有机相进样-电感耦合等离子体原子发射光谱法测定植物油脂中聚二甲基硅氧烷的含量  

Determination of Polydimethylsiloxane in Vegetable Oil by Organic Phase Sampling-Inductively Coupled Plasma Atomic Emission Spectrometry

作　　者：李锦才[1] 陈晓燕[1] 陈树娣[1] 李胜 徐董育[1] 吴蓝洁 LI Jincai;CHEN Xiaoyan;CHEN Shudi;LI Sheng;XU Dongyu;WU Lanjie(Shenzhen Academy of Metrology Quality and Inspection,Shenzhen 518131,China)

机构地区：[1]深圳市计量质量检测研究院,深圳518131

出　　处：《理化检验（化学分册）》2023年第9期1105-1110,共6页Physical Testing and Chemical Analysis(Part B:Chemical Analysis)

基　　金：深圳市自然科学基金(JCYJ2021032414180412);国家市场监管管理总局“揭榜挂帅”科技项目(2021YJ029)。

摘　　要：为解决现有测定植物油脂中聚二甲基硅氧烷的电感耦合等离子体原子发射光谱法(ICP-AES)存在因标准溶液与样品基质差异较大、塑料材质溶出硅而导致测定结果偏高的问题,提出了题示方法,并考察了稀释剂的类型和性质、稀释比例以及容器材质对测定结果的影响。试验得出有利于等离子体稳定的稀释剂参数范围:蒸气压(20℃)0.032~0.287kPa,密度(20℃)0.798~0.881g·mL^(-1),运动黏度(20℃)2.47~15.8mm2·s^(-1)。当待测溶液的运动黏度(20℃)小于6.35mm2·s^(-1)时,工作曲线的相关系数大于0.9995,以ICP溶剂为稀释剂,当植物油脂与稀释剂的稀释比例为1∶4(质量比)时,方法检出限较低。在聚二甲基硅氧烷的提取过程中,不论塑料离心管是否经过加热处理均会使提取液中的待测物质含量有着不同程度的增加,玻璃材质的比色管则无影响。优化的试验条件如下:取4g样品置于50mL玻璃比色管中,加入ICP溶剂至总质量为20g,混匀,于70℃超声提取2h,再加入15mL 1.37mol·L^(-1)盐酸溶液充分混匀,静置分层,取上清液置于玻璃比色管中,采用ICP-AES测定其中聚二甲基硅氧烷的含量。结果表明,通过加入适量的空白植物油脂的基质匹配法有效校正了样品基质对测定结果的干扰,聚二甲基硅氧烷的质量分数在0.500~10.0mg·kg^(-1)内与对应的硅元素发射强度呈线性关系,检出限为0.30mg·kg^(-1)。按照标准加入法进行回收试验,回收率为95.6%~106%,测定值的相对标准偏差(n=7)为1.1%~3.4%。采用本法与GB 5009.254-2016第二法火焰原子吸收光谱法测定同一实际加标样品,两种方法所得测定结果一致。In order to solve the problem of high determination results caused by significant differences between the standard solution and the sample matrix,and the dissolution of silicon from plastic materials in the existing method of inductively coupled plasma atomic emission spectrometry(ICP-AES)for the determination of polydimethylsiloxane in vegetable oil,the method mentioned by title was proposed,and effects of the types and properties of diluents,dilution ratios,and container materials on the determination results were investigated.The range of diluent parameters which was beneficial for plasma stabilization was optimized by the test,with vapor pressure(20℃)from 0.032kPa to 0.287kPa,density(20℃)from 0.798g·mL^(-1) to 0.881g·mL^(-1),and kinematic viscosity(20℃)from 2.47mm2·s^(-1) to 15.8mm2·s^(-1).When the kinematic viscosity(20℃)of the solution to be tested was less than 6.35mm2·s^(-1),the correlation coefficient of the working curve was above 0.9995.When the dilution ratio of vegetable oil to diluent was 1∶4(mass ratio),the detection limit of the method was lower,using ICP solvent as the diluent.In the extraction process of polydimethylsiloxane,no matter whether the plastic centrifuge tube was heated or not,the content of the substance to be tested in the extraction solution increased to varying degrees,while there was no effect using the colorimetric tube made of glass material.The optimized experimental conditions were as follows.The sample(4g)was taken and placed in a 50 mL-glass colorimetric tube.ICP solvent was added till to a total mass of 20g,and then the mixture was mixed well and extracted by ultrasonic for 2hat 70℃.15mL of 1.37mol·L^(-1) hydrochloric acid solution was added,following mixing well and settling to layer.The supernatant was taken and placed into a glass colorimetric tube,in which polydimethylsiloxane was determined by ICP-AES.As shown by the results,the matrix matching method effectively corrected the interference of the sample matrix on the determination results by adding a

关 键 词：植物油脂 电感耦合等离子体原子发射光谱法(ICP-AES) 基质匹配 容器材质 聚二甲基硅氧烷 

分 类 号：O657.3[理学—分析化学]