Online zinc reduction-sequential injection analysis for the determination of nitrogen species in extracts of riverine sediment

Abstract

Background: The substitution of hazardous analytical reagents such as Cd with benign alternatives for chemical determination is one of the principles of green chemistry. An eco-friendly Zn reduction method for nitrate determination was developed to achieve this end. Methods: Online zinc reduction-sequential injection analysis (ZnR-SIA) protocol was developed for the determination of nitrogen (N) species in the Lagos Lagoon sediments by modification of some standard methods. Results: The novel application of boric acid-borate buffer employed in borate-buffered granular Zn reduction suppressed gas evolution from the Zn micro-column, making the Zn reduction adaptable to online use, unlike the frequently used ammonia-ammonium buffer. Further results showed that the sampling rate for the two-zone stack was 65 h

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“…It eliminates the generation of toxic products associated with the use of cadmium – a metal commonly used in the determination of nitrate. 65 The reagents sulfanilamide and NED compete for the reaction with nitrite. For this reason, each component of the Griess reagent was added in separate fluidic layers to ensure the analyte would react sequentially and to increase the stability and lifetime of the device.…”