Method and apparatus for detecting and integrating chromatographic peaks
AssigneeSpectra-Physics, Inc.
InventorBarrett L. Tomlinson
Life of this patent
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Abstract
Chromatographic peaks of varying width are detected and integrated by a method and apparatus that uses only the leading edge of the peak itself to detect the onset of the peak and to select for integration of the peak a filter detector having a time constant which matches the filter characteristics to the signal being monitored. A plurality of filter detectors having different time constants are used for identifying the beginning of a peak. The output of all of the filter detectors is scanned to identify the onset of a peak, and the most appropriate filter detector is selected for integrating the peak.
Claims6
In a method of integrating peaks in a chromatographic analysis of the kind in which time varying signals are fed to a filter detector which detects weighted average slope or curvature over a time period in order to detect the presence of the peak to be integrated, the improvement comprising,
- using a multiplicity of filter detectors having different averaging time periods for detecting the presence of a peak,
- scanning the output of the filter detectors to find a detecting filter detector whose output detects the presence of a peak,
- then selecting as the integrating filter detector a filter detector whose averaging period is closely matched to the shape of the detected peak as detected by the detecting filter detector, and
- integrating the peak with the selected filter detector.
A method of detecting and integrating peaks in a chromatographic analysis and comprising,
- converting an analogue time-voltage signal to a digital representation,
- feeding the digitized signal to a plurality of digital filters, the output signals of which represent a weighted average curvature or slope over various length time periods,
- scanning the outputs of the digital filters to select one whose averaging period is comparable to the width of the peak to be integrated, and
- integrating the peak using the selected digital filter.
In apparatus for integrating peaks in a chromatographic analysis of the kind in which time varying signals are fed to a filter detector which detects weighted average slope or curvature in order to detect the presence of the peak to be integrated, the improvement comprising,
- filter detector means comprising a multiplicity of filter detectors having different averaging time periods for detecting the presence of a peak,
- scanning means for scanning the output of the filter detectors to find a detecting filter detector whose output detects the presence of a peak,
- selecting means for selecting as the integrating filter detector a filter detector whose averaging period is closely matched to the shape of the detected peak as detected by said detecting filter detector, and
- integrating means for integrating the peak with the integrating filter detector.
Apparatus for detecting and integrating peaks in a chromatographic analysis and comprising,
- converter means for converting an analogue time-voltage signal to a digital representation,
- feeding means for feeding the digitized signal to a plurality of digital filters, the outut signals of which represent a weighted average curvature or slope over various length time periods,
- scanning means for scanning the outputs of the digital filters to find a detecting digital filter with the shortest length time period which detects the presence of a peak,
- selecting means for selecting as the integrating filter a filter whose averaging period is comparable to the width of the peak to be integrated as detected by said detecting digital filter, and
- integrating means for integrating the peak with the integrating filter.
Dependencies are inferred from the claim text.