Tri-probe fluorescent sensor array for a wide concentration range and high precision identification of aqueous organic amines

Abstract

Aqueous organic amines are threatening to organisms and ecosystem balance. Although many techniques have been used for detection, the simultaneous identification of both its type and concentration is still challenging due to its structural similarity and low environmental concentration. Sensor array is a powerful sensing technology to identify analytes via unique fingerprint patterns. However, the information from general sensor array based on the weak interaction limited its discernibility ability to similar substances. Here, we propose to design molecules with various sensing units based on strong interactions and hence rich spectral change, then construct a tri-probe sensor array for efficient fluorescent differentiation of aqueous organic amine. Different fluorescence responses to different concentrations and types of organic amines were produced by this array. Varied interaction between the probes and the amines was proved by NMR spectra analysis. The combination of probes can produce rich and complementary fluorescence changes. These unique fluorescence response patterns can be well identified and processed using hierarchical analysis (HCA) and linear discriminant analysis (LDA), enabling the 99.35% accurate differentiation of 5 concentration orders (1 μM ~ 10 mM) of 6 kinds of amines. Blind detections for samples of diethylamine, diisopropylamine in tap water and propylamine, hexylamine, trimethylamine, triethylamine in other five domestic wastewater all can be classified and distinguished successfully. The influence of temperature, pH and mental ions are also considered. This sensing method, with the feature of facile preparation, fast response, and excellent discrimination accuracy, can provide a potential option for fast quality test of water.