Analytical properties of some commercially available nitrate reductase enzymes evaluated as replacements for cadmium in automated, semiautomated, and manual colorimetric methods for determination of nitrate plus nitrite in water

Abstract

Front Cover. Schematic model of eukaryotic nitrate reductase showing the domain structure of each monomeric unit of homodimer. Cofactor binding sites are shown for each domain of the subunit. Reaction catalyzed by nitrate reductase is also shown. Courtesy of W.H. Campbell, Ph.D., Nitrate Elimination Company, Lake Linden, MI 49945.Back Cover. Reaction sequence of nitrite produced by enzymatic reduction of nitrate with Griess reagents-sulfanilamide and N-(1-Naphthyl) ethylenediamine-to form a pink azo dye with an absorption maximum of 543 nanometers.For more information on the USGS-the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1-888-ASK-USGS.For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprod To order this and other USGS information products, visit

Seasonal variation in the nitrate concentration of groundwater samples surrounding the Dangkor Municipal Solid Waste Landfill

“…The nitrate concentration may then be interpreted in terms of its source and compared with permissible WHO standards for drinking water (Mor et al, 2006). This method is commonly used in the literature for determining the concentration of nitrate ions in groundwater as it is simple to conduct, rapid, and effective, even if there is cadmium contamination present in the sample (Patton & Kryskalla, 2013;Patton & Kryskalla, 2011;Campbell et al, 2006).…”

A pocket-sized 3D-printed attenuated total reflection-infrared filtometer combined with functionalized silica films for nitrate sensing in water

“…Up to date, nitrate is quantified either spectrophotometrically as nitrite after reduction catalyzed by Cd-salt or enzymes, via ion chromatography, or via ion-selective electrodes. 4 In addition, broad-band ultraviolet/visible spectroscopy-based on-line probes for water monitoring have emerged. 5 These systems have been employed for complex water streams, e.g.…”

Water and nutrient budgets for Vancouver Lake, Vancouver, Washington, October 2010-October 2012

“…Lake samples were collected directly into bottles for whole water (unfiltered) samples; for filtered samples, a 0.45-micron capsule filter (Pall Aquaprep ® ) was Unfiltered total nitrogen (TN) and total phosphorus (TP) samples were acidified by adding a 1 mL solution of 4.5 normal sulfuric acid (H 2 SO 4 ) to each bottle and then chilled before analysis at NWQL by digestion (Fishman, 1993;Patton and Kryskalla, 2003). Dissolved nutrients (ammonia, nitrate plus nitrite, nitrite, total dissolved nitrogen, and total dissolved phosphorus) were kept cold and shipped to NWQL for analysis using established methods (Fishman, 1993;Patton and Kryskalla, 2011;Patton and Kryskalla, 2013;). Particulate nitrogen and carbon samples were collected in baked, amber glass bottles; a known volume of sample was filtered through a 25-mm baked, glass fiber filter; and then the filter was folded and wrapped in aluminum foil.…”