Technical data

196 Understanding Your Agilent ChemStation
8 Automation
Cyclic Recalibration Sequences with Multiple Vials Containing the Same Dilution of a Standard
Cyclic Recalibration Sequences with Multiple Vials Containing
the Same Dilution of a Standard
Cyclic Recalibration Sequence with “Round-Robin” Calibration
Vial Usage
When running a large sequence that performs cyclic recalibrations, that is,
performs an automatic recalibration after a fixed number of sample injections,
there is a potential risk of emptying the volume of calibration vial during the
course of the sequence. The ChemStation sequence table provides a means of
using a series of vials that contain the same dilution of a standard to be used
in a round-robin fashion.
With this capability, large sequences can be defined with automatic
recalibrations at fixed intervals using multiple calibration vials for each level
and each calibration vial would be consumed to the same extent.
By defining an appropriate number of calibration vials, it is even possible to
guarantee that each calibration vial is only used once. This is an important
requirement in cases where a fresh calibration vial is required for every
recalibration, for example, because the analyte evaporates once the septum is
punctured or starts degrading after getting in contact with the steel needle.
The following section describes how the ChemStation sequence table needs to
be set up to fulfill these requirements.
Determine the total number of calibration vials for each level based on the
estimated calibrant usage throughout the sequence.
Set up a separate cyclic recalibration line for each calibration vial. Lines
defined for the same calibration level must be in adjacent sequence lines and
the defined vial positions must be adjacent, too. Choose an identical
recalibration interval for all calibration lines. For example, if your sequence
should recalibrate after every 6 sample injections, set the recalibration
interval to 6.