Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Bromates”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 487 records · Page 27Linked to original sources
PubMed2005

[Study on the combination of preozonation and post-ozonation-BAC process for drinking water treatment].

This study was conducted to illustrate the effectiveness of preozonation or O3-BAC or combination of these two process in controlling DBPs for treating a dam source water in South China through SBR and continuous flow (200 L/h) experiments and the variables in the treatment train included the point of preozonation with respect to coagulation; the point of ozonation with respect to BAC, the ozone dosage required for preozonation and the Br- content of raw water. Results indicated the reduction in DBP formation potential closely paralleled the reduction in UV absorbance, and trihalomethane and haloacetic acid formation potential can be removed under a dose of preozone at 0.5 - 1.0 mg/L, at the same time, ozone by-products (bromate and formaldehyde) can be controlled in low level. The continuous flow experiment results show that combination of preozonation and O3-BAC process has obviously positive effects on the removals of particles with a size above 2 microm, COD(Mn), and TOC. However, DBPs formation can be controlled by the removal of organic matters.

Charcoal↗
PubMed2006

[Study on determination of trace nitrite and reaction mechanism by two-wavelength negative absorption-catalytic spectrophotometry].

A new method was proposed for the determination of trace nitrite by two wavelength negative absorption catalytic spectrophotometry based on the catalysis of nitrite on the oxidation fading reaction of acridine orange by potassium bromate in phosphoricacid medium. The additive value of negative absorbances at two wavelengths was linear to the nitrite concentration in the range of 1.0 x 10(-5)-5.0 x 10(-7) mol x L(1). The method has been used to the determination of nitrite in environment water sample with satisfactory

English Abstract↗
PubMed1990

[Bromatometric determination of oxprenolol].

A bromatometric method was elaborated for the quantitative determination of oxprenolol. 15 to 150 mg of oxprenolol dissolved in 10 cm3 of water is brominated by adding 20.00-40.00 cm3 of 0.02 or 0.1 N potassium bromate solution followed by 0.5-3 g of potassium bromide and 1-10 cm3 of 10% w/w hydrochloric acid. After a reaction time of 15 min. 2-10 cm3 of 10% w/w potassium iodide solution is added followed by 20-40 cm3 of chloroform. The liberated iodine is titrated with standard 0.1 N or 0.01 N sodium thiosulphate solution. A blank titration is also performed and the oxprenolol content is calculated from the difference of the two titrations. Under these conditions one oxprenolol molecule reacts with six bromine atoms. The relative standard deviation is 1.31%.

Bromine↗
PubMed1981

Bromination methods for determination of phenylephrine hydrochloride in nose drops, salicylamide in tablets, and tetracycline hydrochloride in capsules.

Two methods, kinetic and titrimetric, based on an electrophilic substitution reaction with bromine, are described for the assay of phenylephrine hydrochloride in nose drops, salicylamide in tablets, and tetracycline hydrochloride in capsules. The kinetic method depends on the linear relationship between concentration of the drug (microgram/mL) and time (s) for nuclear monobromination, indicated by bleaching of the methyl orange acid color. The titrimetric method is based on addition of excess of bromate-bromide with subsequent determination of excess bromine by an iodide-thiosulfate procedure. This method is also used to count the number of bromine atoms necessary for the electrophilic substitution reaction. Preservatives or tablet-capsule bases do not interfere in either method. Recoveries of drugs added to laboratory-prepared samples were good. As indicated by the F-test, the methods are equally reproducible.

Bromine↗
PubMed1981

Improved 4-aminoantipyrine colorimetry for detection of residual hydrogen peroxide in noodles, fish paste, dried fish, and herring roe.

Improved 4-aminoantipyrine (4-AA) colorimetry was developed for the detection of minute quantities of residual hydrogen peroxide in several kinds of food. Hydrogen peroxide in the sample was stabilized with potassium bromate and extracted with cold methanol. The methanol extract was diluted with phosphate buffer, protein was eliminated with zinc sulfate, and the extract was reacted with phenol, 4-AA, and peroxidase to the stable quinoneimine dye. The weak color solution was purified with Florisil column chromatography, concentrated, and determined by colorimetry. Recoveries of hydrogen peroxide from samples fortified at 0.5, 2, and 10 ppm ranged from 70.7 +/- 8.9 to 98. 5 +/- 1.2%. Color development was linear with amount of H2O2 from 0.5 to 20 micrograms, corresponding to 0.05-2 ppm in samples.

