Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2000-07-01

Study on using I- as heavy atom perturber in cyclodextrin-induced room temperature phosphorimetry.

L Li, X Hai, A Tong

Index: Spectrochim. Acta. A. Mol. Biomol. Spectrosc. 56A(8) , 1513-21, (2000)

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Abstract

A cyclodextrin induced room temperature phosphorimetry (CD-RTP) for determine beta-NOA, which using I- as a heavy atom perturber (HAP) and sodium sulfite as a deoxygenator, was developed. The phosphorescence peak wavelength maxima lambda(ex)/lambda(em) = 287/496,521 nm. The analytical curve of beta-NOA gives a linear dynamic range of 2.0 x 10(-7)-6.0 x 10(-6) mol/l and a detection limit of 4 x 10(-8) mol/l. The relative standard deviation (RSD; n = 7) was 3.2% for the 4.0 x 10(-6) mol/l beta-NOA in spiked apple samples. The influence of I- concentration on RTP lifetime of beta-NOA was studied in detail, the static Stern-Volmer equation for phosphorescence was derived and the luminescence kinetic parameters were calculated. It is found that the relation between I- concentration (x) and RTP lifetime (tau) can be expressed as tau = 1.047 e(-0.354x) and the rate constants of phosphorescence emission k(p) and non-radiation process k(i) from T1 --> S0 were 0.9551 s(-1) and 0.4276 s(-1) l(-1) mol, respectively.