Robustness parameter

In Analytical method, Diluent is buffer pH 3.0 use for mobile phase. If buffer pH change to 2.8 for Robustness parameter, what diluent to be use?? is original diluent pH 3.0 or change parameter diluent of pH 2.8 to be used???

Dear Sachin,

The impact of deliberate alteration of mobile phase pH change on the chromatography elution pattern is what is to be assessed. The diluent will remain same as the method is finalized using the decided diluent. So no change of diluent is to be done.