Question

You are given a sample of blood for analysis and the experimental protocol requires the following steps: 1. Pipette 0.5 mL of blood into 1.0 mL of saline in a fresh test tube. 2. Remove 0.05 mL of this sample and add to 1.0 mL of the assay reagent in a fresh test tube What is to total dilution of the blood after step 2 in the protocol?

Answer 1

The blood is diluted to 4.9 folds.

Step-by-step explanation:

Steps: 1. Pipette 0.5 mL of blood into 1.0 mL of saline in a fresh test tube.

Initial volume of the Volume of blood before any dilution ,V= 0.5 mL

Volume of saline = 1.0 mL

Volume of the solution after mixing = 0.5 mL + 1.0 mL = 1.5 mL

Step : 2. Remove 0.05 mL of this sample and add to 1.0 mL of the assay reagent in a fresh test tube.

On removal of 0.05 mL from 1.5 mL the volume becomes:

= 1.5 mL - 0.05 mL = 1.45 mL

And 1.0 ml of the essay reagent is added in to 1.45 mL of the solution obtained just above:

Volume of the blood solution = 1.45 mL + 1.0 mL = 2.45 mL

Final volume of the blood solution after dilution = ,V'= 2.45 mL

Fold - dilution =
`(V)/(V')`

V =Volume of original solution before dilution

V' = Total Volume of solution after dilution

`=(0.5 mL)/(2.45 mL)=(1)/(4.9)`

The blood is diluted to 4.9 folds.