LOD and LOQ

Various LOD and LOQ estimation concepts are described in detail with examples. Data analysis on linear regression is also discussed. Understanding of practical hand-on experience on excel work sheet operation is explained for the benefit of new chromatographers. - Ramalinga Prasad Kuppa.

[@rupanalam1369]

Sir, how does zero concentration of impurity give any response? Please share a complete lecture on impurity method validation.

[@pharmaworldk1473]

It is only noise...

[@livingbeings4739]

@@pharmaworldk1473 Qq

[@ajitjadhav607]

Dear sir, Kindly explain the calculation formula for below assay test. Dissolve 50 mg sample of sodium chloride in 50 mL of water and titrate against 0.1 N silver nitrate VS. 0.1N silver nitrate is equivalent to 5.844 mg of sodium chloride. Explain the formula for calculation.

[@pharmaworldk1473]

Equivalent weight of NaCl is 58.44. So, 0.1 N will have a factor of 5.844. That means each ml of 0.1 N AgNO3 will be equivalent to 5.844 mg of NaCl. So, for example, if volume consumed is 11.2 ml, the sample contains 11.2 x 5.884 mg of NaCl, which is equal to 65.4528 mg. Further it is simple to extrapolate by multiplying with 100 and dividing by weight of sample. You have to make correction for exact normality of AgNO3.(It may not be exactly 0.1N. It may be 0.09 or 0.12 etc..)

[@ajitjadhav607]

@@pharmaworldk1473 Thnk u so much sir for your reply. pl confirm the weight in mg or gm ?

[@pharmaworldk1473]

You have to use same unit of measure, either grams or milligrams.

[@devangacharya2860]

In equation of LOD and LOD why s:n ratio taken 3 and 10?

[@pharmaworldk1473]

This is a statistical analysis requirement. You remember the thumb rule for connection between LOD and LOQ.

[@prasadsunkari9814]

Just like a book readind

[@KIRANKUMAR-mo4zz]

What is know and unknow impurity in Rs please explain sir

[@pharmaworldk1473]

Known impurity means, it's structure is established. Unknown impurity means, it's structure is not known. Any impurity more than 0.1% should be identified. You may refer ICH Q3A for more detailed information. If still there are queries, I'll be happy to respond.

[@KIRANKUMAR-mo4zz]

Thanks sir

[@adnanazhar7227]

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