Data Processing

Home || HPLC Topics || LC-MS TOPICS || HPLC Course || Educational || Links
Courses& Events || Personal || FTIR || Contact Me

8. Data Processing

In principle in every HPLC system there is some sort of a processing device that performs integration of the peaks in the chromatogram and provides report of the retention times and areas of every peak. Every data station has its own characteristics for data processing and it has to be learned properly to be able to perform accurate integration of the peaks.

Every data system has "Integration Events", parameters that help the software define the peak properly. All advanced data processing systems have reports where the chromatogram is shown and the integration marks are shown clearly. An accurate integration is done when the peak's start, end and maximum are defined properly. For details see: http://www.forumsci.co.il/HPLC/Integration_events.pdf.

In every modern integrator it is possible to define a minimum peak width. If the parameter given to the software is too small, not all the peak will be defined, and if the value given is too high, the definition will include excessive area.
In every integrator it is possible to define minimum height, or slope, above which the integrator will decide that this is the peak's starting point. If the value given to the software is too high it might miss the sample components' peaks or will start them later than it should or end them too early, and if the value given is too low the baseline noise might be defined as peaks.
In every data processing unit there is an option for definition of the sample components, their retention time window and other related parameters.
In many advanced software there are method for reporting of the results, which can be revised and customized according to the users needs. The more advanced is the software there is more control on the customization of the report and the various calculations.
Advanced chromatographic data systems do not allow that raw data will be manipulated and changed, and have optional definitions for limited access and privileges to various functions unless the operator is skillful enough (see: http://www.21cfrpart11.com/index.html)

The typical software today also includes measurements of system suitability and other quantitative calculations so that the final result will be given by the software without using auxiliary spreadsheet software to get the final value of identification, quantitation and quality of the measurement.

More information:
http://21cfrpart11.com/files/library/compliance/cds_1.pdf

http://21cfrpart11.com/files/library/compliance/cds_2.pdf
http://21cfrpart11.com/files/library/compliance/urs.pdf

Introduction

1-3: Solvent delivery system

4. The column

5 - Detector

6- Injector

7-Gradient and isocratic

8-Data Processing