Mr. Hamta,

Not, you cant'! PEG has only s-s* and n-s* trransitions below 200 nm. You could pay attention to the following discussion:

1. "What is the interpretation if we get step like absorption in uv vis spectroscopy?" ( https://www.researchgate.net/post/What_is_the_interpretation_if_we_get_a_step_like_absorption_in_UV-Visible_Spectroscopy)

There are shown the type of the substances that could be identified qialitatively and presumably quantitatively if, however, the corresponding UV-bands are intensive, meaning that the electronic transition is probable. 

Thanks for your answer dear Bojidarka

Adequate volume of PEG-200 to 600 aqueous solution can be evaporated to dryness in rotavap followed by silylation and GC-MS. Very easy quantification.

Pankaj: PEG (molar mass about 20,000) has two OH end groups that you propose to silylate, and do GCMS. It is not a viable approach.

Dear Afshin,

the colleagues are right, PEG has no UV active chromophore. If you cannot get a suitable detector (Corona detector or refractive index detector), you may however use inverse detection: Add the chromophore to your eluant so that the (any!) analyte that passes your UV detector replaces this chromophore  => you get a negative peak! Change polarity of the detector unit and you have a working system.

It is easier than it sounds...:-)

Keep in mind that PEG is typically not a pure compound and may consist of several chain length subunits - you may thus want to quantify against the batch used.

Good luck!

Best regards

Holger

Those interested at this question, can possibly find useful to check a discussion on the analysis of triethylene glycol in water elsewhere at this forum:  https://www.researchgate.net/post/How_can_we_determine_Triethylene_glycol_in_water

Moreover, for your possible interest, let me add that the analysis of ethylene glycol in sea water was also addressed: https://www.researchgate.net/post/Can_you_suggest_a_method_for_ethylene_glycol_determination_in_sea_water

PEG ELISA can be used