Journal of Analytical Methods in Chemistry / 2014 / Article / Tab 1

Research Article

A Modified o-Phthalaldehyde Fluorometric Analytical Method for Ultratrace Ammonium in Natural Waters Using EDTA-NaOH as Buffer

Table 1

The main analytical parameters of the typical reported OPA methods.

SamplesTechnologyReagentReaction temperatureWorking range (nmol/L)LOQ (nmol/L)Reference

Standard solutionManualOPA, mercaptoethanolRoom temperature[7]
Fresh waterFlow injectionOPA, Na2SO3,
Fresh/saline watersFlow injectionOPA, Na2SO3, tetraborate30°C250–50000250[9]
SeawaterManualOPA, Na2SO3, tetraborateRoom temperatureND–10000ND[10]
SeawaterGas diffusionOPA, Na2SO370°CND–40000ND[11]
SeawaterFlow injectionOPA, Na2SO365°C100–600100[12]
SeawaterAutonomous batch analyzerOPA, Na2SO3Room temperature200–1000200[13]
SeawaterMultipumping analyzerOPA, Na2SO3, tetraborate63.5–86.5°C13–100013[14]
SeawaterSolid extraction technologyOPA, Na2SO3, tetraborate75°C1.67–3001.67[15]

LOQ: the lower limit of quantitation, the lowest concentration of the standard curves or working range reported in the corresponding reference.
ND means “no data.”