Hi all, 

I “inherited” a Flash 2000 HT and have begun analyzing materials for CN isotopes. Among the inheritance was the SmartEA option which I installed. The system interfaces through a Conflo IV to a Delta V Advantage IRMS. The unit works well and I have no trouble obtaining N and C peaks – both with the TCD and the IRMS, all with appropriate delay through the SmartEA additional tubing. Because my anticipated sample stream will contain unknowns, I’d like to use the SmartEA autodilution (I will likely not know the CN ratio for samples coming in, so pre-defining dilution will be challenging). I followed the Conflo IV manual to set up the reference regression – but I cannot get the autodilution to work during run(s). I took the opportunity to replace the aging computer, so I have a clean IsodatNT install (latest service pack - .94). That did not help. I still cannot get any dilution using reference automatic. 

Here are the details: 

Set up a sequence with ~0.050 to 1.000 mg standard (urea). Used “Start Reference Regression” for the first standard, then “Add Reference Regression” for each subsequent (0.050, 0.100, 0.250, 0.500, 0.750 and 1.00 mg – roughly). Subsequent samples produced “infos” similar to the below after running: 

Set Reference Dilution to 49 [%]
Peak Center found at [57209]
Sample Dilution found at 0 []
Detector Signal added: Ret:110.562[sec]  Ampl:64757 [mV] : 13:11:21 
N2 Expected MS Signal is: 0.000 [mV] 
Set Sample Dilution to 0 [%] 
Sample dilution: 000 0 
Detector Signal added: Ret:219.562[sec]  Ampl:42148 [mV] : 13:13:12 
CO2 Set Reference Dilution to 27 [%] 
Expected MS Signal is: 0.000 [mV] 
Set Sample Dilution to 0 [%] 
Sample dilution: 000 0

The TCD had varying amplitudes (mV intensity), yet no matter what, the sample dilution was set to 0 (because the Expected MS Signal was always 0.000 [mV]?). The Conflo IV manual does not mention using these sequence line(s), but I also tried the same series of standards using “TCD MS Calibration Start” and “TCD MS Calibration Add” for the first and remaining standards. Results for subsequent samples were the same as above, always “Expected MS Signal is: 0.000 [mV].”

In the Databases directory, the following have been created, so it’s doing something: 
Flash TCD CO2 BlankData.iso
Flash TCD CO2 Reference.iso
Flash TCD N2 Reference.iso

I’m at a loss for anything else to try… I must be missing something. Could be the way I’m searching, but I cannot find any posts in the IsoGeoChem archive addressing this issue? Any ideas?