The calibration regulations for microwave digestion instruments are mainly based on relevant national standards and industry specifications to ensure the accuracy and stability of the instrument. The following are the key steps and requirements of the verification regulations:
Preparation before verification:
Conduct a comprehensive inspection and cleaning of the instrument to eliminate the influence of external factors on the calibration results.
Ensure that the environmental conditions meet the requirements, such as temperature (15 ℃~35 ℃), humidity (not exceeding 85%), air pressure (80kPa~106kPa), etc., and that there are no corrosive or flammable gases indoors, with good ventilation devices.
Verification items:
Temperature technical requirements: including temperature deviation, temperature uniformity, temperature fluctuation, etc. For example, the technical requirement for temperature deviation is ± 5 ℃ within the range of 100-200 ℃; The technical requirement for temperature uniformity is that the temperature difference between different digestion tanks at the same time point should not exceed 6 ℃ (≤ 100 ℃) or 10 ℃ (100-200 ℃); The temperature fluctuation requires that the temperature change in any digestion tank within the specified time should not exceed ± 3 ℃ (≤ 100 ℃) or ± 5 ℃ (100-200 ℃).
Pressure technology requirements: involving pressure indication errors, etc. For example, at a pressure point of 0.5 MPa, the allowable error is ± 0.1 MPa; At a pressure point of 10.0MPa, the allowable error is ± 0.7MPa2.
Verification method:
Use specialized measurement standards and other equipment to perform calibration, such as microwave specific temperature data recorders, digital pressure gauges, and pipettes. These tools need to meet specific technical specifications, such as a temperature data logger with a resolution of no less than 0.1 ℃ and an allowable error of ± 0.5 ℃; The accuracy level of the digital pressure gauge is 0.2.