Measurement; Measuring Procedure; Judging The Results; Example Causes Of Measurement Errors - AND BM Series Instruction Manual

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Using the predetermined pipette volume, perform the measurement the specified times.

ISO 8655 recommends ten measurements for each for the volumes described below.

 At the nominal volume of a fixed volume pipette

 At the following three points of an adjustable volume pipette

1. 10% of the maximum volume or the lower limit of the adjustable volume range, whichever is greater.

2. 50% of the maximum volume

3. 100% of the maximum volume

NOTE

Pipette volumes and number of measurements can be changed.

WinCT-Pipette converts the mass values into volumetric values, compares these with the

predetermined judgment standard and performs judgment whether the pipette will pass or fail.

 Judgment standard

The averaged value (exceeds / does not exceed) the specified maximum permissible error.

Repeatability (exceeds / does not exceed) the specified maximum permissible error.

Evaporation of the test liquid

Evaporation of the distilled water dispensed from the pipette into the sample cup can be a cause of

measurement error.

To reduce errors caused by evaporation

Be sure to use the evaporation trap. Using the evaporation trap, evaporation of the test liquid can

be reduced to 0.05 mg per minute (0.05 L per minute).

 Use the display lock function of the BM series. For details, refer to "10-1 Display Lock Function".

Water temperature and barometric pressure

Correctness of the Z factor, that is used to convert a mass value to a volumetric value, depends on

the density by the water temperature.

The barometric pressure, even if changed in the range between 950 hPa and 1050 hPa, influences

measurements only by 0.01%.

Water temperature, if changed by 5°C, influences measurements by 0.11%.

9. MEASUREMENT

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Bm-014