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PubMed2006

Perchlorate in water via US Environmental Protection Agency Method 331 Determination of method uncertainties, lowest concentration minimum reporting levels, and Hubaux-Vos detection limits in reagent water and simulated drinking water.

US Environmental Protection Agency (EPA) Method 331 determines perchlorate in drinking water using non-suppressed ion chromatography with tandem mass spectrometry. This study reports the results of calibration and recovery studies in reagent water, as well as of a recovery study in simulated drinking water (i.e., total dissolved solids are 500 mg/mL each of chloride, sulfate, and bicarbonate). The perchlorate concentrations in the study ranged from 0.05 to 64 ng/mL. At 95% confidence, the Hubaux-Vos detection limit (H-V DL) was 0.04 ng/mL for the calibration study and the simulated-drinking-water recovery study, and 0.03 ng/mL for the reagent-water recovery study. The lowest concentration minimum reporting level was 0.03 ng/mL for reagent water and 0.0 7 ng/mL for simulated drinking water, again at 95% confidence.

Calibration↗
PubMed2005

Temporal and spatial variation of perchlorate in streambed sediments: results from in-situ dialysis samplers.

The fate of perchlorate (ClO4-) in streambed sediments is becoming a concern due to the increasing number of groundwater and surface water contamination sites in the United States. Dialysis samplers were deployed at three sites over a period of 1 year to determine the vertical distribution of ClO4- in sediment pore water. Results indicated that the spatial and temporal ClO4- penetration into sediments could be affected by numerous factors, such as temperature, microbial degradation, ClO4- surface water concentration, and sediment physico-geological properties. In general, maximum ClO4- penetration into sediments at the studied sites was 30 cm below the sediment-water surface. The vertical sequential depletion of electron acceptors in sediments suggested that microbial reduction was responsible for ClO4- depletion in stream sediments. Biodegradation of ClO4- occurred over a seasonally variable active depth zone of 1-10 cm. Results implied that there was a rapid natural attenuation potential of perchlorate in saturated near-surface sediments.

Dialysis↗
PubMed2004

Vibrational spectral studies of L-methionine L-methioninium perchlorate monohydrate.

The infrared and laser Raman spectra of L-methionine L-methioninium perchlorate monohydrate were recorded at room temperature and the vibrational assignments of the observed wave numbers were made. The presence of both the carbonyl and the ionized carboxylic groups has been identified in the title complex. The L-methionine and L-methioninium the cation have different conformations. This together with the different environment has seen by the two -CH(2)- groups in each skeleton cause several of the group wave numbers to occur as doublets or as broad bands. The perchlorate anion was found to be in the T(d) symmetry in the methionine environment. The coordination to other ligands in the crystal through hydrogen bonding does not affect this symmetry. The extensive intermolecular hydrogen bonding in the crystal was identified by the shifting of bands due to the stretching and bending modes of the various functional groups. Fermi resonance has also been observed.

Methionine↗
PubMed2005

Infrared and Raman spectroscopic studies of l-valine l-valinium perchlorate monohydrate.

FT-IR and FT-Raman spectra were recorded and analyzed for l-valine l-valinium perchlorate monohydrate crystals. The wave number assignments have been made for the functional groups, viz. COOH, COO(-), --[NH(3)](+), C--(CH(3))(2), C--C--N and C--H. One of the two amino acid residues remains in the zwitterionic form while the other residue exists in the cationic form. The symmetry of the ClO(4)(-) anion has been found to be lowered corresponding to ClO(2) group. The hydrogen bonds that prevail between amino acid residues, perchlorate anion and water molecule influence the wave numbers of several stretching and deformation modes to deviate from the expected values.

Hydrogen Bonding↗
PubMed2004

Fate of perchlorate-contaminated water in upflow wetlands.

