Research On The Detection Of Bromate In Drinking Water And Flour Products

As the disinfection by-product in bottled drinking water, bromate (BrO3-) got increasingly concerned. Bromate was used as flour additive in the past, which can significantly improve the rheological properties of dough, such as gluten strength, flexibility and extensibility, as well as the effectiveness and taste of baked products. However, bromate is determined as a potential human carcinogen. Excessive consumption of bromate would damage human blood system, central nervous system and kidney. Based on this background, bromate had been forbidden used in food in many countries include China. In the presented paper, the detection methods for bromate was developed, especially the ion chromatography determination and the pretreatment methods.(1) A method was developed to determine the trace bromate in drinking water by ion chromatography (IC), comparing with the rapid detection bromate apparatus. The IC determination was performed in a Shodex IC SI-52 4E (250 mmx4.0 mm) analysis column (45℃) by 300μL injection and using 3.6 mM Na2CO3 as a mobile phase with the flow rate of 0.7 mL/min. A good linearity of bromate was obtained within the range of 10-100μg/L (r>0.999). The limit of detection for the method was 7.0μg/L. The average recoveries of bromate were ranged from 71% to 97% with the relative standard deviations of less than 4%(n=6).(2) A method for determination of BrO3- and Br- using ion chromatograghy coupling with inductively coupled plasma mass spectrometry (IC-ICP-MS) was developed. BrO3 and Br were separated on a Hamilton PRP X-100 (150x4.1mm,10μm) column guarding with a On-guard II RP (4 X50mm) column with 10mmol/LNH4NO3 eluent solution at 2 mL/min. By using 200μL sample loop, the detection limits for BrO3- and Br- were 0.35μg/L and 0.36μg/L, respectively. BrO3- had good linearity in range 4.8 ng/L-160.0 ng/L. The standard solution linear equation was y=250.31x-45.43, R2=0.9999. Br- had good linearity in range 4.2ng-140.0ng/L. The standard solution linear equation was y=186.84x-127.10, R2=0.9994. Recoveries of spiked samples were 98.9%-109.5% and 97.4%-106.1%, respectively.(3) A method for the determination of bromate and bromide in flour was developed by ion chromatography (IC) coupled with accelerated solvent extraction (ASE). The bromate and bromide were extracted with ultra-pure water and quartz sand as a base material at 100℃and 10.0 MPa. The determination was performed in a Shodex IC SI-52 4E (250 mm×4.0 mm) analysis column (45℃) by 300μL injection and using 3.6 mM Na2CO3 as a mobile phase with the flow rate of 0.7 mL/min. Agood linearity of binary mixtures of bromate and bromide was obtained within the range of 1.00-6.00 mg/kg (r>0.9995). The limit of detection for the method was 2.1 ug/kg. The average recoveries of both bromate and bromide were ranged from 94.06%-102.77% with the relative standard deviations of less than 3%(n=6).