Detection of estradiol and testosterone in hair of cattle by HPL/EIA

 This study concerns the detection of natural steroid hormones in hair of cattle. Estradiol (E₂) and testosterone (T) were chosen as representatives of estrogens and androgens. In particular, the influence of age, sex and hair pigmentation on the steroid concentrations was investigated. Samples were obtained from numerous steers, cows, bulls, and female and male calves. The extraction procedure for E₂ and T from hair comprised liquid-liquid and solid-phase extraction and was followed by an essential high-performance liquid chromatography (HPLC) step for further purification of the extracts. Final quantification was performed with specific enzyme immunoassays (EIA). Lower E₂-concentrations were detected in the hair of some steers, cows, and bulls (approximately 1 ng/g), in several of these hair samples the concentrations of E₂ were below the limit of detection. Testosterone was measured in the hair of steers (approximately 3 ng/g), cows (approximately 6 ng/g), and bulls (in average 15 ng/g). There was a significant difference in the testosterone concentrations of white (approximately 8 ng/g) and of black hair (approximately 33 ng/g) of bulls. In hair from all male and female calves, E₂ and T were measured. The concentrations amounted approximately to 9 ng E₂/g and 3 ng T/g for female calves and to 5 ng E₂/g and 7 ng T/g for male calves. There was no significant influence of sex or hair colour on the steroid concentrations in hair of calves. The results suggest that the method is a powerful means to detect natural steroid hormones in hair of animal origin. Received: 2 August 1996/Revised: 30 August 1996/Accepted: 5 September 1996     

Cs[Er10(C2)2]I18 und [Er10(C2)2]Br18: zwei neue Beispiele für „reduzierte”︁ Halogenide der Lanthanide mit isolierten [M10(C2)2]-Clustern

Cs[Er₁₀(C₂)₂]I₁₈ and [Er₁₀(C₂)₂]Br₁₈: Two New Examples for Reduced Halides of the Lanthanides with Isolated [M₁₀(C₂)₂] Clusters Cs[Er₁₀(C₂)₂]I₁₈ is obtained from the reaction of ErI₃ with caesium and carbon in sealed tantalum containers at 700°C and [Er₁₀(C₂)₂]Br₁₈ through the metallothermic reduction of ErBr₃ with rubidium in the presence of carbon at 750°C in sealed niobium containers. The crystal structures {Cs[Er₁₀(C₂)₂]I₁₈: triclinic, P1 ; a = 1 105.2(8) pm, b = 1 112.0(7) pm; c = 1 122.9(8) pm; α = 66.91(3)°, β = 87.14(3)°; γ = 60.80(3)°; Z = 1; R = 0.049, R_w = 0.043; [Er₁₀(C₂)₂]Br₁₈: monoclinic, P2₁/n, a = 971.8(6) pm, b = 1 623.4(9) pm, c = 1 163.8(6) pm, β = 104.00(6)°; Z = 2; R = 0.077, R_w = 0.057} contain isolated dimeric [Er₁₀(C₂)₂] clusters. Due to the inclusion of C₂ units, the octahedra are elongated in the direction of the pseudo C₄ axis. The connecting edges of the two octahedra are exceptionally short (316.7 pm and 314.8 pm respectively). The dimeric units are connected via X^i?a and X^a?i (X = Br, I) bridges according to [Er₁₀(C₂)₂XX]X. Cs⁺ is surrounded by a cuboctahedron of iodide ions in Cs[Er₁₀(C₂)₂]I₁₈.     

