Fávero José Arnaldo Dibbern, Tubino Matthieu
Instituto de Química, Universidade Estadual de Campinas, CP 6154, 13084-971 Campinas, SP, Brazil.
Anal Sci. 2003 Aug;19(8):1139-43. doi: 10.2116/analsci.19.1139.
A selective, sensitive, rapid and simple-handling analytical method for the determination of cyanide at low detection limits in surface and underground water, soil and industrial waste samples was developed. The method is based on a reaction, proposed by Guilbault and Kramer, where free cyanide reacts with p-nitrobenzaldehyde to form an intermediate cyanohydrin, which reacts with o-dinitrobenzene to give a highly colored purple compound. The original procedure was modified for application in a small device containing a gas-permeable membrane. The cyanide is converted in the volatile hydrogen cyanide, which permeates through a PTFE membrane, reaching colorimetric reagents. In order to obtain semi-quantitative results, printed color scales were built. The method allows rapid, accurate, selective, low-cost and simple-handling determinations of free cyanide, even in complex samples. About 150 real samples were analyzed. Less than 10 ng of free cyanide per ml (10 microg l(-1)) can be easily detected. For more concentrated solutions, the results had been compared to those obtained using differential pulse polarography. The standard addition method was used for more diluted solutions.
开发了一种用于测定地表水、地下水、土壤和工业废水样品中低检测限氰化物的选择性好、灵敏度高、快速且操作简便的分析方法。该方法基于吉尔博和克莱默提出的一种反应，即游离氰化物与对硝基苯甲醛反应形成中间氰醇，该氰醇再与邻二硝基苯反应生成一种颜色很深的紫色化合物。对原程序进行了改进，以应用于一个包含透气膜的小型装置中。氰化物转化为挥发性氰化氢，它透过聚四氟乙烯膜，与比色试剂接触。为了获得半定量结果，制作了印刷色标。该方法能够快速、准确、选择性地、低成本且操作简便地测定游离氰化物，即使在复杂样品中也是如此。分析了约150个实际样品。每毫升中少于10纳克（10微克/升）的游离氰化物能够轻松检测到。对于浓度更高的溶液，已将结果与使用微分脉冲极谱法获得的结果进行了比较。对于稀释度更高的溶液，则使用标准加入法。
