A novel method for the determination of ⁹⁹Tc in water samples was developed using stable Re as a chemical yield tracer and TiCl₃ as a reducing agent. The influences of several experimental parameters, including TiCl₃ concentration, HCl concentration and reaction time, on the reduction of TcO₄⁻ and ReO₄⁻ as well as Ti(OH)₃-TcO₂-ReO₂ co-precipitation were investigated. Tc(VII) and Re(VII) retained on TK200 resin were effectively eluted by 5 mL of 1 mol/L NH₄SCN, which can be directly mixed with the scintillation cocktail for liquid scintillation counting. The results show that the chemical behaviors of Tc and Re are very consistent in the whole procedure. The decontamination factors of potential interferences from β-emitting nuclides mainly released from nuclear fuel reprocessing plants were also evaluated, and the minimum detectable activity concentration was calculated to be 0.08 Bq/L for ⁹⁹Tc in water samples with a counting time of 2 h.

使用稳定的 Re 作为化学收率示踪剂和 TiCl ₃作为还原剂，开发了一种测定水样中⁹⁹ Tc的新方法。_{研究了TiCl 3}浓度、HCl浓度和反应时间等几个实验参数对TcO ₄ ^-和ReO ₄ ^-的还原以及Ti(OH) ₃ -TcO ₂ -ReO ₂共沉淀的影响。保留在 TK200 树脂上的 Tc(VII) 和 Re(VII) 被 5 mL 的 1 mol/L NH _{4有效洗脱}SCN，可直接与闪烁混合物混合进行液体闪烁计数。结果表明，Tc和Re的化学行为在整个过程中非常一致。还评估了主要从核燃料后处理厂释放的 β 发射核素的潜在干扰的去污因子，计算出水样中⁹⁹ Tc 的最小可检测活度浓度为 0.08 Bq/L，计数时间为 2 h。