Application of an automated AGE-CHS unit for water DIC-14 analyses at HEKAL Laboratory
Mihály Molnár1, Róbert Janovics1, Virág Gergely1, Dávid Sóvágó1, Balázs Áron Baráth1, Gergely Orsovszki2, Mihály Veres2, Anita Molnár2
11 INTERACT Centre, Institute for Nuclear Research, Debrecen, Hungary, 2Isotoptech Zrt, Debrecen, Hungary
keywords: water, DIC, radiocarbon, automated, graphitization
The aim of this study was to demonstrate overall performance of an Automated Graphitization Equipment (AGE-III, IonPlus) and its Carbon Hydrolyses unit (CHS) for dissolved inorganic carbon (DIC) C-14 AMS analyses at HEKAL AMS Facility (Debrecen, Hungary). The AGE-CHS system was not specified for water DIC preparation that’s why we applied a small modification on the sample tray block of the CHS unit. The modified sample tray block was able to handle 40 ml septa sealed glass vials, the proper size for 20 ml water samples (Septa-Co.).
After the small mechanical modification of the tray block, the AGE-CHS system became capable to handle water samples for DIC-14 preparation, using its original sampling and sample preparation system and software, provided by the IonPlus AG manufacturer. In AGE-CHS unit, the sample processing steps are tuneable in the driving software, according the desired applications. Comparing the regular carbonate preparation protocol of AGE-CHS unit, we have applied a bit longer He flushing time (5 mins) before acid addition and a bit longer sample transport/focusing time (5 mins) when the liberated CO2 is transferred from the reaction vial to the zeolite trap of the AGE system.
In this study we have tested the ultimate performance of the AGE-CHS for water DIC-14 analyses, including: C yield, different sample sizes, memory effect, cross contamination, process blank level and repeatability using multiple, parallel real water DIC samples and IAEA-C1 and -C2 standard reference material. The performance of the AGE-CHS unit was rather same (or even better) than the off-line, manual sample processing we routinely apply for water DIC-14 analyses at HEKAL.
The research was supported by the European Union and the State of Hungary, co-financed by the European Regional Development Fund in the project of GINOP-2.3.4-15-2020-00007 “INTERACT”. Prepared with the professional support of the Doctoral Student Scholarship program of the co-operative doctoral program of the Ministry of Innovation and Technology financed from the National Research, Development and Innovation found. This work was carried out in the frame of a János Bolyai Research Scholarship (to Mihály Molnár) of the Hungarian Academy of Sciences.