Chromatography Forum

Hi

Years ago, when I used to do a lot of GC, I recall that Valco offered something that was essentially a non-radioactive ECD.

So my question: does anyone have experience with this. Or does anyone know of another vendor that may offer non-radioactive ECDs.

(by the way we are working on Agilent systems)

We would much appreciate any suggestions.

Thanks

From what little I know about ECDs, the problem is you need to generate free electrons. The best way to consistently do that is with something that emits beta particles.

I had no idea they made non-radioactive ECDs and it would seem to me that by generating free electrons in another way would decrease the sensitivity/reliability.

Out of curiosity: why would you want a non-radioactive ECD anyway? Don't these things emit femtocuries of radiation?

from Valco's web site VICI.com:

VICI PDDs (pulsed discharge detectors) utilize a stable, low powered, pulsed DC discharge in helium as an ionization source. Eluants from the column, flowing counter to the flow of helium from the discharge zone, are ionized by photons from the helium discharge. The bias electrode(s) focus the resulting electrons toward the collector electrode, where they cause changes in the standing current which are quantified as the detector output. Performance is equal to or better than detectors with conventional radioactive sources.

In the electron capture mode, the PDD is a selective detector for monitoring high electron affinity compounds such as freons, chlorinated pesticides, and other halogen compounds. For this type of compound, the minimum detectable quantity (MDQ) is at the femtogram (10-15) or picogram (10-12) level. The PDD is similar in sensitivity and response characteristics to a conventional radioactive ECD, and can be operated at temperatures up to 400°C. For operation in this mode, He and CH4 are introduced just upstream from the column exit.

Found out recently that Valco-VICI is discontinuing the Agilent plug in ECD-PDD.

Hi Russ,
To clarify your statement, Valco produces hundreds of PDD's every year (for over 15 years) and the D-2 Non-Radioactive ECD is suitable for any ECD application. There are no plans to discontinue the D-2 non radioactive PD-ECD.

The D-2 can be retrofitted to any model of GC which has enough physical space and in countries with strict radiation laws, the VICI PD-ECD is the only detector for electron capture analysis. The PD ECD has equal or better sensitivity compared to a radioactive ECD, without requiring regular safety checks ie. wipe tests, NRC record keeping and inspection, disposal fees, and radiation safety training.

The D-2 PD-ECD can be fitted to Agilent benchtop GCs where the detector signal can be captured through an auxilary detector input or an external A/D box.

The D-2 was the original non-radioactive ECD, the D-5 was offered for some time and was an Agilent specific version of the D-2. The level of plug-and-play for the D-5 was higher, but was not significant enough to displace the popularity of the D-2. Therefore the D-5 did not continue on market, and the D-2 still is the choice for integrators for non-radioactive ECD on Agilent platforms, as well as every other brand of GC.

There are no plans to discontinue the D-2 non radioactive PD-ECD.

Check this out:

http://www.srigc.com/2005catalog/cat50.htm

it's true that ECDs emit a very low radiation but
customs law become a problem.

Adam,

Please contact me off-line at aicmm at flash dot net.

Best regards.

D Ashworth: Wish I had heard your information about the D-2 before I speced out a new GC with an ECD. I talked to someone at Valco and was told the D-5 was discontinued and got the impression (obviously incorrect) that the D-2 may be going away also.