work in low wavelenght

[sara allen]

I am working on sucralose tablet and sacchet determination.
I use ACN/Water in 190 nm.In this wavelenght, sample energy is low and peaks are not repeatable. I try TFA 0.02 % instead of water , but its not useful.
I dont have RI & ELSD detectors.
Please, dont hesitate me from your advices.

[AA]

I hate to be the one to break it to you but you are wasting your time untill you invest in either a RI or ELSD. I am being totally serious here, even trying to do this at 190nm, you will not be sucsessful (as you are already finding out). The compound itself can be retained on amino columns using ACN/Water mixtures but you really need RI or ELSD, MS works too.

[Bruce Hamilton]

190nm wavelength is just too difficult to work at, unless you keep everything sparged/purged, and you have a very good detector and solvent grades.

As you don't have RI, ELSD, or presumably an ion chromatograph with pulsed amperometric detection, and if your institution rolling in the green stuff, buy one of them ( or all ), or a MS.

If your institution is not affluent, the next choice would be to choose a method that derivatises the the sucralose. I suggest you search the literature, but here's one idea from Pubmed...

" Determination of sucralose in foods by HPLC using pre-column derivatization. [Article in Japanese]
Nojiri S, Nakazato M, Kasuya Y, Takano I, Oishi M, Yasuda K, Suzuki S.
Shokuhin Eiseigaku Zasshi. 2002 Oct;43(5):289-94.

The development of a sensitive pre-column derivatization high-performance liquid chromatography (HPLC) method for determination of sucralose is reported. Sucralose is converted into a strongly ultraviolet (UV)-absorbing derivative, possessing strong absorption at 260 nm, by treatment with p-nitrobenzoyl chloride (PNBCl). Homogenized samples were dialyzed and washed with a Bond Elut ENV cartridge, then the eluate was evaporated to dryness and the residue was derivatized. Subsequently, the sucralose derivative was purified with hexane-ethyl actate (9:1) in a silica cartridge, and then the sucralose derivative was eluted with acetone. HPLC was performed on a phenyl column, using acetonitrile-water (73:27) as a mobile phase with UV detection (260 nm). The calibration curve was linear in the range of 1 microgram/mL to 50 micrograms/mL of sucralose. "

Please keep having fun,

Bruce Hamilton

[sara allen]

Thanks a lot from your response.
I have lactose in formulation.
Do you think this derivatization method is useful?

Thanks,

[Bruce Hamilton]

I have lactose in formulation.
Do you think this derivatization method is useful?

No idea. Why not search Pubmed, and use Google, to see if one of the other published derivatisation methods appears more suitable?. If you get the article, you could also email the authors and ask them what issues they encountered. I'd suggest choosing a couple of different published articles, and try out those methods on your samples.

Another alternative is to ask the producers of sucralose if they have any methods suitable for your application.

Bruce Hamilton

[Uwe Neue]

There are also post-column derivatization methods around. They may be preferred since it may be difficult to get a single derivative from sugars.