“Deconvolution” is a term often applied to the process of decomposing peaks that overlap with each other, thus extracting information about the “hidden peak”. Origin provides two tools to perform peak “deconvolution”, depending upon the existence of a baseline.
We have put together an Origin Project (OPJ) that includes two folders: the Multiple Peak Fit Tool folder and Peak Analyzer folder. You can download this OPJ file (Peak_Deconvolution.zip, 22.7KB) to learn how to perform peak deconvolution.
In this blog post we will discuss how to:
- Visually pick and fit peaks around chosen peak centers using the Multiple Peak Fit tool.
- Detect the baseline and fit peaks while simultaneously fitting a baseline using the Peak Analyzer.
Multiple Peak Fit — No Baseline Involved
The use of the Multiple Peak Fit tool is simple and straightforward. It basically involves four steps:
- Go to the menu Analysis: Peaks and Baseline :Multiple Peak Fit to open a dialog.
- Select a function from Peak Function drop-down list for fitting and click OK to proceed to locate peaks.
- Point your mouse and double-click on the desired peak positions to add peaks.
- Click the Fit button in the Get Points dialog to fit all specified peaks and the detailed results about each peak will be summarized in a table.
Peak Analyzer — Baseline Involved
If the data comes with a non-constant baseline, the Peak Analyzer would be useful to detect the baseline. Later you can choose to subtract it or fit it while fitting the peaks. It generally involves two major steps:
- Detect the baseline
- Fit the Peaks
To open the Peak Analyzer wizard, you need to go to the menu Analysis:Peaks and Baseline: Peak Analyzer. When the wizard opens, a preview window is automatically generated in order to provide real-time monitoring of the fitting process. Set your Goal to Fit Peaks (Pro)(available in OriginPro) to initiate the process.
Detect the Baseline
Origin provides several options to allow automatic determination of the baseline, and allows for additional adjustment of the associated parameters where needed. Origin also offers an advanced baseline-creation mechanism to let users manually pick anchor points and subsequently interpolate or even fit them to make the baseline. In this section, I will show you how to:
- Pick anchor points
- Interpolate/Fit anchor points
Picking anchor points usually involves three steps:
- Select User Defined from the Baseline Mode drop-down list and you will see the auto-determined anchor points.
- Uncheck the Enable Auto Find checkbox to enable editing anchor points. Click the Modify/Del button to move existing anchor points to their proper positions or delete bad ones.
- Click the Add button and double-click desired positions on the curve to add more anchor points.
When the anchor points are determined, you can either connect them by interpolation or fit them.
To interpolate the anchor points, select Interpolation from Connect by drop-down list and choose a method from Interpolation Method.
To fit the anchor points, select Fitting(Pro) from the Connect by drop-down list and select a fitting function from the Function drop-down list under the Fitting node.
Fit the Peaks
- Click the Find button to find ordinary peaks.
- Uncheck the Enable Auto Find checkbox and click the Add button to manually pick missing peaks.
- Double-click on desired peak positions to add peaks and click Done.
- Click the Fit button in the next page and the Finish button in the middle panel to fit. A report is generated with detailed information about the fitting and each peak.