Simultaneous separation and detection of monochloramine, nitrite, and nitrate by step-gradient mixed-mode ion chromatography: Translation from benchtop to portable ion chromatograph.

Background: Nitrite (NO) and nitrate (NO) can be produced in the distribution systems of chloraminated drinking water due to the nitrification of ammonia. The most applied inorganic chloramine for this purpose, namely monochloramine (NHCl), is also released into aquatic environments from water treatment plants' effluent and within industrial waste streams. Within the treatment process, the continuous monitoring of disinfectant levels is necessary to limit the harmful disinfectant by-product (DBP) formation.

Multi-wavelength deep-ultraviolet absorbance detector based upon program-controlled pulsing light-emitting diodes.

A novel approach for multi-wavelength ultraviolet (UV) absorbance detection has been introduced employing a single board computer (SBC) with a field programmable gate array (FPGA), Red Pitaya SBC, to generate separated micro pulses for three deep-ultraviolet light-emitting diodes (DUV-LEDs), λ = 235, 250, and 280 nm, along with data acquisition and processing via a custom-made program. The pulse set generation and data acquisition were synchronized using the SBC. The outputs of the three pulsing DUV-LEDs were combined and transmitted to the flow cell via a solarisation resistant trifurcated optical fiber (OF).