I recently visited GERSTEL KK in Tokyo to learn about a new chromatographic technique – Selectable 1D/2D-GC/MS.

I started my trip early Saturday morning to fly to Tokyo, a flight of thirteen hours. I arrived very early Sunday morning feeling a little worse for wear. After resting for the remainder of the weekend, I was fully fired up to start my training on Monday morning.

The GERSTEL Selectable 1D/2D-GC/MS is a flexible system, based on a single standard GC/MS instrument. It is both a routine GC-MS and also a complex problem solving system, that offers heart-cutting and two-dimensional separation on demand.

Because of this dual functionality, when questions arise regarding a poorly resolved section of the standard one-dimensional chromatogram, the section in question can be transferred to a 2nd dimension GC column, with different polarity to greatly improve the separation. Both columns are installed in the same GC and are heated independently using Low Thermal Mass (LTM II) technology.

The process of cutting a section of a chromatogram and introducing it to another column is called heart-cutting. The 1D/2D system can be used to determine analytes in either the 1st or the 2nd dimension in a flexible manner, without having to reconfigure the hardware at all. Neither the GC run, nor analyte detection is interrupted when this happens. Detection of the analytes transferred to the 2nd column uses the same detector(s) used for the 1st dimension: MSD and Olfactory Detection Port (ODP), in this case.

During my time in Tokyo we covered many aspects of the 1D/2D system including; installation and functionality of the LTM II modules which are core components of the system. Core functionality including Dean’s switch and splitter was also covered.

We looked at building a system from the ground up including the use of xDCalc software to calculate system pressures and the required lengths of connection and restriction capillaries to ensure optimum linear velocities through the two LTM columns in the system. We also covered all aspects of software operation which is achieved via GERSTEL Maestro and MSD Chemstation.

An important part of the system is the Aroma Office 2D software. This is a database application that uses Retention Indices (RI) to search the data acquired with 1D or 2D GC/MS.

The Aroma Office database contains many hundreds of entries for flavour and fragrance compounds from published literature. With Aroma Office, a cross search can be performed by using two different RIs acquired from both 1st and 2nd dimensional chromatograms. This combined with the selectable 1D/2D-GC/MS system provides an easy to use and highly accurate search result for flavour and fragrance compounds. Valuable, when many significant compounds give poor identifications using MS.

After going through the theory, building the system from scratch and discussion on applications, it was time to put the system through its paces.

We successfully applied the 1D/2D-GC/MS system to the analysis of coffee powder using automated solvent extraction and large volume injection, followed by 1D/2D-GC-O/MS. We successfully heart-cut key flavour compounds from the complex coffee matrix and acheived excellent resolution on the second column.

The next we tackled was to analyse a selection of whiskies using fully evaporative dynamic headspace (FET DHS) followed by 1D/2D-GC-O/MS, again following this analysis we managed to heart-cut and identify trace aroma compounds from the samples.

All in all, a very rewarding trip. I learnt a tremendous amount regarding the Selectable 1D/2D-GC/MS system which I am putting to good use immediately.

I made great friends with the guys at GERSTEL KK and sampled some amazing food.

I had never been to Japan before this visit, but I will definitely be returning.

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My previous post distinguished itself by generating by far the biggest response of any blog post I have yet written. Evidently, I struck a chord with many people.

As a consequence, I have decided to make this the topic of my presentation at our conference in June.

The great thing is that there is no shortage of different approaches that can lead you to lower detection limits, making it much more likely to come up with something that works in any given situation.

You can find details of our conference “Automation in the Chromatography Laboratory” by following the link.

If you want to explore any of this sooner than that, I’m happy to have a chat about it at any time. You can either email me on Ray.Perkins@anatune.co.uk or call me on: 01223 279 210

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The analysis of low levels of volatile organics is increasing in importance

Of late, we have had a steady stream of people asking us how to get more sensitivity from headspace sampling. In most cases, the analyst has made a good job of optimising the vial chemistry, has fine-tuned the instrumental parameters and still doesn’t have enough horsepower.

