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How to know if it is SLS or SLES liquid?
Here a supplier is selling SLS liquid but i doubt if it is SLS or SLES. Is there any to identify if it is SLS or SLES?
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7 Replies
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Ideally, you would take a sample and run it through an IR Spectrophotometer. Then you could just compare it to a standard. That is what big/medium sized companies do. You should also have a Certificate of Analysis which lists specification ranges. You could also check for 1,4 Dioxane levels. SLS should have none while SLES might have some detectable levels.
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if it’s around 26-28% w/w, chill some of it to 0-5°C - SLS will solidify before it gets that cold, while SLES will remain liquid@Perry IR wouldn’t be much use in this case - the C-O stretches in aliphatic ethers occur at low wavenumbers (1100/cm or less), making them hard to distinguish from the “white noise” often found in that region -
@Bill_Toge - thanks! Admittedly, this is the kind of question we farmed out to our QA/QC department. It seemed they routinely ran IR on everything. Your solution is much more elegant!
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@Perry @Bill_Toge thanks
I will do 5his cold test. It is easy
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Perry said:@Bill_Toge - thanks! Admittedly, this is the kind of question we farmed out to our QA/QC department. It seemed they routinely ran IR on everything. Your solution is much more elegant!
no worries!
infamously I once had a colleague who insisted on taking an IR spectrum of sodium fluoride, which is completely invisible in IR, so the spectrum showed nothing but the airI can only conclude she either slept through the organic/inorganic labs at university or forgot about them completely once she’d left -
I don’t know about SLES but identity determination according to pharmacopeias of longer PEG chains than the 2 in SLES is actually determined using FT-IR.You could check out pharmacopeia guidelines for SLS and SLES… some are identical because they determine the sampe part of the molecule. Maybe a colour reaction in solvents could be feasible? -
@Pharma @Bill_Toge thanks.
I did place it and an SLES 25% liquid in freezer. After sometime this one solidified but SLES 25% was liquid. So i can be sure it is SLS not SLES as Bill said.
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