We use a setup similar to that discussed in Fry et al 2002, RCM 16:854-858. At a minimum you need a GC column for SO2 separation (I prefer the 0.8m teflon ones), copper wires and quartz chips. I do not have a heated transfer line or heated regulators. One thing to be certain of is to use all stainless or teflon on connections. We are using an older conflo that does not have all SS parts so we purchased a specific all stainless regulator and gauge from Porter. We run the SO2 tank through this regulator and capillary via two holed ferrule at our reference one actuator. But I think the newer Conflo has a dedicated SO2 connection. We run inlet valve heaters, but that is it. Our EA to Conflo connection is about 10ft long.
I keep the line from the SO2 tank to the conflo as short as possible because the SO2 is still liquid in my unheated line. Make sure you have a good exhaust drop at the conflo and tank area. We also have an SO2 leak detector nearby.
One thing useful I added was a valve to purge the SO2 regulator at our conflo box, much like the older GC-III interface used. The conflo bleed capillaries typically vent right into the box or not a real directed position. I plumbed larger ID capillary to this valve and it terminates with 1/16" into my exhaust drop. So with a turn of the valve I can quickly drain out the transfer line for the reference, or purge it quickly if the SO2 tank had been shut off. It used to take hours for our SO2 pressure to stabilize or bleed off if we turned the tank off.
We switch back and forth from SO2 to CN with this instrument and it stabilizes quickly. If you need any more specifics about the method we use, feel free to contact me.
Manager, Stable Isotope Core Laboratory
Washington State University
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I have a student that would like to do stable Sulfur isotopes on environmental samples. Does any one doing this have a procedure for this that would tell me what components are needed and how to set it up so the SO2 gets to the mass spec. I believe the the transfer line from the EA to the Delta V needs to be heated, does the inlet and source need to be heated also and how does one heat the transfer line. Any ideas would be appreciated.
UWM-School of Freshwater Sciences
600 E. Greenfield Ave.
Milwaukee, WI 53204