Synthesis and characterization of the ligand, [2-tetradecyl-3,6,9-tris(carboxymethyl)-3,6,9-triazaundecan-1,11-dioic acid, H5L] and its Gd(Ⅲ) chelate are described. Protonation constants for H5L (lgKiH = 10.80, 8.40, 4.30, 2.80, 2.15) and the stability constant for GdL2- (lgK■ = 22.75) were determined by potentiometric titration and are similar with the related values of DTPA and Gd-DTPA respectively. The results obtained show that the basicity of the ligand and the stability constant of its Gd(Ⅲ) chelate are not obviously altered after introduction of a linear chain tetradecyl group at the terminal acetic acid residue of DTPA.
利用4,4’-二羧酸-2,2’-双喹啉？BCA？在碱性条件下能特异性地与Cu（I）离子形紫色配合物建立了循环冷却水中微量铜的BCA比色测定法。Cu（I）与BCA形成紫色配合物的λmax为562 nm,p H 9.0时该配合物的表观摩尔吸光系数E562=7.52×10^3 L·mol-1·cm-1。铜量在0.0-50μmol/L范围内符合比尔定律,相关系数r=0.998,检测限量为0.15μmol/L。循环冷却水中铜含量的BCA比色法测定结果与原子吸收法测定的结果基本一致。
