Chromatography Forum

Q2B gives us a formulation to the calculation of DL : DL = 3.3 σ/S.
Thereof, s(σ)could be estimated based on the calibration curve, that is, as Q2B said " a specific calibration curve should be studied using samples containing an analyte in the range of DL. The residual standard deviation of a regression line or the standard deviation of y-intercepts of regression lines may be used as the standard deviation."
But, I don't know how to calculate.Would somebody kindly give me a example?

hi,
I'll try to be pragmatic. I hope you can make a regression data analysis with MS Excel (you should have select "analysis toolpak" option in Tools>Add-Ins before). Any other stat software would be able to make a regression analysis.
When you select "data analysis" from "tools" excel will ask you to select an analysis from a list. You can select regression and give the y and x range. Then you can see the residual standart error.
Good luck.

s(σ)could be estimated based on the calibration curve

It is true that you could estimate the limit of detection, but I think you still have to prove it by doing the actual experiment to see whether or not your method can deliver.

Thanks. It is of great help for me!

If you have an interest in calculation formula in Excel I would send you (need E-mail). It is not simple like it may seem.

oops!