Urine gross alpha/beta bioassay method development using liquid scintillation counting techniques

Limit of detection comparison on urine gross alpha/beta, H-3, and P-32 analysis between different liquid scintillation counters

“…LSC analysis and sample preparation for gross alpha/beta and H-3-For LSC analyses, we used all instruments in alpha/beta mode and our liquid scintillation counting approach [5,6], which includes pulse shape analysis (PSA) or pulse decay discriminator (PDD) setting optimization and quench curves preparation. H-3 and gross alpha/beta analyses were combined in the same gross alpha/beta method which is recommended for urine screening.…”

“…Those agents included nitromethane for Am-241 and Sr-90/Y-90 quench curves, black tea and 10% urea mixture for H-3 quench curves, and water and nitromethane or a black tea and nitromethane mixture (depending on the instrument) for P-32 quench curves [7]. The parameters such as sample analysis time, external standard analysis time, type of cocktail, and sample/cocktail volume were optimized for 20-mL vial geometry [5,6]. In addition, a region of interest (region in which the given nuclide will be counted) was optimized based on spectra for each nuclide from each instrument.…”

“…Another important characteristic for the choice of the instrument is the analysis turnaround time (sample analysis time plus double external standard analysis time) [6]. The analysis time per sample is 5 minutes for all instruments.…”

“…The analysis time per sample is 5 minutes for all instruments. This analysis time provides reasonable minimum detectable activity and good counting statistics [5,6]. However, the external standard analysis time is different for Tri-Carb and Quantulus series instruments because the external standards in Tri-Carbs have higher activities than in the Quantulus instruments.…”

“…And this will increase the total analysis time till 15 minutes for these instruments. Therefore, the optimization of external standard analysis time was done for instruments Quantulus series and the optimal time was found as 1 minute [5,6]. Thus, the total analysis time for Tri-Carbs is approximately 6 minutes per sample and approximately 7.5 minutes per sample for the Quantulus instruments.…”