The Nebraska DHHS Public Health Environmental Laboratory conducts environmental testing for the state of Nebraska. It employs mandated U.S. Environmental Protection Agency (EPA) methods for the determination of regulated substances such as carbamates in drinking water.
The drinking water program division has to ensure that drinking water is safe and meets detection limit criteria. The Safe Drinking Water Act Testing (SWDA) is provided to municipalities in accordance with federal regulations. The laboratory employs certified EPA Methods to determine if contamination levels exceed regulated maximum contamination levels (MCs) L. These methods are designed to detect the stated drinking water contaminants within the specified detection limits published in the Federal Register.
All procedures are conducted under compliance requirements with audit tracking. In order to ensure that the laboratory is meeting the protocol requirements of both Method and Laboratory practice, the laboratory annually undergoes internal audits conducted by qualified Nebraska DHHS Public Health Environmental Laboratory staff as well as external EPA audits. Typical analyses conducted by HHSR& L include diquat and paraquat (USEPA Method 549.2), Roundup, a glyphosate in drinking water, (EPA Method 547) and carbamate (EPA Method 531.1.) Measurement of Nmethylcarbamoyloximes and N-methylcarbamates in drinking water is performed by direct injection HPLC with postcolumn reaction derivatization. The water sample is filtered and 30 μL is injected into a reverse phase HPLC column. Separation of the analytes is achieved using a methanol/water gradient protocol. The eluted analytes are hydrolysed using Pickering hydrolysis reagent at 100° C. The methylamine formed during the hydrolysis is reacted with o-phthaladehyde and the nucleophile, 2-mercaptoethanol (or nucleophilic Pickering Thiofluor) to form a highly fluorescent isoindole derivative. The optimized Pickering carbamate analytical system allows one to detect a spectrum of carbamates at ppb (ug/L) levels in drinking water. An Agilent 1100 HPLC interfaced with a Pickering Pinnacle PCX instrumentation system was used for the beta-site study.