Skip to main content

Detection of Subpopulations in Near-Infrared Reflectance Analysis

Buy Article:

$29.00 plus tax (Refund Policy)

Abstract:

In typical near-infrared multivariate statistical analyses, samples with similar spectra produce points that cluster in a certain region of spectral hyperspace. These clusters can vary significantly in shape and size due to variation in sample packings, particle-size distributions, component concentrations, and drift with time. These factors, when combined with discriminant analysis using simple distance metrics, produce a test in which a result that places a particular point inside a particular cluster does not necessarily mean that the point is actually a member of the cluster. Instead, the point may be a member of a new, slightly different cluster that overlaps the first. A new cluster can be created by factors like low-level contamination or instrumental drift. An extention added to part of the BEAST (Bootstrap Error-Adjusted Single-sample Technique) can be used to set nonparametric probability-density contours inside spectral clusters as well as outside, and when multiple points begin to appear in a certain region of cluster-hyperspace the perturbation of these density contours can be detected at an assigned significance level. The detection of false samples both within and beyond 3 SDs of the center of the training set is possible with this method. This procedure is shown to be effective for contaminant levels of a few hundred ppm in an over-the-counter drug capsule, and is shown to function with as few as one or two wavelengths, suggesting its application to very simple process sensors.

Keywords: False sample; Near-infrared; Qualitative analysis

Document Type: Research Article

DOI: http://dx.doi.org/10.1366/0003702884429562

Affiliations: 1: Department of Chemistry, Indiana University, Bloomington, Indiana 47405-4001; present address: College of Pharmacy, University of Kentucky, Lexington, KY 40536-0082 2: Department of Chemistry, Indiana University, Bloomington, Indiana 47405-4001

Publication date: November 1, 1988

More about this publication?
sas/sas/1988/00000042/00000008/art00025
dcterms_title,dcterms_description,pub_keyword
6
5
20
40
5

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
X
Cookie Policy
ingentaconnect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more