Abstract
AOAC Official Method 983.02 for potassium in fertilizers contains instrument performance criteria. The Bran & Luebbe Flame Photometer 410 with a TRAACS 800 was evaluated by this method. Noise, drift, carryover, and precision were investigated. Drift and noise were well below the specifications. Carryover was essentially zero. The overall performance of the system based on National Institute of Standards and Technology standards and quality control samples showed an average bias of 0.10%, which is within the method specifications; the absolute values of differences were 0.166% for the citrate extraction and 0.063 and 0.171%, respectively, for the oxalate extractions. The method states that the average bias should be <0.1, and the absolute value of differences should be <0.4. Overall, the system passed all the performance criteria specified in the method.