钙黄绿素荧光光度法测定粉煤灰中痕量钪

研究了钙黄绿素与钪(Ⅲ)的荧光反应。实验表明,在pH 8.5NH3·H2O-NH4Cl缓冲溶液和表面活性剂Triton X-100的存在下,痕量钪(Ⅲ)能和钙黄绿素反应生成络合物,使体系的荧光强度显著增强,激发波长和发射波长分别为495nm和520nm,钪(Ⅲ)的质量浓度在0.021~1.80μg/mL范围内与荧光强度差值(ΔF)的线性关系良好,线性回归方程为:ΔF=3.431+2.473ρ(μg/mL),相关系数r=0.998 1,检出限为0.021μg/mL。干扰试验表明:粉煤灰样品中的钪经1-苯基-3-甲基-4-苯甲酰-5-砒唑酮(PMBP)-甲苯萃取分离后,大多数常见离子不干扰测定。方法应用于粉煤灰中痕量钪的测定,结果与电感耦合等离子体原子发射光谱法(ICP-AES)相符,相对标准偏差(RSD,n=6)为0.57%~1.0%,加标回收率在98%~105%之间。

Determination of trace scandium in fly ash by calcein fluorescence spectrophotometry

The fluorescence reaction between calcein and scandium was studied. The results showed that trace scandium ions could react with calcein to form complex in NH₃·H₂O-NH₄Cl buffer solution at pH 8.5 in presence of surfactant Triton X-100, and the fluorescence intensity of this system was enhanced significantly. The excitation wavelength and emission wavelength was 495 nm and 520 nm, respectively. The content of scandium in range of 0.021-1.80 μg/mL exhibited good linearity to its fluorescence intensity difference (ΔF). The equation of linear regression was ΔF=3.431+2.473 ρ (μg/mL) with correlation coefficient of r=0.998 1. The detection limit was 0.021 μg/mL. The interference tests indicated that most common ions did not interfere with the determination after scandium in fly ash sample was extracted and separated with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP)-methylbenzene. The proposed method was applied to determination of trace scandium in fly ash samples. The results were consistent with those obtained by inductively coupled plasma atomic emission spectrometry (ICP-AES).The relative standard deviation (RSD, n=6) was 0.57%-1.0%. The recoveries were between 98% and 105%.