AWWA WQTC60597

The objectives of this slide presentation were to outline information on assessing Method 1603 performance in the matrix of interest; develop quantitative quality control acceptance criteria in a reference matrix to support future assessments of laboratory performance; and, develop quantitative quality control acceptance criteria in the matrix of interest to support future assessments of method performance. The matrices evaluated included: reference matrix (phosphate buffered saline); and, wastewater matrices (disinfected effluent, and secondary effluent). Initial study issues included: eleven of the twelve laboratories reported abnormal growth patterns on the modified mTEC plates; and, growth restricted to membrane gridlines. Results included: unspiked sample results; overall false positive and false negative confirmation rates; spiked PBS results; and, spiked wastewater results. Quantitative QC acceptance criteria included: initial precision and recovery; ongoing precision and recovery; and, MS and MSD.