As a follow up to the message I posted in October (Injector/Detector temperature verification), we have now developed a procedure which seems to work OK. After a further repeat of the testing, this time with the probes inserted a different way (from the top) and a better adapter in the Split/Splitless inlet, I got satisfactory data.

All the data is within +/- 5% of the set point (one point is 105.4%, but that rounds down!). We have therefore set limits of +/- 10%, since Agilent don't have any limits and I can't find any regulatory requirement for a limit.

If anyone would like a copy of the procedure, please contact me directly. I have also posted this to Agilent, so they may make some use of it too.

I am going to look into improving the procedure further, espcially for the detector as getting the probe to contact sufficiently with the screw thread of the jet is poor (I'm going to see if I can get a jet modified so I can locate the probe inside it).

There is a section in the 5890 user manual which explains why there is a temperature gradient over the injector at least - look in the Inlet Systems section of the Reference Manual (page 6-5 in ours). This also indicates that the highest temperature is 45mm down from the septum, which correlates with the position I found during my trials. I haven't found anything about the detector profile yet.

Please pass on your comments, etc. or if you would like a copy of the procedure.

Tim Cooke
tim_cooke@merck.com