Simultaneous Determination of 3 Anions in Flour by IC with Inline Ultra-Filtration

IC with inline ultra-filtration was applied to simultaneous determination of BrO3- , NO2- and NO3- in flour. The sample (10.00 g) was extracted ultrasonically with water for 30 min and the suspension was made up to 100 mL and centrifuged. The supernatant was filtered with the 0.22 μm inline ultra-filtration system. Twenty μL of the filtrate were separated on Metrosep A Supp 7-250 separation column and Metrosep A Supp 4/5 Guard protective column, using 3.6 mmol·L-1 Na2CO3 solution as mobile phase. Inhibitory conductivity detector was adopted in the determination. Linear relationships were kept between values of peak area and mass concentration of BrO3- , NO2- and NO3- in the ranges of 0.20-10.0 mg·L-1, 0.02-2.00 mg·L-1 and 0.25-30.0 mg·L-1 respectively, with detection limits (3S/N) in the range of 0.20-2.50 mg·kg-1. Three flour samples were analyzed by this method, and recovery was tested by standard addition method, giving values of recovery and RSD′s (n=6) in the ranges of 89.0%-110% and 2.2%-4.6% respectively.