A laboratory technician is required to prepare a quarter normal saline solution (0.22% w/v) from the stock normal saline solution.
1. What is the dilution factor required?
I have 4-fold dilution - is that correct?
2. Ise this dilution factor to calculate the volume of stock needed if one litre of the diluted solution is to be prepared.
I have 0.22 over (divided by) 0.91 = 0.2417582 - is that correct? And how do I then convert it into a fraction in its lowest form?
Thanks.
I don't know how accurately you want this done but I would think a quarter normal solution would be 0.91/4 = 0.2275 in which case 4-fold dilution is needed.
2. I don't think it is needed.
If we use M x mL = M x mL, then
0.91/100 x mL = 0.2275/100 x 1,000
mL = 0.2275*1000/0.91 = 250. mL.
Hi DrBob222,
Thanks for your help.
:-)
To determine the dilution factor required, we need to compare the concentration of the desired quarter normal saline solution (0.22% w/v) with the concentration of the stock normal saline solution.
1. Dilution Factor:
The dilution factor represents the ratio of the concentration of the stock solution to the concentration of the desired solution. In this case, a quarter normal saline solution is required, which is 0.22% w/v.
The concentration of the stock normal saline solution is usually 0.9% w/v, so we can calculate the dilution factor as follows:
Dilution Factor = Concentration of stock solution / Concentration of desired solution
= 0.9 / 0.22
≈ 4.09
Therefore, the dilution factor required is approximately 4.09. So no, a 4-fold dilution is not correct.
2. Calculating the Volume of Stock Solution:
To calculate the volume of stock solution needed to prepare one liter of the diluted solution, we need to use the dilution factor.
Given that the dilution factor is approximately 4.09, we can express it as a fraction in its lowest form by rounding it to the nearest whole number:
Dilution Factor ≈ 4
Now, we can use this dilution factor to determine the volume of stock solution needed:
Volume of stock solution = Volume of diluted solution / Dilution factor
= 1000 ml / 4
= 250 ml
Therefore, you would need 250 ml of the stock normal saline solution to prepare one liter of the quarter normal saline solution (0.22% w/v).
I hope this helps! Let me know if you have any further questions.