Analytical Detection Levels

Analysis	Method Detection Limit (MDL) ¹	Minimum Level of Quantification (ML) ²	Precision ³
Alkalinity	0.2 mg CaCO3/L	0.6 mg/L	+/- 0.2 mg/L
Ammonia-Nitrogen *	0.003 mg/L	0.009 mg/L	+/- 0.003 mg/L
Bromide	0.01 mg/L	0.03 mg/L	+/- 0.01 mg/L
Calcium	0.06 mg/L	0.19 mg/L	+/- 0.06 mg/L
Carbon, Inorganic	0.05 mg/L	0.16 mg/L	+/-0.05 mg/L
Carbon, Organic	0.05 mg/L	0.16 mg/L	+/-0.05 mg/L
Chloride	0.01 mg/L	0.03 mg/L	+/- 0.01 mg/L
Iron	0.06 mg/L	0.19 mg/L	+/- 0.06 mg/L
Magnesium	0.02 mg/L	0.06 mg/L	+/- 0.02 mg/L
Manganese	0.02 mg/L	0.06 mg/L	+/- 0.02 mg/L
Nitrate(+Nitrite)-Nitrogen	0.001 mg/L	0.003 mg/L	+/- 0.001 mg/L
Nitrogen, Total (Persulfate)	0.01 mg/L	0.03 mg/L	+/- 0.01 mg/L
pH	0.1 pH units	0.3 pH units	+/- 0.1 pH units
Phosphorus, Ortho	0.001 mg/L	0.003 mg/L	+/- 0.001 mg/L
Phosphorus, Total	0.002 mg/L	0.006 mg/L	+/- 0.002 mg/L
Potassium	0.03 mg/L	0.10 mg/L	+/- 0.03 mg/L
Silicon	0.20 mg/L	0.6 mg/L	+/- 0.05 mg/L
Sodium	0.01 mg/L	0.03 mg/L	+/- 0.01 mg/L
Specific Conductance	0.4 us/cm	1.3 us/cm	+/- 2% us/cm
Strontium	0.02 mg/L	0.06 mg/L	+/- 0.02 mg/L
Sulfate	0.01 mg/L	0.03 mg/L	+/- 0.01 mg/L
Suspended Sediment	2 mg/L	N/A	+/- 2 mg/L
Total Dissolved Solids	5 mg/L	N/A	+/- 5 mg/L

The semiquantitative limit is the EPA MDL from 40 cfr part 136 as explained in detail in the epa publication http://www.epa.gov/waterscience/methods/det/rad.pdf.
The ML is defined as the lowest level at which the entire analytical system must give a recognizable signal and acceptable calibration point for the analyte. See D. Helsel. 2005. Nondetects and Data Analysis: Statistics for Censored Environmental Data. Wiley. 288 pp., http://www.wiley.com/ or http://www.epa.gov/waterscience/methods/det/rad.pdf.
Precision evaluated by repeated analysis of near detection level standard solutions.

* Please note that for ammonia-nitrogen that the laboratory has been able to produce data with the same precision as stated above at a LOD of 0.005 mg/L.

College of Forestry

Analytical Detection Levels