Bromate determination detection

Separation and detection methods Ion chromatography is routinely used for the isolation of bromate. Diverse detection methods are mentioned in the literature, including isotope dilution analysis (Creed and Brockhoff 1999), conductivity measurement (Jackson et al. 1998), fluorimetric determination (Gahr et al. 1998), ICP-MS (Seubert and Nowak 1998) and spectrophotometry (Achilii and Romele 1999),... 

The results obtained for the vast majority of the laboratories carrying out the ISO 15061 IC method were considered to be fit for the purpose. In addition to this method, five alternative methods suitable for trace bromate determinations were also considered, namely on-line IC-ICP-MS, simple on-line column chromatography ICP-MS, IC with chlorpromazine post-column reaction and colorimetric detection, and fluorescence quenching with Carbostyril (with pre-treatment), which are all capable of achieving a bromate detection limit below 1 xg/L. A field method with methylene blue and fluorescence quenching with Carbostyril without sample pretreatment did not lead to satisfactory results at this level of bromate concentrations. 

Sensitivity for bromate determination has been improved by more than a factor of 10 through the use of a postcolumn derivatization reaction in which HI is generated in situ from K1 and reacts with bromate to form the triiodide anions (la ). In 2000, the U.S. EPA published Method 317.0, which uses postcolumn derivatization with o-dianisidine this reacts with the eluting bromate to form a chromophore, which is then measured with a UVA is detector. This method offers excellent limits of detection, below 1 p-g/L, for bromate, as well as for chlorite and chlorate. 

The titrations should be carried out slowly so that the indicator change, which is a time reaction, may be readily detected. If the determinations are to be executed rapidly, the volume of the bromate solution to be used must be known approximately, since ordinarily with irreversible dyestuff indicators there is no simple way of ascertaining when the end point is close at hand. With the highly coloured indicators (xylidine ponceau, fuchsine, or naphthalene black 12B), the colour fades as the end point is approached (owing to local excess of bromate) and another drop of indicator can be added. At the end point the indicator is irreversibly destroyed and the solution becomes colourless or almost so. If the fading of the indicator is confused with the equivalence point, another drop of the indicator may be added. If the indicator has faded, the additional drop will colour the solution if the end point has been reached, the additional drop of indicator will be destroyed by the slight excess of bromate present in the solution. 

Another interesting TLC method for the isolation and determination of bromate ion in flour dough and breads has been developed [59]. It involves extraction of BrOj from foodstuff, purification on alumina column, TLC separation on silica gel layer developed with water -1- -butanol + n-propanol (1 1 3), and quantification by densitometry. Bromate ion down to 0.1 pg in bread (1.0 g) was detected with tohdin-FIQ reagent. 

Wagner P, Pepich BV, Pohl C, Srinivasan K, De Borba B, Lin R, Munch DJ (2009) EPA Method 302.0. Determination of bromate in drinking water using two-dimensional ion chromatography with suppressed conductivity detection. U.S. EPA, Cincinnati, OH, Available at http //water.epa.gOv/scitech/drinkingwaterAabcert/upload/met302 0.pdf... 

The corresponding sodium salts, which are cheaper, serve equally well. Excess of potassium bromide and hydrochloric acid is added to a solution of the substance to be estimated and the bromate, in the form of a volumetric solution (usually N/5), is run in. The end point (shown by the presence of free bromine) is detectable, quite sharply, by spotting on starch-iodide paper as external indicator. Alternatively the end point may be determined by adding a known amount of bromate in excess, then potassium iodide, and titrating the liberated iodine with thiosulphate. 

Bodor, R., Kaniansky, D., Masdr, M., Silleova, K., Stanislawski, B., Determination of bromate in drinking water by zone electrophoresis-isotachophoresis on a column-coupling chip with conductivity detection. Electrophoresis 2002, 23, 3630-3637. 

The determination of propiolactone with thiosuUate has been described by T ler and Reering it cannot as a rule be applied to the homologs (see section VI.4.C ). The determination of acrylic add with a mixture of potassium bromate and hromide and that of the total acidity by direct -titrstion with sodium methylate in anhydrous methanol have been discussed in the booklets edited by members of the Celanese Corporation of America, They recommend mass cpeciro-graphy for the evaluation of the lactons content of oommerical products and for the detection of certain impurities. 

