Abstract: A method of creating a library of standardized spectral data and identifying a sample by searching the standardized library for a match with the sample spectrum. The method entails determining and applying a transfer function which equalizes instrument bias between instruments and within the same instruments over time. A transfer function is specific to a particular instrument, and is based on the relationship between a reference spectrum of a standard as stored in a library and a spectrum of the standard obtained on the particular instrument of interest. This method provides enhanced library searching capabilities.

Abstract: An improved method is provided for determining when a set of multivariate data (such as a chromatogram or a spectrum) is an outlier. The method involves using a procedure such as Principal Component Analysis to create a model describing a calibration set of spectra or chromatograms which is known to be normal, and to create residuals describing the portion of a particular spectrum or chromatogram which is not described by the model. The improvement comprises using an average residual spectrum calculated for the calibration set, rather than the origin of the model as a reference point for comparing a spectrum or chromatogram obtained from an unknown sample. The present invention also includes separating a complex set of data into various sub-parts such as sub-chromatograms or sub-spectra, so that outliers in any sub-part can be more readily detected.

Abstract: A method of correcting for instrumental changes that influence the spectral response of a mass spectrometer over time. The method entails determining and applying a transfer function which equalizes instrument bias between mass spectrometers and within the same mass spectrometer over time. A transfer function is specific to a particular mass spectrometer, and is based on the relationship between a reference spectrum of a standard as stored in a library and a spectrum of the standard obtained on the particular mass spectrometer of interest. This method facilitates and simplifies recalibration, provides enhanced library searching capabilities for mass spectrometry, and may permit concentration determination from mass spectral data without the need to recalibrate an instrument with multiple standards.

Abstract: The system consists of a light source, a monochrometer, one or more etalons or other stable samples, a detector and a computer to store reference spectra, provide a read out indicative of the spectrum, and to change the instrument response. A transfer function is used to recharacterize the instrument's wavelength position and intensity response to match the actual spectrum with the standard spectrum. In one embodiment, the etalon is used in series with the unknown sample. A spectrum of the sample and etalon is created and is extracted from the spectrum of the sample alone to provide the actual spectrum of the instrument response to the etalon alone. The actual spectrum can then be compared to the standard spectrum and the instrument response recharacterized accordingly.

Abstract: A method for sorting a plurality of diverse objects into groups, each such object being made predominately from at least polyethylene terephthalate and polystyrene and at least two of polyvinyl chloride, polyethylene and polypropylene, the groups consisting at least of objects of like type of polymer identified to be polyethylene terephthalate and polystyrene and at least two of polyvinyl chloride, polyethylene and polypropylene. The method includes three steps. The first step is to irradiate the objects to be sorted with near-infrared radiation. The second step is to measure the diffuse reflectance of the irradiated objects in the near-infrared region to identify the objects as to the type of polymer used to make them. The third step is to direct the objects to their respective groups according to the measurement and identification of the second step.