A smartphone-integrated colorimetric quantitative analysis platform based on oxidase-like Ce(IV)-ATP-Tris CPNs/CNF test strip for detection of inorganic arsenic in rice

Herein, a colorimetric sensing system based on cerium(IV) coordination polymer nanoparticles (Ce(IV)-ATP-Tris CPNs) was proposed for As(V) detection. Ce(IV)-ATP-Tris CPNs show excellent oxidase-like activity, triggering 3,3',5,5'-tetramethylbenzidine (TMB) chromogenic reaction. With addition of ascorbic acid 2-phosphate (AAP) and acid phosphatase (ACP), ACP can hydrolyze AAP to produce antioxidative ascorbic acid (AA), inhibiting TMB chromogenic reaction. After that, introduction of As(V) can inhibit ACP, recovering TMB chromogenic reaction. Therefore, sensitive and selective As(V) detection is achieved. Moreover, Ce(IV)-ATP-Tris CPNs were transformed into cellulose nanofiber (CNF) to form test strip (Ce(IV)-ATP-Tris CPNs/CNF). Inorganic arsenic in rice can be detected by test strip, color of that can be measured by smartphone-integrated colorimetric quantitative analysis platform. Given this, rapid and convenient strip test of inorganic arsenic in rice by using this platform was achieved. Hence, this platform possesses great application potential in the field of inorganic arsenic in rice, even food safety.