Quantitative determination of fluoxetine in human serum by high performance thin layer chromatography

A high performance thin layer chromatographic method was developed and validated for the quantification of fluoxetine in human serum. Fluoxetine was extracted by liquid–liquid extraction method with diethyl ether as extraction solvent. Imipramine was used as internal standard. The chromatographic separation was achieved on precoated silica gel F 254 high performance thin layer chromatographic plates using a mixture of toluene/acetic acid glacial (4:5 v/v) as mobile phase. 4‐Dimethylamino‐azobenzene‐4‐sulphonyl chloride was used as derivatization reagent. Densitometric detection was done at 272 nm. The method was linear between 12.5 and 87.5 ng/spot, corresponding to 0.05 and 0.35 ng/μL of fluoxetine in human serum after extraction process and applying 25 μL to the chromatographic plates. The method correlation coefficient was 0.999. The intra‐assay and inter‐assay precisions, expressed as the RSD, were in the range of 0.70–2.01% (n=3) and 0.81–3.90% (n=9), respectively. The LOD was 0.23 ng, and the LOQ was 0.70 ng. The method proved be accurate, with a recovery between 94.75 and 98.95%, with a RSD not higher than 3.61% and was selective for the active principle tested. This method was successfully applied to quantify fluoxetine in patient serum samples. In conclusion, the method is useful for quantitative determination of fluoxetine in human serum.     

Synthesis and thermal behavior study of complexes of the type [Pd(μ-X)(4-eb-p-phen)]2 (X = Cl,Br, I,N3, NCO,SCN) and 4-eb-p-phen [bis(4-ethylbenzyl)p-phenylenediimine]

The Schiff base bis(4-ethylbenzyl) p-phenylenediimine, 4-eb-p-phen (1), and six new dimeric Pd(II) complexes of the type [Pd(μ-X)(4-eb-p-phen)]₂ {X = Cl (2), Br (3), I (4), N₃ (5), NCO (6), SCN (7)} have been synthesized and characterized by elemental analysis, IR spectroscopy, and ¹H and ¹³C{¹H}-NMR experiments. The thermal behavior of the complexes 2–7 has been investigated by means of thermogravimetry and differential thermal analysis. From the final decomposition temperatures, the thermal stability of the complexes can be ordered in the following sequence: 3 > 4 > 7 > 2 ≈ 5 > 6. The final products of the thermal decompositions were characterized as metallic palladium by X-ray powder diffraction (XRD).     

A fast method for the determination of plutonium in soil and sediment samples

A so-called hour method for the determination of plutonium based on extraction chromatography is validated by its application to several certified soil and sediment samples from the International Atomic Energy Agency's Seibersdorf Laboratory. The results are in good agreement with the reference values. Chemical yields range between 47%–66%, with a mean value of (56±6)%. The possible use of this method for²⁴¹Pu determination is also demonstrated.     

Molecular assembly of two [Co(II)4] linear arrays

Molecular chains of four Co(II) ions stabilized by a bis-β-diketone/pyridyl ligand may be isolated or linked into molecular pairs of two semi-independent such units.     

Highly enantioselective organocatalytic cascade reaction for the synthesis of piperidines and oxazolidines

The synthesis of piperidines and piperidines derivatives in enantiopure fashion has been a challenging goal for organic chemists. In this report we developed a nice cascade reaction for piperidine derivatives based in an amidomalonate Michael addition to enals followed by an intramolecular hemiaminal formation with good yields and enantioselectivities. Moreover we studied the ‘in situ’ intramolecular cyclization of this hemiaminals with alcohols forming fused piperidine-oxazolidines.     

Synthesis, characterization and anti-Trypanosoma cruzi evaluation of ferrocenyl and cyrhetrenyl imines derived from 5-nitrofurane

A series of new cyrhetrenyl and ferrocenylimines complexes derived from 5-nitrofurane were designed, synthesized and characterized. The ¹H and ¹³C NMR spectra indicate that these compounds adopt an anti-(E) conformation in solution, and confirmed for 1b by the X-ray crystal crystallography. The electronic effects of cyrhetrenyl (1b) and ferrocenyl (1a) bound directly to nitrogen have been correlated with the chemical shift of the iminic carbon. The trypanocidal activity (Tulahuen strain of Trypanosoma cruzi) of these compounds has been studied with respect to the substituent on the nitrogen atom of the 5-nitrofurfurylideneamino pharmacophore. Even though all the resulting derivatives were less active than Nifurtimox, the cyrhetrenyl complex (1b), compared with ferrocenyl (1a) or purely organic (4a and 4b) analogues, was more efficient as antichagasic agent. This result is likely due to the enhanced lipophilic character of the molecules or from a possible synergy between the cyrhetrenyl and 5-nitrofurane groups.     

Prediction of the physicochemical properties of gasoline by comprehensive two-dimensional gas chromatography and multivariate data processing

The estimation of physicochemical parameters such as distillation points and relative densities still plays an important role in the quality control of gasoline and similar fuels. Their measurements according to standard ASTM procedures demands specific equipments and are time and work consuming. An alternative method to predict distillation points and relativity density by multivariate analysis of comprehensive two-dimensional gas chromatography with flame ionization detection (GC×GC-FID) data is presented here. Gasoline samples, previously tested according to standard methods, were used to build regression models, which were evaluated by external validation. The models for distillation points were built using variable selection methods, while the model for relativity density was built using the whole chromatograms. The root mean square prediction differences (RMSPD) obtained were 0.85%, 0.48%, 1.07% and 1.71% for 10, 50 and 90% v/v of distillation and for the final point of distillation, respectively. For relative density, the RMSPD was 0.24%. These results suggest that GC×GC-FID combined with multivariate analysis can be used to predict these physicochemical properties of gasoline.