提出了管式炉燃烧-离子色谱法测定石墨烯粉体中氟、氯、溴、硫元素含量的方法。样品经冷冻研磨,分取5~10mg置于燃烧舟中,选择自动推进模式,设置燃烧室温度为1050℃,后燃烧时间为160s。样品充分燃烧后,以30%(质量分数)过氧化氢溶液为吸收液,Metrosep A Supp5阴离子色谱柱为分析柱,含3.2mmol·L^-1Na₂CO₃和1.0mmol·L^-1NaHCO₃的混合溶液为淋洗液,采用电导检测器测定其中F^-、Cl^-、Br^-、SO₄^2-的含量,进而换算为氟、氯、溴、硫元素的含量。结果显示:F^-、Cl^-、Br^-、SO₄^2-的质量浓度在一定范围内与其对应的峰面积呈线性关系,检出限(3S/N)为0.05~0.10mg·L^-1;方法用于测定标准物质ERM-EC-680K中氯、溴、硫的含量,所得测定值均在认定值的不确定度范围内;方法用于实际样品分析,未检出溴元素,并且氯、氟、硫元素的测定值与另外6家实验室的基本一致。

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.