[(1,4,8,11‐Tetraazacyclotetradeca‐1,4,8,11‐tetrayl)tetraacetamide‐κ6N1,N4,N8,N11,O1,O8]copper(II) sulfate 4.5‐hydrate

The crystal structure of the title copper(II) complex, [Cu(C₁₈H₃₆N₈O₄)]SO₄·4.5H₂O, formed with the tetra­amide cyclam derivative 2‐(4,8,11‐triscarbamoyl­methyl‐1,4,8,11‐tetra­aza­cyclo­tetradec‐1‐yl)­acet­amide (TETAM), is described. The macrocycle lies on an inversion centre occupied by the hexacoordinated Cu atom. The four macrocyclic tertiary amines form the equatorial plane of an axially Jahn–Teller elongated octahedron. Two O atoms belonging to two diagonally opposite amide groups occupy the apical positions, giving rise to a trans‐III stereochemistry, while both the remaining pendant side arms extend outwards from the macrocyclic cavity and are engaged in hydrogen bonds with sulfate anions and co‐crystallized water mol­ecules.     

The mono-, sesqui-, and dibromides of indium: InBr,In2Br3, and InBr2

Of the four reduced indium bromides, InBr, In₂Br₃, InBr₂, and In₄Br₇, synthesis, crystal growth and structure determination of the first three is reported. InBr (orthorhombic), Cmcm, Z = 4, a = 446.6(1), b = 1236.8(2), c = 473.9(1) pm, V_m = 39.42(1) cm³ mol^?1) crystallizes with the TlI-type structure. In₂Br₃ (orthorhombic, Pnma, Z = 16, a = 1300.6(5), b = 1649.8(5), c = 1289.7(9) pm, V_m = 104.16(9) cm³ mol ^?1), isotypic with Ga₂Br₃, is according to In₂[In₂Br₆] a mixed-valence In^I–In^II-bromid with eclipsed [In₂Br₆]^2? groups with d(In–In) = 268.8 and 271.6 pm, respectively. InBr₂(?In[InBr₄]) is a mixed-valence In^I? In^III bromide with the GaCl₂-type structure (orthorhombic, Pnna, Z = 8, a = 798.6(2), b = 1038.5(2), c = 1042.5(5) pm, V_m = 65.09(4) cm³ mol^?1).     

Procedure for the quantification of rider peaks.

Rider peaks are small peaks which are not well resolved from a large and asymmetrical neighbour but sit on its trailing side. The usual case is a large, tailed peak which is eluted just in front of the small peak, although the opposite situation can also occur (a small peak in front of a large peak with fronting). The common integration techniques. i.e. separating the peaks by vertical drop or by a tangent and determining area or height, give erroneous results. We propose a method for their quantification with low error. It is necessary to set up a "two-dimensional" calibration by varying both concentrations, i.e. of the large peak and of the rider. This leads to a series of linear equations which describe the rider size, as found by the integrator, as a function of the size of the large peak. The y-axis intercepts i of these equations show a linear relationship with the concentration x of the rider analyte, whereas the slopes s follow a quadratic relationship. These equations can be used to solve the equation y = s(x) x z + i(x) for x (y and z are the integrated peak size of the rider and the large peak, respectively). The procedure was tested with computer-generated peak pairs as well as with HPLC separations of 2,3-dimethylaniline (large tailing peak) and 2,3-dimethylphenol (symmetrical rider peak).     

Anil-Synthese 22. Mitteilung über die Herstellung von Styryl-und Distyryl-Derivaten des Pyridins

Preparation of Styryl and Distyryl Derivatives of Pyridine 2,4-, 2,5- and 2,6-Dimethylpyridines react with anils of aromatic aldehydes in the presence of dimethylformamide and potassium hydroxide to yield the corresponding distyrylpyridines (‘anil synthesis’). Under the same reaction conditions (4-methylstyryl)pyridines are converted to (stilbenylvinyl)pyridines. Similarly, the Schiff's base derived from pyridine-3-carbaldehyde and p-chloroaniline on treatment with methyl- and p-tolyl-substituted aromatic heterocycles gives the corresponding (heteroaryl-styryl)pyridines, whereas with the Schiff's bases derived from pyridine-2- and -4-carbaldehyde side reactions, such as dimerization followed by disproportionation predominate.