UV–vis sensor array combining with chemometric methods for quantitative analysis of binary dipeptide mixture (Gly-Gly/Ala-Gln)

Many endogenous peptides are circulating in bodily fluids at micromole level, and accurate analysis of endogenous peptides at such low level is important. In this study, we presented an extensible, facile and sensitive sensor array based on UV–Vis spectroscopy of the AuNPs combined with chemometric methods for quantitative analysis of binary peptide mixture (Gly-Gly/Ala-Gln) using UV–Vis spectroscopy. High concentration arginine (Arg) and Cr 3+ can induce aggregation of the AuNPs and DNA-AuNPs. However, the glycylglycine (Gly-Gly) and alanyl-glutamine (Ala-Gln) can prevent the AuNPs from aggregation. We investigated the prevention of AuNPs aggregation by using Gly-Gly and Ala-Gln mixtures and constructed sensor arrays for quantitative analyses of Gly-Gly and Ala-Gln mixtures. The color change of the solution is relevant to the dose of the target, and it can be visualized by the naked eyes or monitored by UV–Vis spectrometry. Results showed that the concentrations of Arg and Cr 3+ are the key factors affecting the sensitivity of the sensor array. Whereas when Gly-Gly and Ala-Gln have to be analyzed simultaneously, concentrations of Arg and Cr 3+ both for Gly-Gly and Ala-Gln are difficult to be optimized. Taking the advantages of multivariate analysis and data fusion, PLS models and backward interval PLS (BiPLS) models were built for fused dataset constructed by UV–Vis data obtained at different concentrations of Arg and Cr 3+ . The best results were obtained from the PLS models. The proposed method can be extended to analysis of other peptides in more complex mixture systems.