西维因无保护流体室温燐光的重原子效应和有机溶剂的影响  

Effects of Heavy Atom Perturber and Organic Solvent on Non-protected Fluid Room Temperature Phosphorescence of Carbaryl

作　　者：龙文清[1] 李隆弟[1] 童爱军[1] 

机构地区：[1]清华大学化学系,北京100084

出　　处：《分析化学》2002年第10期1201-1205,共5页Chinese Journal of Analytical Chemistry

基　　金：国家自然科学基金资助项目

摘　　要：在无任何保护性介质存在的水溶液中 ,仅以KI为重原子微扰剂 ,亚硫酸钠为除氧剂 ,西维因 (CBL)能发射强而稳定的室温光 (RTP)信号 ,峰波长λex λem =2 85 4 95 ,5 2 3nm ,光强度与CBL浓度在 10～ 16 0μg L 范围内呈良好线性关系 ,检出限 0 .90 μg L。详细研究了重原子微扰剂浓度对光寿命的影响 ,发现I- 浓度 (x ,mol L)与RTP寿命 (τ ,ms)间的关系能表示为τ =0 .5 2 0e- 0 .4 2 5x,T1 →S0 的光发射速率常数kp 和KI重原子效应常数a分别为 1.92ms- 1 和 1.0 4ms- 1 ·mol·L- 1 。研究还发现 ,少量有机溶剂 (约 3% ,V V)的存在 ,因能增加CBL的溶解度 ,可获得最高的RTP强度 ,使检出限比无有机溶剂时的类似方法降低了约 1个数量级 ,重原子微扰剂的适宜浓度降低了 2 3。所拟定的测定CBL的室温光分析法 ,用于强化的环境土壤及水样中CBL的测定 ,回收率为 95 .2 %～ 10 4 .5 % ,相对标准偏差为 2 .2 6 %～ 3.76 % (n =3)。A strong and stable room temperature phosphorescence (RTP) signal (λ ex /λ em = 285/495,523 nm) can be induced for carbaryl (CBL) aqueous solution in the absence of any protective medium only using KI as a heavy atom perturber (HAP) and sodium sulfite as a deoxygenator. The analytical curve of CBL gives a linear dynamic range of 10～160 μg/L with a detection limit of 0.90 μg/L. Recoveries of 95.2%～104.5% with relative standard deviations ( n =3) of 2.3～3.8% were obtained for CBL ranging from 20 to 140 μg/L in spiked water and soil samples. It is also found that a certain amount (about 3%, V/V ) of organic solvent is needed to obtain the highest RTP intensity of CBL aqueous solution, which can increase the solubility of CBL and prevent CBL from hydrolysis. The influence of I - concentration on RTP lifetime of CBL was studied in detail. The results showed that the relation between I - concentration ( x , mol/L) and RTP lifetime (τ, ms) could be expressed as τ=0.520 e -0.425x , the rate constant of phosphorescence emission k p from T 1→S 0 process was 1.92 ms -1 , and the heavy atom effect coefficient of KI, a, was 1.04 ms -1 ·mol·L -1 .

关 键 词：重原子效应 西维因 无保护流体 室温Lin光 动力学参数 有机溶剂 光谱分析 农药 土壤 水 环境样品 

分 类 号：O657.3[理学—分析化学]