Extraction–Spectrophotometric Determination of Pd(II) with 4-(3,5-Dichloro-2-pyridylazo)-1,3-diaminobenzene and Trichloroacetate. II
作者:C. A. Fontán、C. B. Marone、R. Olsina
DOI:10.1246/bcsj.61.4121
日期:1988.11
The influence of different variables affecting the extraction of Pd(II) with 4-(3,5-dichloro-2-pyridylazo)-1,3-diaminobenzene (3,5-C12PADAB) and trichloroacetate are described. The complexation reaction between palladium(II) and 3,5-C12PADAB, in 1 M trichloroacetic acid aqueous solutions containing ethanol (10% v/v) and an acidity range from pH near 1 to 2 M H2SO4 is completed 10 min after having mixed the reagents. Under these experimental conditions, Pd(II) is extracted into benzene as an colored ion-association compound with trichloroacetate. At 600 nm, Beer’s law is fulfilled up to a Pd(II) concentration of 2.16 ppm, being the most appropriate concentrations for the metal spectrometry those ranging from 0.24 to 2.12 ppm. The apparent molar absorptivity is 8.60×104 dm3 mol−1 cm−1, and the method’s sensitivity (Sandell) of 0.00123 μg Pd(II)·cm−2. The assayed procedures for suppressing the most serious interferences produced by Au(III) and Hg(II) are specified, and the procedure for increasing the tolerance as to Ag(I), Cu(II), Co(II), Cr(III)–(IV), Ir(III)–(IV), Os(VIII), and Ru(III)–(VIII) are described.
描述了影响 4-(3,5-二氯-2-吡啶基)-1,3-二氨基苯 (3,5-C12PADAB) 和三氯乙酸萃取 Pd(II) 的不同变量的影响。钯(II) 和 3,5-C12PADAB 在含有乙醇 (10% v/v) 的 1 M 三氯乙酸水溶液中以及 pH 值接近 1 至 2 M H2SO4 的酸度范围内,混合后 10 分钟完成络合反应试剂。在这些实验条件下,Pd(II) 被萃取到苯中,作为与三氯乙酸盐形成有色离子缔合化合物。在 600 nm 处,Pd(II) 浓度达到 2.16 ppm 时即可满足比尔定律,金属光谱测定的最合适浓度范围为 0.24 至 2.12 ppm。表观摩尔吸光系数为 8.60×104 dm3 mol−1 cm−1,方法灵敏度 (Sandell) 为 0.00123 μg Pd(II)·cm−2。规定了抑制 Au(III) 和 Hg(II) 产生的最严重干扰的测定程序,以及提高 Ag(I)、Cu(II)、Co(II)、Cr(III) 耐受性的程序)–(IV)、Ir(III)–(IV)、Os(VIII) 和 Ru(III)–(VIII) 进行了描述。