高频感应燃烧-红外吸收法测定石墨烯中总硫含量

Determination of total sulfur in graphene by high frequency induction combustion-infrared absorption method

建立了一种低样品用量的高频感应燃烧-红外吸收测定石墨烯中总硫含量的方法。分别考察了助熔剂的种类、用量、叠放顺序,建立工作曲线所用标准物质等因素对测量结果的影响。结果显示对石墨烯样品进行简单的压缩后,使用0.6g铁屑和0.8g钨锡助熔剂,采用铁屑在下、样品中间、助熔剂在上的叠放顺序,使用低合金钢标准物质建立工作曲线,仅需要0.015g石墨烯样品即可以得到稳定可靠的测试结果。方法的检出限为0.0033%,定量限为0.011%,可用于石墨烯中低含量硫的准确测定。使用最优条件测定市售7个厂家共11个石墨烯样品的总硫含量,测定结果为0.082%~3.60%,与仲裁方法艾士卡法的偏差为-0.07%~0.06%,两种方法没有显著差异。测定结果的相对标准偏差为0.73%~1.97%,精密度优于艾士卡法。同时测试结果也表明,市售石墨烯样品中硫元素含量大多不能忽略不计,在石墨烯的应用过程中需引起足够重视。

Sulfur is one of the main impurities in graphene.Sulfur often degrades various excellent properties of graphene to a great extent.The existing test methods have some shortcomings.The shortcomings include large sample volume and long analysis time.This paper established a method for determining the total sulfur content in graphene with low sample consumption.It was achieved by highfrequency induction combustion infrared absorption method.This paper examined the impact of various factors on the measurement.Including the type,amount of flux,stacking order,and the standard material used to establish the working curve.The results showed that only 0.015g of graphene sample was needed to obtain stable and reliable test results.Necessary conditions included optimization of test parameters and compression of graphene samples.The optimal flux type was 0.6g iron filings and 0.8g tungsten tin flux.The optimal stacking order was to place the iron filings below,the sample in the middle,and the flux on top.The optimal working curve was to establish a working curve using low alloy steel standard materials.The detection limit of the method was 0.0033%,and the limit of quantification was 0.011%.It can be used for the accurate determination of low content sulfur in graphene.The optimal conditions were used to determine the total sulfur content of 11 graphene samples from 7 commercial manufacturers.The measurement result was between 0.082%and 3.60%.The deviation from the arbitration method Esca method was between-0.07%and 0.06%.There was no significant difference between the two methods.The relative standard deviation of the measurement results was between 0.73%and 1.97%.The precision was better than the Eskar method,indicating that the results are satisfactory.At the same time,the test results also show that most of the sulfur content in the commercially available graphene samples cannot be ignored.In the application process of graphene,sufficient attention should be paid.