The potential of natural wetland systems to treat perchlorate-contaminated water was investigated in vertical upflow wetland columns planted with and without Bulrush (Scirpus sp.). In the absence of nitrate (NO3- -N <1mg/L), wetland columns were capable of removing ClO4- to levels below the detection limit (<4 microg/L) for a series of influent ClO4- (4, 8, 16, and 32 mg/L). At an influent ClO4- concentration of 32 mg/L, ClO4- breakthrough was observed with the increase in nitrate concentration. ClO4- and NO3- degradation rate constants (Kpc and KNO3- -N) were also determined using a 1-D transport model with dispersion. Kpc declined with the increase of influent ClO4- and NO3- -N concentration (6.49-0.42 day(-1) for unplanted columns, and 7.80-0.21 day(-1) for planted columns, respectively). KNO3- -N followed similar trends but was relatively higher than Kpc. Plant uptake was directly linked with ClO4- concentration in the rhizosphere, and the stem bio-concentration factor (BCF) was estimated to be 57. A mass balance indicated plant uptake accounted for 0-14.3% of initial ClO4- input. Microbial degradation played a more important role than plant uptake and transformation in ClO4- degradation in this wetland system. This study suggests that constructed wetlands may be a promising technology to treat perchlorate-contaminated waters.

Biodegradation, Environmental↗
PubMed2002

Ergosteroids VII: perchloric acid-induced transformations of 7-oxygenated steroids and their bio-analytical applications--a liquid chromatographic-mass spectrometric study.

Sulfate esters of 7-oxo-delta(5)-steroids can be selectively and quantitatively hydrolyzed to the corresponding free steroids in the presence of carboxylic acid esters by solvolysis with perchloric acid in ethyl acetate at room temperature. Sulfates as well as carboxylic acid esters, methyl ethers, and ketals can be quantitatively converted to the corresponding 3,5-diene-7-one derivatives by heating with perchloric acid in methanol at 65 degrees C. The dienes have a strong UV absorption with maximum centered around 284 nm. These reactions have been used for the characterization and structural elucidation of 7-oxygenated-delta(5)-steroids that are present in complex biomatrices and can also be used for the quantitative estimation of total 7-oxo-delta(5)-steroids (free as well as conjugated) in biological matrices.

Animals↗
PubMed2003

Measurement of chlorite dismutase activities in perchlorate respiring bacteria.

Chlorite dismutase (CD) catalyzes the disproportionation of chlorite to chloride (ClO(2)(-)-->Cl(-)+O(2)) and is present in bacteria capable of cell respiration using perchlorate or chlorate. The activity of this enzyme has previously been measured by monitoring oxygen evolution using a Clark-type dissolved oxygen (DO) probe. We demonstrate here, using two other methods to measure CD activity (a chloride-specific electrode and ion chromatography (IC)) via chloride production, that the DO probe method underestimates dismutation rates. Of the three methods, the chloride probe was the easiest to use and did not require extensive sample handling or post-experimental analysis. Using the chloride electrode method, we determined whole cell rate constants (V(max)=64 U/mg DW, K(m)=0.17 mM) for the chlorate-grown suspensions of Dechlorosoma sp. strain KJ. We compared the CD activities of strain KJ at a fixed chlorite concentration (0.6 mM) to four other perchlorate respiring bacteria (PRB), and to one non-PRB (Pseudomonas aeruginosa). Chlorate-grown cultures of the five PRB strains had CD activities ranging from 25 to 50 U/mg of cell dry weight (DW), while aerobically grown cultures of the PRB had much lower CD activities (0.5-4 U/mg DW). To our knowledge, this is the first systematic comparison of the different methods to measure CD activities, and the first comparison of CD activities of different PRBs.

Aerobiosis↗
PubMed2001

Extraction of cadmium and iodocadmat species by di(2-ethylhexyl) phosphoric acid from perchloric and phosphoric media.

We have investigated the extraction of cadmium with di(2-ethylhexyl) phosphoric acid (HDEHP) in various solvents from perchloric and phosphoric solutions. The distribution coefficient D obtained is not very dependent on the nature and the polarity of the diluent used. The extraction of Cd(II) by HDEHP dissolved in benzene, from sulfophosphoric solutions shows the absence of sulfuric or mixed sulfophosphoric complexes of the metal. However, the presence of iodide anions in aqueous perchloric or phosphoric media results in enhanced extraction coefficient of cadmium with HDEHP (HX) in benzene. The extracted species were found to be CdIX,3(HX)2 and CdI2,3(HX)2 and their formation constants are 0.033 and 0.036, respectively. The recovery of cadmium from phosphoric medium by tributylphosphate (TBP), trioctyl phosphine oxide (TOPO), triphenyl phosphine oxide (TPPO), diphenylamine or their mixtures with HDEHP is lesser than with HDEHP alone.

