Understanding Integration parameters
- Peak width
- Peak threshold
- Skim ratio
- valley-Valley
- Min Height
- Min Area
- Force peak start and end
- Force horizontal baseline
- Negative peaks
- Integration on/off
- Using highlight colours
- Grouping peaks
integration by height or area
Time windows
Using a reference peak
Calibration Options:
- External Standard
- Internal Standard
- Area %
- Standard Addition
- Correlation Factor
When to use single point or multipoint calibration
When you might accept a curve instead of a straight line
- the risks
- how to get a straight lin even if the results give a curve
What is an acceptable r2 value
Preparation of calibration standards
- master standard and dilutions
- Selecting appropriate weights and volumes
- choice of sample solvent
Temperature control - the importance and the pitfalls
- in the lab
- in the autosampler
Bracketed Calibration
Calibration range
Why a calibration curve may not go through zero
Using zero as a point in the calibration curve
The use of blank samples
- proving zero is zero
- checking for carryover
- ghost peaks
Limit of Detection
Limit of Quantitation
What can threaten the integrity of a calibration
- systematic errors
- random errors
- retention time reproducibility (peak area change and incorrect peak assignment)
- purity of standards
- temperature changes
- peak shape changes
- increasing noise
- detector maintenance (eg new lamp)
- integration settings
- presence of unexpected impurities
- poor initial resolution
System Suitability Criteria
Confidence in results - quantifying accuracy and precision
Use of dilution factors |