A comparative study of the gamma transmission technique and Raman spectroscopic method for quantifying solution concentrations
Nguyen Thanh Dat, Tran Trung Nguyen, Tran Vu Thien An, Vo Diep Trung Tin, Nguyen Huynh Duy Khang, Huynh Dinh Chuong, Tran Thien Thanh, Hoang Thi Kieu Trang, Hoang Duc Tam
Measurement 122961
Abstract:
This paper presents a comparative study of two analytical techniques – gamma transmission (GT), using photon energies of 59.54 keV (241Am) and 661.7 keV (137Cs), and Raman spectroscopy (RS) – for quantifying the concentrations of aqueous sodium chloride and aqueous glucose solutions. To assess the accuracy and reliability of concentration determination using GT and RS, two evaluation metrics were adopted: relative uncertainty (RU) and relative deviation (RD) between measured and reference concentrations. For sodium chloride, measurements based on the 661.7 keV peak exhibited inconsistent behavior, whereas the 59.54 keV peak demonstrated robust performance, with RU and RD values below 6.8% and 7.0%, respectively, and a limit of detection (LOD) of 0.62 wt%. In contrast, Raman spectroscopy yielded acceptable RD values (<6.0%) only at concentrations above 12.5 wt%. However, the corresponding RU reached 13.0%, indicating that this approach is not well suited for accurate quantification of sodium chloride solutions. For glucose, consistent results were obtained exclusively using the 59.54 keV peak, enabling reliable measurements at concentrations ≥10 wt%, with RU and RD values below 10.4% and 4.0%, respectively, and an LOD of 3.0 wt%. Raman spectroscopy supported stable quantification of glucose at concentrations ≥10 wt%, achieving RU and RD values below 7.3% and 5.2%, respectively, with an LOD of 1.4 wt%. Overall, gamma transmission using low-energy photons demonstrated reliable quantitative performance for both the investigated sodium chloride and glucose solutions, whereas Raman spectroscopy exhibited superior precision for the investigated glucose solution.
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