Vol.:(0123456789) 1 3 Journal of Radioanalytical and Nuclear Chemistry (2023) 332:5071–5085 https://doi.org/10.1007/s10967-023-09222-7 Using a multistandard color chart guide for digital cameras to detect total uranium in drinking water using arsenazo III: an approach Kamesh Viswanathan Baskaran 1  · Abhijit Saha 2  · Sandeep S. Ghugre 2 Received: 20 July 2023 / Accepted: 17 October 2023 / Published online: 6 November 2023 © Akadémiai Kiadó, Budapest, Hungary 2023 Abstract The present study developed a multistandard color chart for detecting uranium (U) by arsenazo III using digital cameras with color tool measurements and compared it with conventional methods. The color chart is red to dark red as monochromatic for cameras. The detection limit is 5 ng/mL using a preconcentration factor of 100, which is well below WHO guidelines. The digital cameras showed lower bias and better trueness compared to the conventional methods. This provides an advantage in portability, ease of analysis, and no need for high-end instruments/radiochemical laboratories for U analysis in drinking water. Keywords Digital camera · Color chart · Arsenazo III · Uranium · DSLR · Spectroscopy Introduction Uranium (U) is well known for acute and chronic toxicity to the public in drinking water, which accumulates in organs chemically and thereby leads to radiological cancer efects. This is due to its alpha particle emission with a long half-life, such as U-238 (99.274% abundance): 4.5 × 10 9  years; U-234 (0.005% abundance): 2.45 × 10 5  years; U-235 (0.72% abun- dance): 7.04 × 10 8  years; U-233 (trace): 1.59 × 10 5  years; and U-236 (trace): 2.34 × 10 7  years, which appears stable in the normal human life span. The consumption of drinking water by the public is ~ 2.5 L per day. Hence, the limit for U in drinking water is recommended at 30 ng/mL by the World Health Organization (WHO). The guideline limit established by the Atomic Energy Regulatory Board (AERB) in India and Bureau of Indian Standards (BIS) is 60 ng/mL [1–6]. There are two methods reported by researchers: radiometry and nonradiometry for measuring U. The radiometry instru- ments are alpha spectrometry (0.2 mBq/L for 168 h) and liquid scintillation counters (LSCs 0.01 Bq/L in 60 min) [7, 8]. The nonradiometry instruments are X-ray fuorimetry (XRF-0.02 ng/mL), nitrogen laser fuorimetry (0.5 ng/mL) and inductively coupled plasma-mass spectrometry (ICP- MS–0.5 ng/mL) [9–12]. These reported methods demand drinking water to flter, preconcentrate, digest minerals and chemically separate either ion-exchange chromatography or cloud point extraction (CPE) to remove interferences. The major advantage is direct analysis and a low-level detection system. The major cons are its high cost, time-consuming process, specialized requirement of radiochemical labs, repeated time standardization requirement upon operation with stable/unstable isotopes, and high maintenance to detect the precise and reliable quantifcation of U. Measuring ultralow-level analysis in drinking water is not needed for regulatory limit monitoring. An alternative technique is essential in terms of low-cost, efciency, low turnaround time and reliable quantifcation for water quality monitoring systems. Several researchers reported the use of a visible spectrophotometer (VS) with various chromo- phores, which was able to detect near levels of regulator limits. These include arsenazo III (50 µg/g in solid matri- ces and 50 ng/mL in liquid matrices), gold nanoparticles (AuNp) coupled with arsenazo III (212 ng/mL), alizarin red S (1.97 µg/mL) and 4-(2-thiazolylazo)-resorcinol immobi- lized in a tri-(2-ethylhexyl) phosphate plasticized-cellulose triacetate matrix-based optode membrane sensor (50 ng/ mL) [13–17]. However, the above chromophores were pre- pared with a preconcentration technique from 500 mL drink- ing water to attain the regulatory limit, which adds 4–8 h * Kamesh Viswanathan Baskaran kameshbaskaran.rnd@charusat.ac.in 1 Dr KC Patel Research & Development Centre, Charotar University of Science and Technology (CHARUSAT), CHARUSAT Campus, Changa, Gujarat 388421, India 2 UGC-DAE Consortium for Scientifc Research, Jadavpur University Salt Lake Campus, Kolkata, West Bengal 700098, India