Ampyrone↗
PubMedDate not supplied

Enhancement of ethylenethiourea recoveries in food analyses by addition of cysteine hydrochloride.

The effectiveness of cysteine hydrochloride (Cys-HCl) as a preservative of ethylenethiourea (ETU) in product matrixes and during analysis was studied. ETU recoveries were adversely affected by certain product matrixes when fortified directly into the product. Recoveries in 8 selected food items were 0-92% when analyzed 30 min after fortification and 0-51% when analyzed after 24 h. When Cys-HCl was added to product prior to fortification, recoveries increased to 71-95% even after frozen storage for 2-4 weeks. Cys-HCl was added during analysis of 53 untreated items. Recoveries improved an average of 15% with Cys-HCl. Without Cys-HCl, recoveries were erratic (20-98%), but with Cys-HCl, recoveries were 68-113%. Other antioxidants (sodium sulfite, butylated hydroxyanisole, butylated hydroxytoluene, and vitamins A and C) also were evaluated as ETU preservatives. When lettuce was treated first with sodium sulfite and then fortified with ETU, recoveries averaged 86%; without sodium sulfite, they averaged 1%. The other antioxidants were less effective for preserving ETU in lettuce, giving only 8-46% recoveries. The effect of oxidizers (potassium bromate, sodium hypochlorite, and hydrogen peroxide) on ETU recovery was also determined. Recovery of ETU from a baby food product (pears and pineapple) was 82%; with oxidizers, recoveries were 0-8%.

Antioxidants↗
PubMedDate not supplied

[Acute intoxication by cosmetics].

Intoxications due to cosmetics are of various types, but certain substances may be particularly harmful, especially when the constituants include acetone, boric acid and borates, ethyl alcohol, bromates, formol, methyl alcohol, propylene glycol, thallium, thioglycolate.. Every cosmetic substance may induce accidental intoxications. Most often, fluid cosmetics are absorbed either by children or by feeble-minded subjects. In all intoxication, one must take account of the age and weight of the patient, of the quantity absorbed, of the toxicity and of the constituants of the substance.

Adolescent↗
PubMed1994

Antibody binding of circulating ergot alkaloids in cattle grazing tall fescue.

Direct evidence linking alkaloids found in endophyte-infected tall fescue forage with the livestock disorder known as fescue toxicosis is lacking. Physiologic effects of fescue toxicosis include reduced serum prolactin concentration in cattle. A monoclonal antibody specific to the lysergic moiety of ergot alkaloids was developed in mice after creating an immunogen by linking lysergol to human serum albumin. The antibody was specific to the lysergic moiety and, therefore, it cross-reacted with ergot alkaloids, lysergic acid, and lysergol. The antibody did not cross-react with alkaloid derivatives that had bromated or hydrogenated lysergic ring moieties. Fescue toxicosis conditions were elicited in yearling Angus steers by permitting them to graze endophyte-infected tall fescue containing > 650 micrograms/kg of ergovaline for 60 days. Passive immunization of steers by infusion of the monoclonal antibody increased serum prolactin concentration by 7 ng/ml, beginning immediately after infusion. Control steers did not respond to treatment with bovine serum albumin. Active immunization of yearling Angus heifers with immunogens containing lysergol or ergonovine linked to human serum albumin resulted in an antibody response.

Animal Feed↗
PubMed1995

Evaluation of certain food additives and contaminants.

This report presents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives and contaminants, with a view to recommending acceptable daily intakes for humans, and to prepare specifications for the identity and purity of food additives. The first part of the report contains a general discussion of principles governing the toxicological evaluation of food additives and contaminants, including flavouring agents, and the establishment and revision of specifications, with comments concerning limits for arsenic, lead and heavy metals. A summary follows of the Committee's evaluations of toxicological data on various specific food additives (including tert-butylhydroquinone, mineral oils, waxes and alitame) and on beta-cyclodextrin, nitrate, nitrite, potassium bromate and the contaminants ochratoxin A and patulin. Annexed to the report are a table summarizing the committee's recommendations for acceptable daily intakes of these substances and changes in the status of specifications, and a list of further toxicological studies required or desired.

Antioxidants↗
PubMed1993

[Substitution of ascorbic acid for potassium bromide in the making of French bread].

