Explaining Baseline Codes and Baseline Code Descriptions for OpenLab CDS

Answer

This Information Applies To: Agilent OpenLab CDS 

Issue

Identifying the baseline codes and baseline code descriptions for OpenLab CDS

Background

• OpenLab CDS Data Analysis includes the same integration algorithms as available in both OpenLAB CDS ChemStation Edition and OpenLAB CDS EZChrom Edition. The processing method supports all the initial and timed events from ChemStation or EZChrom. In each method, you must select the integrator that you want to use. In the Processing Method, select General > Properties > Global > Select integrator > select either ChemStation integrator or EZChrom integrator (Figure 1). ChemStation integrator is selected as default. 
  
  For more details, see ChemStation integrator and EZChrom integrator.

Figure 1: ChemStation integrator vs EZChrom integrator in Processing Method

• In the integration results of a report, each peak is assigned a code that describes how the signal baseline was drawn. They are called "Baseline Codes" for the Chemstation integrator, and "Baseline Code Descriptions" for the EZchrom Integrator. The baseline codes are included in the Injection Results table (Figure 2) and in all default report templates (Figure 3).

Figure 2: BL code column in Injection Results

Figure 3: Baseline type in reports

Resolution 

Identifying Baseline Codes for ChemStation Integrators
In the integration results of a report, each peak is assigned a two-, three- or four-character code that describes how the signal baseline was drawn.

• First character: Baseline at start
• Second character: Baseline at end
• Third character: Error/peak flag
• Fourth character: Peak type

Character 1 and 2
The first character describes the baseline at the start of the peak and the second character describes the baseline at the end of the peak:

• B The peak started or stopped on the baseline.
• P The peak started or stopped while the baseline was penetrated.
• V The peak started or stopped with a valley drop-line.
• H The peak started or stopped on a forced horizontal baseline.
• F The peak started or stopped on a forced point.
• M The peak was manually integrated.
• U The peak was unassigned.
  Additional flags may also be appended (in order of precedence).

Character 3 
The third character may be a blank space, and describes an error or peak flag:

• A The integration was aborted. For example due to the integration events ON/OFF, or due to the end of signal run time.
• D The peak was distorted (bad peak shape).
• Blank space: The peak is a normal peak.

Character 4
The fourth character describes the peak type. It is shown only for forced integration events, or if manual integration has been triggered. For example, you use an integration event to define a solvent peak, or you use manual integration to correct the baseline or to delete a peak:

• S The peak is a solvent peak.
• N The peak is a negative peak.
• + The peak is an area summed peak.
• T Tangent-skimmed peak (standard skim).
• X Tangent-skimmed peak (old mode exponential skim).
• E Tangent-skimmed peak (new mode exponential skim).
• m Peak defined by manual baseline.
• n Negative peak defined by manual baseline.
• t Tangent-skimmed peak defined by manual baseline.
• x Tangent-skimmed peak (exponential skim) defined by manual baseline.
• R The peak is a recalculated peak.
• f Peak defined by a front shoulder tangent.
• b Peak defined by a rear shoulder tangent.
• F Peak defined by a front shoulder drop-line.
• B Peak defined by a rear shoulder drop-line.
• U The peak is unassigned.

Identifying Baseline Code Descriptions for EZchrom Integrators
A baseline code consists of two letters. The first letter denotes the peak beginning baseline type and the second letter indicates the peak ending baseline type.

• B Baseline
• C Exponential
• f Force Peak Start or Stop (user defined)
• I Peak ended by Integration Off event
• N Begin negative peak
• P End negative peak
• H Forward horizontal
• h Backward horizontal
• M Manual baseline or Manual peak
• m Move baseline Start/Stop
• S Shoulder
• T Tangent skim
• V Valley
• v Forced valley point
• x Split peak
• E End of chromatogram encountered before the end of peak was found. End of chromatogram used as peak end.
• R Reset Baseline
• L Lowest Point Horizontal

Learn how to effectively operate your Agilent OpenLab CDS Software: HPLC-OLII-1140eV2 - Agilent Infinity LC systems with OpenLab CDS - Integration and viewing results (Ver. 2.6) e-learning course available from Agilent education