Development of a micro dual beam fluorometric detector specific for microchip analysis of benzo[a]pyrene and benzo[k]fluoranthene in diesel exhaust particulate samples

We developed a device and some systems for detecting benzo[a]pyrene (B[a]P) and benzo[k]fluoranthene (B[k]F). The device uses a UV light-emitting diode that emits light with a wavelength of 370 nm and a violet laser diode that emits light with a wavelength of 395 nm as excitation light sources. The detection method is based on the following observation: characteristic fluorescence is emitted from both B[a]P and B[k]F, with intensities up to 10 times greater than those from 22 other polycyclic aromatic hydrocarbons (PAHs). The excitation and emission wavelengths for fluorescence from B[a]P and B[k]F are 370 and 429 nm, and 395 and 429 nm, respectively. Further, we calculated their concentrations in diesel exhaust particles by means of two calibration curves determined using a mixture of 24 PAHs. The detection limits of the proposed device with a microchip are 5.58 microg L(-1) for B[a]P and 6.03 microg L(-1) for B[k]F. We applied this method to analyze B[a]P or B[k]F contained in three types of diesel exhaust particles, and the results agreed well with those obtained by liquid chromatography.     

Mikroanalyse mit Hilfe von Ionenaustauschern. XXVII

Zusammenfassung Eine Reihe neuer und empfindlicher Harztüpfelmethoden zum Nachweis von Fluoridspuren wird vorgeschlagen. Die Entfärbung farbiger Metallchelate durch Substitution mit Fluorid sowie der Farbwechsel durch Bildung fluorhaltiger ternärer Komplexe an Anionenaustauscherkügelchen schwacher Eigenfarbe lassen sich erfolgreich anwenden. Die Erfassungsgrenze beträgt 85 ng F^– bei der Beryllium(II)-Chromazurol-S-Methode, 57 ng F^– bei der Aluminium-(III)-Hämatoxylin-Methode und 80 ng F^– bei der Cer(III)-Alizarin-komplexon-Methode. Einflüsse störender Begleitionen werden beschrieben.

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Microanalysis with the aid of ion-exchange resins. XXVII

Summary A series of new sensitive resin spot tests for the detection of fluoride is proposed based on the decolorization of the coloured metal chelates by substitution with fluoride as well as the colour change by the formation of ternary fluorocomplexes on the beads of pale-coloured anion-exchange resins. Limits of identification are determined to be 85 ng, 57 ng and 80 ng of fluoride for the tests using beryllium(II)-Chrome Azurol S, aluminium(III)-haematoxylin and cerium(III)-Alizarincomplexone, respectively. Influences of the interfering ions are also studied.

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Vorgetragen bei der 18. Hauptversammlung der Japanischen Gesellschaft für Analytische Chemie, Sapporo, Japan, 2. Oktober 1969. Vortrag Nr. 2D14.     

High-performance liquid chromatographic analysis of beta-carbolines in human scalp hair

A chromatographic method was studied for the quantitation of beta-carbolines in hair as potent biomarkers. Under optimal conditions, human scalp hair was enzymatically digested to release analytes effectively. The hair digests were treated with fluorescamine before serial extractions to inhibit the artifactual production of beta-carbolines during analysis and purify them selectively, followed by reversed-phase high-performance liquid chromatography with fluorometric detection. Hair samples were found to contain beta-carboline and 1-methyl-beta-carboline, which were identified by tandem mass spectrometry, but not their reduced form 1,2,3,4-tetrahydro-beta-carboline and 1-methyl-1,2,3,4-tetrahydro-beta-carboline. Both beta-carboline and 1-methyl-beta-carboline were quantified in the concentration range of 0.1-10.0 ng/ml. Their mean recoveries from hair digests were 70-72%, and the intra- and inter-assay RSD ranged between 6.0 and 10.3% in spiking experiments with standards (1.0 ng/ml). When quantitatively analyzing scalp hair collected from alcoholics, smokers, non-smokers and autistics, beta-carboline and 1-methyl-beta-carboline showed the concentrations of ng/mg levels or less which characterized different hair samples. The proposed method will be useful for detecting the in vivo concentration changes of beta-carbolines associated with alcohol abuse, smoking behavior and neuropsychiatric disorder.     

Colloidal gold nanoparticles as catalyst for carbon-carbon bond formation: application to aerobic homocoupling of phenylboronic acid in water

Gold nanoparticles (<2 nm) stabilized by poly(N-vinyl-2-pyrrolidone) (Au:PVP NPs) were prepared by reduction of AuCl4- with NaBH4 in the presence of PVP and characterized via an array of methods including optical absorption spectroscopy, transmission electron microscopy, X-ray diffraction, X-ray absorption near-edge structure, extended X-ray absorption fine structure, and X-ray photoelectron spectroscopy. We demonstrate for the first time that the Au:PVP NPs act as catalyst toward homocoupling of phenylboronic acid in water under aerobic conditions. Suppression of biphenyl formation under anaerobic conditions indicates that molecular oxygen dissolved in water is intimately involved in the coupling reactions. A mechanism of the aerobic homocoupling catalyzed by the Au:PVP NPs is proposed on the basis of a crucial role of dissolved oxygen, steric effects on the product yields, and the well-established mechanism for the Pd(II)-based catalysts.     

