The structure of tanachin

1. The new sesquiterpene lactone tanachin (I) has been isolated from a chloroform extract ofTanacetum pseudoachillea C. Winkl. 2. With the aid of double and triple resonances, the chemical shifts and coupling constants of the protons of (I) have been determined. On the basis of these results and by the application of a paramagnetic shift reagent —Eu (FOD)₃ — the structure of 1,6-dihydroxygermacr-4,10(14),11(13)-trien-8,12-olide has been established for tanachin. The orientations of the hydroxy groups have been determined.     

Analytical pitfalls in hair testing

This review focuses on possible pitfalls in hair testing procedures. Knowledge of such pitfalls is useful when developing and validating methods, since it can be used to avoid wrong results as well as wrong interpretations of correct results. In recent years, remarkable advances in sensitive and specific analytical techniques have enabled the analysis of drugs in alternative biological specimens such as hair. Modern analytical procedures for the determination of drugs in hair specimens—mainly by gas chromatography–mass spectrometry (GC–MS) and liquid chromatography–mass spectrometry (LC–MS)—are reviewed and critically discussed. Many tables containing information related to this topic are provided.     

Determination of selected elements by X-ray fluorescence spectrometry in liquid drug samples after the preconcentration with thioacetamide

Preconcentration performance characteristics of precipitation of Mn, Fe, Co, Cu, Zn, Pb, Hg, and Cd and with subsequent filtration through cellulose nitrate membrane were investigated for the X-ray spectrometry identification and determination of trace metal ions in drug samples. The method was optimised for several parameters, including pH and amount of thioacetamide. The investigated analyte ions were collected on cellulose nitrate membrane filter (Pragopor 4) as sulphides after the reaction with thioacetamide. Optimal reaction conditions were found out (pH 8.5 for Fe, Zn, Hg, and Cd and pH 11.5 for Mn, Co, Cu, and Pb; 1.2 mL of added thioacetamide). Thereafter, the content of these elements was determined in the samples of drugs—NaCl, glucose and dextrane. The rapidity of this method, its polycomponent character and low detection limits (for filters: Mn—1.09 μg, Fe—1.08 μg, Co—0.82 μg, Cu—0.42 μg, Zn—0.61 μg, Pb—0.45 μg, Hg—0.42 μg, and Cd—0.99 μg) have proved this method to be very promising in rapid screening used in quality control of drugs.     

New terpenoid coumarins from Ferula tadshikorum

Two new terpenoid coumarins — tadzhiferin (I) and tadzhikorin (II) — have been isolated from the fruit ofFerula tadshikorum M. Pimen. On the basis of physicochemical and spectral investigations, the structure of 7-(9′-hydroxy-3′,7′,11′-trimethyldodeca-2′,6′,10′-trienyloxy)coumarin is proposed for (I) and that of 7-(4′-acetoxy-9′-hydroxy-3′,7′,11′-trimethyldodeca-2′,6′,10′-trienyloxy)coumarin for (II).     

Chemical synthesis and enzymatic assembly of fragments of the DNA coding immunodominant epitopes of human immunodeficiency virus

More than twenty 13- to 55-membered oligo(poly)nucleotides have been synthesized by the H-phosphonate solid-phase method in the manual variant using an original procedure. From the oligonucleotides obtained, seven DNA duplexes coding immunodominant epitopes of HIV-1 proteins have been formed: 598–609 and 737–748 gp41, 91–115 and 105–115 gag, and 940–951 pol and a number of its mutants. The ligase assembly and polymerization of the DNA duplexes obtained has been carried out. The efficiency of ligation amounted to from 60 to 90%. The possibility of their directed polymerization was determined by the flanking of the duplexes by partially completed half-sites of restrictases BamHI and XhoI. Abbreviations adopted: HIV-1 — human immunodeficiency virus, type 1; (+)-chain — the coding chain — and (−)-chain the chain complementary to the coding chain of the DNA duplex; CPG — controlled-pore glass; PAAG — polyacrylamide gel; Py — pyridine.     

Intermolecular interactions in 2,4-dinitrophenylhydrazine hydrochloride hydrate: X-ray structural and quantum mechanical study

2,4-dinitrophenylhydrazine hydrochloride hydrate (I) was determined by X-ray crystallography, and the intermolecular interaction energies were calculated in terms of Natural Bond Orbital analysis. The asymmetric unit of (I) consists of a dinitrophenylhydrazinium cation, a chloride anion and a water molecule. The interatomic distances and angles in (I) show no unusual values. In the structure there are intermolecular N—H⊎⊎⊎O, N—H⊎⊎⊎Cl, O—H⊎⊎⊎Cl, C—H⊎⊎⊎O hydrogen bonds with bonding energy ranging form 16.03 to 0.76 kcal mol⁻¹. These hydrogen bonds create the following N1 motifs: 6D, S(5), S(6), C(6), C(9). N₁D motifs become infinite at the third level and are 2C₃²(6), C₃²(7).      