The potassium bromate (PB) is the flour improving additive for bread making, most widely used in Venezuela. This additive has been reported to have hazardous effects. For this reason it has been forbidden in various countries. In order to find a substitute for PB, the feasibility of using ascorbic acid (AA) in bread making flours was considered. Flours with 80, 40 and 20 ppm of AA were tested and contrasted with an experimental and industrial flour with 80 ppm of PB, maximum quantity allowed by the Venezuelan Legislation. The effect of these additives was evaluated on French bread, of high consumption in our country. It was found that the bread prepared using the flour containing 20 ppm of AA did not present significant differences from those made out of the pattern flour, concerning their organoleptic and physico-chemical properties. It was demonstrated that it is technically feasible to replaced 80 ppm of PB for 20 ppm of AA in the flours, without affecting the bread acceptability.

Animals↗
PubMedDate not supplied

[Significance of bromide levels in evaluation of the hemato-encephalic barrier during acute viral meningitis].

INTRODUCTION: Inflammatory diseases of the CNS are associated with increased permeability of blood-brain barrier due to vasculitis of cerebral blood vessels leading to regional ischaemia and necrosis. Many substances pass easily from the serum into the CSF through inflamed and damaged blood-brain barrier. Bromide partition test is one of the parameters for evaluation of the blood-brain barrier integrity during CNS inflammatory diseases. As early as 1929 Walter published a monograph on blood-brain barrier accentuating the value of bromide partition test for evaluation of the functional status of blood-brain barrier. In healthy individuals bromide partition test usually ranges from 2.9-3.5. In most patients with TB meningitis bromide partition test remains below 1.6 while it is usually higher in patients with serous meningitis of other aetiologies. However, the low bromide partition test may associate also some other viral and other serous meningitides accompanied with severe lesions of the blood-brain barrier, resulting in increased passage of sodium bromide from the serum into the CSF, so that the serum/CSF ratio is lower. The aim of th study was to calculate and analyze the results of bromide partition test in patients with acute viral meningitis and hyperproteinorachia above 0.70 g/l and to calculate and analyze the results of bromide partition test in patients with TB and parasitic meningitis. The results of bromide patirion tests were compared with results of other parameters for evaluation of the blood-brain barrier function. METHOD: Titration method was used to determine the serum sodium bromide and CSF ratio. Sodium bromide oxidation into sodium bromate was the principle, where addition of potassium iodide is followed by release of equivalent amount of elementary iodide. Iodide is titrimetrically evidenced with thyosulphate, with starch as an indicator. In addition to bromide partition test functional condition of blood-brain barrier was also evaluated by albumin coefficients, albuminorachia and total proteinorachia. RESULTS: In 6 of 30 patients (20%) with acute viral meningitis the bromide partition ratio was below 1.6, suggesting severe damage of blood-brain barrier in these patients: albumin coefficients exceeded 16.7 (mean = 24.7), albuminorachia was over 0.90 (mean = 1.38 g/l), and total proteinorachia over 3.0 g (mean = 3.1 g/l). The aetiology was confirmed in all patients: lymphocyte choriomeningitis virus in 5, COX B1 in one. Values of bromide partition test were higher on follow-up examination, and values of other parameters decreased, suggesting restitution of blood-brain barrier. The results are given in Table 1. Most severe damage of blood-brain barrier was evidenced in patients with lymphocyte choriomeningitis. Parameters for evaluation of functional condition of blood-brain barrier in patients with lymphocyte choriomeningitis and TB meningitis with most severe damage of the barrier, were compared. The results are given in Table 2. No differences between the compared parameters were found, i.e. no difference in the severity of blood-brain damage. Bromide patition test values were below 1.6 in all patients with TB meningitis and in 3 of 5 patients with parasitic meningitis. DISCUSSION: Numerous studies have shown that bromide patition test value during TB meningitis was usually below 1.6. This is probably due to hypersensitivity reaction of the meninges to tuberculin which is located intrathecally and leads to blood-brain barrier damage. Use of antituberculous drugs does not affect the bromide partition test values in early stages of the disease. In all of our 15 patients with TB meningitis the bromide partition test values were below 1.6, coinciding with reference reports. However, we also measured bromide partition test values below 1.6 in 6 (20%) of 30 patients with acute viral meningitis with proteinorachia above 0,70 g/l (ABSTRACT TRUNCATED).

Acute Disease↗
PubMedDate not supplied

Phase III interlaboratory study of FETAX. Part 3. FETAX validation using 12 compounds with and without an exogenous metabolic activation system.

