"Concentration of ammonium {NH4+ CAS 14798-03-9} per unit volume of the sediment pore water [dissolved plus reactive particulate <0.4/0.45um phase] by centrifugal extraction, filtration and colorimetric autoanalysis"@en . . "SDN:P01::ISMJUN04" . "Concentration (mass or moles) of the specified analyte determined by colorometric autoanalysis of a water sample separated from a wet sediment sample by centrifugation and filtered through a 0.4 or 0.45um pore filter."@en . .