Application of microextraction by packed sorbent to isolation of psychotropic drugs from human serum

A method of microextraction by packed sorbent (MEPS) followed by liquid chromatography with diode array detection has been developed and optimized for the extraction of six tricyclic antidepressants (amitriptyline, nortriptyline, imipramine, desipramine, doxepin, nordoxepin) from human serum. The optimal parameters of MEPS extraction (type of sorbent, volume of sample, composition, and volume of washing and elution solutions) for these drugs in spiked samples were defined. The developed MEPS procedure was validated and then successfully applied to the analysis of serum reference material. The limit of detection (0.02–0.05 μg/mL), intraday (2.7–8.8%) and interday (4.4–11.6%) precision (RSD), and the accuracy of the assay (94.5–108.8%) at three concentration levels—0.2, 0.5, and 0.8 μg/mL—were estimated. The accuracy of the method was evaluated by the analysis of certified reference material. Moreover, the validated procedure was compared with the solid-phase extraction technique. Finally, microextraction by packed sorbent was assessed as a suitable tool in forensic and clinical methods for serum sample preparations.     

Possibilities of determination of alteration degree of rocks by thermogravimetry

Rhyolite-rhyodacite tuff samples were analysed by X-ray powder diffraction, ICP-OES and thermogravimetric (TG) methods to determine mineral and major element composition as well as different types of bound water, respectively. Similarly to CIA values, some TG parameters (H₂O[I] — water released up to ca. 200–220°C; H₂O[III] — water loss above 500–550°C and H₂O[I+III]) show positive correlation to the amount of secondary minerals. Moreover, these parameters are in close positive correlation to CIA values. Our results suggest that TG determination of different types of bound water may serve as a useful tool for estimation and characterisation of alteration degree of rocks.     

Assessing indoor air exposures using passive sampling with bioanalytical methods for estrogenicity and aryl hydrocarbon receptor activity

Passive air sampling was undertaken using polyurethane foam passive air samplers at three types of locations, including indoors (six offices) at buildings in the central business district (CBD) and at a private suburban home (indoor and outdoor) located 9 km from the CBD in Brisbane, Queensland, Australia. Estrogenic (E-SCREEN—MCF7-BOS) and aryl hydrocarbon receptor (AhR) (CAFLUX—H4G1.1c2) activity were assessed for samples collected from each of these locations. The samples were tested either as crude extracts (“untreated”) or were subjected to H₂SO₄ silica gel (“treated”) for each location in order to determine whether chemicals, which are not resistant to this treatment like polycyclic aromatic hydrocarbons, potentially account for the observed activity. In most cases, H₂SO₄ treatment resulted in a statistically significant reduction of potency for both endpoints, suggesting that chemicals less resistant to treatment may be responsible for much of the detected biological activity in these locations. Estrogenic potency measurements (<0.22–185 pg m⁻³) were highest in the indoor offices, followed by the indoor suburban home and finally the outdoor suburban home (which was not estrogenic). Total AhR activity for crude extracts (1.3–10 pg m⁻³) however was highest for the outdoor suburban home site. Levels of polycyclic aromatic hydrocarbons were monitored indoors and outdoors at the suburban home. At that location, polycyclic aromatic hydrocarbon air concentrations were on average approximately two times higher outdoor than indoor, while AhR potency was five times higher outdoor than indoor. No significant correlation was found between the estrogenic and AhR activity (P = 0.88) for the sites in this study. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Comparison of the application of Debye-Huckel and specific ion interaction theories for the complexation of tungsten(VI) with ethylenediaminediacetic acid

Equilibrium of the reaction of tungsten(VI) with ethylenediaminediacetic acid (EDDA) has been investigated in aqueous solution of pH 7.5 and 25°C. All measurements have been carried out at different ionic strengths ranging from (0.1 to 1.0) mol dm⁻³ (NaClO₄). According to our results the metal to ligand ratio is 1: 1. Stability constants and stoichiometry of the complex have been determined from a combination of potentiometric and UV spectroscopic measurements. In this semi-empirical model, two parameters have been introduced in a Debye-Huckel type equation based on the Gauss—Newton nonlinear least-squares method and minimizing the sum of the squares of the errors. Comparison of the ionic strength effect on these complex formation reactions has been made using a Debye-Huckel type equation and Bronsted—Guggenheim—Scatchard specific ion interaction theory (SIT). Published in Russian in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 5, pp. 864–868. The article is published in the original