Determination of Enantiomeric Composition of Tryptophan by Fluorescence Spectroscopy Combined with Principal Component Regression

Abstract

A method which combines fluorescence spectroscopy, guest–host chemistry, and principal component regression (PCR) was proposed for determining the enantiomeric composition of tryptophan (Trp). Fluorescence spectroscopy was used to measure the chiral interaction between the enantiomers of tryptophan and bovine serum albumin (BSA), which plays the role of chiral selector. PCR was used to model the quantitative relationship between the obtained fluorescence spectral data and enantiomeric composition of Trp. Leave-one-out cross validation and external test validation were employed to validate the proposed method. The results demonstrate that the method is practical in quantitatively determining enantiomeric composition of Trp. Moreover, the method shows high sensitivity. When there was 2.50 µmol · L⁻¹ Trp in the solutions, the enantiomeric composition of tryptophan was accurately determined.

Keywords:

• Enantiomeric composition
• Fluorescence spectroscopy
• Principal component regression
• Tryptophan

Acknowledgments

The work is supported by the Natural Science Basic Research Plan in Shaanxi Province of China (Program No. 2010JQ2003), the Open Foundation of the Synthetic and Natural Functional Molecular Chemistry at Northwest University (No. 09014), the Natural Science Basic Research Plan in Shaanxi Province of China (Program No. 2011JQ2001), and National Natural Science Foundation of China (No. 20975081). We greatly appreciate Prof. Jilie Kong (Fudan University, China) for his instruction and cooperation in this work.