Abstract:
The accuracy of an analytical determination is very important in an industrial processes .The quality of analytical determinations can be performed a Shewhart control chart. The control chart provides interpretation of standard of a a analytical determination can be identified in control or out of control.
A suitable check sample was selected to construct a control chart .This check sample need not be identical in old aspect to the sample was sufficiently similar to the test sample in chemical composition and physical state (solid, liquid, or gas) so that the conclusion drawn from the control chart are relevant to the subject subsequent analyses.
After selecting a check sample, start the experiments with the standard procedure.Under these condition composed a training set of 20 initial, independent observation for the check sample .Determine the average and the standard deviation of the training s e t. Enter all 20 observation in a control chart .Then continue the standard procedure for once a day. Once the training set has been completed the control chart is ready to o accept new observations from subsequent determinations of the check sample. New data entered in the control chart reveal whether or not the analytical determination is in control. For this decision we use the warning limits (2s) and the control limits (3s) from their definition it can statistically be expected that one out of every 20 observations will exceed the warning limits and one out of every thousand the control limits.
In the training period, for selected analytical determinations were used to check the
in control or out of control .There were no any out of result in selected analytical
determinations. All the analytical determinations were in control.