Benzene↗
PubMed2002

Infrared and laser Raman studies of L-phenylalanine L-phenylalaninium perchlorate and bis(DL-phenylalaninium) sulphate monohydrate.

Both crystals under study have two phenylalanine groups in the cationic part of the complex. In the L-phenylalanine L-phenylalaninium perchlorate crystal, two phenylalanine groups share one proton and become monoprotonated. In the bis(DL-phenylalaninium) sulphate monohydrate crystal, on the other hand, both the phenylalanine groups are protonated. This leads to several differences in the infrared and Raman spectra of these two crystals. The presence of both the carbonyl and the ionized carboxylic groups has been identified in the perchlorate crystal, while the sulphate crystal has only the carbonyl group. Extensive hydrogen bonding further leads to the shifting of bands due to several stretching and bending modes. It also reduces the Td symmetry of the anions to C2v symmetry causing the degeneracies of several modes to be removed.

Perchlorates↗
PubMed1981

Mechanisms of hydrolysis of adenosine 5'-triphosphate, adenosine 5'-diphosphate, and inorganic pyrophosphate in aqueous perchloric acid.

The acid-catalyzed hydrolysis of adenosine 5'-triphosphate (ATP) has been found to give rise both to adenosine 5'-diphosphate (ADP) and inorganic phosphate and to adenosine 5'-phosphate (AMP) and inorganic pyrophosphate. Kinetic and isotope studies on the mechanism of hydrolysis of ATP therefore depend on a knowledge of the mechanism of hydrolysis of the polyphosphate products, ADP and inorganic pyrophosphate. The latter reactions have been studied over the acidity range 1--5 M perchloric acid at 25 degrees C while the more complex problem of the hydrolysis of ATP has been followed at a single acidity (3 M perchloric acid). The positions of bond fission have been determined for both ATP and ADP.

Adenosine Diphosphate↗
PubMed2002

Evidence of perchlorate (ClO4-) reduction in plant tissues (poplar tree) using radio-labeled 36ClO4-.

Phytoremediation of perchlorate (ClO4) by poplar trees Populus deltoidex nigrawas investigated using small cuttings growing in hydroponic Hoagland solution and plant tissue cultures, consisting of spherical photosynthetic cell aggregates (i.e. nodules) developing in Murashige and Skoog culture medium. Both plants and nodules were grown under a 16 h/8 h photoperiod cycle and under sterile conditions. Degradation experiments, performed by the incubation of pregrown plants and nodules in the presence of 36Cl radio-labeled ClO4- (25 mg L(-1)), showed a reduction of the initial ClO4- concentration in the solution of about 50% after 30 d of incubation. Analysis of the distribution of radioactivity in different plant fractions indicated that 27.4% of the total was translocated to the leaves, while 66.9% remained in the solution. Very little radioactivity (less than 3.0%) was detected in the other parts of the plants. 32.0% of the radioactivity recovered in the solution was shown to consist of 36Cl- and 68.0% of nontransformed 36ClO4-. The radioactivity recovered in the leaf extracts was distributed as chloride (36Cl-) (1.6% of the total), chlorite (36ClO2-) (2.4%), chlorate (36ClO3-) (4.8%), nontransformed 36ClO4- (21.6%), and an unidentified organic compound (1.4%). The radioactivity recovered in the solution containing submerged nodules consisted of 36Cl- (6.4% of the total), 36ClO3- (1.3%), and nontransformed 36ClO4- (51.5%). Radioactivity detected in the nodule extracts was distributed as 36Cl- (2.0% of the total), 36ClO2- (5.2%), 36ClO3- (6.4%), 36ClO4- (22.7%), and an unidentified organic compound (0.5%). These results provide evidence of perchlorate reduction inside poplar tree tissues. 36ClO4- is partially reduced to 36ClO3-, 36ClO2-, and 36Cl-.

