January 2015 APD Update

Jan 2015

 

Well I have finally got the web site up and running. We have been in business now for just over 12 months and what with all the other stuff (getting the lab equipped and then moving it into the new unit) the web site has had to take a back seat, but it is good to get it working. (many thanks to Will at we3create for putting it together).

 

Gas Chromatography-Mass Spectrometry

Over the last moth we have been getting to grips with the new Agilent GC-MS. It is a great bit of kit for looking at unknown materials, but unless you are expert at analysing the MS spectra you are reliant on your database of spectra to identify unknowns. When we got the GC-MS we bought the NIST database. This is really, the industry standard, as it has over 250,000 spectra and is quite reasonably priced. We have decided however to add another database, the Wiley 10th edition. This has an additional 750,000 spectra and should mean that with the analysis of unknowns there is a fair chance that we will have it’s spectra. That being said I will have to start to analyse spectra my self as many of the materials we will see will not be on databases. I can just about do it on simple spectra, but it looks a challenge on some of the large spectra. I suppose the good spectroscopists get an eye for and and start to pick up features that speeds up the process.

Getting to grips with the software on the GC-MS was luckily not the horror that I thought it would be ( computers are not my strength!). Agilent have 2 software packages that come with the instrument- Chemstation and Masshunter. I don’t know how old Chemstation is but it looks really dated. The graphs and reports that it produces are really basic ( in the age of ipads and wide screen TV’s), but it is really easy to use, and for me it is completely intuitive. In 30 minutes most people could master the basics of this I am sure and get good results from the GC-MS. Masshunter on the other hand is much better presented and obviously has much more capability, but with that it is more complex. I will need to put some time in on this one to master it. ( I have booked myself on a 2 day course in March to help on this one).

 

We have also ordered an autosampler for the GC-MS. It will mean that mores samples can be run, and these can be done overnight or over the weekend if required. With the type of analysis that we do more samples means more confidence in the final results, and clients always need an answer quickly.

 

FTIR Microscopy

We have had the Nicolet iNx10 now for 12 months and not had that much use from it, with a lot of routine IR analysis being carried out on the small Bruker Alpha, but recently we have had a few projects where we have had to use its chemical mapping facility. Even though they say that the RT detector can be used for mapping, in reality you need to use the liq. N2 cooled MCT detector, to get any speed and or quality. (It is a bit of a pain having to trundle the Dewar down to the BOC agent at the other end of the industrial estate, but it is worth it). With this it does produce some very interesting maps. There is a correlation routine in the software that will give you a correlation between the map generated and a reference spectra. This is really useful if you are looking for the distribution on a surface of a contaminant.

 

The iNx10 can work in transmission reflection and with the Germanium ATR crystal. Most of our work has been done using the crystal probe, as our samples don’t reflect or transmit much IR radiation. However I have decided to invest in a diamond compression cell. This will take a sample and compress it between 2 diamond discs. The cell then is placed in the IR beam and a transmission spectra is obtained. As the cell can exert a large compressive force most samples will get compressed into a thin section which will be able to transmit IR. We will have to see how well this works, but I am confident that it will come into its own when we get tricky samples, and the spectra that you get in transmission mode are normally very high quality.

 

 

Mechanical Testing

We have had a new addition to the testing gear lately. We have an Imetrum video extensometry. This is a video camera and software package that performs strain measurements on samples under test. You have to spray in a speckle pattern to the specimen so that the software can lock onto the surface pattern. You can carry out simple strain measurements at any orientations, or dual strains to get average strain or Poissons ratio data. (much less trouble than strain gages). The beauty of the system is that it can post process the video at any time. So that if you want a different strain analysis carried out on a test you just reload the video image file and reprocess. It does use a lot of memory as the video files are large, we need to get some bigger hard drives!

 

Derek

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