Novel EPA Ammonia/TKN Method
FIAlab is excited to announce our new EPA-approved method for Ammonia and Total Kjeldahl Nitrogen (TKN analyses), FIAlab 100. This method is included in the EPA Clean Water Act 2021 Methods Update Rule. Our novel method utilizes the o-phthalaldehyde (OPA) method with gas diffusion on a FIAlyzer-1000 platform with in-line fluorescence detection; resulting in a simplified, highly sensitive methodology that is capable of determinations in complex sample matrices. The FIAlab 100 method requires only two reagent streams and one carrier stream, allowing for a significant reduction in the overall platform size and an analytical throughput of up to 50 samples/hour. A single computer interface, FIAsoft, provides real-time signal monitoring and controls the entire analytical process from the autosampler through the FIAlab 100 methodology, signal monitoring, and signal post-processing.
The FIAlab 100 in-line gas diffusion methodology results in negligible matrix interferences as the ammonia analyte diffuses through a gas-permeable membrane into the OPA reagent stream where the fluorophore to be monitored is produced. A copper (Cu) catalyst can be used in place of mercury (Hg) for TKN digestions, as any coloration in the sample remains in the sample stream and is excluded from the detector.
Method schematic and example data.
Furthermore, fluorescence detection allows for increased sensitivity, with a minimum LOD of 0.012ppm N-NH4 and a dynamic range of up to 10ppm N-NH4.
FIAlab Instruments, Inc. Method 100, ‘‘Determination of Inorganic Ammonia by Continuous Flow Gas Diffusion and Fluorescence Detector Analysis,’’ dated April 4, 2018 (FIAlab Instruments, Inc. 2018a). FIAlab Method 100 uses automated flow injection analysis with gas diffusion and fluorescence detector analysis to determine concentrations of ammonia in wastewater, ambient water, and Kjeldahl digestates. FIAlab Method 100 can be obtained from FIAlab Instruments, Inc., 4259 23rd Ave W, Seattle, WA 98199. See the full validated method here.
For more information, see our application note.
Contact sales@flowinjection.com or call (206) 258-2290 for more information
