Transformations in occluded light fraction organic matter in a clayey oxisol: evidence from 13C-CPMAS-NMR and delta13C Signature
نویسندگان
چکیده
منابع مشابه
Elemental quantitation of natural organic matter by CPMAS 13C NMR spectroscopy.
Cross-polarized magic-angle-spinning NMR (CPMAS-NMR) techniques are assumed to be only semi-quantitative in the assessment of carbon distribution in humic substances or natural organic matter, due to a number of interferences such as spinning side bands (SSB) in spectra, paramagnetic species in samples, and low or remote protonation of aromatic carbons. Fast rotor spin rates or direct polarizat...
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Cigarette butts (CBs) are the most common type of litter on earth, with an estimated 4.5 trillion discarded annually. Apart from being unsightly, CBs pose a serious threat to living organisms and ecosystem health when discarded in the environment because they are toxic to microbes, insects, fish and mammals. In spite of the CB toxic hazard, no studies have addressed the effects of environmental...
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Various organic constituents extracted from wheat and from soil organic matter have been analysed for their carbon content, their absolute concentration and their stable carbon isotope ratios. Most organic subfractions from plants, or soil, are 13C-depleted by up to 9.4‰ relative to bulk organic matter, mainly as a result of their higher lipid content. Furthermore, soil organic constituents are...
متن کاملAdvanced CPMAS-13C NMR techniques for molecular characterization of size-separated fractions from a soil humic acid.
A humic acid extracted from a volcanic soil was subjected to preparative high-performance size-exclusion chromatography (HPSEC) to reduce its molecular complexity and eleven different size fractions were obtained. Cross-polarization magic-angle spinning 13C NMR (CPMAS 13C NMR) analysis performed with variable contact-time (VCT) pulse sequences showed that the largest molecular-size fractions co...
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در این پروژه ترکیبات 3-آریل-2h-بنزو[b]-4،1-اکسازین ها از مواد اولیه تجاری مشتقات دو آمینو فنول و ?-هالو کتون های آروماتیک در مایع یونی 1-اکتیل-3-متیل ایمیدازولیوم تترا فلورو بورات([omim]bf4) سنتز شده است. این واکنش توسط باز پتاسیم کربنات محلول از طریق o-آلکیلاسیون و سپس یک واکنش آمیداسیون درون مولکولی خود بخود در مدت زمان کوتاه انجام می شود. ترکیبات 4،1-بنزوکسازین به این روش با بهره خوب تا آلی ...
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ژورنال
عنوان ژورنال: Revista Brasileira de Ciência do Solo
سال: 2004
ISSN: 0100-0683
DOI: 10.1590/s0100-06832004000500003