Biodegradation, Environmental↗
PubMed2006

Electrically controlled anion exchange based on polypyrrole and carbon nanotubes nanocomposite for perchlorate removal.

A simple and highly effective process for perchlorate removal based on electrically switched ion exchange (ESIX) was developed by using polypyrrole (PPy) deposited on high surface area carbon nanotubes. The redox switching of conducting polymers such as polypyrrole is accompanied by the exchange of ions into or out of the polymer. This effect could be used for the development of an electrically switchable ion-exchanger for water purification, particularly for the removal of anions. In the research presented in this paper, the anion-exchange behavior and ion-exchange capacity of electrochemically prepared polypyrrole on glassy carbon electrodes with and without carbon nanotube (CNT) backbones are characterized using cyclic voltammetry and X-ray photoelectron spectroscopy. It has been found that the presence of carbon nanotube backbone results in an improvement in the anion exchange stability of polypyrrole, which may be due to the stronger interaction between carbon nanotubes and polypyrrole. Chronoamperometric studies show that the process of electrically switched anion exchange could be finished within 10 s. The selectivity of PPy/CNTs films for the perchlorate ion is demonstrated using cyclic voltammetry and X-ray photoelectron spectroscopy (XPS). The results of the present study point to the possibility of developing a green process for removing ClO4- from wastewater using such a novel nanostructured PPy/CNT composite thin film through an electrically switched anion exchange.

Anion Exchange Resins↗
PubMed2006

Ion chromatographic determination of perchlorate in foods by on-line enrichment and suppressed conductivity detection.

Systemic uptake of perchlorate anion, a rocket fuel component and potential thyroid function disruptor, by leafy vegetables and other crops grown in contaminated waters is a public health concern. A column-switching anion-exchange chromatographic method with suppressed conductivity detection, described in this paper, achieved a 3-6 microg/kg method limit of quantitation in analysis of the wet weight edible portion of cantaloupe, carrots, lettuce, and spinach samples with field-incurred perchlorate. A test portion was blended with dilute nitric acid, and the extract was filtered under vacuum. A portion of the measured filtrate was acidified to pH approximately 2 by addition of cation-exchange resin, 4 mL was passed through a graphitized carbon cleanup column, and an aliquot of a collected fraction was pushed through a short precolumn for anion extraction, enrichment, and injection onto the analytical column. Statistical comparison with determination by tandem mass spectrometry-ion chromatography analysis of untreated filtrate revealed that the difference between means was not significant at the 95% confidence level (P value > or = 0.12) for crops tested. In addition, the method was applied to cooked vegetables processed as baby food.

Chromatography, Ion Exchange↗
PubMed2005

From solution phase to "on-column" chemistry: trichloroacetimidate-based glycosylation promoted by perchloric acid-silica.

[reaction: see text] Activation of ester-protected glycosyl trichloroacetimidate donors by perchloric acid immobilized on silica afforded 1,2-trans disaccharides in 60-90% yields. Applying this approach to one-pot sequential glycosylation resulted in efficient syntheses of the N-linked glycan trimannoside and Le(X) and Le(A) trisaccharides in very good yield (76%, 62%, and 59% yields, respectively). Solution phase reactions were also translated to a solid phase format; priming the top of a standard silica chromatography column with perchloric acid immobilized on silica facilitated "on-column" glycosylation with subsequent "in situ" purification of products. Coupling yields from this approach were comparable to those obtained from the corresponding solution-phase disaccharide couplings. A series of glycosylated amino acids were also synthesized in high yield with use of the on-column approach.

Acetamides↗
PubMed2000

Trace level determination of perchlorate in water matrices and human urine using ESI-FAIMS-MS.

