Determination of nitrite, nitrate and ammonium nitrogens in soil by FIA.

Flow injection systems for elemental soil analysis determinations

“…Several problems of interferences reported in previous works were overcome by the use of the gas-diffusion unit that permitted the disposal of some interfering species that could not cross the hydrophobic membrane. Shirato et al (1989) described different FIA systems with UV/Vis spectrophotometric detection for determination of N in several forms. For the determination of NO 2 , 40 uL of N-(l-naphthyl) ethylenediamine reagent was injected into a water carrier solution on either end of the sample solution by using a 16-port valve.…”

Conductimetric Gas Separation-Flow Injection Determination of Ammonia in Gaseous Process Streams

“…Spectrophotometric FIA methods are based on Nessler's reagent [28][29][30][31][32] or phenolate (Berthelot's, Indophenol Blue) reaction 6,8,[33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49] . The two methods are selective and sensitive but the former uses a toxic mercury compound and the product is unsufficiently defined, whereas the latter is rather slow and requires a long incubation time even at elevated temperatures.…”

Spectrophotometric determination of traces of nitrite with rhodamine 6 G

“…Apart from various instrumental methods such as polarography [8], flow injection spectrophotometry [9] and voltammetry 1-10-12], nitrites are readily determined by spectrophotometry using diazo-coupling reactions [-13-20]. Some of these methods give good sensitivity [13][14][15][16] but require close control of pH and temperature during diazotization step and relatively long coupling times.…”