氟化物衍生-^(19)F-核磁共振法检测水样中氰化物  

Inspection of Cyanide in Water Samples by ^(19)F-NMR with Fluorinated Derivatization

作　　者：李腾[1,2] 黄桂兰 袁铃[1,2] 周世坤 张何[1,2] LI Teng;HUANG Guilan;YUAN Ling;ZHOU Shikun;ZHANG He(Research Institute of Chemical De fence, Beijing 102205, China;State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China)

机构地区：[1]防化研究院,北京102205 [2]国民核生化灾害防护国家重点实验室,北京102205

出　　处：《理化检验（化学分册）》2018年第4期443-448,共6页Physical Testing and Chemical Analysis(Part B:Chemical Analysis)

摘　　要：取69.8mg·L^(-1)氰化钠溶液0.50mL,用0.25mol·L^(-1)氢氧化钠溶液调节其酸度至pH 12,减压蒸发至干。加入二甲基亚砜(DMSO)0.5mL溶解残渣,随后加入2,2,2-三氟苯乙酮(TFAP)10μL和乙酸酐20μL,室温下反应45min,使氰根衍生为1-氰基-2,2,2-三氟^(-1)-乙酸苯乙酯(CTPA)。取0.30mL上述溶液,加入7.78mmol·L^(-1)乙酸^(-3)-氟苄酯-氘代三氯甲烷(CDCl3)溶液0.2mL为内标,按仪器工作条件进行^(19)F-核磁共振(NMR)分析。试验表明该衍生方法的检出限为0.7mg·L^(-1)。方法不受其他干扰离子(如CO_3^(2-)、B_4O_7^(2-)、Cl^-、SO_4^(2-)等)的影响,具有良好的专属性。选用3种不同水源的水样(自来水、河水、纯水)按所提出方法衍生化并测定,三者的回收率依次为74.0%,74.0%,75.0%,并无大的差别,3种水样测定值的相对标准偏差(n=6)依次为2.1%,2.4%,3.0%。方法曾用于天津8·12爆炸区采集的水样中氰根的测定,获满意结果。An aliquot of 0.50 mL of 69.8 mg·L^-1 NaCN solution was taken and its acidity was adjusted to pH 12 with 0.25 mol·L^-1 NaOH solution.The solution was then evaporated to dryness under reduced pressure.The residue was taken up with 0.5 mL of DMSO,and then CN-in the solution was derivatized with 10μL of TEAP and 20μL of acetic anhydride at room temperature for 45 min to form 1-cyano-2,2,2-trifluoro^-1-phenylethyl acetate（CTPA）.An aliquot of 0.30 mL of the solution was taken and used for 19 F-NMR analysis under the specified instrumental condition after 0.2 mL of 7.78 mmol·L^-1 3-fluoro-benzyl acetate-CDCl3 solution was added as internal standard.As shown experimentally,the detection limit of CN-after derivatization was found 0.7 mg·L^-1.The method was found to be highly specific,as interferences of many co-existing anions,e.g.,CO3^2-,B4O7^2-,Cl-,SO4^2-and etc.were avoided.Three water samples of various origins（i.e.,tap water,river water and pure water）were derivatized and determined by the present method,giving values of recovery of 74.0%,74.0% and 75.0% respectively,showing no significant difference.Values of RSDs（n=6）found for the 3 samples were 2.1%,2.4% and 3.0% respectively.The present method has been used satisfactorily for determination of CN-in some water samples taken from the incidental site of the 8·12 explosion in Tianjin.

关 键 词：^19F-NMR 氰化物 氟化物衍生 水样 

分 类 号：O621.3[理学—有机化学] O621.4[理学—化学]