Simultaneous determination of aromatic amino acids in different systems using three-way calibration based on the PARAFAC-ALS algorithm coupled with EEM fluorescence: exploration of second-order advantages

Abstract

A practical analytical method based on intrinsic fluorescence is proposed for simultaneous determination of L-phenylalanine, L-tyrosine, and L-tryptophan in cell culture and human plasma. By using a three-way calibration method coupled with excitation–emission matrix fluorescence, the proposed method successfully achieved quantitative analysis of the three aromatic amino acids in the two different complex systems simultaneously, even in the presence of three unknown, uncalibrated serious interferents. The method needs little preparation by using “mathematical separation” instead of chemical or physical separation, which makes it efficient and environmentally friendly. Satisfactory results have been achieved for calibration, validation, and prediction sets. For phenylalanine, tyrosine, and tryptophan, the calibration ranges are 6.00 to 60.00, 0.40 to 4.00, and 0.10 to 1.00 μg mL⁻¹ respectively. The average spike recoveries (mean ± standard deviation) are 98.5 ± 7.8%, 103.7 ± 6.9%, and 102.3 ± 7.9% respectively. The relative errors are −4.2%, 6.3%, and −0.8% for predicting real contents of phenylalanine, tyrosine, and tryptophan in cell culture respectively. Additionally, we discussed the potential of the three-way calibration method for determining analytes of interest in different systems simultaneously, to further explore the second-order advantages. The paired t-test results indicate that the predicted results between prediction in two systems simultaneously and prediction in a single system individually have no significant difference. The satisfactory results obtained in this work indicate that the use of the three-way calibration method coupled with the EEM array is a promising tool for multi-component simultaneous determination in multiple complex systems containing uncalibrated spectral interferents.