Standard area vs sample area

Standard area and sample area allowed difference and acceptance criteria.

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Generally, in chromatography analysis (HPLC, GC, LC-MS/MS) the area obtained for standard solution and the area of sample solution should be as close as possible. The dilutions of sample solution should be appropriately made to have almost same concentration as that of standard solution so the areas of sample and standard solutions will be nearly the same.
However, in practice it may be possible to have sample area within the range of 70% - 130% or 50% - 150% of standard area. This is acceptable beacause during analytical method validation the linearity of assay within the range of 50%- 150% is already established. Therefore analytical results obtained are accurate and acceptable if the difference between areas of sample and standard solutions are within this range.


Thank you so much.

You are welcome.

Assay by hplc is failed dut to std area and sample area difference higher. Standard area is higher, We got 80%.
Sample and std preparation is same.
Wt is this reason to fail.
What is the criteria to purchase to std.

Please investigate to identify the root cause of this OOS Lab result (Out of specification). Please follow OOS Investigation guidelines of USFDA and your internal SOP for conducting investigation.

  • Please check Analytical Method Validation (AMV) data for correctness.
  • Use same analytical method for previous passed batches samples to compare the results.
  • Repeat assay by changing the sample solution dilutions so that sample and standard areas are very close to each other and calculate the results.
  • The sample might not be up to the quality standard or as per specification.
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Continued from my previous communication…

The Reference standard must be procured from Authentic sources (like USP, EP, BP etc.). It should be well characterised and its COA should be avaialble (or label information about its purity and lot number etc.)

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Thanks for guidance, we will do investigation.

You are welcome.