[14p-313-1~17] 12.1 Fabrications and Structure Controls

△ [14p-313-12] A Fluorescent Indicator for Strong Acids by Dissolution of Tetra-2,3-pyridoporphyrazine Nanocrystals

〇Yutaro Hirai¹, Sawano Bunji², Takaki Toshihiko², Yabu Hiroshi³ (1.Grad. sch.of Eng., 2.Yamamoto Chemicals Inc., 3.WPI-AIMR, Tohoku Univ.)

Keywords:Phthalocyanine derivatives, pH sensor, nano crystals

In order to measure pH in strong acid region, a stable detection reagent is necessary even under a strong acid condition. Tetra-2,3-pyridoporphyradine (TPP) has high chemical stability and crystallinity, and its nano-crystal is widely used as stable pigments. ZnTPP exhibits red fluorescence, but ZnTPP crystals don’t exhibit fluorescence due to concentration quenching. In this report, we show a UV-assisted synthesis of ZnTPP nano-crystals and application for fluorescence pH sensor at extreme low pH condition by quaternization of ZnTPP nano-crystals. ZnTPP crystals were successfully synthesized and then dispersed into 1 to 10 M HCl aq. UV-Vis and fluorescence spectroscopy revealed that absorption and fluorescence change were observed depending on HCl concentrations at extreme low pH conditions due to quarternization of ZnTPP and dissolution of ZnTPP nano-crystals. These results indicate that ZnTPP nano-crystals can be used for fluorescence pH sensor at extreme low pH.