Peak Detector (Modular LC Fraction Collector Cluster)

The fraction collector supports all Agilent DADs, MWDs, VWDs and FLDs, as well as selected Agilent MSDs and third-party detectors as peak detectors.

If multiple detectors are used, to prevent damaging detectors with low resistance to an increase in back-pressure (for example, RID and FLD) caused by a blockage in the fraction collector, the ones with the highest pressure-resistance should be placed first, and the ones with the lowest pressure-resistance should be placed last.

The UIB (universal interface box) is required for fraction collection triggered by external detectors that are not connected via CAN, for example, MSDs and third-party detectors.

The peak detectors table shows the detectors that are currently present and configured. Only configured detectors can be used as peak detectors. The table contains the following columns:

Detector

The detector module type and serial number

Unit

The detector's units of measurement

Mode

    Select the working mode of each peak detector by clicking in the cell, then clicking the down-arrow and selecting the working mode from the list. You can select from:

  • Off

    The peak detector is not used.

  • Slope

    Detects peaks based on slope values only.

  • Threshold

    Detects peaks based on threshold values only.

  • Threshold and Slope

    Detects peaks based on both threshold and slope values.

Up Slope (/s)

The slope of the rising peak. The slope value is based on the first derivative of the signal (see also Peak Start/Stop Criteria and Working with Slope values).

Down Slope (/s)

The slope of the falling peak. The slope value is based on the first derivative of the signal (see also Peak Start/Stop Criteria and Working with Slope values).

Threshold

The height of the peak that triggers collection (see also Peak Start/Stop Criteria and Working with Slope values).

Upper Threshold

If the peak detection mode is Slope or Threshold and Slope, peak splitting or detector noise might cause unwanted detection of fractions or too many small unnecessary fractions to be collected. To avoid this, set an upper threshold above which slope-based peak detection is disabled.

Use MSD for mass-based Fraction Collection

If an MSD is present in the system, mark the Use MSD for mass-based Fraction Collection to use the MSD method parameters to control the fraction collection.

Do not select the UIB to be used in the peak detectors table. The UIB is needed only to connect the MSD with the LC stack.

Using Multiple Peak Detectors

Select the all peak detectors option to specify that fraction collection starts only when all peak detectors in use meet the trigger criteria.

Select the at least one peak detector option to specify that fraction collection starts when any one of the peak detectors in use meets the trigger criteria.