FETAX (Frog Embryo Teratogenesis Assay-Xenopus) is a 96-h whole-embryo developmental toxicity screening assay that can be used in ecotoxicology and in detecting mammalian developmental toxicants when an in vitro metabolic activation system is employed. A standardized American Society for Testing and Materials (ASTM) guide for the conduct of FETAX has been published, along with a companion atlas that helps in embryo staging and in identifying malformations. As part of the ASTM process, an interlaboratory validation study was undertaken to evaluate the repeatability and reliability of FETAX and to evaluate the potential teratogenic hazard of 12 compounds. Three different laboratories participated in the study. All three participating laboratories had extensive experience with the assay. FETAX intralaboratory and interlaboratory variability, as judged by coefficients of variation, were very low. Potential teratogenic hazard was evaluated using two major criteria from FETAX experiments employing metabolic activation systems (MAS). These were the teratogenic index TI (TI = 96-h lc(50)/96-h ec(50) (malformation)) and the minimum concentration that inhibits growth (MCIG). A compound was considered teratogenic by this criterion when the MCIG was significantly different from controls at concentrations below the 30% level of the MAS 96-h lc(50). Based on the results of this and other studies, a decision table was constructed in order to evaluate additional studies. Severity of malformations caused, especially near the MAS 96-h ec(50) (malformation), were also evaluated. Four compounds were non-teratogenic but two compounds were clearly teratogenic. The remaining six compounds were ranked as equivocal teratogens. The results were discussed in light of the difficulty of producing an adequate decision table. FETAX proved to yield repeatable and reliable data as long as care was taken during range-finding and technicians were adequately trained. The MAS was essential in using FETAX to predict developmental hazard in mammals, and still requires further development.

Acetates↗
PubMedDate not supplied

Hypohalites and related oxidants as chemiluminescence reagents: a review.

This review concerns the use of hypochlorite, hypobromite and related oxidants (such as N-bromosuccinimide and 1,3-dibromo-5,5-dimethylhydantoin) as chemiluminescence reagents and includes references to 249 papers that were published prior to mid-2003. Particular emphasis has been placed on proposed emitting species and the mechanisms of the light-producing pathways. The analytical applications of this chemistry have been summarized in three tables: (1) quantification of hypohalites and related compounds (including halides, which are initially oxidized); (2) enhancement or inhibition of luminol chemiluminescence; and (3) direct chemiluminescence reactions with hypohalite reagents.

Bromates↗
PubMed2002

Salt effects on caffeine solubility, distribution, and self-association.

In this investigation, salt effects on monomeric solubility and distribution are separated from self-association for caffeine. For self-associating compounds, the Setschenow equation is inadequate because it does not separate salt effects into their different contributions. Solubilities of caffeine, theophylline, and theobromine were determined in water and salt solutions at 25 degrees C. Caffeine, theophylline, and theobromine solubilities decreased with added Na(2)SO(4) or NaCl (i.e., salting-out) and increased with added NaClO(4) or NaSCN (i.e., salting-in). Caffeine distribution coefficients (D(W/O)) also decreased with added Na(2)SO(4) or NaCl and increased with added NaClO(4) or NaSCN. To separate salt-caffeine effects from salt effects on caffeine self-interaction, salting parameters (k(s)) were calculated from D(W/O) at infinite dilution instead of solubilities with the Setschenow equation. Caffeine k(s) values were smaller than the Setschenow constants (K) indicating that, for caffeine, K is not simply a salting-in/out parameter. Distribution data were used to characterize caffeine self-association using either a dimerization model (k(d), dimerization constant) or an isodesmic model (k(iso), stepwise association constant). Caffeine self-association constants (k(d) or k(iso)) decreased with NaClO(4) or NaSCN and increased with Na(2)SO(4) or NaCl.

Bromates↗
PubMed1998

Release of two peripheral proteins from chloroplast thylakoid membranes in the presence of a Hofmeister series of chaotropic anions.

The dissociation of two peripheral spinach (Spinacia oleracea L.) thylakoid membrane proteins, coupling factor CF1 and ferredoxin-NADP+-oxidoreductase, in the presence of chaotropic sodium salts has been investigated, using monospecific antibodies against the proteins as probes. Release of both proteins followed the Hofmeister series of anions (Cl- < NO3- < Br- < I- < SCN-). In mixtures, the different salts had an additive effect. In addition, there were also qualitative differences in the action of the anions, such that NaI and NaSCN led to a different concentration and time dependence of the dissociation of the peripheral proteins from thylakoids. An analysis of the temperature dependence of protein release showed that the more chaotropic ions reduced the activation energy required for the dissociation of the proteins from their binding sites on the membrane. The addition of sugars (glucose, sucrose, or trehalose) reduced the amount of protein released from the membranes in the presence of NaI or NaSCN.

