title: Color-Multiplexing-Based Fluorescent Test Paper: Dosage-Sensitive Visualization of Arsenic(III) with Discernable Scale as Low as 5 ppb.
abstract: Fluorescent colorimetry test papers are promising for the assays of environments, medicines, and foods by the observation of the naked eye on the variations of fluorescence brightness and color. Unlike dye-absorption-based pH test paper, however, the fluorescent test papers with wide color-emissive variations with target dosages for accurate quantification remain unsuccessful even if the multicolorful fluorescent probes are used. Here, we report the dosage-sensitive fluorescent colorimetry test paper with a very wide/consecutive "from red to cyan" response to the presence and amount of arsenic ions, As(III). Red quantum dots (QDs) were modified with glutathione and dithiothreitol to obtain the supersensitivity to As(III) by the quenching of red fluorescence through the formation of dispersive QDs aggregates. A small amount of cyan carbon dots (CDs) with spectral blue-green components as the photostable internal standard were mixed into the QDs solution to produce a composited red fluorescence. Upon the addition of As(III) into the sensory solution, the fluorescence color could gradually be reversed from red to cyan with a detection limit of 1.7 ppb As(III). When the sensory solution was printed onto a piece of filter paper, surprisingly a serial of color evolution from peach to pink to orange to khaki to yellowish to yellow-green to final cyan with the addition of As(III) was displayed and clearly discerned the dosage scale as low as 5 ppb. The methodology reported here opens a novel pathway toward the real applications of fluorescent test papers.
authors.affiliation: School of Pharmacy, Nanjing Medical University , Nanjing, Jiangsu 211166, China.
authors.forename: Yujie
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: School of Pharmacy, Nanjing Medical University , Nanjing, Jiangsu 211166, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Huang
authors.affiliation: CAS Center for Excellence in Nanoscience, Institute of Intelligent Machines, Chinese Academy of Sciences , Hefei, Anhui 230031, China.
authors.forename: Cui
authors.initials: C
authors.lastname: Liu
authors.affiliation: CAS Center for Excellence in Nanoscience, Institute of Intelligent Machines, Chinese Academy of Sciences , Hefei, Anhui 230031, China.|School of Chemistry and Chemical Engineering, Anhui University , Hefei, Anhui 230601, China.
authors.forename: Ruilong
authors.initials: R
authors.lastname: Zhang
authors.affiliation: School of Pharmacy, Nanjing Medical University , Nanjing, Jiangsu 211166, China.
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Gu
authors.affiliation: CAS Center for Excellence in Nanoscience, Institute of Intelligent Machines, Chinese Academy of Sciences , Hefei, Anhui 230031, China.
authors.forename: Guijian
authors.initials: G
authors.lastname: Guan
authors.affiliation: CAS Center for Excellence in Nanoscience, Institute of Intelligent Machines, Chinese Academy of Sciences , Hefei, Anhui 230031, China.
authors.forename: Changlong
authors.initials: C
authors.lastname: Jiang
authors.affiliation: School of Pharmacy, Nanjing Medical University , Nanjing, Jiangsu 211166, China.
authors.forename: Liying
authors.initials: L
authors.lastname: Zhang
authors.affiliation: School of Pharmacy, Nanjing Medical University , Nanjing, Jiangsu 211166, China.
authors.forename: Shuhu
authors.initials: S
authors.lastname: Du
authors.affiliation: CAS Center for Excellence in Nanoscience, Institute of Intelligent Machines, Chinese Academy of Sciences , Hefei, Anhui 230031, China.|School of Chemistry and Chemical Engineering, Anhui University , Hefei, Anhui 230601, China.
authors.forename: Bianhua
authors.initials: B
authors.lastname: Liu
authors.affiliation: CAS Center for Excellence in Nanoscience, Institute of Intelligent Machines, Chinese Academy of Sciences , Hefei, Anhui 230031, China.
authors.forename: Ming-Yong
authors.initials: MY
authors.lastname: Han
authors.affiliation: CAS Center for Excellence in Nanoscience, Institute of Intelligent Machines, Chinese Academy of Sciences , Hefei, Anhui 230031, China.|School of Chemistry and Chemical Engineering, Anhui University , Hefei, Anhui 230601, China.|State Key Laboratory of Transducer Technology, Chinese Academy of Sciences , Hefei, Anhui 230031, China.
authors.forename: Zhongping
authors.initials: Z
authors.lastname: Zhang