title: Immobilization of nitrate reductase onto epoxy affixed silver nanoparticles for determination of soil nitrates.
abstract: Epoxy glued silver nanoparticles were used as immobilization support for nitrate reductase (NR). The resulting epoxy/AgNPs/NR conjugates were characterized at successive stages of fabrication by scanning electron microscopy and fourier transform infrared spectroscopy. The immobilized enzyme system exhibited reasonably high conjugation yield (37.6±0.01 μg/cm(2)), with 93.54±0.88% retention of specific activity. Most favorable working conditions of pH, temperature and substrate concentration were ascertained to optimize the performance of epoxy/AgNPs/NR conjugates for soil nitrate quantification. The analytical results for soil nitrate determination were consistent, reliable and reproducible. Minimum detection limit of the method was 0.05 mM with linearity from 0.1 to 11.0 mM. The % recoveries of added nitrates (0.1 and 0.2 mM) were<95.0% and within-day and between-day coefficients of variations were 0.556% and 1.63% respectively. The method showed good correlation (R(2)=0.998) with the popular Griess reaction method. Epoxy/AgNPs bound NR had a half-life of 18 days at 4 °C and retained 50% activity after 15 reuses.
authors.affiliation: Department of Botany, Faculty of Life Sciences, Maharshi Dayanand University, Rohtak 124001, India.
authors.forename: Veena
authors.initials: V
authors.lastname: Sachdeva
authors.affiliation: Department of Botany, Faculty of Life Sciences, Maharshi Dayanand University, Rohtak 124001, India.
authors.forename: Vinita
authors.initials: V
authors.lastname: Hooda
mesh_terms: D000327:Adsorption; D004800:Enzymes, Immobilized / Q000737:chemistry*; D004853:Epoxy Resins / Q000737:chemistry; D017743:Equipment Reuse; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D050901:Nitrate Reductase / Q000737:chemistry*; D009566:Nitrates / Q000302:isolation & purification*; D015203:Reproducibility of Results; D012834:Silver / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000302:isolation & purification*; D013696:Temperature
chemical_list: D004800:Enzymes, Immobilized; D004853:Epoxy Resins; D009566:Nitrates; D012987:Soil; D012989:Soil Pollutants; D012834:Silver; D050901:Nitrate Reductase
keywords: Epoxy; Immobilization; Nitrate determination; Nitrate reductase; Silver nanoparticles