Atomic Absorption Spec

[shinny]

It should be in one of the textbooks...I used Heinemann and Nelson so it's in either of those (most likely Heinemann; *stabs Nelson*).

[khalil]

Yeh i've got heinemann and it doesnt mention it!

[d0minicz]

What doesnt it mention?

[khalil]

Refer to page 1

[d0minicz]

yehhh doesnt mention it ...
which sources do you guys get this information from

[shinny]

Maybe it was just from my teacher...I can't remember D:

[khalil]

Do calibration graphs always start at zero? What if they are negatively sloped? Also, when they are negatively sloped and cross the horizaontal axis, what does it represent?
These questions refer to UV-visible spectroscopy!

[Chemkid]

Calibration graphs usually start at 0, because when the blank solution is introduced to the instrument, it is zeroed to account for the presence of the dissolved substance which is under analysis. Some calibration graphs do not start from 0, as the instrument has not been zeroed. The calibration graph is negatively sloped if we are talking about the intensity of light transmitted (what is not absorbed, and passes throguh the solution). This works logically, as when the concentration, more of the selected wavelength is absorbed, and hence, less light goes through. There are other situations where the calibration curve is negative, but you have to use logic in them.