Analyzing for Bromine by ICP

Bill was analyzing for Br by ICP-OES. He had several samples in a PET matrix with Br concentrations ranging from 1-18%. Bill inquired about any recommended methods of analysis.

Dear Bill,

I assume that the PET matrix referenced is 10-[3, 5-bis(methoxycarbonyl) phenoxy] decyltriphenylphosphonium bromide. If this assumption is correct, I would like to suggest a Schoeniger (sometimes spelled Schoniger) flask combustion of the sample. This technique involves total combustion of the sample in oxygen which converts nonmetallic elements such as bromide to volatile gaseous compounds. These gases can be collected into a suitable absorbing solution which is typically analyzed by Ion Chromatography but could also be analyzed by ICP. In the case of Br (a reducing agent), typically dilute hydrazine sulfate, should be added to prevent the formation of oxyanions for bromide. In the case of an ICP analysis, this reducing agent should still be used because of the possibility of the formation of molecular bromine which will adsorb readily upon plastic surfaces.

The use of ICP to analyze the Br is preferred because of the outside chance of other oxybromides that may be present (i.e., lower worry-factor). Please refer to the spectral data (below) which shows little to no interference from 'all' of the other elements for line 154.065 nm where we measured a DL of 0.02 ug/mL in our laboratory (i.e., a good signal for a 0.1 ppm Br solution).

Please contact me with any further questions.

Serving you in chemistry,

Paul R. Gaines, Ph.D.
CEO of Inorganic Ventures & Fellow Chemist

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