Abstract：The nature of palladium (Ⅱ) and copper (Ⅱ) is very similar, so it is very difficult to determine trace palladium (Ⅱ) in the coexistence of a great quantity of copper (Ⅱ). This paper applied ion floatation-spectrophotometric principle, using 1-( 2-pyridylazo)-2-naphthol (PAN) as collector, and through controlling pH of the solution and determination wavelength, without separation to determine palladium (Ⅱ) content in acetaldehyde catalyst with a great quantity of copper (Ⅱ)． The relative error was 0.61%，and RSD was 2.33%. The results were satisfactory.
[1] DONG Hui-ru，YUE Xiu-yu(董慧茹，乐秀毓). Chinese J. Anal. Chem.(分析化学)，1986，14(8)：569. [2] Dong Huiru，Yue Xiuyu. J. Anal. Lett., 1988，21(6)：1065. [3] Dong Huiru，Yue Xiuyu. J. Anal. Sci., 1989，5(5)：601. [4] LIU Zhi-ming(刘志明). Chinese J. Anal. Chem.(分析化学)，1996，24(6)：1107. [5] SHEN Yi-yang，XING yun，LI Quan-min et al(申义阳，刑 云，李全民等). Chinese J. Appl. Chem.(应用化学)，2001，18(11)：921. [6] Kim Y S，Shin J H，Choi Y S et al. Microchemical Journal，2001，68：99.
