Quality control methods Main quality control methods: First, external quality control: comparison between laboratories, proficiency testing, measurement audit. The second is internal quality control, which mainly includes: (1) Comparative testing of the same sample using different analytical methods (techniques) or different instruments of the same model; (2) Comparative testing of reserved samples by two or more people; (3) The same operator performs comparative testing on the retained samples; (4) Preparation of standard solutions used in daily analysis and testing; (5) Use standard solutions to perform quality control during instrument testing. Quality control plan development and implementation (1) The laboratory should establish a quality control plan for the following year at the end of each year to ensure and prove that the testing process is under control and the accuracy and reliability of the test results. The quality control plan includes proficiency testing and measurement audits. and internal comparisons within the laboratory (such as personnel comparisons, method comparisons, retained samples for retesting), the plan should also include judgment criteria and measures to be taken when suspicious situations occur, and cover all applications for accreditation or those that have been accredited. Detection techniques and methods. (2) The technical person in charge designates senior personnel to be responsible for writing the quality control plan, and the technical person in charge reviews the plan and is responsible for organizing and supervising the implementation of the quality control plan. The technical person in charge conducts statistics and analysis on quality control data, and organizes a review of the feasibility and effectiveness of the above activities. (3) The quality supervisor supervises the testing personnel to complete the sample assessment tasks and comparisons and proficiency testing tests assigned by superiors, supervises the implementation of internal quality control requirements, and reviews the results of comparisons and proficiency testing tests. (4) Testing personnel: Complete the testing work that should be undertaken in quality control activities, and carefully fill in the original testing records. Quality control implementation procedures Inter-laboratory comparison, proficiency testing, measurement audit: (1) Proficiency testing activities organized by laboratory accreditation agencies, or comparison and testing tasks assigned by various testing laboratories. You should actively participate in such tasks. (2) Execution of inter-laboratory comparisons. For comparison tests between laboratories organized by themselves and external laboratories, the technical person in charge will compare the testing items with the same parameters as the external laboratories based on the laboratory's capabilities and select the same testing methods as much as possible. (3) When selecting projects, ensure that the proficiency testing you participate in within 3 years covers all accredited projects in the laboratory. Comparison and proficiency verification tests organized by the laboratory itself, the projects are formulated by senior engineers and submitted to the technical supervisor for approval, which mainly include the following aspects: customer complaint projects; newly launched testing projects; testing projects for instruments and equipment that cannot be traced; usage Items with non-standard testing methods; other testing items that require higher technical level or are necessary. (4) Experimental organization. After clarifying the tasks of the comparison and proficiency testing tests, contact the external laboratories participating in the comparison and proficiency testing tests, arrange the time for the comparison and proficiency testing tests, and calculate the required test funds. The content of the comparison and proficiency testing test implementation plan mainly includes: Project selection for comparison and proficiency testing tests: Generally, priority is given to metrological certification or laboratory accreditation