Mass spectra of complexes of 8-quinolinol with trivalent metals (AL,Ga, In,Sc, Cr and Fe)

The main fragmentation of the compounds MX_3-nox_n (oxH=8-quinolinol. n = 3; M=AL, Ga, In, Sc, Cr or Fe. n = 2; M=In or Fe; X=Cl or Br. InIox₂. n = 1; M=AL, In or Fe; X= Cl or Br) involves loss of X and intact ox_. radicals. The comparative abundances of the fragments are primarily related to the common oxidation states of the metals. For example, all the Mox₃ compounds show the ions [Mox₃]⁺ and [Mox₂]⁺. The ions [Mox]⁺ and [M]⁺ are present when M=Ga, In, Cr or Fe but for the elements with only one oxidation state (Al or Sc) [M]⁺ is absent and [Mox]⁺ has only very low abundance. When M= Cr or Fe metal-containing ions arising from loss of species such as CO, H₂O, HX, C₂H₂, H and OH by fragmentation of the ox ligand are also present; this behaviour is rationalised in terms of the ability of these metals to undergo a unit change in oxidation state. When n=1 the ions [MXox₂]⁺ and [Mox₂]⁺ and when n= 2 the ions [MX₂ox]⁺ and [Mox₃]⁺ are present; these ions arise by ionization and fragmentation of species formed by redistribution reactions in the mass spectrometer.     

Synthesis and Reactivity of the New Chiral Silylphosphite Esters {(+)-O,O-Dimethyl-L-tartrate}POSiR3 (R3 = Ph3, tBuMe2, Et3)

The new, chiral silylphosphite compounds (O,O-dimethyl-L-tartrato)POSiR₃, (R₃ = Ph₃, ^tBuMe₂, Et₃) have been synthesised and their activity as asymmetric phosphonylating reagents investigated.     

Die Methoden zur direkten Messung des osmotischen Drucks

Ohne Zusammenfassung     

Sperm whale three-dimensional track, swim orientation, beam pattern, and click levels observed on bottom-mounted hydrophones

In an earlier paper [Nosal and Frazer Appl. Acoust. 61, 1187-1201 (2006)], a sperm whale was tracked in three-dimensions using direct and surface-reflected time differences (DRTD) of clicks recorded on five bottom-mounted hydrophones, a passive method that is robust to timing errors between hydrophones. This paper refines the DRTD method and combines it with a time of (direct) arrival method to improve the accuracy of the track. The position and origin time of each click having been estimated, pitch and yaw are then obtained by assuming the main axis of the whale is tangent to the track. Roll is then found by applying the bent horn model of sperm whale phonation, in which each click is composed of two pulses, p0 and p1, that exit the whale at different points. With instantaneous pitch, roll, and yaw estimated from time differences, amplitudes are then used to estimate the beam patterns of the p0 and p1 pulses. The resulting beam patterns independently confirm those obtained by Zimmer et al. [J. Acoust. Soc. Am. 117, 1473-1485 (2005); 118, 3337-3345 (2005)] with a very different experimental setup. A method for estimating relative click levels is presented and used to find that click levels decrease toward the end of a click series, prior to the "creak" associated with prey capture.     

Characterization of the flow dynamics of an enzyme reaction system

The characterization of the flow dynamics of an automated enzyme reaction system is discussed. Parametric and non-parametric characterizations are constructed and then tested against actual experiments. The analytical model provides a more compact representation than the numerical model. A second-order lag-plus-dead-time model gives a good fit to the experimental data.     

Extraction of nonstationarity information from correlation noise

A gas chromatograph is used as a model of a monitored process stream, and a method is developed to detect fixed-amplitude changes either in component concentration or system response to a perturbation. The multiple injection input and its advantages are based on the principles of correlation chromatography. The deconvolution of the aperiodic input pattern from the output results in a signal peak representing average system response and correlation “noise” which, when calibrated, gives the direction and magnitude of the change which has occurred. Because of the signal-averaging effect of the multiple inputs and deconvolution process, the effects of random fluctuations and noise are reduced.     

Modifications in the simultaneous determination of carbon,hydrogen, and nitrogen

Summary Improved analytical procedures are presented for the simultaneous determination of carbon, hydrogen, and nitrogen in solid organic materials by the gas volumetric method. The accuracy is improved, and the method is less dependent upon the analyst's technique.

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Zusammenfassung Verbesserte Verfahren für die gleichzeitige gasvolumetrische Bestimmung von Kohlenstoff, Wasserstoff und Stickstoff in festen organischen Verbindungen werden beschrieben. Die Genauigkeit wurde verbessert, und die Ergebnisse sind weniger von der Arbeitstechnik des Analytikers abhängig.

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Résumé On présente une amélioration des procédés analytiques pour le dosage simultané du carbone, de l'hydrogène et de l'azote dans les matériaux solides organiques par la méthode volumétrique gazeuse. La précision est meilleure et la méthode dépend moins de la technique de l'analyste.

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Work was performed under the auspices of the U. S. Atomic Energy Commission.     

