1Automatic liquid dilution deviceCalibration core objectives

Ensure that the volume accuracy and dilution ratio accuracy of the automatic liquid addition diluter meet the standards, and avoid affecting the reliability of experimental data due to equipment deviations.

2、 Preparation before calibration

Environmental conditions: Maintain a laboratory temperature of 20 ± 5 ℃ and humidity of ≤ 70% to avoid temperature fluctuations affecting calibration results.

Tools and standards: Prepare an electronic balance (accuracy ≥ 0.1mg), volumetric flask, distilled water, standard weights, and ensure that the electronic balance is calibrated and qualified in advance.

Equipment status: Check for stable power supply of the instrument, no leaks or blockages in the pipeline, and clean any residual liquid stains on the dispensing needle.

3、 Core calibration steps

1. Calibration of liquid addition volume

Select three commonly used liquid addition volumes (such as 1mL, 10mL, 50mL) and conduct three parallel tests separately.

Use a dry volumetric flask to receive the output liquid of the instrument, weigh it on an electronic balance, and record the data.

Calculate the actual volume according to "volume=mass/density" (density ≈ 1g/cm ³ at distilled water 20 ℃), and compare it with the set value of the instrument. The deviation should be ≤± 1% (according to the equipment manual requirements).

2. Dilution ratio calibration

Set typical dilution ratios (such as 1:10, 1:100) and dilute with a standard solution of known concentration.

Measure the concentration of the diluted solution using corresponding detection methods (such as spectrophotometry) and calculate the actual dilution ratio.

The deviation between the actual ratio and the set ratio should be ≤± 2%, otherwise the instrument parameters need to be adjusted.

3. Repetitive calibration

Select a medium liquid addition volume (such as 20mL), perform 6 consecutive liquid addition operations, and weigh and calculate the volume separately.

Calculate the relative standard deviation (RSD) of 6 measurement results, which should be ≤ 0.5% to ensure instrument stability.

4、 Post calibration processing

If the deviation is within the allowable range, record the calibration data, paste the calibration qualification label, and indicate the calibration date and the next calibration time.

If the deviation exceeds the standard, adjust the volume correction factor of the instrument and recalibrate until it meets the standard.

Organize calibration reports and archive relevant data (including environmental conditions, test data, and deviation results).

5Automatic liquid dilution deviceCalibration precautions

During the calibration process, avoid touching the dispensing needle to prevent contamination or changing the needle position.

After each addition, wait for 3-5 seconds until the liquid is completely drained before weighing to reduce errors.

Calibration cycle recommendation: Simple calibration once a week for daily use, and comprehensive calibration once every 6 months.