Binding Sites↗
PubMed2000

Comparison of mono- and dichlorinated tyrosines with carbonyls for detection of hypochlorous acid modified proteins.

Hypochlorous acid is a potent oxidant capable of oxidizing and chlorinating proteins. Based on its indiscriminant reactivity, it is proposed to play a major role in tissue damage associated with a range of inflammatory diseases. We have determined the relative tendencies for formation of protein carbonyls, chlorinated tyrosine residues, and epitopes recognized by an antibody raised against hypochlorous acid oxidized protein (HOP-1) when albumin is treated with hypochlorous acid. We have also tested the specificity of the HOP-1 antibody by measuring how effectively it recognizes proteins oxidized by hypobromous acid. 3-Chlorotyrosine, along with a new marker of hypochlorous acid dependent protein modification, 3, 5-dichlorotyrosine, was formed at the lowest doses of hypochlorous acid that were capable of generating protein carbonyls. Comparatively high doses of hypochlorous acid were needed to generate epitopes recognized by HOP-1, which were also produced by hypobromous acid. Our study demonstrates that it is advantageous to measure protein carbonyls and HOP-1 epitopes in conjunction with chlorinated tyrosines when attempting to identify the oxidants responsible for inflammatory tissue damage.

Animals↗
PubMed2000

On the irreversible destruction of reduced nicotinamide nucleotides by hypohalous acids.

Degradation of the reduced pyridine nucleotides NMNH and NADH by HOCl involves two distinct stages: a fast reaction, k = 4.2 x 10(5) M(-1) s(-1), leads to generation of stable pyridine products (Py/Cl) with a strong absorption band at 275 nm (epsilon = 12.4 x 10(3) M(-1) cm(-1) in the case of NMNH); secondarily, a subsequent reaction of HOCl, k = 3.9 x 10(3) M(-1) s(-1), leads to a complete loss of the aromatic absorption band of the pyridine ring. HOBr and HOI(I(2)) react similarly. Apparent rate constants of the primary reactions of HOX species with NMNH at pH 7.2 increase in the order HOCl (3 x 10(5) M(-1) s(-1)) < HOBr( approximately 4 x 10(6) M(-1) s(-1)) < HOI(I(2))( approximately 6.5 x 10(7) M(-1) s(-1)). HOBr reacts fast also with the primary product Py/Br, k approximately 9 x 10(5) M(-1) s(-1), while the reactions of HOI and I(2) with Py/I are slower, approximately 1.4 x 10(3) M(-1) s(-1) and >6 x 10(3) M(-1) s(-1), respectively. Halogenation of the amide group of NMN(+) by HOX species is many orders of magnitude slower than oxidation of NMNH. Taurine inhibits HOCl-induced oxidation of NADH, but HOBr-induced oxidation is not inhibited because the taurine monobromamine rapidly oxidizes NADH, and oxidation by HOI(I(2)) is not inhibited because taurine is inert toward HOI(I(2)). Also sulfur compounds (GSH, GSSG, and methionine) are less efficient in protecting NADH against oxidation by HOBr and HOI(I(2)) than against oxidation by HOCl. The results suggest that reactions of HOBr and HOI(I(2)) in a cellular environment are much more selectively directed toward irreversible oxidation of NADH than reactions of HOCl. It is noteworthy that the rather inert N-chloramines react with iodide to generate HOI(I(2)), i.e., the most reactive and selective oxidant of reduced pyridine nucleotides. NMR investigations show that the primary stable products of the reaction between NMNH and HOCl are various isomeric chlorohydrins originating from a nonstereospecific electrophilic addition of HOCl to the C5&dbond;C6 double bond of the pyridine ring. The primary products (Py/X) of NMNH all exhibit similar absorption bands around 275 nm and are hence likely to result from analogous addition of HOX to the C5&dbond;C6 bond of the pyridine ring. Since the Py/X species are stable and inert toward endogeneous reductants like ascorbate and GSH, they may generally be useful markers for assessing the contribution of hypohalous acids to inflammatory injury.

Bromates↗