Difference between linearity and range in analytical method validation?

Answer 1

The previously recorded answer in inaccurate on several levels (see below for quotations of previous repsonse)

Linearity is the correlation of a regression line. Range is typically derived from linearity. Range implies that the method developed corresponds to the "range"between 80-120% (ideally) of the expected sample range (concentration, wt. etc). For content uniformity, range is expected to be 70-130% of the test concentration. These are guidelines governed by ICH Q2 R1 (International Conference for Hamonisation).

In terms of HPLC method development:

LOQ is the smallest amount that will give a S/N ratio of 10 meaning this is the smallest amount you may give a numerical value with confidence. TYPICALLY, THE LOWER RANGE (AND USUALLY LINEARITY) IS LOQ.

LOD is the smallest value that will give an S/N ratio of 3, meaning you can say the specific compound is there qualitatively, but not quantitate the compound.

Previous:

"The range is any value that lies between the limit of detection (LoD) and the limit of quantitation (LoQ). Where the LoD is the lowest concentration that can be accurately measured and the LoQ is the highest concentration that can be accurately measured.

Linearity describes the correlation to a regression line that has been fit to the data that. For some nice pictures to explain this see regression line at:"