The analytical balance is in the laboratoryCommonly usedIt is also one of the most accurate weighing devices, widely used in chemical analysis, biological research, physical experiments, medical research, and other fields.

However, when using high-precision instruments such as analytical scales, many experimenters often encounter various problems. Here are the commonly asked "Ten Questions about Analytical Balance". Come and fill in the gaps and learn how to use analytical balance correctly!

10 Questions on Laboratory Analytical Balance

01. Does the laboratory need to establish a dedicated balance room to store analytical scales? Can it be directly placed on a separate platform in the testing room?

The general requirements for the placement environment of this level of balance are temperature ≤ 30 ℃, humidity ≤ 85%, and temperature difference during operation not exceeding 5 ℃.

But whether it can be directly placed on a separate platform in the testing room should also consider whether there are corrosive gases, vibrations, and air currents in the room. If all meet the requirements, it can be placed.

02. What are scales with different levels of accuracy used for?

① Electronic balance (1/10, 1/100)

Industrial production: weight testing, quality control, and material management

Commercial transactions: weighing and counting of goods

② Electronic precision balance (0.1%)

Research laboratory: precise weighing of trace reagents and substances

Quality Inspection Department: During the quality inspection process, weight testing is conducted on small batches of products

Pharmaceutical manufacturing, industrial processing, precision manufacturing: precise weighing of raw materials, ingredients, and small parts

③ Electronic analytical balance (one ten thousandth, one hundred thousandth)

● Chemical, biological, pharmaceutical, environmental, materials science and other fields: measurement and analysis of trace substances (laboratory)

④ Microanalysis balance (0.1/100000 and above)

Laboratory analysis: molecular experiments, life science research, chemical trace element analysis

Medical diagnosis: Analysis of human blood samples

03. How often should the silicone inside the analytical balance be replaced?

It is not recommended to put desiccants inside the balance, and the temperature and humidity between the scales should be controlled. If you really want to put it on, it depends on the actual situation. If half of it changes color, it needs to be replaced.

In order to control temperature and humidity, it is inevitable to turn on air conditioning or fans in summer. How to avoid the influence of wind on the balance?

① The balance should be placed in the laboratory away from doors and windows;

② When there are multiple scales, the more precise one should be placed inside;

③ It is best to install glass windproof doors on analytical scales, and high-precision micro/ultra micro scales may even require two layers of windproof doors.

05. How to do internal calibration of electronic scales?

① The balance should be preheated for approximately 2-3 hours;

② The balance should be horizontal, otherwise it needs to be adjusted properly;

③ When there is no weighing item on the balance plate, it should display a stable zero position;

④ Press the 'CAL' button to activate the internal calibration function of the balance. Later, the electronic balance will display 'C', indicating that internal calibration is in progress;

⑤ When the electronic balance display shows zero position, it indicates that the electronic balance has been calibrated.

06. How to do electronic balance external calibration?

① The balance should be in a horizontal state and preheated for more than 30 minutes;

② When there is no weighing item on the balance plate, it should stably display as zero position;

③ Press the 'CAL' button to activate the calibration function of the balance;

④ Place the standard weights that meet the accuracy requirements on the scale plate of the balance;

⑤ The display of the balance shows the weight value of the external calibration weight;

⑥ When the displayed value of the electronic balance remains unchanged, it indicates that the external calibration work has been completed and the standard weight can be removed;

⑦ The balance shows that the zero position is in standby mode.

PS: If an error occurs during calibration, the electronic balance display will show "Err" for a short period of time. It should be reset to zero and recalibrated.

How much does weighing paper affect the balance?

① If the sample size is too small during weighing, it may be affected by buoyancy and static electricity, which may cause unstable weighing results;

② The outer edge of the weighing paper exceeds the range of the scale pan, causing the center of gravity of the weighing to shift;

③ The inaccurate weighing results are caused by the contact of the weighing paper with other parts outside the scale pan.

Why can't we directly weigh the required medicine with a beaker without exceeding the range of the balance?

A balance is a precision instrument, and the weight of a beaker is generally large. Even if it is within the weighing range, the impact on the balance when picked up and put down is still more severe than that of weighing paper, and the impact on the balance is also greater. Therefore, it is generally not recommended to use a beaker for direct weighing, but it is not impossible to use it.

09. Should the balance be recalibrated after cleaning?

Just cleaning up does not require calibration, and the balance should not be calibrated frequently. Calibration should only be performed when the error of the balance exceeds the allowable tolerance. If the calibration program is frequently initiated, it indicates that there is a problem with the stability of the balance. You can contact the after-sales service of the purchasing channel for consultation and handling.

10. How to check the performance of the balance?

① Stability

Stability can be divided into long-term stability and instantaneous stability. After being powered on, it maintains the difference in changes in the same measured object weight over different time periods. The smaller the difference in these parameters, the more stable the performance of the electronic balance;

② Linear accuracy

Linear accuracy refers to the deviation between the displayed value and the absolute value throughout the entire weighing range. Even after full-scale calibration, it is difficult to obtain accurate weighing values within the weighing range of electronic scales with poor quality;

③ Repeatability

If the repeatability of the balance is poor, then the collected data is unreliable. Repeatability mainly refers to the fluctuation of numerical values when a balance is repeatedly weighed multiple times, including minimum values, maximum values, and deviations;

④ Sensitivity

Sensitivity refers to the resolution and the time limit reflected by the resolution. Resolution refers to the calibration division value e or display resolution d. The smaller the value, the higher the sensitivity. Reflection time limit refers to the time it takes for the value of a balance to increase by one sensitivity value after adding one sensitivity value. The faster the reflection, the higher the sensitivity.

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