การปรับปรุงวิธีการทดสอบเพื่อให้ได้รับการรับรอง ISO/IEC 17025:2017 ของห้องปฏิบัติการกลางอุทยานวิทยาศาสตร์ภาคเหนือ จังหวัดเชียงใหม่

Abstract

The purpose of this independent study is to improve the testing procedures to align with the resource requirements (Aspect 6) and process requirements (Aspect 7) of ISO/IEC 17025:2017 standards in the chemical analysis of protein in food at the Central Laboratory of Northern Science Park, Chiang Mai Province. This study focuses on implementing the ISO/IEC 17025:2017 standard requirements and the Six Sigma methodology. Prioritized and identified root causes using Pareto charts and fishbone diagrams as well as value analysis and waste identification, and using scientific measurement tools to improve testing methods. The results were compared before and after the scientific method improvements using the HORRAT ratio as a statistical criterion for method validation. Quality control documentation is aligned with the standard using check sheets. The details of the improvements are as follows Before improving, the compliance with Aspects 6 and 7 of the requirements was 61% and 35%, respectively. The efficiency of the devices for both digestion and nitrogen loss showed recovery rates of 27.02 ± 2.06% and 2.64%, respectively. The efficiency of distillation and titration was 13.21%, against a standard range of 98%-102%. Additionally, method validation using reference material showed a value of 3.11 ± 0.15 grams, compared to the standard of 10.91 ± 0.16 grams, with a HORRAT ratio of 5.33, which should be less than 2. None of these values met the standard criteria. Furthermore, the digestion step unnecessarily took 240 minutes, with an additional 60 minutes for sample cooling. After improving, the compliance with Aspect 6 and 7 increased to 96% and 95%, respectively. The efficiency of tools for both digestion and nitrogen loss showed recovery rates improved to 99.96 ± 0.66% and 101.94 ± 0.33%, respectively. The efficiency of distillation and titration increased to 101.69 ± 0.22%. Method validation using reference material showed an improved value of 11.01 ± 0.086 grams, and the HORRAT ratio was 0.77, meeting all standard criteria. Additionally, the process efficiency was improved, reducing the digestion step to 60 minutes and the sample cooling time to 15 minutes, fully complying with ISO/IEC 17025:2017 standard requirements.