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!