title: Powder X-ray diffraction detection on a paper-based platform.
abstract: We developed paper-based powder X-ray diffraction (PP-XRD) to implement phase identification and/or crystal structure determination on paper-based platforms. These aims are not possible with other paper-based detectors, such as Raman spectroscopy and mass spectrometry. PP-XRD overcomes these limitations. Here we reported the simple and low-cost in situ PP-XRD protocol for phase identifications of inorganic and organic materials. We demonstrated that sample amounts of lead nitrate on paper substrate can be reduced into 1/30 of conventional ones by using the standard glass substrate at the same signal-to-noise ratio (S/N) of the X-ray diffraction (XRD) pattern. The paper-based method was comparable in sample quantity and intensity with zero background holder method, even though single crystal Si(100) substrate as zero background holder was used for the specimen preparation of CTAB (C19H42BrN). More importantly, paper substrates helped reduce preferred orientation that was generally present in routine powder XRD. Also, combined with paper chromatography, overlap peaks were eliminated in the XRD detection patterns of lead nitrate and cobalt nitrate hexahydrate. This new PP-XRD protocol may accelerate the process to identify phase or determine the molecular structures of new materials using trace sample directly. It also includes a hyphenated technique of powder XRD with a simple paper-based microfluidic separation of chemical solutions.
authors.affiliation: Separation Science Institute, the Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China; State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710049, PR China.
authors.forename: Liangfei
authors.initials: L
authors.lastname: Ouyang
authors.affiliation: Separation Science Institute, the Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Separation Science Institute, the Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China.
authors.forename: Chaoping
authors.initials: C
authors.lastname: Xu
authors.affiliation: Separation Science Institute, the Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China.
authors.forename: Changgui
authors.initials: C
authors.lastname: Liu
authors.affiliation: Separation Science Institute, the Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China. Electronic address: lheng@mail.xjtu.edu.cn.
authors.forename: Heng
authors.initials: H
authors.lastname: Liang
keywords: Crystal preparation; Hyphenation technique; Paper chromatography; Paper-based device; Powder X-ray diffraction