High-throughput powder diffraction. I. A new approach to qualitative and quantitative powder diffraction pattern analysis using full pattern profiles

Abstract

A new integrated approach to full powder diffraction pattern analysis is described. This new approach incorporates wavelet-based data pre-processing, non-parametric statistical tests for full-pattern matching, and singular value decomposition to extract quantitative phase information from mixtures. Every measured data point is used in both qualitative and quantitative analyses. The success of this new integrated approach is demonstrated through examples using several test data sets. The methods are incorporated within the commercial software programSNAP-1D, and can be extended to high-throughput powder diffraction experiments.

Rapid structural mapping of ternary metallic alloy systems using the combinatorial approach and cluster analysis

“…26,27 We are currently working on integrating these procedures into our data analysis procedures. However, the problems of noisy spectra, preferred orientations, peak shifts within a single phase, and the limited number of known pure phases in the systems we are studying present problems which we are yet to overcome.…”

A Quick Method for the Quantitative Analysis of Mixtures. 1. Powder X-Ray Diffraction

“…Since N ≫ m , the system is heavily over‐determined, and we can use least squares either via singular value decomposition (SVD) or linear regression. We have described the use of SVD in an earlier article10; it is the latter technique that we use here.…”

“…These methods are very effective but can be labor intensive, either in the preparation of samples or in the analysis of the data, and we present here a simple method based on the use of the full diffraction data profiles, but with minimal associated calculation or user interaction. The method has been incorporated into the computer program PolySNAP 10–15. For further discussions on practical aspect of quantitative analysis, there are two very instructive articles concerning a round‐robin organized by the International Union of Crystallography Powder Commission 16, 17…”

Powder diffraction based structural studies of pharmaceuticals

“…This is not to say that the fingerprinting role has been forgotten; rather, this too has been transformed by the introduction of high-throughput crystallisation approaches matched to diffractometers that are capable of generating many hundreds of fingerprints per day. Software that allows these fingerprints to be matched amongst themselves and with others then forms an essential component of the analytical chain [4,5]. Here, we focus on our own recent work on structure determination from powder diffraction data (SDPD) which has been driven largely through an interest in the particular scientific challenges posed by pharmaceutical materials, both as static structures and dynamic systems.…”