OPUS Quantification


Quantification of components or sample properties is very likely the most common application in NIR spectroscopy. The QUANT2 package provides a compre-hensive framework to setup, calibrate and validate PLS (Partial Least Squares) based quantification models.

Multivariate calibration algorithms like PLS correlate spectral intensity (e.g. absorbance values) in specified wavelength regions with concentration values of constituents obtained via appropriate reference methods. The calibration work requires the usage of certain tools, plots and statistics to obtain reliable and robust calibration models.

In the multi evaluation framework two step evaluations offer an additional dimension: nested quantification models allow to further optimize accuracy of methods within defined concentration ranges for each component.



QUANT2 example calibration, prediction vs. true plot

QUANT2 Key Features:

  • PLS Calibration Algorithm with full cross validation and test set validation.
  • Automatic Method Optimization Algorithm: determination of optimized calibration model by automatic permutation of spectral ranges and preprocessing methods.
  • Unlimited Number of Components/Properties and up to 64,000 spectra.
  • Various spectral Pre-processing Methods or sequences with display of pre-processed spectra.
  • Sample Test Set Selection by Component/Property Values or PCA scores in multiple dimensions by Kennard-Stone algorithm.
  • Data Set Reduction by detection and elimination of redundant samples in multidimensional PCA score space by kNN algorithm.
  • Color Marking of Spectra for Follow-up in spectral view and all plots.
Principal component analysis (PCA) score plot
  • Reference Concentration Correlation Matrix to identify components having a high degree of co-linearity between individual components.
  • Automatic Identification and Grouping of replicate samples within the calibration data set.
  • Check of spectral and Prediction Repeatability for replicate measurements of individual samples.
  • Automated Import of Reference Values from spectra files or database.
  • Protection of Method Files to allow usage only for specific instruments, including protection for defined time limits (requires OPUS/VALIDATION Software).
  • Electronic Signature for Method Files according to 21CFR11 requirements (requires OPUS/VALIDATION Software).
  • Calibration Design to create a sample list with uncorrelated compositions based on a given number of components and concentration ranges.
QUANT2: interactive selection of multiple spectral ranges for calibration