Method and apparatus for impurity detection
First Claim
Patent Images
1. An apparatus for detecting an impurity in a sample having at least one component comprising:
- a device for obtaining characteristic measurements for the sample;
a computer linked to said device;
software executing on said computer for selecting a value representing an anticipated number of components in the sample;
software executing on said computer for generating a matrix representing said characteristic measurements for the sample, said characteristic measurements having at least two variables in each dimension;
software executing on said computer for repeatedly selecting a subset within said matrix for analysis of the relation between the component and impurity;
software executing on said computer for constructing a projection matrix by projecting each of said characterstic measurements of said matrix onto said subset to calculate a residual error; and
software executing on said computer for calculating an index from said subset to assess purity of the sample.
1 Assignment
0 Petitions
Accused Products
Abstract
A method and apparatus is provided for detecting an impurity in a sample where an index can be calculated to assess purity in the presence of n major components with signal averaging or noise-filtering automatically built-in. The method and apparatus can be applied to liquid chromatography impurity detection using UV-VIS spectrophotometry based on robust matrix algebra representing the entire spectral space generated by the sample.
-
Citations
12 Claims
-
1. An apparatus for detecting an impurity in a sample having at least one component comprising:
-
a device for obtaining characteristic measurements for the sample;
a computer linked to said device;
software executing on said computer for selecting a value representing an anticipated number of components in the sample;
software executing on said computer for generating a matrix representing said characteristic measurements for the sample, said characteristic measurements having at least two variables in each dimension;
software executing on said computer for repeatedly selecting a subset within said matrix for analysis of the relation between the component and impurity;
software executing on said computer for constructing a projection matrix by projecting each of said characterstic measurements of said matrix onto said subset to calculate a residual error; and
software executing on said computer for calculating an index from said subset to assess purity of the sample. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
6. The apparatus of claim 4 wherein said matrix is dimensioned with data representing retention times for the chromatographic peak and wavelengths for the spectra.
-
7. The apparatus of claim 1 further comprising software executing on said computer for calculating a residual error e according to the equation:
-
8. The apparatus of claim 5 wherein said sub-matrix Rj changes its said values as it moves consecutively from one set of p columns to another such that said sub-matrix Rj is formed by taking the [j−
- (p−
1)/2] th to [j+(p−
1)/2] th column of said matrix represented by R, for each j where (p−
1)/2+1≧
j≧
n−
(p−
1)/2.
- (p−
-
9. The apparatus of claim 1 wherein said index represents a purity index.
-
10. The apparatus of claim 1 wherein said index represents an impurity index.
-
11. The apparatus of claim 10, wherein said impurity index is represented by E according to the equation:
-
12. The apparatus of claim 9 wherein said purity index is represented by kj and is calculated from Sj according to the equation:
Specification