If you are in this position, here are some ideas you can consider.

The figure in brackets represent the approximate gain you can expect to make, compared to the best that static headspace sampling can achieve.

1. Fit a cryotrap between your injector and column and inject larger headspace samples in splitless, rather than split mode. (x10).
2. Convert your system to dynamic headspace sampling (DHS).  This is easy if you have a GERSTEL MultiPurpose Sampler (MPS). If you have a CTC/Agilent CombiPal, it can be converted into an MPS and then upgraded. (x20).
3. If you have a suitable instrument to hand, try purge & trap sampling. This gives similar gains to dynamic headspace sampling (x20).
4. Try Stir Bar Sorptive Extraction in headspace mode (HSSBSE). This drives the equilibrium in the right direction, stripping analytes from the matrix. Good for slightly heavier compounds. Good sensitivity due to splitless injection (x10).
5. If you have plenty of sample available, use Large Volume Headspace - the Entech 7150 concentrator is able to sample hundreds of grams of sample, collect hundreds of milliliters of headspace, cope with large amounts of water, focus all of the analytes and inject everything onto the column without splitting. This is the sledge-hammer solution. If this doesn’t work, then nothing will. (x100).
6. If you think your problem is due to analytes partitioning too weakly into the headspace, try fully evaporative headspace (FET) to eliminate the effect of the matrix (variable, can be x10).
7. If your problem is that you can’t pick out your analytes from the matrix background, consider heart-cutting to separate target analytes from chemical noise. A great way of boosting S/N.
8. Some of these gains are additive, so consider combining some of these ideas (DHS with heart-cutting for example).

Our applications lab is set-up with all of this instrumentation and we have used all of these techniques successfully, at one time or another.

So if you have the problem of insufficient sensitivity in headspace mode, by all means give us a call on 01954 212909, or email enquiries@anatune.co.uk  for more information.  If we can help you, we will.

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Anatune's new home

We are moving to our new building in Cambridge over the weekend of 3rd/4th March. You can find our new address, phone and fax numbers here.

The fitting out of the new building is now complete and it looks really good. Our applications laboratory is the engine-room of our business and the new lab is big, very well laid out and will give us plenty of room for expansion.

Anatune has undergone big changes over the last few years and to my mind, this move represents the final step in our transformation from a small business into a medium-sized organisation with the resources, people, structures and disciplines needed for future growth.

We have arranged several events to celebrate this milestone.

Wellbrook Court Official Opening

This will take place between 4:30 and 6:30 on Wednesday 21st March. We will be inviting Anatune staff, their families, representatives of Anatune’s business partners, plus local and trade press.

I am pleased to reveal that, subject to the demands of unexpected parlimentary business, Andrew Lansley MP has agreed to do us the honour of cutting the ribbon.

Anatune Technology Days

On Thursday 22nd and Friday 23rd of March, we will be holding two open house technology days to which any of our customers are invited. This will enable us to show-off our new building and also showcase some brand-new instruments that will extend the range things we can do for our customers.

Each day starts at 11:00 am and will finish no later than 3:00 pm.

If you can come along, you will be very welcome. Please phone or email Susan Roach on 01954 212909 or email: enquiries@anatune.co.uk

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Down Hall Country House Hotel

June 12 & 13th 2012, Down Hall near London Stansted Airport.

The conference programme for our this popular event is now virually complete.

We have assembled a great programme of talks and we already have a decent number of delegates booked.

If you book on-line or by telephone before the 1st of March, you can do so a discounted “Early Bird” rate.

Are you willing to present a poster?

This year we holding a poster session at 5:00pm on the Tuesday afternoon. If you are interested in presenting a poster on work that you have done, you would be very welcome to do so.

It would be very useful for us to have some idea as to the number of posters we need to plan for, so if you think that you might want to submit a poster, please can you let us know now?

Email: Susan.Roach@anatune.co.uk or call +44 (0)1954 212909

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