Degree Type


Date of Award


Degree Name

Master of Science


Agricultural and Biosystems Engineering

First Advisor

Charles R. Hurburgh, Jr.


The Iowa State University Grain Quality Laboratory (ISU-GQL) provides instrument calibration and measurement services for composition of agricultural products. The Laboratory is pursuing ISO 17025 accreditation. Quality control is one of the ISO 17025 requirements, therefore the objectives of this study are to develop quality control program for Near Infrared Spectroscopy (NIRS), supporting equipment and laboratory room conditions and to develop quality control program for the reference data. The first quality control program includes data from NIRS daily check samples, NIRS duplicate differences, NIRS real time prediction comparison to references, periodic checks and reviews of equipment supporting the NIRS calibration, and a record of laboratory climate conditions. The second quality control program consists of internal data (oven moisture and corn density) which are done by ISU-GQL and external data (proximate analysis, amino acids and fatty acids) which are done by other labs. The quality control activities include setting tolerances, developing appropriate control charts, handling and documenting data, writing Standard Operating Procedures (SOP) of quality control activities, implementing quality control program and estimating cost of quality. The tolerance setting of NIRS that was based on the Standard Error of Prediction (SEP) as described in AACC Method 39-00 appears to give a better control than shewhart control chart. The quality controls for supporting equipment improved the consistency of data generated by the lab. Climate data provides basis to look at error pattern of other data. A better documentation of reference data that utilized Access database gives benefit of easier data searching. By establishing quality control program, ISU-GQL satisfies some objectives of quality control and ISO 17025 requirements.



Digital Repository @ Iowa State University,

Copyright Owner

Maureen Suryaatmadja



Proquest ID


File Format


File Size

231 pages