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Dongsheng Bu (dbu)
Intermediate Member
Username: dbu

Post Number: 19
Registered: 6-2006
Posted on Thursday, December 20, 2007 - 10:05 pm:   

Hello YJUNHAN,

In the Unscrambler MCR UI, higher setting for Sensitivity to pure components may produce larger number of ��pure�� components. The number (3) in your case is program estimated optimum number of pure components, not default number or maximum number for mixture analyses. I know someone got 12 components extracted from a MASS dataset by the use of the Unscrambler.

You may run PCA with your dataset and check total explained variance by first 3 PCs, and the variance explained by PC4 and after. Your data may have rank-deficient issue. It is not always true that all ingredients in a dataset of mixtures can be extracted by MCR. I will be very cautious if I handle a system has more than 10 ingredients. Spectroscopic type, mixture samples�� pattern, and spectral measurement settings may play important role as well. Please check Prof. Roma Tauler��s Home Page and Unscrambler Help for more information. Also, I highly recommend using the Unscrambler version 9.7 which improve MCR speed dramatically.

Happy Holidays.
Dongsheng
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yjunhan (yjunhan)
Member
Username: yjunhan

Post Number: 12
Registered: 7-2006
Posted on Thursday, December 20, 2007 - 10:19 am:   

Have anyone had the experience of the MCR function in the Unscrambler 9.6?
As my understanding, MCR is to extract the pure constituents information out of the mixture's spectral matrix. But there is not way I can set the number of the components. The default is 3, does it mean it assumes that the maximum pure component in the mixture analyte is three?
What if my sample is composed of more than 10 ingredients?
I am not sure whether my understanding is correct. Please do help me. Thanks.

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