Fluorescent Probes For Highly Selective Detection Of Moisture Based On Acenaphthopyrazine Fluorophores

A series of acenaphthopyrazine fluorescent probes were designed and synthesized based on the former studies of our group. Their application performance were also explored. In addition, a HPLC method for the analysis and quality control of pomalidomide, a new anti-tumor drug, was also developed.Acenaphthopyrazines were used as parent structures and n-butylamine, diglycol amine, dimethylamine, dibutylamine and aniline were selected as substituents to synthesize a series of ICT-based polar fluorescent probes, including 3-(butylamino)acenaphtho[1,2-b]pyrazine-8,9-dicarbonitrile (Probe A),3-((2-(2-hydroxyethoxy)ethyl)amino)acenaphtho[1,2-b]pyrazine-8,9-dicarbonitrile (Probe B),3-(dimethylamino)acenaphtho[1,2-b]pyrazine-8,9-dicarbonitrile (Probe C),3-(dibutylamino)acenaphtho[1,2-b]pyrazine-8,9-dicarbonitrile (Probe D) and 3-(phenylamino)acenaphtho[1,2-b]pyrazine-8,9-dicarbonitrile (Probe E). Spectral properties nvestigation in different solvents showed the UV absorption spectra and fluorescence emission spectra of these probes bathochromicly shifted, and the fluorescence quantum yield significantly decrease with the increasing of solvent polarity. For example, the spectral band position of probe A-E bathochromicly shifted 15,18,24,30 and 51 nm, the fluorescence emission spectra bathochromicly shifted 65,30,83,78 and 59 nm when the measurements were conducted in carbon tetrachloride, toluene,1,4-dioxane, THF, ethyl acetate, chloroform, dichloromethane,1,2-dichloroethane, acetonitrile, N,N-dimethylformamide amide (DMF), respectively. Based on the sensitivity of these probes to solvent polarity, Probe A-E were used to detect the water content in organic solvents. The results showed that the fluorescence intensity of the probe A-E decreased with increasing of water content in 1,4-dioxane and tetrahydrofuran (THF). By fitting the data obtained, detection limits of probe A-E for water in 1,4-dioxane were 31,36,26,19,32 ppm, respectively; and for water in THF were 15,73,8,7, 15 ppm, respectively. These probes could be used to detect trace of water in these two solvents. And ICT-based probe D has the lowest limit of detection in THF and 1,4-dioxane by using 3SPK, so far.In addition, an analysis method validation and quality control for a new anti-tumor drug-pomalidomide was conducted, HPLC method was used to detect pomalidomide. The HPLC chromatographic conditions was as follows:Zorbax SB-CN column (4.6*150 mm,5 ?m),240nm,1.0 mL/min,25?,10?L,0.1 mol/L acetic acid (pH= 2.8):methanol= 90:10 (v/v) as the mobile phase A,0.1 mol/L acetic acid (pH= 2.8):methanol= 30:70 (v/v) as mobile phase B, gradient elution. Pomalidomide and impurities concentration and peak area had a good linear correlation with coefficient?0.999 within 0.5-2?g/mL range. These chromatographic conditions have good precision, accuracy, repeatability, and the solution was stable within 18 h with the content of pomalidomide>99%.