The accuracy of an instrument's scale directly affects the accuracy of volumetric analysis. Different levels of instruments allow for different tolerances, for example, a 25 mL pipette of the first level allows for a tolerance of ±0.04 mL. Volumetric instruments should be calibrated for analyses that require high accuracy.
The volume of the volumetric instrument is specified as the volume of the glass instrument at 20 ℃ (V20), the method of correction is to weigh the container can be accommodated (measured into the instrument) or released (measured out of the instrument) the weight of pure water, and then multiplied by the conversion factor (i.e., at different temperatures in the air with brass weights weighing 1 gram of water in the volume at 20 ℃), that is, the volume of this instrument at 20 ℃.
Expanded Information
The basic requirements that should be met by the calibration of instruments are as follows:
1. Environmental conditions If the calibration is carried out in the calibration (calibration) room, then the environmental conditions should satisfy the laboratory requirements for temperature, humidity and other regulations. If the calibration is carried out in the field, the environmental conditions shall be subject to the conditions that can meet the field use of the instrument.
2, the instrument As a calibration of the standard instrument with the error limit should be calibrated to the error limit of the meter 1/3 ~ 1/10.
3, the personnel calibration is different from the calibration, but the calibration of the personnel should be effectively assessed and obtain the appropriate certificate of competency, only the licensed personnel can issue calibration certificates and calibration reports, and only this kind of certificates and reports are considered to be valid.
Approach to instrument calibration
In accordance with the definition of the relevant terms and the actual connotation, calibration is mainly used for higher accuracy requirements, or by the conditions of the limitations, you must use a lower accuracy measuring instruments for higher measurement requirements of the place; calibration is mainly used for the absence of calibration regulations occasions for the new products, special measuring instruments, or accuracy of relatively low requirements for the measurement of testing instruments and for the inspection of the Test hardware or software.
Baidu Encyclopedia - Calibration Instruments
Baidu Encyclopedia - Volume Instruments