[daywalker]

Over 18 months ago I used some sodium cyanoborohydride as a catalyst for reductive amination of proteins to glutaraldehyde-functionalised surfaces in phosphate buffer (PBS) with pH 7.4. Some days ago I found out that a HCN can be a byproduct of that reaction, or that it can also be contained within the NaCNBH₃ as a decomposition products. The concentrations I was using were about 50 mM, which for a volume of 4 ml is about 12 mg of NaCNBH₃.

1) Does anyone know what is the yield of HCN in that case? I remember that there were some gas released, but I always assumed that was H₂.

2) If HCN was not just a byproduct of that reaction, are these levels dangerous? I'm not quite certain if I didn't trash the solution afterwards in the normal water sink in the lab (quite stupid)!

Thanks in advance !

[OC pro]

1 equivalent of sodium cyano borohydride will give 1 equivalent of HCN. Depending on the amount you used it can be of course very dangerous.

[LabRat01]

Over 18 months ago I used some sodium cyanoborohydride as a catalyst for reductive amination of proteins to glutaraldehyde-functionalised surfaces in phosphate buffer (PBS) with pH 7.4. Some days ago I found out that a HCN can be a byproduct of that reaction, or that it can also be contained within the NaCNBH₃ as a decomposition products. The concentrations I was using were about 50 mM, which for a volume of 4 ml is about 12 mg of NaCNBH₃.

1) Does anyone know what is the yield of HCN in that case? I remember that there were some gas released, but I always assumed that was H₂.

2) If HCN was not just a byproduct of that reaction, are these levels dangerous? I'm not quite certain if I didn't trash the solution afterwards in the normal water sink in the lab (quite stupid)!

Thanks in advance !

12 mg of NaCNBH4? That's a tiny, tiny amount. Unless you held it up against your nose and let it decompose while you inhaled it, and even then the risks are very small. In fact, I'd hazard a guess and say that you would inhale more HCN smoking 10 ciggerattes than what you could possibly have inhaled.

But let this serve as a reminder, always be careful in the laboratory, do EVERYTHING in a fumehood to be on the safe side, and touch everything in the lab with a gloved hand. Always make sure you're wearing the correct gloves for the solvents that you're working with. Always wear your googles and lab coat, and never eat or drink in the lab (you'd be amazed to see how easily everything can get contaminated.)

[408]

The LD50 for HCN is around 1mg/kg.  You used 12mg of cyanoborohydride containing less than 12mg of HCN.  Unless you weigh 12 kg you do not really have anything to worry about.  Eating wild almonds is more dangerous than these amounts.