1. Field of the Invention
The present invention generally relates to chromatography data processing systems and methods, and more particularly to a chromatography data processing system and method used with a fluid analyzer to determine fluid composition for a specified fluid analysis type.
2. Discussion of the Background
In recent years, a variety of methods have been employed to process fluid chromatography data in order to determine the composition of a fluid sample, i.e., the fluid components constituting the sample. The fluid sample can be a gas or a liquid sample. The fluid sample is analyzed using a fluid chromatograph, or fluid analyzer 1, as shown in
The type of signal values 13 depends on the type of the employed detector of the fluid analyzer, and which exploits a specific physical or chemical property of the fluid components. For example, a thermal conductivity detector measures the thermal conductivity of components of a fluid sample having a different thermal conductivity than that of a carrier material that carries the fluid sample through the fluid analyzer.
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Further, the fluid component peaks are identified, i.e., the name of a component (e.g., nitrogen, carbon dioxide, etc.) is attributed to each fluid component peak. The identification is carried out using the retention times of the fluid component, each component corresponding to a specific retention time. A reference analysis is often used for comparison. The retention time of a specific fluid component may vary from one analysis to another because of separation column aging, varying analysis conditions (e.g., temperature, or carrier fluid velocity), etc.
Thus, the prior methods discussed above lead only to an approximate peak separation, and the retention times and quantities of the corresponding fluid component or components are not correctly evaluated. The present invention includes the recognition that an unambiguous identification of the fluid components is not always possible, and the chromatography data have to be post-processed by the user, or the user has to intervene during the time the chromatography data are being processed.
The above and other needs and problems are addressed by the present invention, which in first aspects, provides a method and computer program product for treating fluid chromatography data of a specified fluid analysis type, including receiving the fluid chromatography data of a fluid sample including at least one fluid component of the specified fluid analysis type from a detector of a fluid analyzer, the fluid chromatography data comprising signal values as a function of time, and processing the received fluid chromatography data. The processing includes detecting at least one fluid component peak within the signal values for obtaining at least one retention time corresponding to the at least one detected fluid component peak, identifying the at least one fluid component corresponding to the at least one detected retention time using shape recognition through an artificial neural network preliminarily trained for identifying fluid component peaks of fluid chromatography data of the specified fluid analysis type, integrating the at least one detected fluid component peak to determine a quantity of the at least one fluid component detected by the detector of the fluid analyzer, and calculating a fluid sample composition from the at least one identified fluid component and the quantities of the at least one identified fluid component.
In one embodiment of the first aspect, the processing step further includes defining a baseline within the signal values. In another embodiment of the first aspect, the baseline is defined using shape recognition through the artificial neural network. In yet another embodiment of the first aspect, the integrating step comprises deconvoluting at least one unresolved fluid component peak. In a further embodiment of the first aspect, the detecting step includes detecting a peak start on the baseline, discriminating the fluid component peaks from other peaks and noise using a threshold value, and detecting a peak crest and a peak end of each fluid component peak. In another embodiment of the first aspect, the deconvoluting step includes calculating a derivative of the at least one unresolved fluid component peak, and comparing the derivative to a derivative of a resolved fluid component peak. In another embodiment of the first aspect, the method of treating fluid chromatography data further includes calibrating the detector of the fluid analyzer. In another embodiment of the first aspect, the method of treating fluid chromatography data further includes reporting the processed fluid chromatography data.
In a second aspect, the invention provides a device for processing fluid chromatography data of a fluid sample which includes at least one fluid component of a specified fluid analysis type, the fluid chromatography data including signal values as a function of time, the device including an input to receive the fluid chromatography data from a fluid analyzer, a peak detection module configured to detect at least one fluid component peak within the signal values for obtaining at least one retention time corresponding to the at least one detected fluid component peak, a peak integration module configured to integrate the at least one detected fluid component peak, a fluid component identification module comprising an artificial neural network configured to identify the at least one fluid component corresponding to the at least one detected retention time, the artificial neural network being preliminarily trained for identifying fluid component peaks of fluid chromatography data of the specified fluid analysis type, and a calculation module configured to calculate a fluid sample composition.
In an embodiment of the second aspect, the device further includes a baseline definition module configured to define a baseline within the signal values. In another embodiment of the second aspect, the peak integration module includes a peak deconvolution module configured to deconvolute unresolved fluid component peaks.
In a third aspect, the invention provides a system for treating fluid chromatography data of a specified fluid analysis type, the system including a fluid analyzer including an injector, at least one separation column, and a detector, and the device for processing fluid chromatography data according to the second aspect of the invention.
In one embodiment of the third aspect, the system further includes a calibration module configured to calibrate the detector of the fluid analyzer. In another preferred embodiment of the third aspect, the system further includes a reporting module configured to report the processed fluid chromatography data.
In fourth aspects, the invention provides a training method and computer program product for an artificial neural network for fluid component identification for processing fluid chromatography data of a fluid sample of a specified fluid analysis type, the artificial neural network comprising a set of weights to be optimized, the training method including preparing a set of training chromatography data of at least one fluid sample having at least one determined component of the specified fluid analysis type, the training chromatography data comprising signal values as a function of time, creating at least one input vector of selected time values for the set of training chromatography data, and inputting the at least one input vector into the artificial neural network to calculate the optimized set of weights corresponding to the specified fluid analysis type.
In a further embodiment of the fourth aspect, the selected time values correspond to fluid component peak crest signal values.
Still other aspects, features, and advantages of the present invention are readily apparent from the entire description thereof, including the figures, which illustrate a number of exemplary embodiments and implementations. The present invention is also capable of other and different embodiments, and its several details can be modified in various respects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive.
