Juan Yang

7 Questions 11 Answers 0 Followers

Questions related from Juan Yang

What are the examples of dyes that have two absorption peaks?

I am looking for dyes that have two absorption peaks, one at around 800 nm, and another one far from 800 nm. Another possibility is the dye that can shift the absorption from 800 nm to position...

21 November 2018 4,469 2 View

Are there any quick ways to prove the existence of amine in the molecule?

I have a molecule that is the solubility is very low in the solvent. From proton NMR, I cannot see the peak from NH2, so I am wondering if this amine is still safe in the molecule. Does anyone...

20 July 2018 3,399 8 View

How to trap H2S for reaction of bromide with NaSH?

I want to convert bromide to thiol. So I am planning to make a reaction between alkyl bromide with NaSH, and one possible byproduct is H2S, as what I understand from text book. H2S is highly toxic...

20 June 2018 9,172 8 View

Techniques to measure molecular weight?

what are the techniques to measure molecular/oligomers with molecular weight around 1000 Da? GPC? LC-MS? or other possible methods?

01 December 2017 9,507 4 View

Why do I get an abrupt increase in UV-VIS absorbance spectra?

Please see attached the spectra I obtained. The abrupt change is marked with the red circle. I set the lamp switch at 340 nm. Is this change relate with the lamp change? How can I avoid this problem?

11 June 2015 3,253 11 View

Does anyone have any ideas on quenching quinone-related reactions?

Quinones are normally used to quench reactions. But I am working on reactions of quinone itself, and I would like to quench them. Do you have any suggestions on this? Just a situation in my case,...

28 May 2015 2,664 7 View

How might I remove formic acid from HPLC elutes?

I am collecting fractions from HPLC with an eluent of acetonitrile (containing 0.1% formic acid) and water (containing 0.1% formic acid). I want to remove formic acid from rotary evaporation. But...

24 May 2015 3,115 7 View