GIFSQ Tools · Module 3 — Food Microbiology & Enumeration · Tool 043 of 500
Plan a tenfold dilution series. Enter the target dilution and the transfer volumes to get the number of steps, the diluent needed and the step-by-step series.
Try sample values — fills the form with the worked example below.
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Dilution steps
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Total dilution
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Diluent needed (mL)
| Tube | Transfer | Diluent | Dilution after this tube |
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Equation: total dilution = 10⁻ⁿ, where n is the target power of ten · steps = n ÷ log₁₀(step size) · diluent total = steps × diluent per tube.
Method: Serial tenfold dilution, FDA BAM / ISO 6887-1 sample preparation practice. A 1 mL transfer into 9 mL diluent gives a 1:10 step; a 1 mL transfer into 99 mL gives a 1:100 step.
Assumptions: each transfer moves the stated volume; each tube is mixed before the next transfer; a fresh pipette or tip is used at each step.
Limitations: pipetting error compounds at each step; the plan gives the nominal dilution only — the true dilution depends on technique. A target that is not a whole number of the chosen steps cannot be reached with that step size.
Rounding: steps are whole numbers; volumes to 1 decimal place; total dilution shown as a power of ten; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Method: Serial tenfold dilution, FDA BAM / ISO 6887-1 sample preparation practice. A 1 mL transfer into 9 mL diluent gives a 1:10 step; a 1 mL transfer into 99 mL gives a 1:100 step.
Assumptions: each transfer moves the stated volume; each tube is mixed before the next transfer; a fresh pipette or tip is used at each step.
Limitations: pipetting error compounds at each step; the plan gives the nominal dilution only — the true dilution depends on technique. A target that is not a whole number of the chosen steps cannot be reached with that step size.
Rounding: steps are whole numbers; volumes to 1 decimal place; total dilution shown as a power of ten; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Worked example: Target 10⁻⁶ with 1:10 steps, transferring 1 mL into 9 mL diluent each time. Steps = 6 ÷ 1 = 6 steps; diluent needed = 6 × 9 = 54 mL; total dilution 10⁻⁶.
Enter values above to see results.
A 10⁻⁶ target with 1 mL into 9 mL needs 6 tubes and 54 mL of diluent. Mix each tube before the next transfer and change the pipette tip at every step. Tool 043 of 500 — GIFSQ
