Nitrosamines by EI GC/MS?

[MSCHemist]

I am researching a method to do nitrosamines via standard EI single quad GC/MS. I Have been over the literature the past couple days and frankly my head is spinning. There are a dizzying array of sample preps sited and I see most of the apps are now for MS/MS or chemical ionization telling me it is trouble to get specific ions out of the matrix. I see various solvent extraction mainly MeCl2 with evaporation, solid phase extraction with activated carbon followed by articles reporting that AC causes other secondary amines to form nitrosamines, SPME looks the most interesting some use standard addition though and some are for wastewater and my matrix are likely to be finished food products.

Does anyone have any tips as to what is simplest and most reliable?

[Consumer Products Guy]

We used a TEA analyzer for N-nitrosamines on a GC back in the late 1970s-early 1980s (it was even an isothermal-only GC!). That was the first Thermo Electron analyzer, and it was about 5 feet tall, but lots of empty room inside so components were accessible. We even trimethylsilylated N-nitrosodiethanolamine. It was awkward, but it did work, at low levels. What really scares me about this business is: we've done almost everything....

[James_Ball]

I used this for Tobacco Specific Nitrosamines and it may work for what you are doing. I was using LCMSMS but looking at it you could probably use DCM as final solvent and get it to work on GCMS. It does yield a fairly clean extract, even when using Tobacco as the matrix.

https://www.sigmaaldrich.com/content/da ... 407117.pdf

[MSCHemist]

The GC-thermal energy analyzer looks interesting but I am not looking to buy a new GC instrument for this. I only found one or two companies that make it.

The SPE also looks ok, the only trouble is I don't have a vacuum manifold for SPE and I notice they acidify the samples before putting them on the column. At least one of the papers reported that nitrosamines are not stable in acidic solutions.

It looks like a headache. I tried doing GC/MS of acrylamide a while back and it was too dificult to extract unique ions for native acrylamide, and I got closer with derivatization with xanthydrol I still had matrix cleanup issues. The only derivitization I found for nitrosamines involves denitrososifying with hydrobromic acid and I really don't want to get into that. This is a job for GC/MS/MS, chemical ionization or TEA.


I may try SPME or suggest they go contract lab for this.

[James_Ball]

The GC-thermal energy analyzer looks interesting but I am not looking to buy a new GC instrument for this. I only found one or two companies that make it.

The SPE also looks ok, the only trouble is I don't have a vacuum manifold for SPE and I notice they acidify the samples before putting them on the column. At least one of the papers reported that nitrosamines are not stable in acidic solutions.

It looks like a headache. I tried doing GC/MS of acrylamide a while back and it was too dificult to extract unique ions for native acrylamide, and I got closer with derivatization with xanthydrol I still had matrix cleanup issues. The only derivitization I found for nitrosamines involves denitrososifying with hydrobromic acid and I really don't want to get into that. This is a job for GC/MS/MS, chemical ionization or TEA.


I may try SPME or suggest they go contract lab for this.

Only way I was successful with Acrylamide was HPLC, works pretty well with just UV detection. Nitrosamines are probably also easier with HPLC/MS. Ours was a one off sampling set years ago, I found the cartridges a couple months ago and had to look up what I used them for it has been so long.