Liquid Scintillation Counting Methodology for 99Tc Analysis: A Remedy for Radiopharmaceutical Waste

Mumtaz Khan, Wooyong Um

Anal. Chem. 2015, 87, 9054−9060

https://doi.org/10.1021/acs.analchem.5b02279 

Abstract

This paper presents a new approach for liquid scintillation counting (LSC) analysis of single-radionuclide samples containing appreciable organic or inorganic quench. This work offers better analytical results than existing LSC methods for technetium-99 (99gTc) analysis with significant savings in analysis cost and time. The method was developed to quantify 99gTc in environmental liquid and urine samples using LSC. Method efficiency was measured in the presence of 1.9 to 11 900 ppm total dissolved solids. The resultant quench curve proved to be effective for quantifying spiked 99gTc activity in deionized water, tap water, groundwater, seawater, and urine samples. Counting efficiency was found to be 91.66% for Ultima Gold LLT (ULG-LLT) and Ultima Gold (ULG). Relative error in spiked 99gTc samples was ±3.98% in ULG and ULG-LLT cocktails. Minimum detectable activity was determined to be 25.3 and 22.7 mBq for ULG-LLT and ULG cocktails, respectively. A preconcentration factor of 1000 was achieved at 100 °C for 100% chemical recovery.