Question 8 Is the System Pressure OK

The system pressure is higher or lower than normal or is fluctuating up and down. 

It is always advisable to record the system operating pressure at the start of every HPLC sequence or at the beginning of every day in order to establish a baseline or reference for each combination of assay, column, and system. If the operating pressure is considerably higher or lower on any occasion, this usually indicates that something is not right. Sudden increases in pressure are usually due to issues with the column or mobile phase, and sudden drops 

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