Photometric Determination of Ammonium and Phosphate in Seawater Medium Using a Microplate Reader.
To more efficiently process the large sample numbers for quantitative determination of ammonium (NH4+) and phosphate (orthophosphate, PO43-) generated during comprehensive growth experiments with the marine Roseobacter group member Phaeobacter inhibens DSM 17395, specific colorimetric assays employing a microplate reader (MPR) were established. The NH4+ assay is based on the reaction of NH4+ with hypochlorite and salicylate, yielding a limit of detection of 14 µM, a limit of quantitation of 36 µM, and a linear range for quantitative determination up to 200 µM. The PO43-assay is based on the complex formation of PO43- with ammonium molybdate in the presence of ascorbate and zinc acetate, yielding a limit of detection of 13 µM, a limit of quantitation of 50 µM, and a linear range for quantitative determination up to 1 mM. Both MPR-based assays allowed for fast (significantly lower than 1 h) analysis of 21 samples plus standards for calibration (all measured in triplicates) and showed only low variation across a large collection of biological samples.
General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University Oldenburg, Oldenburg, Germany.
Hanna S
HS
Ruppersberg
Maren R
MR
Goebel
Svea I
SI
Kleinert
Daniel
D
Wünsch
Kathleen
K
Trautwein
Ralf
R
Rabus
D064751:Ammonium Compounds / Q000032:analysis* / Q000737:chemistry; D001205:Ascorbic Acid / Q000737:chemistry; D003470:Culture Media / Q000737:chemistry*; D006997:Hypochlorous Acid / Q000737:chemistry; D008982:Molybdenum / Q000737:chemistry; D010710:Phosphates / Q000032:analysis* / Q000737:chemistry; D010783:Photometry / Q000295:instrumentation / Q000379:methods*; D041904:Roseobacter / Q000254:growth & development / Q000378:metabolism; D012459:Salicylates / Q000737:chemistry; D012623:Seawater / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D019345:Zinc Acetate / Q000737:chemistry
D064751:Ammonium Compounds; D003470:Culture Media; D010710:Phosphates; D012459:Salicylates; D006997:Hypochlorous Acid; D008982:Molybdenum; D019345:Zinc Acetate; C022175:ammonium molybdate; D001205:Ascorbic Acid
Ammonium; Microplate reader; Phaeobacter inhibens DSM 17395; Phosphate; Photometric assay; Seawater medium