c******m
发帖数: 884 | 1 orotic acid 有3个pKa, 分别是2.78， 9.45, >13.
如果想让 orotic acid 最大程度溶于有机相 (neutralized)，在多大的 pH 值萃取比
较好？是越酸越好吗？
我现在做固相萃取（ion exchange column)，用 2%formic acid/water (pH=2) 洗固相
，结果洗下来许多orotic aicd, 是不是不够酸？还是 pKa2 和 pKa3 在起作用？
Thanks in advance! |
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a******e
发帖数: 36306 | 2 This item is currently on back order. Estimated availability date is 4/15/
2011 Potassium iodide is used only in radioactive emergencies to protect the
thyroid gland (such as from a nuclear diaster). If you want to supplement
with potassium, we suggest #16112 (potassium orotate). If you want iodine,
we suggest Sea Iodine (#01043) |
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C********7
发帖数: 1035 | 3 关键词：Stimuli-responsive, Thixotropic Hydrogel of Melamine， Zn(II)
orotate complex， Gel-Nano Composite，Multiwalled Carbon Nanotube， FTIR,
TEM, AFM, WAXS,storage modulus (G'), loss modulus (G'')
RSC的新刊物，还没有IF
Send me your name, email, list of publications。
你最好有高分子和化学的背景，有PhD的优先考虑。 |
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s****2
发帖数: 4569 | 4 if it forms TEA salt, say orotic acid.2(3)TEA salts, it readily soluble in
DMF/ACN, even DCM. |
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c******m
发帖数: 884 | 5 Thank you for the reply. Do you mean triethylamine for TEA? If so, I didnot
use any TEA in the previous wash.
The ion exchange (IX) solid phase (SP) contains a linker-piperazine with pKa
of 6, so I load the orotic acid (ORA, pKa1=2.8) with a pH 4.4 (half of 2.8+
6) solution to make sure both SP and ORA are ionized. Then I use 2%Formic
Acid/water (pH=2) to wash (should not elute any ORA out), and then use NH4OH
in MeOH/ACN to elute ORA. But the result shows the acidic wash step elute a
lot ORA. S... 阅读全帖 |
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o******u
发帖数: 60 | 6 沒有人希望你會背上FA裡面thiamine有哪四個decarboxylation reactions
但是他們會希望你知道為什麼酒精中毒的人要在給葡萄糖之前給thiamine
沒有人要背urea cycle
但是你要知道Orotic aciduria和Ornithine transcarbamoylase deficiency 有甚麼不同
東西雖多
重點不多
了解疾病的生化mechanism永遠比死記硬背重要
希望能對你有些許幫助 |
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