Determination of Chlorine and Bromine in Halogenated Butyl Rubber and Stoppers by Oxygen Flask Combustion-Ion Chromatography

The sample was cut into small cubs of about 1 mm³, and 10.0 mg of the sample was taben and wrapped up in a piece of ashless filter paper. 10 mL of water was added to the oxygen flask, and then oxygen was introduced through the oxygen flask at a flow rate of 2 L·min^-1 for 1min. The filter paper of the wrapped sample was ignited and transferred quickly into the oxygen flask, which was sealed tightly and kept standing for 15 min. After shaking, the solution was taken out for IC analysis. Dionex AS19 anion analytical column (4 mm×250 mm, 5.0 μm) with column temperature of 30℃ was used for seperation, and 20 mmol·L^-1 KOH solution was used as mobile phase for elution at a flow rate of 1.0 mL·min^-1. Linear relatioships were found beween values of peak area and concentration of Cl^-, Br^- in the ranges of 0.5-10 mg·L^-1 and 1.0-20 mg·L^-1 respectively. The detection limits (3S/N) were 0.003 mg·L^-1 for Cl^- and 0.025 mg·L^-1 for Br^-. Values of recovery obtained by standard addition method were in the ranges of 96.9%-106% for Cl^- and 90.4%-108% for Br^-, and RSDs (n=6) were less than 3.0%. The method was suitable for use to distinguish and determine the halogens in the halogenated butyl rubber and stoppers.