Can you remove vacuum distillation from tritium sample preparation?
16/07/2025
At a glance
> When preparing samples of tritium for analysis, vacuum distillation is crucial for isolating NaOH and other contaminants prior to liquid scintillation counting.
> In a study at Idaho State University, the Hidex 300 SL was evaluated to determine if its TDCR method could provide more reliable results in the presence of chemiluminescence without vacuum distilling samples first.
> TDCR (Triple to Double Coincidence Ratio) is unique to Hidex LSCs and provides improved chemiluminescence handling.
The importance of vacuum distillation
Vacuum distillation is a critical step in the preparation of tritium samples for liquid scintillation counting. It is used to purify and isolate enriched tritium water of potential contaminants such as sodium hydroxide (NaOH) to produce a clean, distilled sample before analysis.
NaOH, used during electrolytic tritium enrichment, can interfere with scintillation counting by increasing chemiluminescence and quenching, both of which reduce measurement accuracy. Vacuum distillation ensures that only clean water with enriched tritium reaches the LSC, enabling precise and reliable measurements.
Comparing TDCR to traditional LSC
In a study by MS Student Blaine Gustafson at Idaho State University, the Hidex 300 SL was used to determine if the process of vacuum distillation could be removed from the tritium sample preparation process without compromising measurement accuracy. The study evaluated the 300 SL’s Triple to Double Coincidence Ratio (TDCR) to determine if it provided more reliable results in the presence of chemiluminescence than a traditional LS counter.
But what is TDCR?
TDCR is unique to Hidex LSCs, which use three PMT detectors as opposed to the conventional two that other counters use. This three-detector system can automatically calculate counting efficiency, which correlates to quenching. This eliminates the need for an internal radiation source, offering benefits such as no disposal costs, no health hazards when servicing, and no transportation restrictions.
You can learn more about TDCR by watching our video here.
Comparing enriched tritium samples
In Blaine’s study, two batches of enriched tritium samples were prepared. Batch A was vacuum distilled before measurement and Batch B was not vacuum distilled. Both batches were then analysed using the Hidex 300 SL and a TriCarb 3170 with only two PMTs.
> Batch A samples underwent vacuum distillation and produced results closely matching reference values.
> Batch B samples were not vacuum distilled, and showed more variability and interference, even when using the Hidex 300 SL.
Improved chemiluminescence handling using TDCR
The study determined that TDCR provides improved chemiluminescence handling but it does not fully compensate for the absence of vacuum distillation in tritium sample preparation. Eliminating vacuum distillation reduces measurement accuracy, even when using an advanced LSC such as the Hidex 300 SL.
You can read Blaine’s full study, titled Investigation of a Comprehensive Improvement in Low-Level Tritium Analysis by Electrolytic Enrichment and TDCR Technique, by clicking here.
Find out more
You can learn more about the Hidex 300 SL and its improved chemiluminescence handling by clicking the button below to speak to a product specialist directly.