By Eli on Thursday, October 10, 2002 - 01:48 am:
It is a forum for chromatographers. Is there such a forum for other analytical technics. About spectrofotometry?
For identity test, is there a written statement about the permitted tolerance for the measured maximum. How much can differ max. of reference standard and max. of the substnace in formulated preparations, granules for oral suspension for example.
For the spectrofotometer-Control of wavelengths-The permitted tolerance is ±1 nm for the ultraviolet range and ±3 nm for the visible range.
By Anonymous on Thursday, October 10, 2002 - 06:39 am:
I think the tolerance would depend upon how the method was written to begin with. Was it validated with those tolerances?
By Anonymous on Friday, October 11, 2002 - 12:02 am:
What does it mean to validate the method for identity? It needs only selectivity test. Placebo did not show absorption at the wavelength of interest, but there is some movement of the maximum. What is the permitted value for this movement?
By Anonymous on Friday, October 11, 2002 - 08:14 am:
An identity method is a quick determination that the substance is what it is claimed to be. This method can be an LC method, a GC method, an MS method a UV-Vis spectrophotometric method, a colorimetric method, etc. If the substance has a USP monography, it will have an identity test as well.
As to your question in regards of movement. My answer fro 10-10 applies, it depends on what the specifications are in the method. The person who wrote and validated the method writes those specifications depending on what is he/she finds acceptable limits for the method.
If you are setting the limits, set specifications that are tolerable.