Identification of soy protein in meat by pyrolysis-high-resolution gas chromatography

Pyrolysis-gas chromatography was applied to the characterization of ground beef and soy protein isolate and its mixtures at the 50, 30 and 10% levels. A cryogenic trap pyrolysis mode was employed and the volatile pyrolysates were analysed by a high-resolution capillary gas chromatograph. Two phenolic derivatives, o-methoxy- and dimethoxyphenol, as well as 2,3-dithiabutane are uniquely observed at a large concentration in the soy pyrolysate. Quantification of these characteristic compounds allow the estimation of the level of soy inclusion in the mixture. This approach effectively denotes soy addition up to the 10% level in comminuted beef.     

Molecular structures of two unexpected metal complexes obtained from additions of coordinated phosphines to acetylenes

The syntheses and structures of two new compounds are reported. The first compound, [Cr(CO)₄]₂[C₄F₂(PPh₂)₄], obtained from Cr(CO)₄(PPh₂H)₂ and CF₃CCF₃ in the presence of one equivalent of BuLi has a structure with the ligand 1,2,3,4-tetrakis(diphenylphosphino)-1,4-difluorobutadiene chelating to two Cr(CO)₄ groups via the 1,4 and 2,3 phosphine groups. A mechanism for the formation of this compound is suggested which involves sequential deprotonation of a phosphine, nucleophilic attack on the fluorocarbon, and fluoride ion elimination. The second compound, CrC₃₆H₂₈P₂O₇, arises from a similar base promoted reaction of Cr(CO)₄-(PPhH₂)₂ and PhCCCOOEt. Here the expected initial product from cyclization of these reactants acts as a nucleophile to attack a second equivalent of the acetylene. The intermediate carbanion from this reaction can undergo a ring closure by displacement of OEt^-, giving the observed product.     

The mass spectra of substituted 2-methylbenzophenones

The mass spectra of some methoxy and methyl derivatives of 2-methylbenzophenone have been examined. Loss of a substituents from 3′-and 4′-positions as well as the previously known loss from 2′-positions are important fragmentation processes. Thus, these fragmentations are of little use in locating substituents on benzophenones of unknown structure. Deuterium labelling shows the [M - 1]⁺ ion from 3′,4,4′,5,5′-pentamethoxy-2-methyl benzophenone to be due largely to loss of hydrogen from 2′- and 6′-positions.     

Studies on indian medicinal plants-XLIV: Solanoforthine,a new steroidal alkaloid from solanum seaforthianum. a note on the mass spectrum of solanocapsine

The structure of solanoforthine, m.p. 208–10°, [α]_D- 26.6°, a new steroidal alkaloid isolated from Solanum seaforthianum Andr., has been established as 3β-amino-22,26-epimino-16α,23-epoxy-22αH,25βH-cholest- 5- en -23β - ol 3, based on chemical and spectroscopic evidence and by its reduction to solanocapsine 2, another steroidal alkaloid encountered in the same species. The mass spectra of2 and 3 are discussed.     

Tetragonal paramagnetic complex in Gd3+ doped Nd2(SO4)3·(NH4)2SO4·8H2O au]V.M. Malhotra

EPR studies of Gd³⁺ doped in single crystals of Nd₂(SO₄)₃·(NH₄)₂SO₄·8H₂O (hereafter referred to as NASO) at room (RT) and liquid nitrogen (LNT) temperatures exhibit that (1) the metal aquo complex has a tetragonal symmetry with abnormally low magnitudes of crystalline field parameters at RT and (2) NASO undergoes a possible phase transition between RT and LNT.     

Miscibility of small colloidal spheres with large polymers in good solvent

Nearly athermal colloid-polymer mixtures were studied in the "protein limit." A fluid-fluid transition was observed in mixtures of stearyl-alcohol-coated silica particles and large polystyrene coils in toluene. The ratios of the polymer radius of gyration to the particle radii were q=4.1 and q=5.2. The binodal curves and the critical points were determined. Turbidity measurements and analysis for one set of particles allowed the systems to be mapped onto hard sphere-polymer mixtures. A comparison with recent predictions for the miscibility of model mixtures shows that the experimental binodals lie between the two extreme results for ideal and interacting polymers. The critical colloid volume fraction is also found to decrease with increasing size ratios.     

Detection of primary and secondary amines in energy-related materials using an element-selective glow-discharge detector

Mutagenic primary polycyclic aromatic amines present in shale oil and synthetic crudes may be readily detected by a simple derivatization and Chromatographic procedure. Nitrogenous bases and amines are extracted from the sample with dilute mineral acid and derivatized with trifluoroacetic anhydride. The derivatized amines are separated by gas chromatography and specifically detected using a glow-discharge detector tuned to an emission wavelength of fluorine. Under these conditions, the aromatic nitrogenous bases, such as acridine, are not detected even though they are present in the sample. As little as 14 ng of fluorine, arising from the derivative of 33 ng of 2,4,6-trimethylaniline, can be detected. The selectivity of the glow-discharge detector for derivatized amines vs. nonderivatized aromatic nitrogenous bases was estimated to be a minimum of 200:1.     

1H-imidazo[4,5-b] pyrazines. II. 2-carboxylic acid derivatives

Methods for the preparations of 1H-imidazo[4,5-b]pyrazine-2-carboxylic acid and derivatives are reported.     

Trimethylsilylverbindungen der Vb-Elemente. VI. Synthese,Molekül- und Kristallstruktur des Tetrakis(trimethylsilyl)distibans im Vergleich mit Tetraphenyldistiban

Trimethylsilyl Derivatives of Vb-Elements. VI. Synthesis, Molecular and Crystal Structure of Tetrakis(trimethylsilyl)distibine Compared with Tetraphenyldistibine Tetrakis(trimethylsilyl)distibine already isolated by Breunig et al. [9] from cleavage reactions of tris(trimethylsilyl)stibine may also be obtained in high yields from lithium bis(trimethylsilyl)antimonide · 2THF and 1,2-dibromoethane in n-pentane. This compound intensely red in the solid state, but only slightly yellow in solution or in the melt crystallizes in the monoclinic space group P2₁/c with a = 680.6(1); b = 1672.8(2); c = 1190.0(1) pm; β = 119.01(5)°; Z = 2 at +20°C. An X-ray structure determination (R = 0.017) shows the bis(trimethylsilyl)-stibino groups to be arranged in a transoid position. Characteristic bond lengths and angles are: Sb? Sb 286.7(1); Sb? Si 259.4 pm; Si? Sb? Si 94.46(3); Sb? Sb? Si 98.68(3) and 94.43(3)°. As in similiar 2,2′,5,5′-tetramethyldistibolyl published recently by Ashe III et al. [8] this crystal structure, too, is characterized by a nearly linear sequence of Sb? Sb groups. Compared with the sum of van-der-Waals radii the intermolecular Sb-Sb contact in such a chain is shortened from 440 to 399 pm. This probably allows electronic interactions of unknown type responsible for the colour of the crystals. In keeping with this assumption an analogous formation of chains is not found in solid, only yellow tetraphenyldistibine 5 the structure of which has already been studied by Rehder et al. [44].