Determination of Fluorine, Chlorine, Bromine and Sulfur Elements in Graphene Powder by Ion Chromatography with Tube Furnace Combustion

A method for the determination of fluorine, chlorine, bromine and sulfur elements in graphene powder by ion chromatography with tube furnace combustion was proposed. The sample was ground by freezing, and an aliquot of 5-10 mg was placed into the combustion boat. The automatic propulsion mode was selected, and the combustion chamber temperature was set at 1 050 ℃, with the post-combustion time of 160 s. After the sample was fully burned, F^-, Cl^-, Br^- and SO₄^2- were determined by conductance detector with 30% (mass fraction) hydrogen peroxide solution as the absorption solution, Metrosep A Supp5 anion column as the analysis column, and the mixed solution containing 3.2 mmol·L^-1 Na₂CO₃ and 1.0 mmol·L^-1 NaHCO₃ as the eluent, and then converted into the contents of fluorine, chlorine, bromine and sulfur. It was shown that linear relationships between values of mass concentration and peak area of F^-, Cl^-, Br^- and SO₄^2- were kept in definite ranges, with detection limits (3S/N) in the range of 0.05-0.10 mg·L^-1. The determined values of chlorine, bromine and sulfur in the reference material ERM-EC-680K by this method were within the uncertainty ranges of the certified values. This method was applied to the analysis of actual sample. Bromine element was not detected, and the determined values of chlorine, fluorine and sulfur elements were basically consistent with those of other 6 laboratories.