二溴水杨基荧光酮光度法测定铜合金中微量铈组稀土

Determination of the Total Amount of Cerium Group Rare Earths in Copper Alloy by Spectrophotometry with Dibromosalicyl Fluorone

研究了在阳离子表面活性剂溴化十六烷基三甲铵(CTMAB)存在下,9-(3,5-二溴)水杨基荧光酮(DBSAF)与铈组稀土元素(Ln)的显色反应及光度性能,建立了测定稀土元素的新方法。在pH 9.0 NH3.H2O-NH4Cl缓冲溶液中,铈组稀土元素与DBSAF形成稳定的紫红色络合物,其最大吸收峰位于580.0nm波长处,表观摩尔吸光系数可达1.03×105~1.34×105,在25mL溶液中,稀土元素的量在0μg^33.6μg范围内符合比尔定律。该法用于铜合金中微量铈组稀土元素总量的测定,经加标回收试验,回收率在94%~103%,结果满意。

In the presence of s urfactant cetyl trimethyl ammonium bromide （CTMAB）,the photometric analysis properties of color reaction of 9-3,5-dibromosalicyl fluorone （DBSAF） with cerium group rare earth element （Ln） were studied ,new method was founded in the determination of Ln^3＋. The experimental result showed that Ln^3＋ reacted with DBSAF to form a micelle complex with a maximum absorption at 580.0 nm in a pH 9.0 NH3· H2O--NH4Cl buffer solution, the apparent molar absorptivity of the complex is 1.03 × 10^5-1.34×10^5. Beer＇s law was obeyed in the range of 0μg - 33.6μg Ln^3＋ per 25 mL. The proposed method has been applied to the determination of trace amount of the total amount of cerium group rare earth in copper alloy with satisfactory results and it is precise（RSD 〈4‰） ,sensitive accurate（recovery rate 94-103%） and simple.