Could anybody help me how to determine limit of detection during the validation of analytical methods? still i know the theory behind it but don't know practically how to established it?i requires the sequence how i should follow the sequence for the determination of lod?

Here's what I have done - maybe it's right and maybe it's not. I take placebo product and spike it at varying low levels to a point where the signal-to-noise is about 3:1, and consider that my limit of detection. I've also heard that if your realistic range is way higher than limit of detection (such as for sunscreen components which are present in several percent range and LOD is small ppm) then don't spend too much time or work on this. While I'm posting, is cGMP clear on whether linearity should be done on a series of standards or on placebo product spiked with various levels of analyte? Too me, it's not stated clearly.

Use the series of standard for the linearity and the placebo for the recovery (80, 100, and 120%).