Sample and Standard peak area found in the ratio of 1:6 ratio during HPLC analysis

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 Sample peak at RT about 4.5 min. with height of about 90


Standard peak at RT about 4.5 min. with height of about 630

Investigation:
When such phenomenon was observed then analyst was interviewed and detailed discussion done about level of dilutions done during sample and standard solution preparation.

As per the Standard testing procedure, std was to be taken as 50 mg and sample was to taken as Equivalent to 50 mg active substance.

Now, the analyst weighed correctly 50.2 mg of standard but during sample weighing he took the similar weight as 50.5 mg.

Here the point is weight of tablet under analysis is 300 mg. Hence, the actual weight is to be taken as 300 mg as each tablet contains 50 mg of active content. This resulted in Sample peak height to Standard peak height in the ratio of 1:6.

Conclusion: This is the common mistake in pharma lab which is sometime done by analyst. They should clearly distinguish between the word Equivalent and Equal. Though this seems silly mistake but many times such small mistake can give rise to big OOS and OOT in Pharma lab.


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