New PolySNAP Papers: PolySNAP3: a computer program for analysing and visualizing high-throughput data from diffraction and spectroscopic sources Barr, G., Dong, W., & Gilmore, C.J, J. Appl. Cryst., (2009), 42, 965-974. High-throughput powder diffraction V: the use of Raman spectroscopy with and without X-ray powder diffraction data Gordon Barr, Gordon Cunningham, Wei Dong, Christopher J. Gilmore and Takashi Kojima J. Appl. Cryst. (2009). 42, 706–714

Introduction

PolySNAP3 is a computer program for the classification of powder diffraction, spectroscopic and/or raw numerical data either separately or combined. Cluster analysis, multivariate data analysis and extensive data visualiza- tion routines are used to automatically classify the patterns into groups, validate the classification, and thus identify polymorphs, mixtures and salts.

PolySNAP 3 offers more than automation of existing procedures:

• Drastic reduction of analysis efforts and time while increasing sample throughput
• Allowing laboratory staff to concentrate only on significant results, shifting the focus from redundant to effective work.

It is a 4th generation pattern-matching program, and provides an easy to use interface to several powerful and novel statistical methods to rank patterns in order of their similarity to any selected sample, allowing knowns as well as unknowns to be quickly identified. 

In quantitative mode, given a mixture pattern and potenial pure phase patterns, PolySNAP can identify which patterns are in the mixture, and quantify their proportions quickly and easily.

The pattern matching is based on a statistical comparison of each measured datapoint in each pattern. This true full pattern analysis approach takes full advantage of all pattern information including:

• Presence or absence of peaks
• Peak shoulders
• Background regions and more

Consequently, it provides for the most reliable and accurate results possible, even for data of poor quality, as it minimises effects due to factors such as preferred orientation and crystallite statistics.

The pattern matching methods allow:

• Identification of both known and unknown samples
• have I seen this sample before?
• is it new or a mixture?
• Quantitative analysis
• what is in my mixture?
• Quality control
• am I making what I think I'm making? 

 

Primary Program References

PolySNAP3: a computer program for analysing and visualizing high-throughput data from diffraction and spectroscopic sources
Barr, G., Dong, W., & Gilmore, C.J, J. Appl. Cryst., (2009), 42, 965-974.

PolySNAP: a computer program for analysing high-throughput powder diffraction data
Barr, G., Dong, W., Gilmore, C. J., J. Appl. Cryst. (2004). 37, 658–664

Other References

High-throughput powder diffraction V: the use of Raman
spectroscopy with and without X-ray powder diffraction data
Barr, G., Cunningham, G., Dong, W., Gilmore, C.J., and Kojima, T. J. Appl. Cryst. (2009). 42, 706–714

High-throughput powder diffraction. IV. Cluster validation using silhouettes and fuzzy clustering
Barr, G., Dong, W. and Gilmore, C. J. J. Appl. Cryst. (2004). 37, 874-882
   
High-throughput powder diffraction. III. The application of full profile pattern matching and multivariate statistical analysis to round-robin-type data sets
Barr, G., Dong, W., Gilmore, C. J., Faber, J. J. Appl. Cryst. (2004). 37, 635-642

SNAP-1D: a computer program for qualitative and quantitative powder diffraction pattern analysis using the full pattern profile
Barr, G., Gilmore, C. J., Paisley, J., J. Appl. Cryst. (2004). 37, 665–668
   
Automation of Solid Form Screening Procedures in the Pharmaceutical Industry - How to Avoid the Bottlenecks
Storey, R., Docherty, R., Higginson, P. D., Dallman, C., Gilmore, C. J., Barr, G. and Dong, W., Cryst. Rev. (2004). 10, 45-56
   
High-throughput powder diffraction. II. Applications of clustering methods and multivariate data analysis
Barr, G., Dong, W. and Gilmore, C. J., J. Appl. Cryst. (2004). 37, 243-252

High-throughput powder diffraction. I. A new approach to qualitative and quantitative powder diffraction pattern analysis using full pattern profiles
Gilmore, C. J., Barr, G. and Paisley, J. J. Appl. Cryst. (2004). 37, 231-242