All of them are too volatile so that they may not be retained in the GC column. In addition, the MW of HF is 20. What's the mass scan range for your GC-MS? I assume that you don't scan below m/z 35. POF3 may be reactive so that it may be decomposed in the GC injection port.

I really like the idea of analysing Hydrofluoric acid by means of a silica based GC-column.- seriously no the only thing you will get is a quickly decomposing column. Flurorethan on the other hand should be well possible, if you use a thick film and low temperature.

Dear Jae, current quaddupoles usually allow to scan to 2 or 1 amu, so that should (in theroy) be no problem.

HF will degrade a polysiloxane column in a very similar manner as HCl. POF3 is also highly reactive and not appropriate for GC-MS. Fluoroethane should be fine.

It all depends on what F-compounds you are analysing. If it is polar, then you cannot use GC/MS. If it is neutral, you will detect it in GC/MS equipped qith DB-1 or DB-5 columns..

Analysis of F-compounds by GC / MS, is a żeczywiście interesting ways. It is possible, but depends on the F-compounds will be analyzed. Please note that they are most reactive as phosphoric acid or chlorine, and may damage the column. If you analyze the polar groups is the detection of GC / MS will not be difficult. For others you zaopatrzeć a more permanent column.

Thank you for your answers. I don't have much experience with GCMS but i suspected that it would react with the stationary phase. This column was provided to me for this analysis, that's why I wanted to hear some expert knowledge on whether it is possible or not.

All of your compounds of interest have two properties which will prevent them from being suitable for GC/MS analysis, as has already been mentioned earlier: they will destroy your column, and have no retention so will end up in the injection peak. Furthermore, their molecular mass is partly below the usual scan range of 50 to 400 m/z for most GC/MS systems in operation. What you could do, however, is install an inert, short column and do a direct, cold injection of your gas sample on column. Program the MS for the specific mass of the ion you expect from the compound of interest and do a single ion run on the MS. Do this for every compound and you could end up with a simple method for routine determination of your otherwise impossible to determine compounds. Some MS allow to do a multiple ion scan so you could program a run for every molecular ion of each compound of interest. Start the run and do the injection about halfway (manually). You could also include reference or internal standards in your sample for quantification. Think of stable isotopes like 13C, 2H.

Let me know if you need additional info.

Good luck, success with your research

Harrie Verhoeven

PS: make sure to clean your source and prefilters at regular intervals during this experiment. Otherwise the carekeeper of the GC/MS will go for your scalp ;)

Analysisng for HF will be very problematic.

Firstly what is your gas samples stored in, collected in, or prepared in.: Unless it is Teflon lined then the HF is likely to react with your container long before it get to the GC/MS. That goes for POF3 to some extent also.

If you get it into the GC/MS it's like to react as with syringe, injector, columns, source etc.

Hi Mr. Amon.

Sorry, but I never worked with this kind of compound. But you need to know if your target compound is capable to interact with the column. Furthermore, you need to know if your compound is thermostable, and if the dector is apropriated for this kind of compound.

HF is a very strong acid that will damage the stationary phase of the column. POF3 will react too with the stationary phase. Fluoroethane is not aggressive but being very volatile it should elute very early in the first two minutes when usually the GC-MS filament is off because during the first 2 minutes the bulk of the solvent exit the column.

Due to the volatility and reactivity of the compounds you mentioned, you should probably go back to packed column. My suggestion is to contact Restek Performance Coatings Division (www.restek.com), that is specialized in innovative surface treatments for steel, stainless steel, alloys, glass, ceramics, and other materials. Restek surface treatments are chemically inert, ultra pure, and corrosion resistant, making them ideal for analytical uses. For your info you can find an interesting attachment.

http://www.cromatec.com.br/imagem/catalogos/restek/r_coating.pdf

maybe you could use a chemical indirect way being so reactive HF expecially with silicon copmpounds ... I could imagine a for example a trimethyl silyl protected compound that once deprotected by HF (or a fluoride equivalent) shows a specific shift in an adsorbance wavelenght of fluorescence emission (or even LC/GC-MS)

so thath you could quantity F- content .... maybe something like that is already on the market ... (or maybe not :) ...

Just an idea

Best regards

I seem to remember small particles of Teflon for packed columns. With Cold on-column injection, and maybe even chemical Ionization. Chromatography of reactive compounds is very messy.

Most fluorinated organic compounds can be analysed by GCMS - the PFTBA that is used as tuning compound on many GCMS systems is such a compound. However, of the three you want to analyse only fluoroethane is readily amenable to GCMS analysis but not on the column you have. You will need to use a Poroplot Q or similar column to separate it from air that might be present in your sample. The two inorganic gases are very reactive and will react with syringes, inlet liners and the column you want to use. If you have to inject these it would be better to react it with something else and determine the product - for example, HF can be reacted with a small amount of K2CO3 packed in the injector insert to produce CO2 which can then be determined. This is however fairly tedious. It would be much easier and more practical to use FTIR with a gas cell to monitor these compounds.

Alfred Amon did you work out on how to estimate HF?I am currently in the same situation of how best to determine HF using GC