Hi Medhat,

take a look at this discussion:

https://www.researchgate.net/post/Can_I_use_HPLC-UV_to_determination_sugars_Can_I_measure_the_quality_of_fruit_by_estimating_the_sugar2

The answer to your question is then self-explanatory.

Regards Markus

Medhat: For such basic questions, please initially try a keyword search using a search engine (e.g. GOOGLE) before posting here. In doing so, you will practice a researching skill and find the answer(s) you seek in most cases.

When you have a sample that you wish to analyze by HPLC, first look up the compounds physical and chemical properties to determine which detection mode(s) are appropriate. Sugars have poor absorbance so we normally do not use UV detection for them by HPLC (Sorbitol would require detection below 210nm, which is very problematic in general). Traditional methods use RID, ELSD or CAD for detection by HPLC (and there are other methods too). Also, it is very important to identify what the compound is in or present with (the matrix) as the type of sample prep and analysis method will vary depending on what you need to resolve it apart from. These are just a few of the very basic questions we ask as scientists when starting to research a topic.

In general, Mr. Emad - MS detection.

You can search on the internet for column to retain polar compound such as sugar. Phenomenex has a good collection of methods. If you have only UV detector, you can use the negative detection (indirect UV detection), if you are looking at high concentration to be practical. You would add UV absorbing solvent such as acetone in minute amount in the mobile phase so it would not saturate the detector. Sorbital will not absorb UV and will give you a negative peak. Of course, it will not be selective if you have other compounds in matrix eluted at the same time.

As I always say to the new resercher, help yourself for the easy questions by using the internet and leave the tricky on for this board.

Dear Medhat Emad

If you need to analyse D-Sorbitol you need a HPLC system with a refractive index (RI) detector. As described by William Letter, It is not good to use UV detection because of the solvent system absorbed closer wave length to your compound. Given below is the link for the standard method ( SWEDISH STANDARD, SS-EN 15086:2006).

https://www.sis.se/en/produkter/food-technology/general-methods-of-tests-and-analysis-for-food-products/ssen150862006/

Piyal

I recommend William's answer

Best Regards