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answering customer in the CpK and MSA study. 1 day we only produce 2 batch and chemical itself quite sensitive to the heat. pH or viscocity will be varies when chemical temperature raise up or down.
Note: if the viscocity and pH depend on temperature, you can obtain the viscocity (and pH) at a certain temperature with regression analysis and chart if needed the "atemperated" values to a SPC chart.
To conduct an MSA,
* Take some samples (it will be better if are taken from different batches and in different steps of the process <maximize different values of pH / viscocity>)
* divide the samples in several subsamples ( to say something; 5 for each lab operator)
* identify the subsamples so the operators don't know from wich group is each subsample.
* test each subsample by each operator