Retention Time Standards for Sterols

[porto626]

Hello all!

I am new to this forum but I hope to become a daily visitor/contributor. I have been searching everywhere to find standards for the following chemicals but have been completely unable to find anything for them.

22,23-dihydroergosterol
7-dehydrositosterol
7-dehydrostigmasterol
7-dehydrocampesterol
Vitamin D5, D6, and D7

If anyone could point me in the proper direction for finding any of the following standards I would greatly appreciate it. Thank you in advance for your time and effort!

[WillyOne]

We used a standar mixture from "Matreya" commercialized by Teknokroma in Spain. Try to contact them

[porto626]

Thank you for the suggestion but I have tried them already. They have supplied me with a number of different types of sterols in the past but I'm still having trouble finding the specific ones listed above. Do you have any ideas for other manufacturers that might make what I'm looking for?

[WillyOne]

No, sorry