Things you can do with a MultiFlex (No.6) – Liquid Injection

Martin Perkins

10th January 2014

A lab manager in the North of England said to me the other day:

“Your MultiFlex is great at those fancy extraction techniques, but we do liquid injections.”

I replied “We do them too!”

I went on to explain that the MultiFlex has seven liquid injection modes:

  1. The MultiFlex routinely and easily performs conventional hot split injection just like any high quality autosampler.
  2. Hot Splitless is used just as easily, for detection and quantitation at low levels.
  3. Cold On-Column injection is available for applications like Triglycerides, and thermally labile analytes that can decompose inside other injectors.  Just insert an on-column adaptor inside the CIS and mount a thin needle.
  4. Cold Split Injection for difficult matrices takes advantage of the GERSTEL CIS inlet’s accurate linear temperature ramping, and two programmable holds, ideal for leaving high boiling dirt out of the column.
  5. Cold Splitless can do the sample for trace analysis.
  6. Large Volume Injection using solvent venting is ideal to avoiding problematic concentration steps for labile or trace species.  The fine control over injection rate, split, and CIS temperature afforded by the Maestro software enables venting of solvent while keeping analytes.
  7. Stop-flow (a unique capability of the GERSTEL CIS inlet) is ideal for samples in solvents that are not compatible with the GC column.  Instead of time-consuming dry-downs and reconstitutions, or solvent exchange steps, a large volume injection can be made with the column head pressure set to zero (split valve fully open) so that none of the sample (or solvent) can enter the column during the solvent venting step.

An existing MultiFlex configured for thermal extractions can be turned to liquid injection in just three simple steps:

  1. A flick of a finger on the mounting lever allows the TDU to be dismounted from the CIS inlet.
  2. Screw on the septum-less head with the finger-tight knob, and attach the carrier gas feed.
  3. Press RUN.

The MultiFlex has a dual head Multi-Purpose Sampler, so one syringe head is dedicated to injection while the other head can happily spike standards or prep samples without any worry about carry-over of concentrated reagents.

Sample trays can be added to the MultiFlex as required, giving a very large sample capacity.  For example, our Anatune VOC analyser can sample from one hundred and sixty 20ml vials (240 for the dual rail version), and systems can be configured to sample from over six hundred 2ml vials which would be a whole weekend’s runs, including bank holiday!

If you use different injection techniques on the same instrument, then the MultiFlex can save you a lot of time by eliminating re-configuration downtime and automating sample preparation.

If you would like to dicuss this in more detail, please either call us on 01223 279210 or email us at