1. IR sample preparation
for solid samples

2. What is a mull? a mull a suspension of solid sample in mineral oil
It is used to make a thin-film cell from a solid sample

3. Thin film IR cells Salt (NaCl) discs are used To hold the sample
So the holder won’t absorb infrared light
and only sample absorption is detected

4. Sample preparation so dry the sample well
because water etches the IR discs
and emulsifies with oil letting less light through

5. How do I make a mull? grind the sample to a smooth powder
add mineral oil
and mix it
well

6. What should the mull be like?
should look
and spread
like soft butter

7. use clean gloves to work with salt discs
put on an extra pair of gloves
to protect cells
from anything aqueous on your regular gloves

8. applying the mull use a rubber policeman to spread a thin layer
on one disc
lower the 2nd disc
on top of the 1st
and twist the discs
to spread sample evenly

9. placing discs in cell holder
use your finger
to make a platform
in the cell holder
lower in
the NaCl discs
do not wedge them

10. gently
place lid
on top
slide into position
in light beam

11. close
sample
compartment
remove gloves
before using
keyboard

12. to clean discs add a few drops of chloroform to each disc rub gently
to clean off
all traces of sample …

13. Keep discs dry
replace
in desiccator
after cleaning …