Silica Gel Pretreatment - Bonding Alkoxysilanes

[M Farooq]

Would anyone like to share their experience whether acid pre-treatment of silica gel improves the bonding density and stationary phase stability with functionalized triethoxysilanes or not? There is a decent amount of mid-70-80s literature but apparently there is no consensus. The silica gel manufacture must have improved in the last 20 years. Is acid treatment to create silanols and remove metal impurities still beneficial before coupling alkoxysilanes with silica surface? What is the modern view of the initiated?

Thanks.

[Gerhard Kratz]

What was published 20 years ago is still valid. Manufacturers have improved a lot, or better to say, do things different. Since this is a very competitive market nobody will publish secrets.
Modern silica gels are nearly free from metal impurities. Bonding is done with new silanes, different from the chlorsilanes used 20 years ago, for new developments. Take one of the "old" published methods and start to produce your lot#1. With each lot you will do it a little bit different to lot#1.
Maybe lot#1000 will show the best performance you ever saw with a C18 material, will you publish the way you did it?
Hope that soon we will get new publications.

[M Farooq]

What was published 20 years ago is still valid. Manufacturers have improved a lot, or better to say, do things different. Since this is a very competitive market nobody will publish secrets.
Modern silica gels are nearly free from metal impurities. Bonding is done with new silanes, different from the chlorsilanes used 20 years ago, for new developments. Take one of the "old" published methods and start to produce your lot#1. With each lot you will do it a little bit different to lot#1.
Maybe lot#1000 will show the best performance you ever saw with a C18 material, will you publish the way you did it?
Hope that soon we will get new publications.

I agree with the confidential nature of stationary phase synthesis. Since the industry doesn't share their skills with the academicians, the academic labs lag behind these in these stationary phase synthetic skills (lack of time and money to reach lot # 1000, as you say)! The newer academic publications on stationary phase synthesis are neither insightful or in depth as published by the early researchers e.g. Kirkland, Unger and Engelhardt etc.