Bromine. Convergence of bromide, bromate and hydrochloric acid streams leads to formation of the unstable bromine reagent that can be added to the main analytical channel of a flow injection system. The approach was exploited for the spectrophotometric determination of acetylcysteine in sachets [100]. A noteworthy feature is that in-line waste treatment involving elimination of excess bromine was performed by adding an ascorbic acid stream to the main channel after detection. 

More recently, Poul et al (2004) tested iodate alongside bromate in two different in vitro tests - the alkaline Comet assay and the cytokinesis-block micronucleus assay. Iodate concentrations of up to lOmM failed to induce primary DNA damage as determined in the Comet assay, while bromate significantly increased damage at concentrations of 2.5 mM and above. The results of the Comet assay could be confirmed by those obtained in the second test system, which detects not only clastogenic events, but also... 

A flow injection system with a micro-column of strong anion exchanger has been interfaced with an ICP-mass spectrometer via a microconeentrie nebulizer to perform on-line separation and trace determination of bromate in drinking waters (Elwaer, 1999 Elwaer et al, 2000). Method development studies examined the effect of sample injection volume, carrier stream flow rate and eluent concentration on system response. B asic performance data for this method were limit of detection, 0.13 ag/L (500 p-L sample injection) analysis time, 5 minutes per sample precision, 2.6%RSD (at5 g/L). 

T. Takayanagi, M. Ishida, J. Mbuna, R. Driouich and S. Motomizu, Determination of bromate ion in drinking water by capillary zone electrophoresis with direct photometric detection, J. Chromatogr. A,... 

Determination of bromate in drinking waters by 1C with ICP-MS detection... 

The halogens may be determined polarographically by reduction of their halate form (except for chlorate). Bromide, for example, may be determined by DPP after oxidation to the bromate species yielding a cathodic current at 1.53 V versus SCE. The detection limit is 1 X 10 moll . Possible interferences would arise from iodate reduction. 

The combination of the enrichment and enhancement effects in CAdSV has been successfully used for reactions involving either a single or a two-electron reduction. As indicated in Table 3, the inclusion of oxidants, such as nitrite, nitrate, peroxide, bromate, chlorite, chlorate, and hydrogen ions, in solutions have been shown to result in (1) considerable amplification of the voltammetric responses obtained with AdSV, (2) a reduction in detection limits, and (3) improved selectivity. This catalytic current generation has been successfully used for the AdSV determination of inorganic substances, such as Co, Cr,... 

Chiu and Eubanks reported a simple and rapid method based on the strong absorption of the tribromide generated from bromide under an excess of hydrobromic acid. This procedure was used for the determination of bromate by using IC with postcolumn derivatization. Stable tribromide compounds were formed and detected by UV at 267 nm. The commonly occurring anions in typical drinking water are invisible to the detector and, therefore, do not interfere with analyzed bromate ions. ... 

The U.S. EPA Method 321.8 specifies the use of an anion-exchange column and detection of bromate using inductively coupled plasma-mass spectrometry (ICP-MS) in the atmospheric pressure mode. The U.S. EPA Method 326.0 has been developed for the analysis of ultra trace bromate concentrations in drinking water using a postcol-unm derivatization reaction with Mo(VI). A review of the methods of IC determination of inorganic disinfection byproducts published by U.S. EPA has been conducted by Hautman et al. The ISO standards for the determination of inorganic oxyhalides in water are smnmarized in Table 1, and U.S. EPA methods recommended are listed in Table 2. 

Valsecchi, S. Iseroia, A. PoleseUo, S. CavaUi, S. Ion chromatography determination of trace level bromate by large volume injection with conductivity and spectrometric detection after post column derivatisation. J. Chromatogr. A, 1999, 864, 263-270. 

The resulting Br3 /a-CD complex is subject to UV detection at 265 nm. Using this system, the concentration of bromate in a bottled water sample was determined at 6ngl and the calibration had a linear-regression coefficient of 0.996. A similar method was also used to determine trace amounts of separated iodate and nitrite ions in drinking water. Iodate and nitrite in their individual chromatographic peaks form iodine when HI is introduced, after which iodine reacts with excess 1 to form 13 , which in turn forms an inclusion complex with CD. In this process (7-10), CD shifts the equilibrium in (9) to the right, the total concentration of triiodide ion is increased, and therefore, the sensitivity of detection is improved. 

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