This report documents work at the U.S. Geological Sur- vey (USGS) National Water Quality Laboratory (NWQL) to validate enzymatic reduction, colorimetric determinative meth- ods for nitrate + nitrite in filtered water by automated discrete analysis. In these standard- and low-level methods (USGS I-2547-11 and I-2548-11), nitrate is reduced to nitrite with nontoxic, soluble nitrate reductase rather than toxic, granular, copperized cadmium used in the longstanding USGS auto- mated continuous-flow analyzer methods I-2545-90 (NWQL laboratory code 1975) and I-2546-91 (NWQL laboratory code 1979). Colorimetric reagents used to determine resulting nitrite in aforementioned enzymatic- and cadmium-reduction meth- ods are identical. The enzyme used in these discrete analyzer methods, designated AtNaR2 by its manufacturer, is produced by recombinant expression of the nitrate reductase gene from wall cress (Arabidopsis thaliana) in the yeast Pichia pastoris. Unlike other commercially available nitrate reductases we evaluated, AtNaR2 maintains high activity at 37°C and is not inhibited by high-phenolic-content humic acids at reaction temperatures in the range of 20°C to 37°C. These previously unrecognized AtNaR2 characteristics are essential for success- ful performance of discrete analyzer nitrate + nitrite assays (henceforth, DA-AtNaR2) described here.

UV-Visible Spectrophotometry of Water and Wastewater is the first book dedicated to the use of UV spectrophotometry for water and wastewater quality monitoring. Using practical examples the reader is shown how this technique can be a source of new methods of characterization and measurement. Easy and fast to run, this simple and robust analytical technique must be considered as one of the best ways to obtain a quantitative estimation of specific or aggregate parameters (eg. Nitrate, TOC), and simultaneously qualitative information on the global composition of water and its variation.* First electronic library of UV-spectra providing data readily available for researchers and users* Provides a theoretical basis for further research in the field of spectra exploitation* Contains helpful practical applications

Thoroughly updated and revised, this second edition of the bestselling Soil Sampling and Methods of Analysis presents several new chapters in the areas of biological and physical analysis and soil sampling. Reflecting the burgeoning interest in soil ecology, new contributions describe the growing number and assortment of new microbiological

Chemical, Gas, and Biosensors for the Internet of Things and Related Applications brings together the fields of sensors and analytical chemistry, devices and machines, and network and information technology. This thorough resource enables researchers to effectively collaborate to advance this rapidly expanding, interdisciplinary area of study. As innovative developments in the Internet of Things (IoT) continue to open new possibilities for quality of life improvement, sensor technology must keep pace, Drs. Mitsubayashi, Niwa and Ueno have brought together the top minds in their respective fields to provide the latest information on the numerous uses of this technology. Topics covered include life-assist systems, network monitoring with portable environmental sensors, wireless livestock health monitoring, point-of-care health monitoring, organic electronics and bio-batteries, and more. - 2020 PROSE Awards - Winner: Category: Chemistry and Physics: Association of American Publishers - Describes the latest advances and underlying principles of sensors used in biomedicine, healthcare, biotechnology, nanotechnology and food and environment safety - Focuses on sensors' methods of data communication, logging and analysis for IoT applications - Explains the specific requirements of sensor design and performance improvement, helping researchers enhance sensitivity, selectivity, stability, reproducibility and response time