The ruthenium catalyzed N-alkylation and N-heterocyclization of aniline using alcohols and aldehydes

Aniline reacts with saturated and 2,3-unsaturated alcohols in the presence of ruthenium catalyst at 180°C to give N-alkylanilines and 2,3-alkylquinolines in good yields.     

New process for producing cellulose acetate from wood in concentrated acetic acid

To explore further potential applications of acetic acid pulp, an investigation was conducted to develop a direct method for producing cellulose acetate from wood in combination with atmospheric acetic acid pulping. The process consists of delignification, totally chlorine-free bleaching, and esterification, with the concentrated acetic acid aqueous solution being used as only solvent throughout the process. The acetic acid pulp with kappa number of 30 and ISO brightness of 16 was bleached with 5% ozone on pulp to kappa number of 1.4 and brightness of 61. The resulting bleached pulp was further bleached with peracetic acid to kappa number of less than 1.0 and brightness of 68. The final bleached acetic acid pulp was acetylated with acetic anhydride in the concentrated acetic acid for 45 min to produce cellulose acetate with an apparent degree of substitution (DS) of 2.54. Although the product was lower grade compared with commercially available cellulose diacetate because it was prepared from the chemical pulp but not dissolving pulp, the product was almost soluble in acetone. Eventually, the DS of the acetone-soluble fraction was 2.62. The acetone solubility might be attributed to the original acetic acid pulp that had been partially acetylated during the pulping.     

1,3-Dipolar cycloaddition reactions of 3-acylimino-1-methylbenzimidazolium betaines

3-Acylimino-1-methylbenzimidazolium betaines undergo 1,3-dipolar cycloaddition reactions with activated alkenes (methyl acrylate, acrylonitrile, and fumaronitrile) and methyl propiolate to produce 2-substituted 1-methylbenzimidazoles. The transformation involves the initial formation of a 1,3-dipolar cycloadduct followed by the N? N bond cleavage. The primary adducts can be isolated from the reaction with methyl acrylate and acrylonitrile.     

New routes to the v-triazolo[1,5-a]pyridine and pyrazolo[1,5-a]pyridine ring systems

New routes to the v-triazolo[1,5-a]pyridine and pyrazolo[1,5-a]pyridine ring systems are described. Treatment of the N-amine salts of 2-picolinealdehyde oxime or 2-pyridyl ketone oximes with polyphosphoric acid gave v-triazolo[1,5-a]pyridines in fair yields. Treatment of 2-picolyl ketones or their oximes with O-mesitylenesulfonylhydroxylamine produced directly pyrazolo-[1,5-a]pyridines. These reactions were extended to the quinoline cases.     

Thermodynamics of the N2/N3- redox couple in a LiBr-KBr-CsBr melt

Nitrogen electrode reaction has been investigated in a LiBr-KBr-CsBr melt containing Li3N. The reaction N3- --> 1/2N2 + 3e- is confirmed by quantitative analysis of anodically evolved gas. The Nernst relation holds for the rest potential of Ni electrodes at a nitrogen gas pressure, pN2, of 0.05-1.0 atm and an anion fraction of the N3- ions, xN3-, of 0.003-0.010 (anion fraction). Then, the standard formal potential of the N2/N3- couple, , is evaluated to be 0.251 +/- 0.009 V versus Li+/Li (pN2 = 1 atm, xN3- = 1) at 673 K. The dependence of on the temperature (570-730 K) gives a linear relation, whose slope is (-0.930 +/- 0.117) x 10(-3) V K(-1). Thermodynamic quantities for the formation of Li3N in the melt are also estimated.     

Ubiquitous 8 and 29 kDa gold:alkanethiolate cluster compounds: mass-spectrometric determination of molecular formulas and structural implications

The molecular formulas and charge state distributions of thus-far known ubiquitous alkanethiolate-protected gold clusters with core-masses of 8 and 29 kDa were assessed using electrospray ionization mass spectrometry. The 8 and 29 kDa clusters were determined to be composed of single species, [Au38(SCn)24]z and [Au144(SCn)59]z, respectively, with charge states of z >/= 0. Possible geometric structures for Au38(SCn)24 and Au144(SCn)59 are discussed, based on the structures of relevant systems that have been recently determined experimentally and theoretically: [Au25(SR)18]- and Au102(SR)44, in which the Au cores are protected by monomers [-SR-Au-SR-] and/or dimers [-SR-Au-SR-Au-SR-]. Their preferential formation and chemical robustness are proposed as being associated with high stability due to geometric factors, while the Au-thiolate interface takes on common motifs regardless of the underlying Au core.