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Method Abstract 120

MA 120 / BROMATE ANALYSIS

ANALYSIS OF BROMATE IN DRINKING WATER BY HPLC AND POST-COLUMN DERIVATIZATION

Bromate is a disinfection by-product that is formed when Ozone reacts with naturally occurring Bromide in drinking water. Bromate is a known animal carcinogen and has also been listed as a Group 2B toxin: probable human carcinogen. The U.S.EPA Method 300.1 employs conductivity as the means of detection which works well for most anions. However, the method is non-specific and coeluting interferences cannot be identified. The more recent U.S.EPA Method 317.0 utilizes a Bromate-specific reagent in a post-column reaction. This allows for a very specific and sensitive assay for Bromate in complex matrices.
 

METHOD

Equipment

  •  LC with a binary pump 
  •  UV/VIS detector
  • Pickering Laboratories dual reagent PCX5200 Post-column derivatization instrument
  • Pickering Laboratories anion-exchange column, 4.6 x 150mm (Cat. No. 0785150)

Reagents

  •  9.0 mM Sodium carbonate
  •  Conc. Nitric acid (70 %)
  •  Potassium bromide
  •  o–Dianisidine dihydrochloride
  •  Methanol

LC Conditions

LC Column Temperature: 42˚C
Sample Injection Volume: 250 μL
LC Flow Rate: 1.3 mL/min
Mobile Phase: 9 mM Na2CO3
  

Post-column Conditions

Post-column System: Pinnacle PCX
Reactor Volume: 0.5 mL
Temperature: 60 ˚C

Reagento–Dianisidine dihydrochloride (Add 40 mL of 70 % HNO3 to 300mL deionized water in a 500mL volumetric flask. Dissolve 2.5g KBr in this solution. Dissolve 250 mg of o–Dianisidine dihydrochloride in 100 mL of Methanol and add to the Nitric acid/KBr solution and dilute to volume.)

Flow Rate: 0.7 mL/min

Detection: UV/VIS detector, λ max = 450 nm

chart-m-120

REFERENCES
U.S.EPA Method 317.0. Determination of inorganic oxyhalide disinfection by-products in drinking water using ion chromatography with the addition of a post-column reagent for trace bromate analysis.
H.P.Wagner, B.V.Pepich, D.P.Hautman and D.J.Munch, J.Chromatography A, 882 (2000) 309 – 319.
C.R.Warner, D.H.Daniels, F.L.Joe and G.W.Diachenko, Food Additives and Contaminants, vol. 13, No.6 (1996) 633 – 638.