Krzysztof Kilian

Spectrophotometric study of Cd(II), Pb(II), Hg(II) and Zn(II) complexes with 5,10,15,20-tetrakis(4-carboxylphenyl)porphyrin

The reaction of 5,10,15,20-tetrakis(4-carboxylphenyl)porphyrin (TCPP) with Cd(II), Pb(II), Hg(II) and Zn(II) was studied spectrophotometrically and kinetics, equilibrium constants as well as photodecomposition of complexes were determined. It was verified that these metal ions with large radius accelerate the incorporation reaction of zinc into TCPP. On the basis of the mechanism and kinetics of this reaction, a sensitive method for the spectrophotometric determination of trace amounts of Zn(II) has been developed. The molar absorptivity of examined Zn-TCPP complex and Sandells sensitivity at 423 nm were 3.5x10(5) M(-1) cm(-1) and 18.3 ng cm(-2). The detection limit for the recommended procedure was 1.4x10(-9) M (0.9 ng ml(-1)) and precision in range 20-100 ng ml(-1) not exceeds 2.7% RSD. The proposed method applied for zinc determination in natural waters and nutritional supplement was compared with AAS results and declared value.

On-line enrichment system for manganese determination in water samples using FAAS

An on-line preconcentration procedure for the determination of manganese using flow-injection approach with flame atomic absorption spectrometry as a detection method is described. The proposed method is based on the complexation between Mn(II) and 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP). Two approaches were investigated for enrichment of manganese; the formation of Mn-TCPP complex in a solution followed by its retention on a sorbent and the sorption of manganese ions onto the TCPP-modified resin. The best results was obtained for the first approach when 10(-5)M reagent was on-line mixed with an aqueous sample solution and passed through the microcolumn packed with anion-exchange resin Amberlite IRA-904 for 5min. The sorbed complexes were then eluted with 0.5ml of 2M HNO(3). A good precision (2.2-3.1% R.S.D. for 50mugl(-1) manganese) and the enrichment factor of 30 were obtained with the detection limit of 12mugl(-1) for 5min loading time. The interference of anions and cations has been studied to optimize the conditions and the method was applied for determination of manganese in natural water samples. The results obtained by FI-FAAS and ETAAS (as a reference method) were not statistically different for a significance level of 0.05.

68Ga-DOTA and analogs: Current status and future perspectives

The construction of the 68Ge/68Ga generator has increased application of radiopharmaceuticals labeled with this isotope in medicine. 68Ga-PET is widely employed in the management of neuroendocrine tumors but favorable chemistry with tri- and tetraaza-ring molecules has opened wide range of 68Ga application in other fields of PET imaging. This review covers the radiopharmaceuticals labeled with gallium in molecular imaging and shows perspectives on the use of gallium-68 as a substitute for technetium-99, fluorine-18 and carbon-11 in some applications.

Synthesis, quality control and determination of metallic impurities in 18F-fludeoxyglucose production process

AIM The aim of this study was to synthesize 18FDG in some consecutive runs and check the quality of manufactured radiopharmaceuticals and to determine the distribution of metallic impurities in the synthesis process. BACKGROUND For radiopharmaceuticals the general requirements are listed in European Pharmacopeia and these parameters have to be checked before application for human use. MATERIALS AND METHODS Standard methods for the determination of basic characteristics of radiopharmaceuticals were used. Additionally, high resolution γ spectrometry was used for the assessment of nuclidic purity and inductively coupled plasma with mass spectrometry to evaluate metallic content. RESULTS Results showed sources and distribution of metallic and radiometallic impurities in the production process. Main part is trapped in the initial separation column of the synthesis unit and is not distributed to the final product in significant amounts. CONCLUSIONS Produced 18FDG filled requirements of Ph.Eur. and the content of radionuclidic and metallic impurities was in the acceptable range.

The fast method of Cu-porphyrin complex synthesis for potential use in positron emission tomography imaging

Porphyrin based photosensitizers are useful agents for photodynamic therapy and fluorescence imaging of cancer. Additionally, porphyrins are excellent metal chelators, forming stable metalo-complexes and (64)Cu isotope can serve as a positron emitter (t1/2=12.7h). The other advantage of (64)Cu is its decay characteristics that facilitates the use of (64)Cu-porphyrin complex as a therapeutic agent. Thus, (64)Cu chelation with porphyrin photosensitizer may become a simple and versatile labeling strategy for clinical positron emission tomography. The present study reports a convenient method for the synthesis of Cu complex with tetrakis(4-carboxyphenyl)porphyrin (TCPP). The experimental conditions for labeling, such as the metal-to-ligand molar ratio, pH and time of reaction were optimized to achieve a high complexation efficiency in a short period of time as possible. In order to accelerate the metallation, the use of substitution reactions of cadmium or lead porphyrin and the presence of reducing agent, such as ascorbic acid, hydroxylamine and flavonoid - morin, were evaluated. The optimum conditions for the synthesis of the copper complex were borate buffer at pH9 with the addition of 10-fold molar excess, with respect to Cu(2+) ions and TCPP and ascorbic acid which resulted in reduction of the reaction time from 30 min to below 1 min.

