What is the mechanism for the reaction of NHS ester at low pH with a protein?

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Pectin-rich extract fractionated by AEX: Acidic fractions contain low amounts of uronic acids?

Hello researchers, there is a phenomenon I have no proper explanation for: I have a pectin extract containing around 65% uronic acids according to the m-hydroxybiphenyl method (Blumenkrantz and...

27 May 2022 6,749 0 View

Cleaning DEAE-Sephacel outside column and repack?

Hello researchers, I am rather new to chromatography and I am having a problem with my anion exchange column which contains DEAE-Sephacel. The backpressure of the column became so high that I...

03 February 2022 4,620 2 View

Is the glass transition temperature of sucrose concentration-dependent?

Hello dear researchers, I was wondering if the glass transition temperature of sucrose is dependent on the concentration of the sucrose. In literature I found the value -32°C, but there was no...

01 May 2018 3,444 4 View

Temperature anomaly during freeze-drying?

Hello dear researchers, I am doing some experiments with the freeze-dryer at the moment and I am experiencing a temperature anomaly that I cannot explain. I tried it with pure water, 1M sucrose...

19 April 2018 2,516 4 View

Conjugation of PEG-Amine to an Amino Acid Using EDC?

I am attempting to conjugate PEG to an amino acid at the C-terminus, for the purposes of producing nanoparticles. I have been told that PEG modified with amine groups can be used for this purpose,...

31 July 2024 2,033 1 View

How do you obtain a Letter of Access for Citizen Researchers?

Please may I ask if non-salaried Public Contributors conduct data collection interviews or Focus Groups with NHS patients as part of your study? This means that the Public Contributor will either...

29 July 2024 3,085 0 View

EDC carbodiimide and NHS easter 's half life among different pH?

It has been long known that EDC carbodiimide and NHS easter's half life agains hydrolysis are highly related to pH. However, very surprisingly, not yet found a paper giving a table/chart of their...

25 July 2024 8,738 0 View

When I am trying to distill triethyl amine while drying it over calcium hydride. How do I design the setup to let hydrogen escape without losing NEt3?

I am new to research. The boiling point of triethyl amine (NEt3) is 89 degrees centigrade. I am skeptical that when I will let the hydrogen escape which is getting generated in situ, I will also...

21 July 2024 7,284 4 View

What is the exact procedure and materials for converting from ester to carbolic acid by base hydrolysis??

11 July 2024 4,645 3 View

Determination of fatty acids in fish?

I measured the fatty acids in the fish, using the internal standard method in the national standard method, I first extracted the fish oil with cable extraction, please ask me how many grams of...

02 July 2024 900 1 View

Methods of O-methylation of amino acids without interfering the amine groups?

Hello guys. I have faced the problem of being in need of carboxyl-methylated amino acids. Amino acids I need are not available in the market so I need to synthesize them by myself. So thus I'm...

16 June 2024 9,920 3 View

How to purify Schiff base product?

How to stabilise the Schiff base product and avoid it from reverse back to the aldehyde and primary amine.

09 June 2024 9,264 5 View

HOW CAN I COMBINE HYDRAZINE DERIVATIVE AND ESTER (i.e., to replace alkoxy part with hydrazine derivative)?

REACTION PROCEDURE, ARTICLE RELATED TO IT AND SOME PRECAUTIVE MEASURES.

02 June 2024 5,177 5 View

Separation of Cholesteryl esters from alkanes/alkenes?

Greetings We are trying to study Cholesteryl esters. We start with MeOH/Chloroform extraction and then remove most of the noise by silica column, but the Cholesteryl esters come out with...

02 June 2024 5,545 0 View