IR sample IR sample preparationpreparationfor pure for pure liquidliquid samples samples

What is a thin film cell?What is a thin film cell?

a thin film cella thin film cell is a drop of pure liquid sampleis a drop of pure liquid sample sandwiched between salt (NaCl) sandwiched between salt (NaCl)

discsdiscs

Thin film IR cellsThin film IR cells

Salt (NaCl) discs are usedSalt (NaCl) discs are used To hold the sampleTo hold the sample So the holder won’t absorb infrared So the holder won’t absorb infrared

lightlight and only sample absorption is and only sample absorption is

detecteddetected

Sample preparationSample preparation

so only so only drydry (anhydrous) samples are (anhydrous) samples are usedused

because even traces of water etch because even traces of water etch the IR discsthe IR discs

affecting the path length of light affecting the path length of light and the optical quality of discsand the optical quality of discs

use clean glovesuse clean glovesto work with salt discsto work with salt discs

put on an extra put on an extra pair of glovespair of gloves

to protect cells to protect cells from anything from anything

aqueous on your aqueous on your regular glovesregular gloves

Preparing salt discsPreparing salt discs

Slide off Slide off The top of theThe top of the DesiccatorDesiccator

Remove Remove Salt discsSalt discs

replacereplace desiccator coverdesiccator cover immediatelyimmediately

remove discsremove discs from sleeves andfrom sleeves and rest on kim wiperest on kim wipe

to clean discsto clean discs

add a few dropsadd a few drops of chloroformof chloroform to each discto each disc

rub gently rub gently to clean offto clean off all traces of all traces of

samplesample ……

adding sampleadding sample add one or two add one or two

dropsdrops of sampleof sample in the middle in the middle of the 1of the 1stst disc disc lowerlower the 2the 2ndnd disc disc on top as shownon top as shown to spread sampleto spread sample evenlyevenly

placing discs in cell placing discs in cell holderholder

use your fingeruse your finger to make a to make a

platformplatform in the cell holderin the cell holder

lower inlower in the NaCl discsthe NaCl discs ddoo not wedge not wedge

themthem

gentlygently place lidplace lid on topon top

slide into slide into positionposition

in light beamin light beam

close close sample sample compartmentcompartment

remove glovesremove gloves before usingbefore using keyboardkeyboard

to clean discsto clean discs

add a few dropsadd a few drops of chloroformof chloroform to each discto each disc

rub gently rub gently to clean offto clean off all traces of all traces of

samplesample ……

Keep discs dryKeep discs dry

replace replace in desiccatorin desiccator after cleaningafter cleaning ……