development of colorimetric detection of 2,4,5-trimethyloxazole in volatile organic compounds based on porphyrin complexes for vinegar storage time discrimination

2,4,5-trimethyloxazole, an important volatile organic compound, is widely detected in food products such as wine and vinegar. the current study presents a colorimetric sensor array (csa) made of porphyrins and ph indicator for analysing the 2,4,5-trimethyloxazole in complex volatile organic compounds (vocs). based on density functional theory (dft), time-dependent density functional theory (tddft) and uv spectral analysis, porphyrin complexes were synthesized and optimized specifically for the discriminating of 2,4,5-trimethyloxazole. we explored the possibility of porphyrins binding with vocs, and the binding energies, dipole moments or equilibrium constants of optimized porphyrins have an upward trend after combining with 2,4,5-trimethyloxazole. the colorimetric dye of 5,10,15,20-tetrakis(4-fluorophenyl)-21h,23h-porphine zinc (tpp-zn-f) is found specifically sensitive to the compound of 2, 4, 5-trimethyloxazole. the optimized porphyrin can resist the interference of complex vocs, and the accuracy of characterization of 2,4,5-trimethyloxazole was improved. finally, csa composed of tpp-zn-f and two chemoselective dyes shows a great ability to identify the storage time of vinegar, and the rates of lda and knn algorithms to predict vinegar samples are 92.5% and 100%, respectively.