[ranjithe]

Dear friends, Is there any methods available to analyse sugars from direct seawater. Since i am having RP-HPLC equipped with RI detector. Please suggest me some methods. One more question is how to concentrate seawater for HPLC analysis.

[Arkcon]

Please don't use ALL CAPITALIZATION when posting.  It is the same as yelling, and seems rude to the reader.

Your application is a little tough, you are asking for something very specific, but yet, your instrumentation is locked at a certain setup, but you're not specific enough about that setup.  I'm barely making sense, but bear with me.

A quick google of "HPLC amino sugar" produces a couple of commercial sites on the topic.  Analysis of amino sugars is a very specialized application, so you should work with vendors, purchase the specialized equipment -- columns and derivitizing agents, perform the analysis the way they say, and get your result.  I suspect you don't want to change your instrument setup.

OK, a quick google of "HPLC amino sugar reverse phase" gives me this literature citation -- http://www.ncbi.nlm.nih.gov/pubmed/8122785  There are probably tons more.  But still, that reference mentions specialized extraction, derivitization and a special column.

If you really want to do this your own way, you'll have to build the procedure yourself from first principles.  How to concentrate from seawater, and how to separate.  Do you have any starting insights?  Where did the problem come from?  Who can you work with to solve this topic?  What sort of standard will you use?  If you have a sample of amino sugar, how does it run on your system?  Do you like the results of a pure standard?  Because if you don't, you'll hate the results from concentrating sea water.  Refractive index detectors give very low signals.