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IR sample preparation. for pure liquid samples. What is a thin film cell?. a thin film cell is a drop of pure liquid sample sandwiched between salt (NaCl) discs. Thin film IR cells. Salt (NaCl) discs are used To hold the sample So the holder won’t absorb infrared light
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IR sample preparation for pure liquid samples
What is a thin film cell? • a thin film cell • is a drop of pure liquid sample • sandwiched between salt (NaCl) discs
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
Sample preparation • so only dry (anhydrous) samples are used • because even traces of water etch the IR discs • affecting the path length of light • and the optical quality of discs
use clean glovesto work with salt discs • put on an extra pair of gloves • to protect cells • from anything aqueous on your regular gloves
Preparing salt discs • Slide off • The top of the • Desiccator • Remove • Salt discs
replace • desiccator cover • immediately • remove discs • from sleeves and • rest on kim wipe
to clean discs • add a few drops • of chloroform • to each disc • rub gently • to clean off • all traces of sample • …
adding sample • add one or two drops • of sample • in the middle • of the 1st disc • lower • the 2nd disc • on top as shown • to spread sample • evenly
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
gently • place lid • on top • slide into position • in light beam
close • sample • compartment • remove gloves • before using • keyboard
to clean discs • add a few drops • of chloroform • to each disc • rub gently • to clean off • all traces of sample • …
Keep discs dry • replace • in desiccator • after cleaning • …