Air compressor for FID air.

Discussions about GC and other "gas phase" separation techniques.

22 posts Page 2 of 2
Olivialisa wrote:
MSCHemist wrote:
Can you use Inland 45 for lubricating such compressors. At least that oil designed for GC/MS roughing pumps does not putout any significant volatile hydrocarbons.

I have not experience to Inland 45. How much capacity of it and CFM at producing Pressure?


The Inland45 is a type of oil used inside the compressor.

If used instead of normal oil there will be less hydrocarbons in the air stream from the compressor.
The past is there to guide us into the future, not to dwell in.
Personally I'd recommend drying the air before it gets to the gas generator, preferably from an oil-less compressor. Far less problems in the long term.

I'm currently using an Ekom dental compressor with dryer, supplying a Parker Balston 78-40 TOC gas generator, a bit dated now but similar to this
tphase wrote:
Personally I'd recommend drying the air before it gets to the gas generator, preferably from an oil-less compressor. Far less problems in the long term.

I'm currently using an Ekom dental compressor with dryer, supplying a Parker Balston 78-40 TOC gas generator, a bit dated now but similar to this


We use a hospital grade refrigerated dryer for our house air. It removes the moisture and hydrocarbons really well. Before we added the dryer we didn't use the house air much, and when we tried to start using a nitrogen generator we had moisture problems and we actually drained almost 10 gallons of water from the lowest point in the air lines :roll: . Don't have that problem now.
The past is there to guide us into the future, not to dwell in.
Using a modified 1500w oil-free compressor 200L/min with a 80L airtank (original tank was only 16L). After the compressor i have 2 water separators in series, because is situated in the basement + the swedish humidity i use to drain the compressor and the separators every week or when needed.
The pipe is about 40m long and at the entrance in the lab there are 2 other water separators in series. Before the GC inlet i have a moisture and a hydrocarbon filter.
It might be overkill but better nice clean dry air than dirty FIDs.
FWIW, I run four nearly identical Buck/SRI 910 GCs that have a TCD and FID in series.

I've yet to actually have a need to dig in to one, but each has a built-in air compressor to run the FID. I'm not sure what sort of compressor or how large it is, but it's a beautifully elegant solution. The baseline is a bit higher than I'm use to seeing on zero grade or UHP air, but it otherwise works perfectly, gives a stable baseline, and I can't hear it over the oven fan in the GCs.

I'm running a 5890 now off of a cylinder, but that's just until I get around to plumbing it into house air. Admittedly our house air system is geared toward scientific instruments and, among other things, supplies air to the AA, purge gas for probably a half dozen FTIRs(I run three off of it, and there are a few others scattered around in research labs), and runs the pneumatics both on the MALDI-TOF and on all four of our NMRs(400mhz, 2x500mhz, 700mhz). Even though it has HC and water scrubbers in the distribution room, it will still get a secondary set before running into the FID.
Definitely go with an oil-free compressor.

Example 1. When the R&D lab's original oil-free compressor for "house air" went dead after a couple of decades, to save money an oil-lubed compressor was purchased; it had an oil separator device which required periodic cleaning/dumping of condensed oil, but budget cuts to service staffing caused oil to get into all the lines. Luckily, we had a Balston air purifier for our GCs mounted high on a shelf, so that saved our GCs, and we later put clear filters stuffed with cotton on all the air outlets.

Example 2. A rocket scientist at one of our manufacturing plants thought it would be simpler and cost saving to use their house air with one of their 5890 units; but they had an oil-lubed compressor, and got liquid oil coming out of the 5890 FID, and all over the top of the unit. This was shoved into their warehouse, then offered to us without that disclosure. I cleaned all the FID parts, pulled contaminated insulation out of the oven area, and stuffed fiberglass tape into the voids. We could only take the GC to 200C because higher temperatures would smell up the whole lab, so it was used for just one of our assays, and did work fine that way.

So NO oil.
Or just use Inland 45. If it is good enough for GC/MS it should be way more than sufficient for FID/NPD/FPD... I'd put a hydrocarbon trap on just in case.
22 posts Page 2 of 2

Who is online

In total there are 13 users online :: 0 registered, 0 hidden and 13 guests (based on users active over the past 5 minutes)
Most users ever online was 599 on Tue Sep 18, 2018 9:27 am

Users browsing this forum: No registered users and 13 guests

Latest Blog Posts from Separation Science

Separation Science offers free learning from the experts covering methods, applications, webinars, eSeminars, videos, tutorials for users of liquid chromatography, gas chromatography, mass spectrometry, sample preparation and related analytical techniques.

Subscribe to our eNewsletter with daily, weekly or monthly updates: Food, Environmental, (Bio)Pharmaceutical, Bioclinical, Liquid Chromatography, Gas Chromatography and Mass Spectrometry.

Liquid Chromatography

Gas Chromatography

Mass Spectrometry