Quality control procedure

Introduction

When a series of runs is performed, irregularities in samples or in system or column performance can produce errors that will make the results inaccurate.

A quality control procedure can be added to a method to be used for a test run during the series of runs. The control procedure can ensure that the results remain within acceptable limits. If the result from the test run is unacceptable, the system can be paused so that the error is not repeated in subsequent runs.

How to create the quality control procedure

The easiest way to create the quality control procedure is to edit an existing procedure that includes a peak integration. The table below describes how to do this.

Step	Action
1	Choose Procedures:Edit:Open in the Evaluation module. Result: The Open Procedure dialog box opens.
2	Select the procedure (Global) Integrate_and_Print. Click the OK button. Result: The Procedure Editor opens with the procedure displayed.
3	Select the REPORT instruction in the procedure. Choose Other and QC_TEST in the Instruction field.
4	Type appropriate values in the Parameter field. See "QC_TEST Parameter descriptions" below. Click the Replace button. Result: The REPORT instruction is replaced by the QC_TEST instruction.
5	Choose File:Save As. Result: The Save As dialog box opens. Type a name for the procedure (for example QC_test). Select the Global procedure check box if the procedure is to be available to all users. Note: If you select File:Save to save the procedure it will replace the (Global) Integrate_and_Print procedure.

Illustration: The Procedure Editor

The illustration below shows the Procedure Editor with the QC_TEST instruction displayed:

QC_TEST parameter descriptions

The table below describes the parameters for the QC_TEST instruction.

The example values are used in the illustration above.

Parameter	Description
Peak table source	The peak table indicated in the PEAK_INTEGRATE instruction (Example: A).
Left limit	The retention value where the control instruction will begin (Example: 0).
Right limit	The retention value where the control instruction will end (Example: 100). Note: The control instruction will be applied to the run up to the sequence in the method where the control instruction is inserted: The controlled part of the run will end at the Right limit if this retention value is reached before the control instruction is reached in the method. If not, the controlled part of the run will end when the control instruction is reached in the method.
Peak selection on	The criteria for peak identification (Example: RETENTION).
Order number	The sequential order number of the peak (Example: 1).
Peak table parameter	The peak table parameter that will be tested by the control instruction (Example: RETENTION).
Less than	Values less than the parameter value will be out of the acceptable range (Example 10).
Greater than	Values greater than the parameter value will be out of the acceptable range (Example 11).
QC Action	The action the system will take when the controlled value is out of the acceptable range (Example: PAUSE).
Message text	Free text message that is displayed when the controlled value is out of the acceptable range (Example: Retention out of range!)

Note: All values must be included before the instruction can be inserted.

How to add the quality control procedure to a method

The table below describes how to add the quality control procedure to a method.

Step	Action
1	Open the method in the Method Editor. Click the Run Setup icon. Result: The Run Setup for the method opens.
2	Select the Evaluation Procedures tab. Click the Import button. Result: The Import dialog box opens.
3	Select the quality control procedure you created and saved (Example: QC_test) in the Select field. Click the Import button. Result: The quality control procedure is added to the available evaluation procedures. Click the Close button.
4	Click the check box to de-select the quality control procedure. Note: If the quality control procedure is selected it will initiate a new manual run at the end of the method run.
5	Click the Text Instructions icon. Select the last instruction in the method. Select Other:Evaluate in the Instructions field. Select the quality control procedure in the Procedure list. Click the Insert button.
6	Choose File:Save or Click the Save icon. Result: When the method run is performed the quality control procedure will create a second chromatogram. If the controlled value is outside the acceptable range, the system will be paused.

2005-06-15