Development of paper-based microfluidic strips for quantification of ammonia

Water is one of the most valuable and crucial of life and therefore accurate monitoring and assessment of water resources for sustainability is imperative. Conventional water investigation includes manual gathering of tests, their transportation and resulting examination in the research center. This is time and labour-intensive, costly and requires exceptionally qualified personnel. Sovereign of this procedure empowers more continuous examination, sparing time and cash for analysts, ventures and administering bodies. Consequently, there is requirement for advancement of minimal effort ecological microfluidic paper-based expository gadget that is fundamental for compelling administration of our profitable water assets. This will address the huge and growing demand for low-cost ammonia sensors as legislation becomes more stringent and as more frequent monitoring becomes essential for legislative compliance. Subsequently, this thesis reports on the development of a low-cost, colorimetric, wax- printed microfluidic paper-based analytical device (µPAD) to detect ammonia in industrial wastewaters. Microfluidic innovation was utilized to facilitate the examination of analytes on the colorimetric explanatory techniques onto a convenient detecting gadget. This therefore empowers the blending of little volumes of analytes with synthetic reagents to form a coloured/hued product in the sight of the analyte of interest. The µPAD fabricated was an oval shaped pattern which was designed on Corel draw software. The hydrophilic segments were made by printing a chromatographic paper with hydrophobic paper sizing agents utilizing a standard Xerox wax printer (Xerox colorqube 8570). The quantification of ammonia in wastewater was performed on the µPADs using two typical colorimetric methods namely, Nessler reagent and Salicylate. The reaction of ammonia with the Nessler reagent resulted in a brown or intense yellow colour whereas with the salicylate method, the final colour was green. For both methods, the colour intensity increased proportionally with the analyte concentration, and all images of the μPADs were captured and colorimetrically analyzed with ImageJ software for quantification. The analytical performances of the µPAD were linear from 0 to 5 mg L-1 with a limit of detection of 3.37 mg L-1 and 3.20 mg L-1 for the Nessler vii reagent and salicylate methods respectively. The validity and accuracy of aforementioned methods was supported by the standard UV Visible spectrophotometric method and applied to the measurement of wastewater effluent samples. Wastewater samples were analyzed and the results obtained were similar to those obtained with a spectrophotometric method, demonstrating that the µPAD is suitable to determine ammonia in wastewater.</jats:p

Development of a paper-based microfluidic device for the quantification of ammonia in industrial wastewater

Ammonia is a toxic pollutant increasingly found in urban and industrial wastewater and unprotected surface water. Industry discharges and fertilizer run-off release ammonia into sewers and streams, overloading wastewater treatment plants and causing fish deaths in surface water such as rivers, sea and lakes. The purpose of this study was to develop and evaluate the effectiveness of the microfluidic paper-based device (µPAD) for the quantification of ammonia in wastewater. The µPAD fabricated had an oval-shaped pattern which was designed using CorelDraw software. The hydrophilic zones were created by printing a chromatographic paper with a Xerox wax printer (Xerox colorqube 8570). The modified version of the colorimetric method using Nessler reagent was combined with microfluidic technologies to create a low-cost monitoring system for detection of ammonia in wastewater. The method allows for ammonia determination in the range of 0–5 ppm (mg/L) with a limit of detection of 3.34 ppm. This study indicated that a µPAD was successfully used to quantify the concentration of ammonia in wastewater.</jats:p