By Roel Merckx on Thursday, August 19, 2004 - 12:24 pm:
What are the possible causes or how to interpret a calibration curve which doesn't pass through zero?
By bert on Thursday, August 19, 2004 - 11:18 pm:
What do you mean by not passing through zero? Did you include a blank, which revealed response for your analyte or does the calculated regression line not pass zero. If it is the regression line, is the deviation from zero statistical significant?
By Brent on Friday, August 20, 2004 - 07:17 am:
It doesn't have to pass through zero, though often the y-intercept is small enough that it might as well be zero.
Here's a nice little test. Integrate a blank sample with no peak. You will not get zero integration.
By syx_gf on Sunday, August 22, 2004 - 05:48 pm:
there is a reference from vam about preparation of calibration curve: a guide to best practice.
It said that leverage problem of a calib curve can be arose when calib stds are prepared by sequential dilution of a stock soln or in other words, the stds should be independent, and should not be prepared from a common stock soln)