title: Simple digestion procedure followed by the azomethine-H method for accurate boron analysis and discrimination between its fractions in wastewater and soils.
abstract: Excess boron is a growing environmental problem. It often affects agricultural yields, where reuse of wastewater for irrigation is practiced. This problem raises the need for reliable, simple and economical methods to monitor boron concentrations in wastewater and soil extracts. One such method, the commonly used azomethine-H spectrophotometric method, suffers from color interference, originating from high concentrations of dissolved organic matter, when applied to many wastewater and agricultural soil extracts. Moreover, this method only quantifies free dissolved boron and lacks the ability to quantify boron that is adsorbed to either the dissolved organic matter or suspended solids that are present in the sample. This work suggests a modification of the standard azomethine-H method, in which the solution is digested with potassium persulfate prior to the standard procedure. We show that this pretreatment can overcome the color interference and lead to highly accurate and precise boron analyses in wastewater. In soil extracts, the boron concentrations obtained using the suggested procedure were better correlated to inductively coupled plasma (ICP) spectrometry results than those measured by the standard method, because whereas the standard method quantifies the free dissolved boron only, the modified method, like the ICP method, quantifies the total dissolved boron in the sample. Thus, the suggested modification can be used to quantify the respective distributions of free dissolved boron, boron adsorbed to dissolved organic matter and boron adsorbed to suspended solids in soil extracts and water samples.
authors.affiliation: Department of Environmental Hydrology and Microbiology, Zuckerberg Institute for Water Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, 84990 Midreshet Ben-Gurion, Israel. amgross@bgu.ac.il
authors.forename: Amit
authors.initials: A
authors.lastname: Gross
authors.forename: Anat
authors.initials: A
authors.lastname: Bernstein
authors.forename: Raya
authors.initials: R
authors.lastname: Vulkan
authors.forename: Jorge
authors.initials: J
authors.lastname: Tarchitzky
authors.forename: Alon
authors.initials: A
authors.lastname: Ben-Gal
authors.forename: Uri
authors.initials: U
authors.lastname: Yermiyahu
mesh_terms: D000327:Adsorption; D001895:Boron / Q000032:analysis* / Q000737:chemistry; D004784:Environmental Monitoring / Q000379:methods; D009282:Naphthalenesulfonates / Q000737:chemistry*; D015203:Reproducibility of Results; D012987:Soil / Q000032:analysis*; D012989:Soil Pollutants / Q000032:analysis*; D013882:Thiosemicarbazones / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D009282:Naphthalenesulfonates; D012987:Soil; D012989:Soil Pollutants; D013882:Thiosemicarbazones; D014874:Water Pollutants, Chemical; C097966:azomethine H; D001895:Boron