Related Substance Analysis via HPLC

[jayroseville58]

Any justification why is it okay to have greater sample concentration compared than standard concentration when dealing with the calculation of percent impurity?

[scottythree]

Sometimes just to see the impurities you have to over load the system with your API (max out the reading on the detector). Since you still need to establish system suitability your standard needs to be within the range of readability of your detector hence the standard is not at the same concentration of your sample.