High-field asymmetric waveform ion mobility spectrometry (FAIMS) separates perchlorate from interfering isobaric ions of bisulfate and dihydrogenphosphate in the gas-phase. The use of a new FAIMS prototype and waveform generator, along with the use of a mixed carrier gas, in this electrospray ionisation (ESI)-FAIMS-mass spectrometry (MS) study gave a detection limit for perchlorate in a relatively "clean" matrix of tap water of 0.050 ppb. Flow injection analysis (FIA) of dilutions of fortified waste water, a fortified river water certified reference material (CRM; SLRS-4, National Research Council of Canada), and a fortified human urine Standard Reference Material (SRM; 2381, National Institute of Standards and Technology) gave detection limits of 0.37 ppb, 0.50 ppb, and 4.8 ppb, respectively, in the undiluted matrices.

Environmental Monitoring↗
PubMed1973

The use of sodium perchlorate in deproteinization during the preparation of nucleic acids.

Sodium perchlorate in high concentrations will remove from solution the detergent sodium dodecyl sulphate and protein complexed with it. This and the failure of proteins to be precipitated by ethanol from solutions containing a high concentration of sodium perchlorate can be utilized as efficient, rapid and simple deproteinization procedures during the preparation of nucleic acids.

Adenine↗
PubMed1996

Comparison of the effects of perchlorate and Bay K 8644 on the dynamics of cytoplasmic Ca2+ concentration and insulin secretion in mouse beta-cells.

Non-inbred ob/ob mice were used to study the dynamics of cytoplasmic Ca2+ concentration ([Ca2+]i) in isolated pancreatic beta-cells using microfluorimetry with fura 2/AM as probe, and the dynamics of insulin secretion in isolated pancreatic islets. D-Glucose (20 mM) caused a transient peak increase in [CA2+]i which changed to either an oscillating or a flat, elevated phase. The lag-time before the first peak increase in [Ca2+]i was markedly shortened by 12 mM ClO4- and the glucose-stimulated level of [Ca2+]i after the first peak was clearly elevated by the anion. ClO4- did not change the basal [Ca2+]i at 3 mM glucose. Extracellular Ca2+ deficiency abolished the effect of high glucose and ClO4- on [Ca2+]i. This suggests that ClO4- acts as an amplifier of transmembrane Ca2+ inflow. The L-type Ca2+ channel agonist, Bay K 8644 (0.01-1.0 microM), strictly reproduced all the effects of perchlorate on the glucose-stimulated beta-cell [Ca2+]i. Both phases of insulin release (20 mM glucose) were markedly enhanced by ClO4- (12 mM) or Bay K 8644 (1.0 microM). The lag-time for glucose-stimulated insulin release was shortened by both agents. Taken together, these data strengthen the idea that perchlorate amplifies the glucose-stimulation of [Ca2+]i and insulin release by directly modifying the function of the L-type Ca2+ channel. This effect can induce both a more prompt onset of and an amplified level of beta-cell secretory activity.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1997

Diagnostic value of 123iodine scintigraphy and perchlorate discharge test in the diagnosis of congenital hypothyroidism.

AIM: Forty children suffering from congenital primary permanent hypothyroidism were studied to determine the diagnostic impact of 123I scintigraphy in comparison to laboratory findings and ultrasonography. METHODS: In all patients 123I scintigraphy was performed after intravenous administration of 3.7 MBq 123I. If accumulation of the radiotracer in thyroid tissue occurred a perchlorate discharge test was performed subsequently. RESULTS: Scintigraphy revealed athyrosis in 7 children. In 11 children a lingual thyroid was observed. Deficiency in iodine organification was diagnosed by a significant discharge of 123I in 15 patients. In four of these children the diagnosis of Pendred's syndrome could be established. Ectopic thyroid tissue could be demonstrated only by scintigraphy where clinical examination and sonography failed in the diagnosis in all cases. Hypoplasia of the thyroid gland as it was diagnosed in 2 cases by ultrasonography appeared to be unlikely because a normal 123I uptake was seen in these patients. In 2 patients with scintigraphic proven athyrosis an orthotopic gland had been considered by ultrasound. In 50% of our patients the final diagnosis could only be established if 123I scintigraphy and perchlorate discharge test were performed. CONCLUSION: This findings suggest that scintigraphy is indispensible in the correct diagnostic work up of congenital hypothyroidism.

Child↗