Automatic in-syringe dispersive liquid–liquid microextraction of 99Tc from biological samples and hospital residues prior to liquid scintillation counting

Abstract

A new approach exploiting in-syringe dispersive liquid-liquid microextraction (DLLME) for (99)Tc extraction and preconcentration from biological samples, i.e., urine and saliva, and liquid residues from treated patients is presented. (99)Tc is a beta emitter with a long half-life (2.111 × 10(5) years) and mobility in the different environmental compartments. One of the sources of this radionuclide is through the use of its father (99m)Tc in medical diagnosis. For the first time a critical comparison between extractants and disperser solvents for (99)Tc DLLME is presented, e.g., tributyl phosphate (TBP), trioctylmethylammonium chloride (Aliquat®336), triisooctylamine (TiOA), as extractants in apolar solvents such as xylene and dodecane, and disperser solvents such as acetone, acetonitrile, ethanol, methanol, 1-propanol, and 2-propanol. The system was optimized by experimental design, and 22.5% of Aliquat®336 in acetone was selected as extractant and disperser, respectively. Off-line detection was performed using a liquid scintillation counter. The present method has a (99)Tc minimum detectable activity (MDA) of 0.075 Bq with a high extraction/preconcentration frequency (8 h(-1)). Urine, saliva, and hospital residues were satisfactorily analyzed with recoveries of 82-119%. Thus, the proposed system is an automatic powerful tool to monitor the entry of (99)Tc into the environment. Graphical Abstract (99m)Tc is widely used in Nuclear Medicine for diagnosis. Its daugther (99)Tc is automatically monitored in biological samples from treated patients by in-syringe dispersive liquid-liquid microextraction.

The Automation Technique Lab-In-Syringe: A Practical Guide

“…Moreover, the online coupling of LIS-DLLME of phthalates and UV-filters to GC-MS via a micro-injection valve was reported including in-syringe silylation inside the extractant [34,35]. DLLM-extract collection for posterior scintillation counting of the enriched 99Tc was reported where LIS automation significantly improved the time efficiency of an otherwise tedious sample cleanup [36].…”

Dynamic Flow Approaches for Automated Radiochemical Analysis in Environmental, Nuclear and Medical Applications

“…For radioactive material characterization in nuclear decommissioning and waste management, constructional and operational materials (e.g., concrete, graphite, steel, ion exchange resin and coolant from nuclear reactors) are typically required to be analyzed for a number of radionuclides (e.g., 3 H, 14 C, 36 Cl, 41 Ca, 55 Fe, 63 Ni, 90 Sr, 99 Tc, Pu isotopes, 241 Am and 244 Cm) [28,29]. The large variations in radioactivity levels and sample matrix compositions occur often as challenges in the relevant radiochemical analyses.…”

“…Thorough radiochemical separation/analysis of the produced radioisotopes from the target materials (e.g., organic solvent or metal foil) is required to ensure their purity [30][31][32][33][34] and to monitor their entry into the environment [35,36]. * Offline separation or measurement.…”

“…Furthermore, extraction times are usually short in DLLME since the extraction equilibrium is quickly reached due to the enhanced transfer area for the extraction. An approach exploiting LIS-DLLME for 99 Tc extraction and preconcentration from biological samples (urine, saliva and liquid residues from treated patients) has been developed [36]. This system is very simple, comprising an eight-port multiposition selection valve connected to a multisyringe burette equipped with a 5 mL glass syringe.…”

“…One of the main constraints in most commercial software packages is the high specificity for a certain configuration. To avoid the inconvenience, some in-house developed software based on LabVIEW [26,62,82], LabWindows [37,70,103,104] and Delphi plus Visual C++ (Autoanalysis software) [12,27,36,[42][43][44][45]47,53,61,105,106] respectively, has been widely applied in the radioanalytical field. In most cases of online radionuclide detection, signals from the detectors (e.g., LSC and ICP-MS) are directly collected and processed by standalone software associated with the detection instruments.…”