A sensitive spectrophotometric method for the determination of gold (III) with 5-p-dimethylaminocinnamylidene-1-phenyl-2-thiobarbituric acid (DACTB) is described. DACTB reacts easily with gold (III), forming a blue complex in diluted hydrochloric acid which can be extracted with chloroform. The chloroform solution of the complex has an absorption maximum at 622 nm against a reagent blank and shows a constant absorbance over the final hydrochloric acid concentration range of 0.02-0.07 M. Beer's law holds over the range of 0.1-0.9 μg/ml of gold (III) at 622 nm. The molar extinction coefficient of the complex is 1.1×105·l·mol-1·cm-1. The coefficient of variation was 1.34% for 0.5 μg/ml of gold (III). The coexistence of cations such as Pd (II), Fe (II), Ce (IV), and Mn (VII) interfered considerably with the determination.
描述了用 5-对二甲基
氨基肉桂基-1-苯基-2-
硫代
巴比妥酸 (
DACTB) 测定
金 (III) 的灵敏分光光度法。
DACTB 很容易与
金 (III) 反应,在稀
盐酸中形成蓝色络合物,可用
氯仿萃取。相对于试剂空白,该络合物的
氯仿溶液在 622 nm 处有最大吸收,并且在 0.02-0.07 M 的最终
盐酸浓度范围内显示出恒定的吸光度。比尔定律在 0.1-0.9 μg/ml
金的范围内成立(III) 622 nm。该配合物的摩尔消光系数为1.1×105·l·mol-1·cm-1。 0.5 μg/ml
金 (III) 的变异系数为 1.34%。 Pd(II)、Fe(II)、Ce(IV)和Mn(VII)等阳离子的共存对测定有很大干扰。