14 replies to this topic

[goku]

Ok all,

Will get resv shipped from China bc bulk orders.

I will post pic and HPLC soon

[goku]

Here is HPLC and pic of raw powder at factory:

Attached Files

•  Resverartol_98___65288_HPLC__65289_.rtf   30KB   57 downloads
•  res_powder.jpg   42.39KB   4 downloads

[niner]

Cool, a 21st century Faberge Egg. So what's the broad peak eluting around 2 minutes? Some solvent or other, I'd guess. That looks like a pretty low resolution chromatogram. We would want to run a more sophisticated analysis, including heavy metals.

[Anthony_Loera]

Thats great Goku,

Can you get an independent test done here in a US lab? Remember, VP stated 99% as well, but came back as only 87%.
It will help folks here know they are getting what they paid for.

A

[Hedgehog]

Here is HPLC and pic of raw powder at factory:

Is that the HPLC data for the lot/batch you got? while I can't read chinese but the numbers say around 96%


────────────────────────────

1 1.994 306089 13662

2 11.328 Resveratrol 6897016 187655








So if you add the numbers up and then divide by the Resveratrol number you get 96%. Still very very good. But if they are selling resveratrol as 99% and they gave you this then something doesn't add up.

[Hedgehog]

Thats great Goku,

Can you get an independent test done here in a US lab? Remember, VP stated 99% as well, but came back as only 87%.
It will help folks here know they are getting what they paid for.

A

yes VP came back as 87% by weight however area by HPLC was 99-100%. meaning a lot of different things. I asked VP for more details and he is going to ask a few questions for me with regards to the analytical company and its method of testing. However, since the area was 99-100% which is what I saw (and everybody else is) it might mean other vendors have lower amounts then expected when tested by this method. This way of testing is sorta like comparing oranges and apples. They also used a DAD which is a very good detector. Will post more after VP emails...

[goku]

Ok Hedgehog, lemme check this out with them, I did same calc, but my math is wrong

maybe they sent me HPLC for wrong batch or misunderstood, hopefully not scamming me

Edited by goku, 20 February 2008 - 06:42 AM.

[Hedgehog]

96%?

No, the HPLC is clearly 98%, read again. Definitely >98% if you know how to read these

I understand how to read but you have to do math in order to understand what you are reading...

峰面积 = Peak area
Peak Peak Area
RT 1.994 = 306089
RT 11.328 = 6897016
Total or 总计 = 7203105

Area % = (6897016/7203105)*100% = 95.75%

If you they sold it to you as 98% tell them to give you a discount so you can sell it cheaper to us. Also I didn't see a lot number or batch number. So we don't even know if that HPLC data is for the lot you have. Maybe they gave you the wrong HPLC data?

[goku]

So you people know though, as a good deed, you can get >98% purity T-resveratrol for 590 per KG from Changsa for even 1 KG orders. And I think that includes shipping

99% is more like 740

these are just 1 KG orders, if you buy large in bulk, it's cheaper still.

largest raw manufacturer from my extensive research of calling all these damn companies.

and PLEASE ppl, mention my name if you buy from them


Email is: Changsha.raw.materials.cn@gmail.com


The only had Bank wire transfer and Western Union both to china that you can pay with.

[goku]

And Hedgehog, I asked lab tech and he says:

"before 3 mins that peak area ( 1.994 306089) it is come from Solvent, not from the Resversatrol , so can not count in HPLC"

He says that's why your calculations seem to say 96%, check again and you will see it is 98%

[niner]

And Hedgehog, I asked lab tech and he says:

"before 3 mins that peak area ( 1.994 306089) it is come from Solvent, not from the Resversatrol , so can not count in HPLC"

He says that's why your calculations seem to say 96%, check again and you will see it is 98%

I thought that was going to be the case, but it's not very satisfying. Why can't they evaporate it? What is the solvent, anyway? If it's ethanol, then no big deal, but there are a lot of solvents that I wouldn't want to ingest. If you're paying for a kilo, but there's 40 grams of solvent, then you can't really call it 98%... And the resolution of the chromatogram was so low that you can't see any of the minor peaks that have to be there.

[goku]

they use carbinol and ethanol.

[malbecman]

Actually, I doubt that the solvent peak is in the product. More than likely, it is the solvent they used to dissolve the resveratrol before they injected it onto the HPLC, eg, methanol , ethanol, acetonitrile, etc. You can't inject a solid. The solvent peak, being very polar, always comes out first and usually has a large peak as its absorbance is usually much more than the compound you are measuring, eg, resveratrol. So its really not fair to compare the peak areas of the solvent and the resveratrol. Its all derived from Beer's law (what a name), Absorbance = concentration X extinction coefficient(absorbance of a particular compound at a certain wavelength) X path length.

Also, When you receive your product, its a fine powder (hopefully) so the vast majority (>99.9%) of the solvent used in its synthesis and purification has evaporated.

[Hedgehog]

And Hedgehog, I asked lab tech and he says:

"before 3 mins that peak area ( 1.994 306089) it is come from Solvent, not from the Resversatrol , so can not count in HPLC"

He says that's why your calculations seem to say 96%, check again and you will see it is 98%

I thought that was going to be the case, but it's not very satisfying. Why can't they evaporate it? What is the solvent, anyway? If it's ethanol, then no big deal, but there are a lot of solvents that I wouldn't want to ingest. If you're paying for a kilo, but there's 40 grams of solvent, then you can't really call it 98%... And the resolution of the chromatogram was so low that you can't see any of the minor peaks that have to be there.

Typical you want to dissolve your substance in a mobile phase such as your first mobile phase. If you do this you normally don't get a solvent peak. Plus I was not aware that this peak was a solvent nor was it labeled that way. If you take away the solvent peak you could call it 100% resveratrol. The solvent peak is probably close to the void volume the RT is close to 2min. Anyways it is not pretty but if that is the solvent then it works for me. Maybe next time use some HPLC grade solvent.

Edited by hedgehog_info, 20 February 2008 - 06:04 PM.

[Mind]

OK, another nice discussion about testing products has emerged, however, I just want to remind everyone that what goku did is against the forum rules. Direct selling of products within forum posts is not allowed and will get you a warning (suspension for repeated offenses). If I had seen this thing when it first started I would have deleted it immediately.

For businesses, banner space is available.

This late in the game, I will just delete the sections that say "I am selling stuff now".