clo would increase membrane resistance and thus the hyperpolarization observed on reactivation of the electrogenic Na pump. Neither of these was observed. The PCl/PK ratio obtained from changes in Em on rapid changes in Clo and Ko gives a value for PCl which is an order of magnitude lower: 4 X 10(-9) cm s-1, using Casteels' (1969 b) value for PK. These observations can be reconciled by a substantial proportion of the measured Cl movements being carrier-mediated. The presence of the stilbene derivative DIDS greatly slowed both the steady-state efflux and uptake of 36Cl, as has previously been shown for the loss and reaccumulation of Cl ions on removal and replacement of Clo. PCl calculated in the presence of DIDS was about 5 X 10(-9) cm s-1. The nominal absence of CO2 and HCO3, which slows the reaccumulation and loss of Cl, had no effect on the steady-state fluxes. This indicates that the carrier operates in the self-exchange mode in the steady state.

Analysis of the free nucleotide pools of mammalian tissues by high-pressure liquid chromatography

Perchloric acid extracts of tissues were neutralized with tri- N-octylamine and, after removal of ClO 4 −, subjected to preliminary purification on a Cu 2+-loaded column of Chelex 100. A high-pressure liquid chromatographic (HPLC) anion-exchange procedure was developed and gave good resolution of the naturally occurring free nucleotides on a single column. Where heterogeneous peaks eluted, an effective supplementary analysis was achieved by reverse-phase HPLC. An HPLC paired-ion technique was also evaluated for use in nucleotide analysis. Although anion-exchange was best for overall separation of nucleotides, both reverse-phase and paired-ion chromatography gave excellent separation of cyclic nucleotides. Reduced pyridine nucleotides were detected and measured in the form of their acid-decomposition products. The recovery of nucleotides was examined throughout the described analytical techniques and shown to be quantitative.

Reactions of chlorine oxide radicals. Part 5.—The reaction 2ClO (X2Π)→ products

Ground state ClO, X2Π, ν″= 0, free radicals, generated at 298 K in a discharge-flow system, are removed in kinetically second order reactions (1), ClO + ClO[graphic omitted] all products. (1) The overall rate constant k1(at 298 K) has been determined mass spectrometrically using molecular beam sampling: k1=(2.25± 0.30)× 10–14 cm3 molecule–1 s–1. Absolute ClO radical concentrations were determined by conversion of ClO into NO2 via the reaction, NO + ClO → NO2+ Cl.The mechanism of reaction (1) is considered in detail. Studies using atomic resonance spectrometry have confirmed that formation of Cl atoms, reaction (1b), is a major reaction channel in the second order decay of ClO: ClO + ClO [graphic omitted] Cl + ClOO; (1b) reaction (1a) has also been identified, ClO + ClO [graphic omitted] Cl + OClO; (1a) however, this reaction channel for removal of ClO, although important at elevated (flame) temperatures, represents only about 5 % of the total reaction (1), of ClO + ClO, at 298 K.