1. , Maureen Suryaatmadja 1 (maureen@iastate.edu), Dr. Charles R Hurburgh 1 Jr. (tatry@iastate.edu) Department of Agricultural and Biosystems Engineering 1 Iowa State University Ongoing Quality Control Program for NIRS-based Service and Research Laboratory Introduction ISU-GQL performs Near Infrared (NIRS) instrument calibration. ISU- GQL provides services of measuring the chemical composition and biological properties of agricultural products using NIRS instruments. (e.g. corn and soybean, N ~ 20,000 samples/year) ISU-GQL has many brands of NIRS instruments: Infratec, Bruins Omega, Perten DA7200, Zeiss Corona, NIRS6500. ISU-GQL wants to meet quality standard based on ISO 17025. Quality Control is specifically stated in ISO 17025 section 5.9. Other sections of ISO 17025 that may support Quality Control: Section 4.12 - documentation Section 5.2 - training Section 5.3 - laboratory facilities Section 5.5 – equipment Objectives To develop quality control program for NIRS instrument, supporting equipment and laboratory climate. Activities Setting tolerance. Developing appropriate control charts. Handling and documenting data. Implementing quality control program. Writing procedures of quality control activities. NIRS Quality Control Program Supporting Equipment Quality Control Program ItemSEPType Cum. Ave 95% CL 0.33* SEP 95% CLSED 95% CL Base calibration0.57SECV Base Calibration Temp + Stabilization0.55SECV Original Calibration 20040.47SECV Base Calibration Temp + Stabilization (Val 2004)0.32SECV Validation 553075 (Crop 2004)0.38SEP Validation 1241350 (Crop 2004)0.48SEP0.460.920.150.300.210.43 Table 1. Tolerance Development of Method 2 Method 1: average ± 2 standard deviation Method 2: 10- pts moving average ± 2 (0.33 SEP) Method 1: average differences ± 2 standard deviation of differences Method 2: 10- pts moving average ± 2 (√2 0.33 SEP) AACC Method 39-00 : Standard Error of Precision ≤ 0.33 SEP Tolerance: Y= X ± 2 SEP Laboratory Climate Quality Control Program Conclusion Control charts using fixed tolerances that derived from SEP as described in AACC Method 39-00 are more appropriate than Shewhart control charts: Fixed tolerances come from the expected performance of NIRS instruments. Equipment quality control can improve consistency of data generated by lab. Climate data provides basis to look at error patterns. I SU-GQL satisfies some requirements stated in ISO 17025 : quality control, documentation, laboratory facilities, and equipment. Lab data generated by ISU-GQL is prepared for third party audit. Laboratory Procedure Figure 1. NIRS Quality Control Program Flowchart Figure 2. NIRS Daily Check Control Chart Figure 3. NIRS Duplicate Differences Control Chart Figure 4. Original NIRS vs. References Control Chart Equation 1. Standard Error of Prediction Figure 5. Daily Check Samples Figure 6. Infratec 1241 Instrument Figure 7. Balance Q/C Chart Figure 8. Seed Counter Q/C Chart Figure 9. Kettle Grain Test Weight Chart Figure 10. GAC Grain Test Weight Chart Figure 12. Monthly Humidity Chart Figure 13. Monthly Temperature Chart Method 1 Method 2 Method 1 Method 2