催化光度法测定粉煤灰中微量钍

Determination of Trace Thorium in Fly Ash by Catalytic Spectrophotometry

在pH 2 .0的HNO3 介质中 ,痕量钍 对过氧化氢氧化苦胺酸偶氮变色酸 (PAACA)的褪色反应有强的催化作用。加入乳化剂OP能提高其灵敏度 ,催化程度与钍 量线性相关。借此建立了测定痕量钍 的分光光度法。结果表明 :有色溶液的最大吸收波长为 5 4 5nm ;方法检出限为 0 .80 μg/L ;线性范围为 4 .0～ 12 0 μg/L ,钍 的标准加入回收率在 98.5 %～ 10 3.6 %之间。结合PMBP 甲苯萃取分离 ,用于测定粉煤灰中的微量钍 。

Trace Th catalyzes strongly decolorization reaction of picraminicazochromotropic acid(PAACA) by oxidizing with H 2O 2 in pH 2.0 HNO 3 solution,the addition of emulsor OP can further increase the sensitivity of the reaction and its catalytic extent is linear with the contents of Th.Based on this study,a catalysis spectrophotometric method for determining trace Th was developed.The results show that the maximun absorption of the color solution is at 545 nm and the detection limits of the method is 0.80 μg/L for Th. Beer′s law is obeyed for Th in the range of 4.0～120 μg/L,and the recovery of standard addition of Th is 98 5%～103.6%.Combined with 1-phenyl-3-methyl-benzoylpyrazolone-6-toluene extraction,the method has been applied to the determination of trace Th in fly ash with satisfactory results.