1.1 ,This test method covers the determination of total nitrogen (TN) and total dissolved nitrogen (TDN) in surface water, seawater, groundwater, wastewater, and wastewater effluents in the range from 0.2–,10 mg/L N. Concentrations from 10–,500 mg/L are possible when used in conjunction with manual or automatic dilution, or automatic injection of less sample volume. The EPA 40 CFR Part 136 Appendix B Method Detection Limit (MDL) is 0.05 mg/L N. Higher concentrations may be determined by sample dilution. Lower concentrations may be possible by injecting larger sample volumes. Follow the manufacturer’,s instructions.