The fundamental purpose of laboratory quality control is to ensure the accuracy of its test results, for which the laboratory carries out quality control in accordance with the requirements of CNAS-CL10, "5.9 Quality Assurance of Testing and Calibration Results" in the "Guidelines for Recognition of the Competence of Testing and Calibration Laboratories in the Field of Chemical Testing", in which the use of standards/standards for chemical composition analysis of hazardous substances is mainly in the field of trace elements. According to the requirements of CNAS-CL10 "Guidelines for the Application of the Accreditation of Testing and Calibration Laboratories in the Field of Chemical Testing", "5.9 Quality Assurance of Testing and Calibration Results", the laboratory carries out quality control, in which the use of certified Reference Standards and sub-standard substances is the more commonly used way of internal quality control in the laboratory. Therefore, how laboratories use Reference Standards to monitor and evaluate the test data obtained will have a great impact on the effectiveness of quality control.
Standard substances or sub-standard substances can be certified standard substances or standard substances prepared by the laboratory. For the certified standard substances, the laboratory in accordance with its preservation conditions and instructions for use under the premise of normal testing; for the self-prepared standard substances, first of all should be based on CNAS GL03 "proficiency testing specimen uniformity and stability evaluation guide" to determine whether the control sample is homogeneous, the use of the "t-test" method to determine whether the control sample is stable. The "t-test" method is used to determine whether the control sample is stable. Under the premise of ensuring uniformity and stability, it is also necessary to use certified standard substances to confirm the characteristic value or the same industry authority to confirm the laboratory at the same time.
Use of Standards and Evaluation of Results
Often, standards are added to the actual samples to be analyzed during the testing process, so that the quality level of the standards can be used to measure the quality of the entire testing process. On this basis, the Hughart process control theory is introduced, i.e., such quality control activities over a period of time in a continuous cycle, the overall level of the test process over a period of time can be obtained data. The laboratory evaluates the single and phase data through different statistical methods, which allows the assessment of the quality over the full time period. Laboratory control samples (LCS) may be done once per batch of samples prepared or once every 20 samples.The LCS should be prepared at the matrix and content levels normally encountered, and the results of the measurements can be analyzed and evaluated by creating quality control charts.
Whenever an unsatisfactory result occurs during the testing of a standard, corrective action should be taken to identify the cause in terms of personnel, equipment and facilities, the environment, samples and methods, and then to take appropriate preventive measures to avoid recurrence of the problem in the future.
In the laboratory daily use of standard substances for internal quality control, should be used En value, CD value, Z value and draw control charts and other appropriate ways to evaluate the data, the quality of the test results of the most level of the most processing, a more objective understanding of the laboratory's ability to detect, find and improve unqualified testing; but also ding according to the trend of the data changes in the level of quality. At the same time, it is also based on the trend of data changes, the quality level of some of the top see, take timely preventive and corrective measures, and ultimately achieve the purpose of quality assurance.
Suggested applications:
1. Laboratory personnel assessment and method validation.
2. Laboratory internal quality control and production of control charts.
3. Customer audits of suppliers, on-site blind sample assessment.
4. Customers to organize the supplier's ability to carry out inter-laboratory comparison
We Dongguan Longchang Intelligent Technology Research Institute has the ability to develop standard substances, if you have a need for standard substances or questions, you can call: 0769-86836273-643