The embodiments of the present invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which:
a and 3b show examples of splitting unresolved fluid component peaks;
Various embodiments and aspects of the invention will now be described in detail with reference to the accompanying figures. The terminology and phraseology used herein is solely used for descriptive purposes and should not be construed as limiting in scope. Language such as “including,” “comprising,” “having,” “containing,” or “involving,” and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited. Exemplary embodiments of the invention will now be described in detail with reference to the accompanying figures, in which like elements may be denoted by like reference numerals for consistency.
In one aspect, embodiments of the invention relate to a chromatography data processing system used with a fluid analyzer of a specified fluid analysis type to determine a fluid composition of various fluid samples, the fluid chromatography data processing system using an artificial neural network (ANN). The specified fluid analysis type can relate naturally to any suitable type of gas analyses, for example, in the oilfield (e.g., in bottom hole or explosive environments), or in laboratory applications.
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In step 102, peaks are detected by the peak detection module within the signal values received from the detector of the fluid chromatograph. Generic noise of the baseline for the current fluid sample analysis is automatically detected. Then, a first threshold value is determined, and only the signal values exceeding the first threshold value are taken into account for peak detection. A second threshold value is used to discriminate spikes from fluid component peaks within the signal values exceeding the first threshold value. This way, the peak start time of the fluid component peaks is detected. The peak start time is the moment when the corresponding fluid component reaches the detector of the fluid analyzer. The peak top time and the peak end time are then detected. The peak end time is the moment when the corresponding fluid component stops arriving at the detector of the fluid analyzer, and the peak top time is the moment when the peak reaches its maximum value.
In step 104, the detected fluid component peaks are identified, e.g., a fluid component corresponding to a specific fluid component peak is identified for each fluid component peak. To this end, the fluid component identification module includes an artificial neural network. The artificial neural network works based on shape recognition. The chromatography data (e.g., the signal values as a function of time) forms a pattern of fluid component peaks, and the artificial neural network is configured to recognize this pattern. The artificial neural network has been trained beforehand (e.g., before the current analysis of a fluid sample) in order to be able to recognize patterns corresponding to specific fluid samples.
In step 106, the baseline of the chromatography data is defined. This can be done by recording a blank analysis, e.g., only a carrier material is eluting through the fluid analyzer, at determined operational conditions (temperature, carrier material, eluting velocity, etc.). Some known points of the baseline can be fed into the system after receiving signal values from the detector when a fluid sample is analyzed. These known points can be, for example, signal values before the first peak, after the last peak, or between peaks (e.g., no fluid components are eluting from the separation column). The baseline can also be defined by using shape recognition through the artificial neural network.
In step 108, the detected fluid component peaks are integrated after subtracting the baseline from the signal values in order to determine the area of the fluid component peaks using the integration module. The area of the fluid component peaks gives information about the quantity of the corresponding components within the sample, e.g., their concentration.
In one embodiment of the invention, unresolved fluid component peaks within the signal values can be detected. This can be done by performing a derivative of the signal. The derivative of the signal at the fluid component peaks is compared to the derivative of a known mono-component peak. Thus, multiple peak tops or shoulders are identified.
If unresolved fluid component peaks are present within the signal values, the detected unresolved fluid component peaks are deconvoluted at step 110 in order to obtain resolved fluid component peaks. Each unresolved fluid component peak is thus split into several resolved fluid component peaks such that the sum of the resolved fluid component peaks is the unresolved fluid component peak. To this end, the peak deconvolution module is implemented with the peak integration module. The deconvolution step can include calculating a derivative of the unresolved peaks, and then comparing the derivative of the unresolved peaks to a derivative of a resolved fluid component peak.
In step 112, the composition (e.g., components and their concentrations) of the analyzed fluid sample according to the processed fluid chromatography data of the specified analysis type is calculated using the calculation module. In addition, average molar mass, heat content, and/or other critical properties can be calculated.
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Embodiments of the invention discussed herein can include one or more of the following advantages. For example, due to the fluid component identification through pattern recognition using an artificial neural network, the fluid chromatography data processing device is insensitive to analysis operation variations, such as temperature fluctuations, flow rate variations, or different types of carrier materials. The fluid component peaks can be identified unambiguously in any relative concentration. Furthermore, the deconvolution step allows the fluid component identification module to correctly evaluate the retention times of the fluid components.
The above-described devices and subsystems of the exemplary embodiments of
One or more interface mechanisms can be used with the exemplary embodiments of
It is to be understood that the devices and subsystems of the exemplary embodiments of
To implement such variations as well as other variations, a single computer system can be programmed to perform the special purpose functions of one or more of the devices and subsystems of the exemplary embodiments of
The devices and subsystems of the exemplary embodiments of
All or a portion of the devices and subsystems of the exemplary embodiments of
Stored on any one or on a combination of computer readable media, the exemplary embodiments of the present invention can include software for controlling the devices and subsystems of the exemplary embodiments of
As stated above, the devices and subsystems of the exemplary embodiments of
While the present inventions have been described in connection with a number of exemplary embodiments, and implementations, the present inventions are not so limited, but rather cover various modifications, and equivalent arrangements, which fall within the purview of the appended claims.
The present invention claims benefit of priority to U.S. Provisional Patent Application Ser. No. 60/983,889 of Paul GUIEZE, entitled “CHROMATOGRAPHY DATA PROCESSING METHOD,” filed on Oct. 30, 2007, the entire contents of which are hereby incorporated by reference herein.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US08/81752 | 10/30/2008 | WO | 00 | 6/11/2010 |
Number | Date | Country | |
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60983889 | Oct 2007 | US |