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This is really motivating me to switch to hydrogen.
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Discussions about GC-MS, LC-MS, LC-FTIR, and other "coupled" analytical techniques.
I thought it was really expensive compared to our cost, until I looked up the T cylinder, which is almost 10x larger than our standard cylinders. Ours are running a little less than $200, which is almost twice the new price for the T cylinders.Two months ago a T cylinder of UHP He was $375. It just jumped to $830 for my latest cylinder. Another supplier can't get He at all for at least a couple months.
This is really motivating me to switch to hydrogen.
Its the 96 mass in BFB that gets too large at the expense of mass 95 which becomes proportionally lower and that affects the 174/95 ratio. I assume the hydrogen is adding a proton to the 95 mass. The other losses were as I said for brominated and chlorinated compounds about 25% of the signal area you would get with helium. It helped me to purge with argon or nitrogen and then dry purge with helium for 1 minute before desorption. In my experience hydrogen reacts more with the 8260 analytes under argon or nitrogen but less so with helium; that helped the recoveries of halogenated compounds.James:
We are still looking in to switching to hydrogen and already have switched everything but the GCMS units. 8260/624 is almost impossible until some allowances are made from EPA.
What is the main problem with 8260? Tuning or reactivity? The tune criteria were adjusted in 8260D to allow hydrogen but there wasn't much input on problems labs were facing.
Reactivity is another can of worms all together.
This was the main problem for us also. If we could switch to 8260D it would be great but we do as many or more 624.1 samples and 524.2 and 524.3. I didn't lose that much 95 to affect the 174 ratio, but could almost never get the 96 down low enough. The longer I ran hydrogen the better it got, but I went from 96 being almost 85% versus 95 down to about 20% which was still too high for most methods. Someone from Tekmar said they made it pass with a flow rate of 0.3ml/min carrier, but that is barely 2 psi even with a 30mx0.18 column, very difficult to maintain at a steady flow.I also, am using nitrogen from a dewar as my purge gas and general use gas.
Its the 96 mass in BFB that gets too large at the expense of mass 95 which becomes proportionally lower and that affects the 174/95 ratio. I assume the hydrogen is adding a proton to the 95 mass. The other losses were as I said for brominated and chlorinated compounds about 25% of the signal area you would get with helium. It helped me to purge with argon or nitrogen and then dry purge with helium for 1 minute before desorption. In my experience hydrogen reacts more with the 8260 analytes under argon or nitrogen but less so with helium; that helped the recoveries of halogenated compounds.James:
We are still looking in to switching to hydrogen and already have switched everything but the GCMS units. 8260/624 is almost impossible until some allowances are made from EPA.
What is the main problem with 8260? Tuning or reactivity? The tune criteria were adjusted in 8260D to allow hydrogen but there wasn't much input on problems labs were facing.
Reactivity is another can of worms all together.
I am glad we are down to about 1.5 cylinders per week (I think 1A 9" diameter). I remember when it was 3-4 per week before switching the GC/ECD and FID to hydrogen.I finally got around to calling today.
We're at $205, which is up from $175 earlier this year on a "300" sized cylinder. Still, the price increase was moderate enough that I went ahead and ordered 3.
Now to get more chains and clamps rigged before they come tomorrow...
I was at $265 most of last year. I assume a "300" cylinder is 291CF which is what my "T" cylinder holds. Maybe I need to check around for another supplier. And this is for UHP 5? 99.999%?I finally got around to calling today.
We're at $205, which is up from $175 earlier this year on a "300" sized cylinder. Still, the price increase was moderate enough that I went ahead and ordered 3.
Now to get more chains and clamps rigged before they come tomorrow...
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