A new PVC membrane strontium ion-selective electrode has been constructed using 6-(4-nitrophenyl)-2-phenyl-4,4-dipropyl-3,5-diaza-bicyclo[3,1,0] hex-2-ene (NPDBH) as a neutral ionophore. The electrode was prepared with 7% NPDBH (as ionophore), 57% acetophenone (as plasticizer), 30% PVC and 6% oleic acid (as lipophilic additive). The electrode responds to Sr2+ ion with a sensitivity of 28.2+/-0.5 mV/decade over the range 1.0 x 10(-6)-1.0 x 10(-1) mol L(-1) and in a pH range of 3.0-10.0. The limit of detection was 2.4 x 10(-7) mol L(-1). It has a response time of <20s and can be used for at least three months without any divergence in potentials. The proposed electrode shows good discrimination of Sr2+ ion from several cations. The effect of organic solvents on electrode response was examined. The results show that this electrode can be used in ethanol media up to 15% (v/v) concentration without interference. The isothermal temperature coefficient of this electrode amounted to 0.00019 V/ degrees C. The electrode was found to work well under laboratory conditions. It was successfully applied to the determination of strontium ions in human urine and bone digests.
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http://dx.doi.org/10.1016/j.talanta.2007.05.034 | DOI Listing |
Chem Sci
May 2023
Institut für Anorganische Chemie, Universität Stuttgart Pfaffenwaldring 55 70169 Stuttgart Germany
Electron-deficient, -aromatic 2,5-disilyl boroles are shown to be a flexibly adaptive molecular platform with regards to SiMe mobility in their reaction with the nucleophilic donor-stabilised precursor dichloro silylene SiCl(IDipp). Depending on the substitution pattern, selective formation of two fundamentally different products of rivalling formation pathways is achieved. Formal addition of the dichlorosilylene gives the 5,5-dichloro-5-sila-6-borabicyclo[2.
View Article and Find Full Text PDFOrg Lett
October 2022
Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588, Japan.
A traditional cobalt catalyst system still contains undiscovered reactivity. Depending on the tertiary phosphines and substrates used, the catalytic system using CoBr/tertiary phosphine/Zn/ZnI catalyzes divergent cycloadditions of internal alkynes with conjugated dienes, yielding 3-alkenylcyclobut-1-enes, bicyclo[3.1.
View Article and Find Full Text PDFA new series of flexible 5'-norcarbocyclic aza/deaza-purine nucleoside analogs were synthesized from 6-oxybicyclo[3.1.0.
View Article and Find Full Text PDFJ Am Chem Soc
December 2020
Institut für Anorganische Chemie, Georg-August Universität Göttingen, Tammannstraße 4, 37077 Göttingen, Germany.
Metathesis reaction of a dilithio borole dianion, a cyclic π-ligand isoelectronic to ubiquitous cyclopentadienyls, with two equivalents of "silicocenium" cation [Cp*Si] as a source of low-valent Si(II), cleanly gives a borole half-sandwich π-complex of Si(II) and silicocene. The resulting half-sandwich complex is a neutral isoelectronic analogue to the iconic silicocenium cation and features the rare structural motif of an apical silicon(II) atom with an energetically high lying lone pair of electrons that is shown to be accessible for coordination chemistry toward tungsten carbonyl. Protonation at the Si(II) atom with [H(OEt)][Al{OC(CF)}] induces formal oxidation, and the compound rearranges to incorporate the Si atom into the carbocyclic base to give an unprecedented cationic 5-sila-6-borabicyclo[2.
View Article and Find Full Text PDFFood Chem
January 2019
Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China; Sino-African Joint Research Center, Chinese Academy of Sciences, Wuhan 430074, China. Electronic address:
Volatile aroma of kiwifruit is a mixture of complicated and time-dependent compounds, and thereby the study of these compounds required distinguished analytical techniques as well as robust data analysis techniques. In this work, we report on the volatile fingerprints and biomarkers of three representative kiwifruit cultivars with commercial importance using headspace solid-phase microextraction gas chromatography-mass spectrometric (HS-SPME-GC-MS) coupled with multivariate analysis. As a result, 95 volatiles have been analyzed from the fingerprints, and ultimately six of which were identified as volatile biomarkers of the kiwifruit cultivars studied, which are formic acid octyl ester, 2-Methylbicyclo[4.
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