How to revive CaCl2 desiccant at home?

CaCl2 desiccant is usually used to dehumidify in closets and cabinets. CaCl2(calcium chloride) is a hygroscopic substance that means if you put in in the air it would absorb the water from the air. That is because calcium chloride(anhydrous) has a very high enthalpy change of solution.

 A box of used calcium chloride desiccant

 If we just put the box of used CaCl2 desiccant into a trash can that would be not environmental protection at all. So we can use a easy way to revive our CaCl2 desiccant.

Before we start to revive our desiccant , we need the tools as follow:

1. A iron pot or a pan
2. A heater (gas or electronic as you want)
3. A thermometer (~200℃ or higher)


 Calcium chloride has five hydrate state:
                772 °C   (anhydrous)
                260 °C   (monohydrate)
                176 °C   (dihydrate)
                45.5 °C  (tetrahydrate)
                30 °C     (hexahydrate)

We are going to let the CaCl2˙6H2O becomes into CaCl2˙H2O. Because it is enough to be a useful desiccant.

First, pour the calcium chloride solution(the liquid inside the box) into a iron pot and then boil it.

At first, it would look like it. 

Later on, it would become gelly liquid, and it will still boil.

When the temperature is get over 176°C, it means the liquid has become monohydrate. 

The you can take you pot away from the heater and let it cool down. While it cooling down , smashing it a the same time.

Finally, you will get a fresh powder of calcium chloride monohydrate.

 Put the powder into the box, and you can put the desiccant in to your closet again.

Cellular total RNA extraction from a ALL(Acute lymphocytic leukemia) patient's cells

There are two mainly way to extract RNA from cells.
    1. Use guanidinium thiocynate-phenol-chloroform to extract (traditional way)
    2. Silica column chromatography

Today, we choose traditional way to extract RNA from  a ALL(Acute lymphocytic leukemia) patient's cells. ALL is a form of leukemia, it may be caused by metabolic-genetic disorders,so we can know if a person would be a ALL patient by genomic tests.

First, we take 0.5ml TRIzol reagent(a mixture of guanidinium thiocyanate and phenol ) into an eppendorf with 0.17ml sample. Add 200uL chloroform into the eppendrof and mix it well then put the eppendrof on o ic bath for five minutes.

TRIzol reagent

In this reagent, I listed the using and properties of each chemical compound:

        Guanidinium thiocyanate:

         Guanidinium thiocyanate is a substance used as a general protein denaturant. It is also used to lyse cells and during lysing cell is to prevent activity of RNase enzymes by denaturing them.

        Phenol:

        Phenol dissolves in water would be a weak acid. RNA has a lot of dipoles, so it is readily dissolve into an acidic and polarity phase.

        Chloroform:
         It is a kind of organic solvent. It provide an organic phase let DNA to dissolve in. It could also denature protein and protein would float on the face of chloroform. Otherwise, RNA would dissolves in water phase and the density of chloroform is higher then water, so we can suck out the upper phase(water) easily by a pipetment.

After five minutes, put the eppendrof in a refrigerated centrifug with 12000rpm, 4℃,ten minutes.

The white fuffy between phases is protein.

(I sucked out the upper phase so it looks no so much) 

Suck the water phase into a new ependrof, and add the same volume(as water phase) of isopropanol into the eppendrof. Then put the eppendrof on a ice bath for 45 minutes. In this process, RNA would precipitate.

Then put the eppendrof in a refrigerated centrifug with 12000rpm, 4℃,ten minutes.

 RNA is under the eppendrof

Pour out  all the isopropanol inside the eppendrof, and add 1ml 75% ethanol and then put the eppendrof in a refrigerated centrifug with 12000rpm, 4℃,ten minutes.

Pour out all the ethanol inside then put the eppendrof in a vacuumed centrifug to vapor out all ethanol.

A vacuumed centrifug is running

Add 20uL DECP water into the eppendrop to dissolve RNA.

Suck out 4uL RNA solution and mix it with 996uL DECP water , and measure OD_260/280 nm

A UV-Visual spectrometer(Just need 1.0uL sample)

260/280 means the purity of RNA
260/230 means the containing of organic solvent

Finally, we got a 2617.8 ng/uL RNA sample from a ALL patient's cells.