Peptide hydrolysis using borosilicate vials ?
Posted: Wed Jul 17, 2019 6:28 pm
I am trying to complete peptide hydrolysis with a big amount of samples at the same time (up to 30 samples).
Here are my constraints :
1. I don't want to recover the amino acid composition, I just want to cleave most of the bonds. I don't seek high hydrolysis/recovery quality, but rather the high throughput.
2. I don't have any specialized material at my disposal.
I saw a lot of papers referring to hydrolysis vials to perform the hydrolysis under vacuum, but hydrolysis vials are very expensive and are not appropriate for a high throughput experiment.
I was considering simply performing 6M HCl hydrolysis at 110°C for 24h, in borosilicate autosampler vials with screwed caps (PTFE/silicone septa), using a block heater.
However, the caps all slightly unscrew during the hydrolysis, and my samples evaporate.
Has anyone successfully tried to do peptide hydrolysis in screw-capped vials before? If so, what am I missing? Are my caps unsuitable?
Thank you very much for your answers !
Re: Peptide hydrolysis using borosilicate vials ?
Posted: Fri Jul 19, 2019 9:12 am
Short answer: yes, normal caps will be completely useless for this application.
Obviously I don't know the aim of the experiment, but if, in order to achieve high throughput, you accept some sort of inefficient, partial hydrolysis, you could well be developing a method that generates meaningless data quickly, where perhaps it would be better to go with a method that generates useful data slowly.
The special hydrolysis vials are expensive, but they're good. Protein hydrolysis is actually quite a chemically demanding method, and by no means trivial. If you're committed to doing it on a reasonable number (30) of samples, it's probably best to grasp the nettle, buy as many tubes as you can afford, and work through batchwise using a standard, proven method. If you can get 8 or 10 tubes, then you can do the whole lot in 3 or 4 batches. It won't be fast, because there are overnight steps, and you need to clean and dry the tubes between batches, but it will be worth it. It will work! A typical HPLC vial and lid has no hope of containing 6M HCl at 110 degrees. To be honest, given that the things you're using in the hydrolysis are fairly unpleasant, it's probably sensible from a safety perspective to use correctly-made glassware rather than try to improvise. If your cost-constraints are imposed from management, these are arguments you can use.