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- Posts: 102
- Joined: Wed Feb 22, 2012 7:24 pm
Hi all,
I have been doing Silane/Chlorosilane analysis on a OV-1 30m x 0.53mm column. This has worked just fine, but the chlorosilanes are no longer part of the picture and I am more interested in separating air gases and silane (SiH4). Ideally, I want to separate N2, Ar, Silane, H2. On my OV-1 column, H2 is very quickly followed by N2/Ar followed by SiH4. The peaks are clustered very tightly and don't resolve well except at low concentrations (1000ppm and lower). And N2/Ar doesn't resolve at all of course.
To get a better separation I tried a Carboxen 1010 PLOT column, also 30m x 0.53mm. Ar/N2 looked good, but the silane never came off the column! I did not expect that, since even though silane is pyrophoric and extremely easy to oxidize to form solids, it is nonetheless fairly stable below 300C.
I did find these previous topics
viewtopic.php?f=2&t=6023
viewtopic.php?f=2&t=11162
which point me towards a Carboxen 1000 (not available in PLOT that I can tell), or a Carbopack B, or maybe a Hayesep N or perhaps a Tenax GR?
Rod aka Chromatographer1 also did suggest that a "long high loading methyl silicone column" (I think OV-1 qualifies?) would maybe do the trick, but I guess my column length/loading isn't enough? (and it will never be enough to separate the Ar/N2).
Any thoughts? I am familiar with and comfortable with doing heart cuts / 2D GC. However, a single column solution is of course preferable if the performance is OK.
I am thinking about trying a small packed Carboxen 1000, like a 2m x 1/16". I'm also curious if anyone can explain why silane didn't come off the PLOT column. Or if I should try to get my money back or something.
Regards,
AP
I have been doing Silane/Chlorosilane analysis on a OV-1 30m x 0.53mm column. This has worked just fine, but the chlorosilanes are no longer part of the picture and I am more interested in separating air gases and silane (SiH4). Ideally, I want to separate N2, Ar, Silane, H2. On my OV-1 column, H2 is very quickly followed by N2/Ar followed by SiH4. The peaks are clustered very tightly and don't resolve well except at low concentrations (1000ppm and lower). And N2/Ar doesn't resolve at all of course.
To get a better separation I tried a Carboxen 1010 PLOT column, also 30m x 0.53mm. Ar/N2 looked good, but the silane never came off the column! I did not expect that, since even though silane is pyrophoric and extremely easy to oxidize to form solids, it is nonetheless fairly stable below 300C.
I did find these previous topics
viewtopic.php?f=2&t=6023
viewtopic.php?f=2&t=11162
which point me towards a Carboxen 1000 (not available in PLOT that I can tell), or a Carbopack B, or maybe a Hayesep N or perhaps a Tenax GR?
Rod aka Chromatographer1 also did suggest that a "long high loading methyl silicone column" (I think OV-1 qualifies?) would maybe do the trick, but I guess my column length/loading isn't enough? (and it will never be enough to separate the Ar/N2).
Any thoughts? I am familiar with and comfortable with doing heart cuts / 2D GC. However, a single column solution is of course preferable if the performance is OK.
I am thinking about trying a small packed Carboxen 1000, like a 2m x 1/16". I'm also curious if anyone can explain why silane didn't come off the PLOT column. Or if I should try to get my money back or something.
Regards,
AP
