Bromate, determination water

Figure 2.1 Ion chromatographic determination of bromate in water (after Ingrand et at, 2002). Reprinted from Trends in Analytical Chemistry, Vol. 21, No. 1, Ingrand eto/., Determination of bromate... , pp. 1-12,2002, with permission from Elsevier...

Previous sections of this chapter discussed the details of newly developed analytical methodologies and strategies for bromate separation and trace quantification. This confirms the current vast interest of the analytical community in bromate determination as a result of ongoing regulatory requirements. The acceptance of such methods depends mainly on the analytical performance as related to accuracy and precision. However, despite all analytical efforts, very little work has been done to investigate the stability of bromate species between sampling and analysis in different water matrices. Studies of bromate stability in water matrices should be carried out before any analytical methodology can be approved. 

In the analysis of raw and drinking water components are of interest that are formed during the chlorination with for instance hypochlorite or chlorine dioxide and are physiologically active. Such components are amongst other bromate- and iodine-containing substances. After concentration of the sample bromate is determined with IC. The limit of the bromate determination is Ipgl. ... 

Thompson, K.C. Guinamant, Jl-. Ingrand, V. Elwaer, A.R. McLeod, D.C. Schmitz, F. Swaef, G. QueauviUer, P. Interlaboratory trial to determine the analytical state-of-the-art of bromate determination in drinking water. J. Environ. Monit. 2000, 2,416-422. 

In alkaline solution the activation parameters are A/f = 22.5 kcal mol- and A5 = —19 cal deg mol, determined from ki values [equation (6)]. The activation parameters for exchange with DgO are the same, within experimental uncertainty. The kinetic salt effect was also studied for this bromate-water oxygen exchange. The experiments in alkaline solution were not successful, but sufficient results were obtained to yield further information germane to the ko and k paths of equation (6). The effects of added cations (Li+, Na+) on oxygen-exchange rates between bromate and water have been discussed in terms of ion association. ... 

To determine the purity of a sample of arsenic(III) oxide follow the general procedure outlined in Section 10.127 but when the 25 mL sample of solution is being prepared for titration, add 25 mL water, 15 mL of concentrated hydrochloric acid and then two drops of indicator solution (xylidine ponceau or naphthalene black 12B see Section 10.125). Titrate slowly with the standard 0.02M potassium bromate with constant swirling of the solution. As the end point approaches, add the bromate solution dropwise with intervals of 2-3 seconds between the drops until the solution is colourless or very pale yellow. If the colour of the indicator fades, add another drop of indicator solution. (The immediate discharge of the colour indicates that the equivalence point has been passed and the titration is of little value.)... 

Discussion. These anions are both determined as silver bromide, AgBr, by precipitation with silver nitrate solution in the presence of dilute nitric acid. With the bromate, initial reduction to the bromide is achieved by the procedures described for the chlorate (Section 11.56) and the iodate (Section 11.63). Silver bromide is less soluble in water than is the chloride. The solubility of the former is 0.11 mg L 1 at 21 °C as compared with 1.54 mg L 1 for the latter hence the procedure for the determination of bromide is practically the same as that for chloride. Protection from light is even more essential with the bromide than with the chloride because of its greater sensitivity (see Section 11.57). 

In situ densitometry has been the most preferred method for quantitative analysis of substances. The important applications of densitometry in inorganic PLC include the determination of boron in water and soil samples [38], N03 and FefCNfg in molasses [56], Se in food and biological samples [28,30], rare earths in lanthanum, glass, and monazite sand [22], Mg in aluminum alloys [57], metallic complexes in ground water and electroplating waste water [58], and the bromate ion in bread [59]. TLC in combination with in situ fluorometry has been used for the isolation and determination of zirconium in bauxite and almnimun alloys [34]. The chromatographic system was silica gel as the stationary phase and butanol + methanol + HCl -H water -n HF (30 15 30 10 7) as the mobile phase. 

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. 

Achilii M, and Romele L (1999) Ion chromatographic determination of bromate in drinking water by post-column reaction with fuchsin. J Chrom... 

Jackson LK, Joyce RJ, Laikhtman M, and Jackson PE (1998) Determination of trace level bromate in drinking water by direct injection ion chromatography. J Chromate A 829 187-192. 

Ion chromatography is used at the City of Lincoln, Nebraska, Water Treatment Plant Laboratory to analyze water samples taken from sampling sites in the distribution system around the city. The common anions determined by IC are not only nitrate, nitrite, fluoride, and sulfate, but also bromate. Bromate is found in the water because the Lincoln plant treats the water with ozone. Adding ozone to the water oxidizes any bromide to bromate. Bromate is regulated at 10 parts per billion (ppb) its concentration must be determined. 

Determination of Inorganic Oxyhalide Disinfection By-products in Drinking Water using Ion Chromatography with the Addition of a Postcolumn Reagent for Trace Bromate Analysis... 

Determination of Bromate in Drinking Waters by Ion Chromatography Inductively Coupled Plasma-MS... 

Creed JT, Brockhoff CA, Martin TD (1997) EPA Method 321.8. Determination of bromate in drinking waters by ion chromatography inductively coupled plasma-mass spectrometry. U.S. EPA, Cincinnati, OH, Available at http //www.epa.gov/microbes/m 321 8.pdf... 

Zakaria P., Bloomfield C., Shellie R. A, Haddad P. R Dicinoski G. W. Determination of bromate in sea water using multi-dimensional matrix-elimination ion chromatography. Journal of Chromatography A 2011 1218(50) 9080-9085. 

The stock solution, ca. 0.3 mol dm-3, of hydrobromic acid was prepared from a twice-distilled sample of the hydrobromic acid. Its bromide content was determined gravimetrically as silver bromide. Triplicate runs agreed to within 0.02%. The silver + silver bromide electrode was of the thermal type, prepared by heating twice recrystallized silver bromate (10 mass percent) and silver oxide (90 mass percent) at a temperature of 820° K. The preparation of the silver oxide, the preparation of the hydrogen electrodes, the design of the cell, the purification of the hydrogen gas, and other experimental techniques, have been described earlier (13,14,15). The water bath in which the cells were immersed was controlled to within 0.02°K. 

Quantitative Determination. — Dissolve 0.10 to 0.15 gm. of sodium bromate, previously dried for twenty-four hours over sulphuric acid, in 20 cc. of water, add 3 gm. of potassium iodide and 5 cc. of hydrochloric acid, and titrate the liberated iodine with decinormal sodium thiosulphate. 

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