An Optimized Spectrophotometric Approach Based on p-Dimethylaminobenzaldehyde for Reliable Urea Monitoring in Environmental and Industrial Samples

Dr. Hany Hassan El-Feky

Dr. Elfeky is a highly accomplished analytical chemist, researcher, and industrial laboratory professional with over 20 years of industrial and academic experience in nanotechnology, analytical chemistry, advanced materials, and quality control. He earned his B.Sc. in Chemistry with Honors from Alexandria University, Egypt, followed by M.Sc. and Ph.D. degrees in Nanoscience and Nanotechnology from the Department of Chemical Engineering, Universitat Rovira i Virgili (URV), Tarragona, Spain, supported by prestigious international research fellowships.

Dr. Elfeky has built a distinguished career by bridging scientific research and industrial practice. His work spans analytical method development and validation, membrane technology, nanomaterials, spectrophotometry, quality management systems, and industrial laboratory management. He is particularly recognized for developing and implementing innovative spectrophotometric methods for urea determination in industrial laboratories, resulting in internationally published analytical methodologies and enhanced quality control performance. His research has contributed to advances in both analytical chemistry and membrane science, leading to publications in internationally recognized journals including Analytica Chimica Acta, Journal of Membrane Science, and Microporous and Mesoporous Materials. Dr. Elfeky has presented his research at major international scientific conferences and actively contributes to the global scientific community through peer-review activities for international scientific journals, the evaluation of scientific contributions submitted to international conferences, and participation in the assessment of scientific research quality and excellence.

As Laboratory Manager at the Operational and Quality Control Laboratories Sectors at Abu Qir Fertilizers and Chemicals Industries Company, he leads laboratory operations, quality assurance activities, and continuous improvement initiatives that support operational excellence and compliance with international standards. His recent work has focused on developing practical analytical solutions for industrial process monitoring and quality control, particularly for fertilizer and chemical manufacturing industries.

Selected Recent Publications

Abstract

SETAC Europe 36th Annual Meeting, Maastricht, The Netherlands

Reliable quantification of nitrogenous compounds such as urea is critical for both environmental assessment and industrial process control. In this study, an optimized spectrophotometric method was developed using p-dimethylaminobenzaldehyde (PDAB) as a derivatizing reagent under controlled acidic conditions. The approach was designed to overcome reproducibility issues related to the aging of acidic PDAB solutions, variations in analytical parameters, and the detection of low urea concentrations. The color reagent was prepared by dissolving PDAB in a 1:1 (v/v) mixture of glacial acetic acid and water, followed by the addition of concentrated sulfuric acid (H2SO4). A Central Composite Design (CCD) within the framework of Response Surface Methodology (RSM) was employed to optimize the reagent composition, identifying an optimal PDAB:H2SO4 molar ratio of 1:0.89, which produced the maximum absorbance at 430 nm for a 10 mg/L urea concentration. Kinetic evaluation confirmed the stability of the chromogen formed at low urea levels, supporting high-throughput laboratory operation. The method was validated according to the Standard Methods for the Examination of Water and Wastewater (Part 1040), exhibiting excellent linearity (R² > 0.99), precision indicated by inter-laboratory relative standard deviations below 5 %, and recovery between 90 % and 110 % at three concentrations (10, 50, and 100 mg/L). The limits of detection and quantitation were 2.2 mg/L and 10 mg/L, respectively. The procedure demonstrated strong robustness with minimal sensitivity to experimental variations and provided an efficient means to minimize interferences from ammonia and hydrazine compounds commonly present in fertilizer effluents. Overall, this enhanced PDAB-based approach provides a simple, sensitive, and reproducible analytical tool for the monitoring of urea in diverse matrices. Its adaptability for both environmental samples and fertilizer industry applications makes it a practical and sustainable alternative to more time-consuming conventional techniques.