2.3 Main Characters of Coordination Compound in the System of (Ga()- o-CIPF-CTMAB-Tween-80) (1)The colouration of this system develops at room temperature and a maximum and constant absorb:.nce can be reached after 10min.At higher temperature the absorbance will be reduced. (2)The absorbance of this system remains stably at room temperature at least within 12h,so that it is'proved to be more stable than various ternary systems. (3)By the method of molar ratio,method of equilibrium shift and method of straight linc,it has been shown that the composition ratio of Ga:o-CIPF is1:2. (4)By the test of electrophoretic property,it has been observed that the coloured coordination compoundm igrates toward the anode.Besides,the colour- ed coordination compound can be adsorbed by the anionice xchanger.Hence the coordination compound should be charged negatively. 3 Analytical Application 3.1 Influence of Foreign lons From Table 1,it is shown tuat the high valent ions and Al(),Cu(I), In(I)interfere seriously.By the solvent extraction with butyl acetate, most of the interfering metal ions can be removed and the residual small amo- unts will not interfere again.From the laboratory data,conclusion can be drawn that the co-existence of 700 fold Bi,Zn,Cu,Al or Fe;170 fold Mo, W or Zr;and equal amount of In do not interfere the spectrophotometric determ ination of microamount of gallium after their prior separation by the solvent extraction with butyl acetate. 3.2 Spectrophotometric Determination of Microamount of Gallium When the gallium is determined by mono-wavelength method,Beer's law is obeyed over a concentration range of 0~5.0ug/25ml of gallium,and the molar absorptivity is 1,66x1051.mol-1.cm-.Since the absorption peak of the coloured coordination compound is not situated away from that of its rea- gents blank (AA=48nm),so that a deep background is caused at them.of the coordination compound,which is not desirable.To overcome it,a dual- wavelength mcthod is applieds,.If an instrumenl of dual-wavelength is used,the absorbance of the coloured coordination compound,4:and 42,are measured at 578nm and 530nm respectively against its reagents blank as refer- 389一 一 一 一 》 — 、 · · 。 ， ‘ 。 ， ， ， 一 。 ， ， 。 手 。 ， 飞， ， ， “ ’ ， 皿 ， 一 ， ， ， ， 。 一 五 ， ， 一 。 件 ， ‘ 一 一 一 · △几 ， 住 久。 二 一 · ， 〔 ’ ” 〕 一 ， ，