论文部分内容阅读
在pH9.4～10.0的条件下,Be~(2+)与铬天青S及溴(氯)化十六烷基吡啶生成红色三元络合物。该络合物最大吸收波长为520纳米(nm),克分子消光系数为2.65×10~4,络合物组成为Be~(2+):CAS:CPB为1:3:2。采用正交优选法对测定的各种条件进行研究。本方法的特点是能够消除铝的干扰,在显色时,可允许1毫克铝的存在。用乙酰丙酮一四氯化碳萃取富集铍,水样中铍的检出下限可低达1.0PPb。 对于微量铍的测定,近年来除国外有所报道外,国内也有不少资料报道。一般认为采用铬天青S、羊毛络青R在季胺盐、氯化十六烷基三甲胺、十四烷基苄基氯化铵等存在下生成三元络合物的颜色反应,使灵敏度和精密度均大为提高。 据资料报道:在pH4.5—6.9范围内,Be~(2+)与铬天青S、溴化十六烷基吡啶形成兰色络合物,最大吸收波长为625纳米,克分子消光系数高达8.1×10~4,但铝的干扰严重。在pH约9.4左右时,Be~(2+)与铭天青S、溴化十六烷基吡啶形成红色络合物,最大吸收波长为520纳米,其灵敏度较兰色络合物略低。 我们对此红色络合物进行研究,测定pH9.4时三元络合物的组成为Be:CAS:CPB=1:3:2,克分子消光系数ε_(520nm)=2.65×10~4。采用正交选优设计对测定铍的诸因索进行选择,特别是铝元素干扰的试验,证明此法能克服大量铝的干扰。先用乙酰丙酮一四氯
At pH 9.4 ~ 10.0, Be 2+ reacted with chrome azure S and cetyl pyridinium chloride to form a red ternary complex. The complex has a maximum absorption wavelength of 520 nanometers (nm), an extinction coefficient of 2.65 × 10 ~ 4 and a complex composition of Be ~ (2 +): CAS: CPB of 1: 3: 2. Orthogonal optimization method to determine the conditions of the study. This method is characterized by the ability to eliminate the interference of aluminum, allowing for the presence of 1 mg of aluminum in color development. With acetylacetone carbon tetrachloride enrichment beryllium, beryllium detection limit of the water can be as low as 1.0PPb. For the determination of trace beryllium, in addition to foreign reports in recent years, there are a lot of domestic data reported. Generally believed that the use of chrome azure S, wool lutein R in the quaternary ammonium salt, cetyltrimethyl ammonium chloride, tetradecylbenzyl ammonium chloride, etc. generated ternary complex color reaction, the sensitivity And precision are greatly improved. According to the data reported: Be ~ (2+) forms a blue complex with chrome azure S and cetylpyridinium bromide at a pH range of 4.5-6.9, with a maximum absorption wavelength of 625 nm, a molar extinction coefficient Up to 8.1 × 10 ~ 4, but the interference of aluminum is serious. At pH about 9.4, Be ~ (2+) forms a red complex with Mingtianqing S and Cetylpyridinium bromide. The maximum absorption wavelength is 520nm, and its sensitivity is slightly lower than that of the blue complex. The red complex was studied. The composition of the ternary complex at pH 9.4 was determined as Be: CAS: CPB = 1: 3: 2 and the molar extinction coefficient ε 520nm was 2.65 × 10 ~ 4. Orthogonal optimal design of the beryllium determination of the cable to choose, especially the aluminum element interference test, prove that this method can overcome a large number of aluminum interference. First with acetyl acetone tetrachloride