Making a tin sample cup for the Flash Analyzer

Tutorial: how to make the tin sample cups

There are many sizes of sample tins available; choose the size that is best for your sample mass.

The easiest way to make the tin sample cups is to buy them pre-formed. They are slightly more expensive but in my opinion it is worth it to not waste your time making them. However, if you want to save the money or have thousands of the un-formed tin slips, you might as well give it a go.

There are two ways to do this, especially if your Flash came with one of these strange metal cylinders that, hopefully, I am using correctly.

Set up, remember to keep space sterile.

Use this other tool to carefully begin forming the capsule.

Carefully form the tin and pull it out.

Finished tin. Awesome! (I'm not impressed)

Step 2: done.

Step 1: fold tin around tool.

 








This is an easier way to make the tins. It's faster and the tin doesn't rip as much.


Now you are ready to make those useless tin slips into useful capsules for your Flash.

Preparing my CN Flash samples

Over the last few weeks, I have been preparing my actual soil samples to run using the CN Flash Analyzer. This involved several steps.

1. thaw the frozen sample
2. homogonize sample
3. mass out about 1 gram of sample
4. dry the sample in a drying oven at 105C for 24hrs
5. sieve sample through 2mm sieve
6. grind sample into a fine consistency
7. mass about 35mg of sample into tin capsule
8. ball capsule using Z technique

To grind the samples, I used a large(ish) mortar and pestle. I tried using several mortar and pestle sets with variable success. The small lab set we had laying around didn't work well at all. Grinding those first few samples took about 10min each! I watched my life slowly tick by. Since then I have used my dad's mortar and pestle from our kitchen. I was shocked at how much better it worked. Each sample was finely ground in about 15 SECONDS!!! I didn't believe it at first. 

A fine soil sample using mortar and pestle.

The four samples in the lower left have been ground compared to the others that are only sieved.

This is my preferred set up to mass out sample and put it in the tin capsules. I've got my samples, ethanol, chem wipes, forceps (2), capsule storage trays, tin capsules, and of course the 5 point balance. Remember to sterilize and wipe your work space after each sample. Also, zero the balance with the tin capsule on it before adding sample.

My prep space, Hands Off!

Keep in mind, accidents and spills happen in the lab, no matter how careful you are. While preping my 40 samples, I spilled, like, 4 soil samples, and a LOT of it. That is why you should start with more sample than you think you are going to use or need. Also, then you have extra prepared sample around in case you need to run more tests.

Sample, I have forsaken thee. (my bad)

My finished samples, Yay!

Filling and balling tin capsules for the Flash CN analyzer

When preparing samples for the Flash CN analyzer, it can be difficult to explain how to use the capsules and use the Z folding technique. Hopefully these videos will help you understand the necessary techniques. It might take many samples before you are comfortable with the techniques, and might be even longer until you can do them without spilling too much. Obviously, I am not there yet. When preparing your final samples, make sure to use gloves and work on a sterilized surface. These videos are just for tutorial purposes (do as I say, not as I do).

This first video shows how to fill the tin capsules. When figuring out how much of sample x is  your target milligrams size, it is helpful to add less than you think it will be. It is hard to remove excess sample once in the tin without spilling it all out. As you can see, the microscoopula is not exactly a precision tool. When massing your samples, use a five decimal point balance. Remember to zero the balance with the empty tin capsule on ti before adding sample.

This second video shows how to fold the tin into a Z, fold the tin over to seal it, and then press it into a ball. It is easiest to do this with a pair of forceps.

Hopefully these videos have been helpful. Good luck and happy analyzing!

 For a laugh, check out how steady my hands are. You defiantly don't want me preforming your surgery, lol.