Comparative Study of Sc(III) Sorption onto Carbon-based Materials

ABSTRACT The sorption behavior of Sc(III) on different materials including activated carbon (AC), carbon nanotubes (CNTs), graphene oxide (GO), and the chelating resin Chelex 100 was investigated. In general, the sorption of scandium increases with increasing pH. For pH in the range from 2.5 to 5.5, the sorption of Sc(III) onto CNTs, GO, and Chelex 100 is quantitative, whereas a significantly lower amount of scandium ions was retained on AC. The specific amount of Sc(III) adsorbed at pH 2 attained 2.1, 2.9, 36.5, and 37.9 mg g−1 for AC-COOH, Chelex 100, GO, and CNTs-COOH, respectively. At pH 4, a similar value was obtained for oxidized AC (2.2 mg g−1), whereas the specific amount adsorbed significantly increased for Chelex (23.4 mg g−1). The highest values were obtained for GO (39.7 mg g−1) and oxidized CNTs (42.5 mg g−1). Better kinetic retention was observed at pH 2 for CNTs and GO, whereas at pH 4 the kinetic behavior of Chelex 100, GO, and CNTs toward Sc(III) was comparable.

Separation and purification of scandium: From industry to medicine

Scandium and its compounds are used in many modern industrial fields due to its unique chemical and physical properties. It is mainly recovered from residues and wastes in the production of other metals. The exploitation of the ores and wastes could contaminate water and soil creating environmental problems. This paper discusses recent developments and tendencies in scandium separation, purification and preconcentration from different wastes, residues, environmental samples as well as in the production of radiopharmaceuticals for nuclear medicine, both in the laboratory and on the industrial scale. The period reviewed here mainly includes publications that have appeared, since 2010.

Synthesis of 11C-methionine through gas phase iodination using Synthra MeIPlus synthesis module

Abstract A method of 11C-methionine synthesis using ‘bubbling’ method is presented. 11C-methionine was synthesized via 11C methylation from L-cysteine thiolactone (2 mg) in a 300 μL solution of 2:1:1 (v/v) 1 M NaOH, ethanol, and water at ambient temperature (85°C, 5 min). The radiochemical purity of radiotracer was higher than 99% and enantiomeric purity (L-11C-methionine) was 91.6 ± 0.4%. The final product met the requirements of European Pharmacopoeia monograph. The proposed 11C-methionine synthesis is a reliable tool for routine manufacturing in clinical applications and animal studies.

Distribution and separation of metallic and radionuclidic impurities in the production of 18F-fluorodeoxyglucose

In this study the identification, determination and distribution of metallic and radionuclidic contaminants in the synthesis of 18F-fluorodeoxyglucose are presented. Samples of irradiated 18O-enriched water, purification columns (anionic, C18, Al2O3), final product and wastes were examined. Metallic contaminants were determined by ICP-MS and the radionuclide impurities by high resolution germanium gamma-spectrometry. Fifteen radionuclides were identified in the samples. The enriched water contained cationic contaminants (55Co, 56Co, 57Co, 58Co, 57Ni, 52Mn, 7Be) while the anionic (95Tc, 95mTc, 96Tc, 183Re) were mostly retained in the QMA column. The sources of contamination by metals and radionuclides were determined. Results obtained by ICP-MS generally confirmed the radionuclide distribution obtained by gamma spectrometry.

Separation of 44Sc from Natural Calcium Carbonate Targets for Synthesis of 44Sc-DOTATATE

The rapid increase in applications of scandium isotopes in nuclear medicine requires new efficient production routes for these radioisotopes. Recently, irradiations of calcium in cyclotrons by α, deuteron, and proton beams have been used. Therefore, effective post-irradiation separation and preconcentration of the radioactive scandium from the calcium matrix are important to obtain the pure final product in a relatively small volume. Nobias resin was used as a sorbent for effective separation of 44Sc from calcium targets. Separation was performed at pH 3 using a column containing 10 mg of resin. Scandium was eluted with 100 μL of 2 mol L−1 HCl. Particular attention was paid to the reduction of calcium concentration, presence of metallic impurities, robustness and simple automation. 44Sc was separated with 94.9 ± 2.8% yield, with results in the range of 91.7–99.0%. Purity of the eluate was confirmed with ICP-OES determination of metallic impurities and >99% chelation efficiency with DOTATATE, followed by >36 h radiochemical stability of the complex. A wide range of optimal conditions and robustness to target variability and suspended matter facilitates the proposed method in automatic systems for scandium isotope separation and synthesis of scandium-labeled radiopharmaceuticals.