Design and synthesis of a squaraine based near-infrared fluorescent probe for the ratiometric detection of Zn2+ ions

A ppb level turn-on fluorescence chemosensor for the detection of Zn2+

“…The detection limit of DMPSQ was calculated to be 80 ppb (1.2 nM) in ethanol, which was derived by using the formula 3σ/k where σ stands for the standard deviation of the blank samples and k is the slope of linear fit curve. [13,15] The 80 ppb detection limit also verified by experiment, as shown in the inset of Fig. 5(b).…”

“…reported a squaraine-based ratiometric Zn 2+ chemosensor with a detection limit of 61 nM. [13] Compared to previous result, the DMPSQ has a lower detection limit with simpler detection procedure. To the best of our knowledge, DMPSQ is among the most sensitive Zn 2+ A c c e p t e d M a n u s c r i p t 4 probes reported.…”

“…After purification, the result violet solid formed flake-shaped crystals, reaching yield up to 90%. The 1 H NMR, 13 C NMR, MS and IR spectra of DMPSQ are provided in the supplementary materials.…”

“…[10] To achieve improved sensitivity, recent developments focus on squaraine sensors with turn-on fluorescence responses. [11][12][13] Most of the squaraine-based ion sensors are constructed by a combination of squaraine chromophores with coordination sites. [8,9,12] Despite the success in achieve various interesting properties, the resulting compounds have a tendency of becoming increasingly complex, which may lead to problems like difficulty in synthesis and high cost for practical applications.…”

A colorimetric and fluorescent probe for multiple transition metal ions (Cu2+, Zn2+ and Ni2+): Fast response and high selectivity

“…[23][24][25] Furthermore, most developed chemosensors were limited in organic solution and become invalid as soon as contacting with water. [26][27][28] It remains a challenge to design a chemosensor that not only can detect but also differentiate Cu 2+ , Zn 2+ and Ni 2+ , especially in aqueous solution.…”