无保护流体室温燐光法测定色氨酸的研究

Determination of Tryptophan by Non-protected Fluid Room Temperature Phosphorescence

建立了一种仅用KI为重原子微扰剂、Na2SO3为除氧剂的无保护流体室温燐光测定色氨酸的方法,详细研究了测定条件及有机溶剂的影响。本法的线性范围为1.2×10-7～1.0×10-5mol/L,检出限为1.1×10-8mol/L,相对标准偏差2.47%～3.24%。已用于大米、花生、大豆及竹笋中色氨酸的测定,与荧光法比较,分析结果相符。

A non-protected fluid room temperature phosphorimetry (NP-RTP) for determination of Tryptophan, which only using potassium iodide as a heavy atom perturber and sodium sulfite as a deoxygenator, was proposed. The influence of determination conditions and organic solvent on NP-RTP of Tryptophan were studied in detail. The phosphorescence peak wavelength is λ_(ex)/λ_(em)=287/445 nm. The analytical curve of Tryptophan gives a linear dynamic range of 1.2×10^(-7)～1.0×10^(-5) mol/L with a detection limit of 1.1×10^(-8) mol/L. The method was applied directly to determination of Tryptophan in rice, peanut, soybean and bamboo shoot with satisfactory results. The relative errors were -3.22%～(3.00%) as compared with fluorospectrophotometry and the relative standard deviations (RSD) were (2.47%～)3.24% for Tryptophan in the above samples. The organic solvent added to the luminescent system decreases the RTP intensity, but does not affect the form and the peak wavelength of the RTP spectra. No phosphorescence response is observed in the presence of thallium nitrate (0.020～0.20 mol/L) as a heavy atom perturber.