Simultaneous determination of carbon,hydrogen, and nitrogen. Part II

Summary An analytical procedure is described which allows the simultaneous determination of carbon, hydrogen, and nitrogen in solid organic materials by gas-volumetric techniques. The accuracy is comparable to that obtained with the more conventional methods.On a routine basis, six to ten complete sets of determinations can be made per 8-hour day. The exact number will depend upon the samples being analyzed and the analyst's skill.

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Zusammenfassung Ein Verfahren zur gleichzeitigen gasvolumetrischen Bestimmung von Kohlenstoff, Wasserstoff und Stickstoff in festen organischen Verbindungen wird beschrieben. Die Genauigkeit ist mit jener der üblichen Verbrennungsverfahren vergleichbar.Bei Serienarbeit können in 8 Stunden sechs bis zehn vollständige Analysen ausgeführt werden. Die genaue Zahl hängt von der Art der Proben und von der Geschicklichkeit des Analytikers ab.

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Résumé On décrit un procédé analytique permettant de doser simultanément le carbone, l'hydrogène et l'azote dans les corps organiques solides au moyen de techniques fondées sur une mesure de volume gazeux. La précision est comparable à celle que l'on obtient avec les méthodes plus conventionnelles.On peut réaliser six à dix séries complètes de dosages en une journée de 8 heures, dans un travail de routine. Le nombre exact dépendra des échantillons que l'on analyse et de l'habileté de l'analyste.

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Part I, UCRL-5134, Chem. Abstr.52, 16 118c (1958).

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This work was performed under the auspices of the U. S. Atomic Energy Commission.     

Solid-state Structures and Solution Behavior of Alkali Salts of the [\hbox{Nb}_{6}\hbox{O}_{19}]^{8-} Lindqvist Ion

The hexaniobate Lindqvist ion has long been known as the dominant specie in alkaline niobium oxide solutions. Recent advances in heteropolyniobate chemistry continue to be greatly aided by use of alkali salts as soluble precursors; in particular, potassium, sodium and lithium hexaniobate salts. We report here the solid-state characterization and solution behavior of Li, K, Rb and Cs Lindqvist salts. Synthesis and single-crystal X-ray diffraction data is reported for nine new hexaniobate salts. These structures differ in the number of charge-balancing alkali cations, protonation of the clusters, relative arrangement of the clusters and alkali metal cations, amount of lattice water and its mode of interaction with other lattice species. Trends of alkali-cluster bonding are observed as a function of alkali radius. Protonation of the clusters in the solid-state is influenced by the method of crystallization of the salt. Lability of the cluster oxygens is observed by solution ¹⁷O NMR experiments. Rates of isotopic enrichment of the bridging oxygen, terminal oxygen and bridging hydroxyl cluster sites are compared for aqueous solutions of Li, K, Rb and Cs hexaniobate salts. Parameters influencing the oxo-ligand exchange rates of the salts are discussed relative to their use as heteropolyniobate precursors.This paper is dedicated to Professor Michael T. Pope on the event of his retirement to acknowledge his fruitful career in polyoxometalate chemistry.     

Identification and quantification of urinary benzo[a]pyrene and its metabolites from asphalt fume exposed mice by microflow LC coupled to hybrid quadrupole time-of-flight mass spectrometry

Prolonged, extensive exposure to asphalt fume has been associated with several adverse health effects. Inhaled polycyclic aromatic hydrocarbons (PAHs) from asphalt fume exposure have been suspected of inducing such effects. In this study, a bioanalytical method was proposed and evaluated to identify and quantify benzo[a]pyrene and its hydroxy-metabolites. This method is based on coupling a microflow liquid chromatography (LC) to a hybrid quadrupole orthogonal acceleration time-of-flight mass spectrometry (Q-TOFMS). In the experiment, thirty-two B6C3FI mice were exposed to asphalt fume in a whole body inhalation chamber for 10 days (4 h day(-1)) and twelve other mice were used as controls. The asphalt fume was generated at 180 degrees C and the concentrations in the animal exposure chamber ranged 175-182 mg m(-3). Benzo[a]pyrene and its metabolites of 3-hydroxybenzo[a]pyrene, benzo[a]pyrene-7,8-dihydrodiol(+/-), benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide(+/-), and benzo[a]pyrene-7,8,9,10-tetrahydrotetrol(+/-) in the urine of asphalt fume exposed mice were identified and found at 3.18 ng 100 mL(-1), 31.36 ng 100 mL(-1), 11.56 ng 100 mL(-1), 54.92 ng 100 mL(-1), and 45.23 ng 100 mL(-1) respectively. The results revealed that the urinary benzo[a]pyrene and its hydroxy-metabolites from exposed mice were at significantly higher levels (p < 0.001) than those from the control groups. Compared with several other technologies such as HPLC-UV and HPLC-fluorescence, the new method is more sensitive and selective, and it can also provide additional useful information on the structures of the metabolites. Hence, this method can be used to perform the assessment and to study the mechanisms of the adverse health effects. The fragmentation patterns established in this study can also be used to identify and quantify PAH metabolites in other biological fluids.