用计算机系数矩阵研究铋(Ⅲ)—硫氰酸铵—吐温—80显色体系

STUDY ON THE COLOUR SYSTEM OF BISMUTH (Ⅲ)-AMMONIUM THIOCYANATE-TWEEN-80 WITH THE COMPUTER COEFFICIENT MATRIX

研究Ｔｗｅｎ水溶液中硫氰酸铋（Ⅲ）配合物的吸收光谱，得到λｍａｘ＝４７０ｎｍ，较ＤＭＳＯ、水介质中显色反应的灵敏度提高一倍．在显色条件ｐＨ＝０．６６，Ｉ＝０．３２下，硫氰酸铵浓度在０．２０～０．３２ｍｏｌＬ－１范围内Δε与硫氰酸铵浓度呈函数关系．用改善了的Ｙａｔｓｉｍｉｒｓｋｉｓ方法处理数据，得到β１＝０．８５７，β２＝３．２０，β３＝４．０９，β４＝７．５０及Δε１＝１．６０×１０３，Δε２＝５．７８×１０３，Δε３＝４．４４×１０３，Δε４＝７．３４×１０３．并测出显色反应的热力学参数ΔＨ＝－１１７．８ｋＪｍｏｌ－１，ΔＧ＝－５．０６ｋＪｍｏｌ－１（ｔ＝２５℃）．

This paper studies the absorption spectra of Bismuth(Ⅲ) Thiocyanate in the Tween-80-H 2O solution,in which λ max is equal to 470 nm and the sensitivity of this colour reaction is higher than those in the DMSO or water. In the colour condition of pH=0.66 and I =0.32,Δ ε is a function of when is 0.20￣0.32 mol·L -1 .The stability constants has been determined by the modified Yatsimirskiis method to be β 1=0.857,β 2=3.20,β 3=4.09,β 4=7.50 respectively,and the molar extinction coefficients to be Δ ε 1=1 .60×10 3,Δ ε 2=5.78×10 3,Δ ε 3=4.44×10 3 and Δ ε 4=7.34×10 3.The thermodynamical functions of this colour reaction have been determined to be Δ H =-117.8 kJ·mol -1 and Δ G =-5.06 kJ·mol -1 (Temperature=25℃) respectively.