The dilutions cover the range from 1/2 to 1/100 unevenly.In fact, the 1/2 vs. 1/3 dilutions differ by only 1.5-fold in concentration,while the 1/10 vs. 1/100 dilutions differ by ten-fold. If you are going tomeasure results for four dilutions, it is a waste of time and materialsto make two of them almost the same. The dilution factor chosen for the series of calibration standards is achievable by using serial dilution. The progression of calibration standard concentration is always a geometric series. Consider the example of making the first standard at 1/3 the concentration of the known, the next calibrant would be 1/9th the concentration of the known.

There are many ways of expressing concentrations and dilution.

Using C₁V₁ = C₂V₂

Serial Vs Parallel Dilution Method Pdf

To make a fixed amount of a dilute solution from a stock solution, you can use the formula: C₁V₁ = C₂V₂ where:

V₁ = Volume of stock solution needed to make the new solution
C₁ = Concentration of stock solution
V₂ = Final volume of new solution
C₂ = Final concentration of new solution
Example: Make 5 mL of a 0.25 M solution from a 1 M solution
Formula: C₁V₁ = C₂V₂
Plug values in: (V₁)(1 M) = (5 mL)(0.25 M)
Rearrange: V₁ = [(5 mL)(0.25 M)] / (1 M)V₁ = 1.25 mL
Answer: Place 1.25 mL of the 1 M solution into V₁-V₂ = 5 mL – 1.25 mL = 3.75 mL of diluent

Using Dilution Factors

To make a dilute solution without calculating concentrations, you can rely on a derivation of the above formula:
(Final Volume / Solute Volume) = Dilution Factor (can also be used with mass)

This way of expressing a dilution as a ratio of the parts of solute to the total number of parts is common in biology. The dilution factor (DF) can be used alone or as the denominator of the fraction, for example, a DF of 10 means a 1:10 dilution, or 1 part solute + 9 parts diluent, for a total of 10 parts. This is different than a “dilution ratio,” which typically refers to a ratio of the parts of solute to the parts of solvent, for example, a 1:9 using the previous example. Dilution factors are related to dilution ratios in that the DF equals the parts of solvent + 1 part.

Serial Vs Parallel Dilution Method Pdf

Example: Make 300 μL of a 1:250 dilution
Formula: Final Volume / Solute Volume = DF
Plug values in: (300 μL) / Solute Volume = 250
Rearrange: Solute Volume = 300 μL / 250 = 1.2 μL
Answer: Place 1.2 μL of the stock solution into 300 μL – 1.2 μL = 298.8 μL diluent

Step Dilutions

If the dilution factor is larger than the final volume needed, or the amount of stock is too small to be pipetted, one or more intermediary dilutions may be required. Use the formula: Final DF = DF1 * DF2 * DF3 etc., to choose your step dilutions such that their product is the final dilution.

Serial Dilution Experiment

Example: Make only 300 μL of a 1:1000 dilution, assuming the smallest volume you can pipette is 2 μL
Choose step DFs: Need a total dilution factor of 1000. Let’s do a 1:10 followed by a 1:100 (10 * 100 = 1000)
Formula: Final Volume / Solute Volume = DF
Plug values in: (300 μL) / Solute Volume = 10
Rearrange: Solute Volume = 300 μL / 10 = 30 μL
Answer: Perform a 1:10 dilution that makes at least 30 μL (e.g. 4 μL solute into 36 μL diluent), then move 30 μL of the mixed 1:10 into 300 μL – 3 μL = 297 μL diluent to perform the 1:100 dilution

Serial Dilutions

Parallel Dilution Formula

A dilution series is a succession of step dilutions, each with the same dilution factor, where the diluted material of the previous step is used to make the subsequent dilution. This is how standard curves for ELISA can be made. To make a dilution series, use the following formulas:

Serial Vs Parallel Dilution Method Definition

Move Volume = Final Volume / (DF -1)
Diluent Volume = Final Volume – Move Volume
Total Mixing Volume = Diluent Volume + Move Volume
Example 1: Make a 7-point 1:3 standard curve, starting Neat, such that you can pipette duplicates of 50 μL per well
Calculations:
- Calculate the minimum diluent volume per step: 50 μL per well * 2 for duplicates = 100 μL minimum. Add extra volume to compensate for pipetting error, for example, 20 μL, which brings our desired Diluent Volume to 120 μL
- Calculate Move Volume: Move Volume = 120 μL / (3-1) = 60 μL
- Calculate Total Mixing Volume: Total Mixing Volume = 120 μL + 60 μL = 180 μL
Answer:
- Prepare the first point of the standard curve, which is 180 μL of Neat standard
- Prepare the diluent for the rest of the points, or six aliquots of 120 μL of diluent
- Move 60 μL of the first point into the second and mix thoroughly, move 60 μL of that into the next, and so on

Serial Vs Parallel Wiring

Example 2: Make a 7-point 1:2 standard curve, starting at a 1:5, such that you can pipette duplicates of 50 μL per well
Calculations:
- Calculate minimum diluent volume per step: 50 μL per well * 2 for duplicates = 100 μL minimum. Add extra volume to compensate for pipetting error, for example, 20 μL, which brings our desired Diluent Volume to 120 μL
- Calculate Move Volume: Move Volume = 120 μL / (2-1) = 120 μL
- Calculate Total Mixing volume: Total Mixing Volume = 120 μL + 120 μL = 240 μL
- Calculate first point dilution volumes: you need 240 μL of a 1:5
Answer:
- Prepare the first point of the standard curve, which is a 1:5, so pipette (240 μL /5) = 48 μL solute into 192 μL diluent
- Prepare the diluent for the rest of the points, or six aliquots of 120 μL of diluent
- Move 120 μL of the first point into the second and mix thoroughly, move 60 μL of that into the next, and so on

There are many ways of expressing concentrations and dilution.

Using C1V1 = C2V2

Serial Vs Parallel Dilution Method Pdf

Using Dilution Factors

Serial Vs Parallel Dilution Method Pdf

Step Dilutions

Serial Dilution Experiment

Serial Dilutions

Parallel Dilution Formula

Serial Vs Parallel Dilution Method Definition

Serial Vs Parallel Wiring

Using C₁V₁ = C₂V₂