Standard Data Analysis -Integration
ChemStation - Level 1 - Training
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Integration locates the peaks in a signal and calculates their
size
What is Integration
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The Integration Process consists of the following:
• construct initial baseline
• peak recognition – Start and end Time
• finds the apex of the peak
• baseline allocation (construction)
• peak area measurement
Integration Process
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1 Slope and Curvature within limit
2 Slope and curvature above limit: peak?
3 Slope remains above limit: peak recognized
4 Curvature becomes negative: front inflection
5 Negative slope: Apex
6 Curvature becomes positive: rear inflection point
7 Slope and curvature within limit: end of peak?
8 Slope and curvature within limit: end of peak
5
1
2
3
4 6
7
8
Start, End and Apex of a Peak
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Fit highest data point and those on each sideto a quadratic equation, solve for highest point
Determining Peak Apex
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BB
BV
VB
BB
BV
VB
Baseline Tick Marks
The default baseline is constructed as a series of straight line segments between: the start of the baseline, the tick marks, and the end of the peak.
Default Baseline Construction
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Standard or Enhanced Integrator The ChemStation includes two integrators:
the Enhanced Integrator (default) and the Standard Integrator (Genie)
New methods by default use the Enhanced Integrator and can not be down graded to the Standard Integrator
Old methods can be
updated to use the Enhanced Integrator ormaintained using the Standard Integrator so customers
can continue using validated methods.
The default method “defoldlc.m” has the Standard Integrator
The default method “def_lc.m” has the Enhanced Integrator
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Both integrators co-exist so you may continueto use validated methods
The Enhanced Integrator offers better: baseline allocation on wandering baselines rejection of noise peaks through the use of an initial peak
height parameter control of integration start and stop marks peak allocation on noisy signals peak shoulder allocation through second derivative
calculations
Standard or Enhanced Integrator
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Loading Signals
Select path, data file name and channel
Select
or ‘Load Signal’ from File Menu
Show/Hide the Signal Information
Choose to load all available or selected signals only
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You may also integrate by:
•Selecting Integrate or Auto Integrate• from the Integration menu.•Selecting the Integration Tool.•Running a method where the Run• Time Checklist includes Data Analysis
When a Signal is Loaded, Integration May Occur Automatically
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Initial Values
ThresholdPeak WidthArea RejectShoulders
Standard Integrator - Initial Values
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What timed events could you use to fix the
integration below?
Standard Integrator - Timed Events
What timed events could you use for this integration?
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Auto Integrate determines the optimum values for the initial threshold, peak width, and area reject by integrating the chromatogram twice.
Threshold - based on signal range and averaged baseline noise.Peak Width - proportional average of the peak widths of the first five peaks.Area Reject - 1/1000st of the greatest area found.
Auto Integration - Standard Integrator
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Select Integration Tasks Integrate CurrentChromatogram
Auto Integrate
Integration Events
Manual IntegrationDraw Peak Baseline
Manual IntegrationNegative Peaks
Manual IntegrationTangent Skim
Manual IntegrationSplit Peaks
Manual IntegrationRemove Peaks
Integration Tools - Standard Integrator
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The Enhanced Integrator offers better: baseline allocation on wandering baselines rejection of noise peaks through the use of an initial peak
height parameter control of integration start and stop marks peak allocation on noisy signals peak shoulder allocation through second derivative
calculations
Enhanced Integrator
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You may update methods developed on previous revisions of the ChemStation to the new Enhanced Integrator. Once you have updated the new method, you cannot revert back to the old integrator.
Enhanced Integrator
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Enhanced Integrator UI Define integration parameters just by selecting and clicking on the chromatogramThere are two sets of
integration events :
- intial events
- time-based
Use: Slope Sensitivity to define peak sensitivityPeakwidth to set an initial sampling interval for the
integrator to distinguish peaks from baseline noise
Area Reject to filter small peaksHeight Reject to set noise rejection
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Advanced Baseline
12 13 14 15 16 17 18 19 20
Abso
rbance
Time [min.]
Options OffAdvanced Integration
Options OnAdvanced Integration
Peak
Baseline
Peak
AreaUnassigned
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Using Initial Parameters
Peak Width
HeightReject
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Add Timed Events
Delete a Timed Event
Enhanced Integrator - Timed Events
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Solvent peak (Skim peak)
Tangent Peak
Straight Line Calculation
Exponential Calculation
Tangent Skim
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Shoulders occur when two peaks are so close together that no valleyexists between them
Peak with shoulders
Tangent Shoulders Drop Line Shoulders
Shoulder Detection
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Enhanced Integrator - Auto Integration
Examines beginning and end regions to estimate noise.
Assigns initial Slope Sensitivity and Height Reject.
Assigns temporary Peak Width value for first pass integration.
Sets Area Reject to zero.
Performs trial integration, may be repeated several times.
Calculates Peak Width based on early eluting peaks.
Refines Slope Sensitivity and Height Reject.
Computes Area Reject from initial Peak Width and noise level.
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Integration TasksIntegrate CurrentChromatogram
Auto IntegrateIntegration Events
Set Baseline Now
Set Baseline Hold
Set Tail Tangent Skim
Set IntegrationSet Slope Sensitivity
Set Area Reject
Set Fixed Peak Width
Set Detect Shoulders
Enhanced Integrator - Tool Bar
Use Auto Integrate to find suitable integration events
Only visible with
integration events open
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Save Events to Method
Save Integration Events as Part of a Method
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Manual Integration
Manual integration events
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Manual Integration
Use Cursor tools to perform manual integration by selecting the required action and dragging a line over or clicking on the chromatogram (depending on the task)
Zoom in using the zooming tools to better view your baseline
The new integration results are immediately visible in the user interface
If your chromatography is so demanding that you can’t use the the automatic integration process
Use the manual integration tool set
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Option 1: Save Manual Integration to Method
Select Integration, Copy Manual Events to Method
Save Manual Integration - To the method
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Step 1: Select View, Windows Functions, Save Window
Save Manual Integration - To the Raw Data File
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Note: manual changes are stored in the raw data file directory.
Step 2: Click OK to use default name or rename
Save Manual Integration - To the Raw Data File
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Select View, Windows Functions, Load Window
To Recall Manual Integration From Data File
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Lab Time !!!!! Lab 5 - Integration