(99m)Tc (6.0067 h half-life) is an artificial radionuclide largely used in diagnostic medicine. Its daughter (99)Tc is a beta emitter of great concern because of its long half-life (2.111 × 10(5) years) and presumed mobile behavior in the environment. To monitor the (99)Tc in urine from treated patients, an automatic Lab-on-valve (LOV) system for separation and preconcentration of (99)Tc was developed. TEVA resin was selected since it retains pertechnetate ion selectively from diluted nitric acid solutions. After elution, (99)Tc is detected using a liquid scintillation counting (LSC) detector. The present method has been successfully applied to urine samples with low (99)Tc content (recoveries between 94-111%). The minimum detectable activity (MDA) of the developed method is 0.1 Bq or 1 Bq L(-1) (expressed as activity concentration), when preconcentrating 100 mL of sample. The high durability of the resin, together with the low amount of resin required (32 mg), the good reproducibility (RSD 2%, n = 5) and the high extraction frequency (up to 12 h(-1)) makes of the present method an inexpensive, precise and fast useful tool for monitoring (99)Tc in urine samples.

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.

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The reaction of 4′-(2-thienyl)-2,2′:6′,2,2′′-terpyridine (S-terpy) with the heterometallic complexes [Au2Ag2R4(OEt2)2] n (R = C6F5, C6Cl5) leads to the compounds [{Au­(C6X5)2}­Ag­(S-terpy)] n (X = F (1), Cl (2)). The X-ray diffraction analysis of the complexes shows an alternating disposition of the metals −Au–Ag–Au–Ag– in 1D infinite polymeric chains. Despite the fact of having the same metallic sequence, the spatial arrangement observed for both complexes is very different, since for [{Au­(C6F5)2}­Ag­(S-terpy)] n (1) the metals adopt a zigzag disposition, whereas an helicoidal distribution of the interacting metals is observed for the complex [{Au­(C6Cl5)2}­Ag­(S-terpy)] n (2). These different arrangements are related to the perhalophenyl ligands present in the complexes, which appear with different spatial dispositions, being staggered in the case of C6F5 (1) and almost eclipsed in the case of C6Cl5 (2). In order to explain the reasons for these different structural arrangements, we performed a DFT-D3 computational analysis and a subsequent study of the qualitative characterization of the noncovalent interactions (NCIs) in real space.

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