Total cyanide mass measurement with micro-ion selective electrode for determination of specific activity of carbon-11 cyanide. (August 2015)

• Record Type: Journal Article
• Authors: Shea, Colleen; Alexoff, David L.; Kim, Dohyun; Hoque, Ruma; Schueller, Michael J.; Fowler, Joanna S.; Qu, Wenchao
• Is Part Of: Applied radiation and isotopes. Volume 102(2015:Aug.)
• Page Start: 48
• Page End: 54
• Publication Date: 2015-08
• Subjects: Carbon-11 Cyanide -- Automated [11C]HCN production system -- Micro-ion selective electrode -- Specific activity; Radiology -- Periodicals; Radiation -- Industrial applications -- Periodicals; Nuclear chemistry -- Periodicals; Internet resource; Periodical; 660.298
• DOI: 10.1016/j.apradiso.2015.04.014
• Languages: English
• ISSNs: 0969-8043

Abstract

Abstract: In this research, we aim to directly measure the specific activity (SA) of the carbon-11 cyanide ([ 11 C]CN¯) produced by our in-house built automated [ 11 C]HCN production system and to identify the major sources of 12 C-cyanide ( 12 CN¯). The [ 11 C]CN¯ is produced from [ 11 C]CO2, which is generated by the 14 N(p, α) 11 C nuclear reaction using a cyclotron. Direct measurement of cyanide concentrations was accomplished using a relatively inexpensive, and easy to use ion selective electrode (ISE) which offered an appropriate range of sensitivity for detecting mass. Multiple components of the [ 11 C]HCN production system were isolated in order to determine their relative contributions to 12 CN¯ mass. It was determined that the system gases were responsible for approximately 30% of the mass, and that the molecular sieve/nickel furnace unit contributed approximately 70% of the mass. Beam on target (33 µA for 1 and 10 min) did not contribute significantly to the mass. Additionally, we compared the SA of our [ 11 C]HCN precursor determined using the ISE to the SA of our current [ 11 C]CN¯ derived radiotracers determined by HPLC to assure there was no significant difference between the two methods. These results are the first reported use of an ion selective electrode to determine the SA of no-carrier-added cyanide ion, and clearly show that it is a valuable, inexpensive and readily available tool suitable for this purpose. Highlights: Measurement of cyanide mass contribution from different component of automated [ 11 C]HCN production system. Determination of specific activity of [ 11 C]HCN by micro ion selective electrode.