[Omim]_(6)Mo_(7)O_(24)碳糊离子选择性电极测定环境水体中的PF_(6)^(-)  

Determanation of PF_(6)^(-) in Environmental Water by [Omim]_(6)Mo_(7)O_(24) Carbon Paste Ion Selective Electrode

作　　者：石金伟 郭子娴 田树梅 李明[1] SHI Jinwei;GUO Zixian;TIAN Shumei;LI Ming(College of Environmental Science and Engineering,Yangzhou,University,Yangzhou 225100,China)

机构地区：[1]扬州大学环境科学与工程学院,扬州225100

出　　处：《理化检验（化学分册）》2021年第3期193-198,共6页Physical Testing and Chemical Analysis(Part B:Chemical Analysis)

摘　　要：采用自制的[Omim]_(6)Mo_(7)O_(24)碳糊离子选择性电极(ISE)测定水中PF6^(-)的含量。试验采用1-辛基-3-甲基咪唑四氟硼酸盐和钼酸铵制备[Omim]_(6)Mo_(7)O_(24)固态离子液体,并用傅里叶变换红外光谱仪(FT-IR)和X射线衍射仪(XRD)进行表征,结果表明:[Omim]_(6)Mo_(7)O_(24)固态离子液体已被成功制备;热重(TG)分析结果表明:该离子液体在28~280℃内的热稳定性较好。将制备的[Omim]_(6)Mo_(7)O_(24)固态离子液体粉末与石墨粉按照质量比为1:9的比例混合,再将该混合粉末与二甲基硅油按照质量比6:1的比例混合制备碳糊ISE。在30℃下,以碳糊ISE为指示电极,Ag/AgCl电极为参比电极,在体积比为1:1的工作缓冲溶液(由硼酸、柠檬酸和磷酸钠混合制备,pH 9)和Na2EDTA溶液的混合溶液中测定水中PF6^(-)的含量。结果显示:在PF6^(-)的浓度为1.0×10^(-8)~1.0×10^(-1)mol·L^(-1)时,其浓度的负对数与对应的碳糊ISE电位响应值呈线性关系,检出限为5.4×10-9 mol·L^(-1)。PF6^(-)的加标回收率大于95.0%,测定值的相对标准偏差(n=5)不大于2.5%。采用该方法和离子色谱法同时分析了3组PF6^(-)盲样,取得了较为一致的结果。用该方法分析环境水体时,由于PF6^(-)的易水解性,未检出PF6^(-)的残留,采用该方法考察了PF6^(-)在常规酸度范围(pH 6~8)水体中的水解过程,发现PF6^(-)的半衰期为0.426~0.444 h,且常规水体的酸度变化不会影响PF6^(-)的水解。A self-made[Omim]_(6)Mo_(7)O_(24)carbon paste ion selective electrode(ISE)was used to determine the content of PF6^(-)in water.The solid ionic liquid[Omim]_(6)Mo_(7)O_(24)was prepared by 1-octyl-3-methylimidazolium tetrafluoroborate and ammonium molybdate,and characterization results from FT-IR and XRD showed that solid ionic liquid[Omim]_(6)Mo_(7)O_(24)was successfully prepared.The TG analysis showed that the ionic liquid had good thermal stability in the range of 28-280℃.After mixing the solid ionic liquid[Omim]_(6)Mo_(7)O_(24)powder with graphite powder with the mass ratio of 1,9,the above mixed powder was mixed with dimethyl silicone oil with the mass ratio of 6:1 to prepare carbon paste ISE.The content of PF6^(-)in water was determined at 30℃with carbon paste ISE as indicator electrode and Ag/AgCl electrode as reference electrode in the mixed solution composed of working buffer solution(containing boric acid,citric acid and sodium phosphate,pH 9)and Na2 EDTA solution with volume ratio of 1:1.The results showed that the linearity relationship between the negative logarithm of PF6^(-)concentration and carbon paste ISE potential response was kept in the range of 1.0×10^(-8)-1.0×10^(-1)mol·L^(-1),with detection limit of 5.4×10-9 mol·L^(-1).The recovery of PF6^(-)obtained was more than 95.0%,and the RSD(n=5)of the determined values was less than 2.5%.Three groups of PF6^(-)spiked blind samples were analyzed by the proposed method and ion chromatography from reference,obtaining a consistent result.When using this method to analyze the environmental water,due to the easy hydrolysis of PF6^(-),no residue of PF6^(-)was detected.Therefore,this method was used to investigate the hydrolysis process of PF6^(-)in water with a normal acidity range(pH 6-8),finding that the half-life of PF6^(-)was in the range of 0.426-0.444 h,and the acidity changes of conventional water did not affect the hydrolysis of PF6^(-).

关 键 词：[Omim]_(6)Mo_(7)O_(24)固态离子液体 碳糊离子选择性电极 PF_(6)^(-) 环境水体 

分 类 号：O657.1[理学—分析化学]