Chromatography Forum

I would like to add headspace capability to my lab, mostly for measuring residual solvents in oils. I have seen the excellent review from Restek here, but although I have personal experience with the "pressure loop" style of headspace unit (Tekmar, Agilent), I have none at all with the "syringe" type (CTC PAL, Gerstel) or the "balanced pressure" type (Perkin Elmer). Can any of you give me some comparisons of the three types of headspace autosampler for this application?

Thanks!

Looks like your article gives you quite a good comparison betwen the different methods. None are perfect but they all work. I can't comment regarding the reliability of specific systems but suggest that you consider Dani/Gentech headspace systems. Having spent the last 20 years making the Agilent Headspace units they now make more than one type and are currently supplying Thermo Buy direct , get the best without the added margin.

Having used both loop and syringe types; the I got better performance form the loops. Nevertheless, all the loop headspacers I used (Agilent, VArian/Tekmar, Dani) were compromised by some really poor design and construction issues. I have never used a pressure balanced type.


Peter

**Disclaimer** EST Analytical provides syringe based systems ( https://www.youtube.com/watch?v=nAX-y_-jULI ) but used to provide both loop and pressure balanced systems.

For most applications, any of the methods will work. There are a few exceptions:
Loop systems in general, can provide higher temperature than Pressure balanced or Syringe based
Loop systems have more surface area and can lead to higher levels of carryover for some applications
Loop and Pressure balanced have transfer lines which can be problematic with carryover and in some case with sulfur compounds.
Syringe systems are more limited in temperature (typically less than 150 degrees C), but can also provide liquid injection, some on board sample prep and SPME capability

I have used both loop and syringe. Previously, I always thought loop was better. But recently, when I started to use syringe (CTC PAL) and see that syringe type is just as good in quantitative analysis (if not better), while can be used for liquid injection and applied for both inlets.

All are useful.

You need to have experience with your analytical needs to know which works best for you.

Have a vendor develop a method you require and compare results.

Rodney George

Hi Rodney

welcome back !

Peter

Likewise, Rod - been missing your tips here. Hope all is well.