On-site low-level uranium analysis in process and waste streams solutions by a portable spectrophotometer

Abstract The analysis of uranium content in waste solutions of nuclear and industrial facilities is of great importance due to its environmental and process implications. The current research focused on developing an analytical procedure for on-site determination of uranium concentration in process and industrial waste solutions. The complexing reagent 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Br-PADAP) was employed to selectively bind uranium, followed by detection of the resulting absorbance signal using a simple, portable, and low-cost spectrophotometer. The overall analytical procedure is intentionally straightforward, enabling rapid field implementation by non-specialized personnel and eliminating the need for laboratory-based analysis. A systematic study was conducted to identify and optimize the key parameters affecting the method’s performance, ensuring robustness and reproducibility under field conditions. The method exhibited a linear response within the 0–50 mg L −1 range (R 2 = 0.999), with a detection limit of 0.05 mg L −1 , LOQ of 0.15 mg L −1 , and accuracy of approximately 10%, defined as the average relative deviation from nominal concentrations. These analytical figures confirm that the developed procedure is particularly suited for routine monitoring of uranium in process and waste streams, while pre-concentration would be required for trace-level determination in environmental waters.