This video will show you how to make a caseinate solution.
Here are the equipment needed.
Since only a small amount of caseinate is needed, it is recommended to use only a quarter of the weighing paper.
Fold the weighing paper into half for convenience.
Tare the balance with the weighing paper.
Use the spatula tip to obtain the caseinate.
You should NEVER put any chemical back into the original container.
Any extra caseinate can be directly disposed in the garbage bin since it is not hazardous.
Transfer the caseinate into a microfuge tube carefully
and add the appropriate amount of dd water to prepare the 2 milligram/milliliter stock solution.
Vortex the microfuge tube briefly.
Please note that vortexing too vigorously will introduce a lot of foam in the solution.
In a small test tube, prepare 5 ml of a 10x diluted solution from the 2 mg/ml caseinate solution.
Read the absorbance of the diluted solution using the TECAN spectrophotometer
or the Shimadzu spectrophotometer at 280 nm.
Always handle the cuvette at the top by the edge to prevent contaminating the light path.
The Shimadzu spectrophotometer has a reference slot and a sample slot.
In this session, a cuvette with dd water will stay in the reference slot for your sample measurement.
To start, blank the spectrophotometer using dd water.
Place two cuvettes, both with dd water, in the slots,
place the cuvette so the 1 cm path length of the cuvette is parallel to the path of the light beam.
Then close the sliding door and press “Auto Zero”.
To read the absorbance of the sample, discard the dd water from the sample slot,
transfer the sample into the cuvette, then place in the sample slot.
Close the sliding door again, press “start” to read the absorbance.
Discard the solution, rinse with dd water, then repeat measurement of the diluted solution to collect triplicate data.
When finished, remove the cuvettes from the spectrophotometer
and discard the solutions into a waste beaker before disposing the cuvettes into the garbage bin.
Turn off the spectrophotometer if you are the last group to read your samples.
If you are reading your absorbance using the TECAN spectrophotometer,
you should put your cuvette such that the 1 cm path length of the cuvette is parallel to the arrow on the TECAN spectrophotometer.
In addition, the Nanodrop spectrophotometer will be used to read the absorbance of the undiluted solution.
On the computer, double click on “ND-1000” to open the program and select “UV-Vis” setting.
Initialize the instrument by first cleaning it using dd water and wipe dry with kimwipes.
Add 2 ul of dd water to the sensor pedestal using a P20 Pipetman.
Gently put down the arm of the Nanodrop spectrophotometer and press OK.
Change both wavelengths to 280 nm.
Press Blank to blank the spectrophotometer.
To read a sample, wipe the sensor with kimwipes, then add 2 ul of sample to the pedestal.
Put down the arm and press Measure to obtain the absorbance reading.
Clean the pedestal with dd water, dry and repeat twice more with your sample to obtain triplicate data.
When your measurement is complete, clean the pedestal with dd water and dry with kimwipe.
Place a kimwipe between the sensor pedestals for proper storage.