Jixin handling the chemistry

Talking so much about the machine, however, please do not forget that I am a chemist. Therefore, I should transfer my chemistry knowledge to my magic box. Imaging I would like to analysis how many plutonium atoms there are in 200 litre of seawater with the help of my machine, how should I do?

Let’s start from the beginning. If I directly pass this 200 litre through my automatic box, to only grab plutonium and get rid of the other non-interested stuff, it will not be possible. The volume is too big to pass directly into the system, and the machine cannot tolerant this high workload and it would also be very time consuming. Therefore, I need chemistry to reduce the 200 litre seawater to smaller volume then pass the pre-concentrated sample into the machine for further purification of plutonium. To do pre-concentration, firstly I chose co-precipitation. We add some chemicals that could form insoluble substance which could adsorb plutonium and grab plutonium settle down into the bottom of the seawater. In my case I use simply Fe. I acidify the seawater with some acids, then add Fe, then add alkaline solution (e.g., NaOH) to let them for Fe(OH)₂/Fe(OH)₃ precipitate. Once the Fe(OH)₂/Fe(OH)₃ particles are form, plutonium will be attached to these particles and separated from the larger volume seawater. In the picture you see me working with this.

Afterwards, I just discard the water on the surface by siphoning and collect the remaining residue for the next operation. Fe is an amazing element, by looking at its colour; we could disgust its valence. When Fe is Fe(II), the residue should be green colour while Fe(III) is brown colour. In my work, I normally repeat the co-precipitation several times to pre-concentrate plutonium to smaller and smaller volume. In most cases, I could reduce the 200 litre seawater to less than 50 millilitres. You can image how amazing it is, I could enjoy the colour changes and could play the magic with changing the form and/or size of samples, e.g., I can change liquid to solid, or back and forth, I can reduce or increase the volume of sample, etc. Finally I could use my magic machine to only grab plutonium for the measurement.

Here again, I would like to give another example. Imagine: how could I get to know how many plutonium atoms contained in one kilo seaweed? Seaweed has an amazing ability to trap a large number of elements in seawater.  Play with chemistry. Because seaweed is solid, I cannot direct it directly into my machine. Therefore, firstly, I need to extract plutonium from the seaweed leaves into solution form. But at the very beginning, I need to combust the sample to burn off the carbon substance and also break up the structure of the seaweed tissues in a muffle oven under 550 ºC. Then I add strong acids to leach plutonium out of the sample matrix into the acid solution. Following this, I use again the co-precipitation operation to pre-concentrate this acid solution to a smaller volume. Then pass the final sample solution into my magic box for the purification of plutonium.