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1.
报道了用火焰原子吸收光谱法测定裂解汽油中铅的方法。用碘 二甲苯溶液对汽油进行氧化处理,用稀硝酸进行萃取,萃取后浓缩液用原子吸收光谱法进行测定。铅含量在0~7.0μg·ml-1范围内符合比耳定律。对汽油样品进行分析时,相对标准偏差小于3.95%,对样品进行加标回收试验,回收率为97.7%~101.7%,方法的精密度和准确度良好。 相似文献
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《Tetrahedron》2004,60(31):6533-6539
A series of N-methoxy- and N-para-methoxyphenylacetamides simultaneously substituted at the α position by a benzyl and an allyl group have been treated with phenyliodine(III)bis(trifluoroacetate) to generate stabilized N-acylnitrenium intermediates. It has been observed that, when starting from N-methoxy substituted amides, such intermediates are intramolecularly trapped by nucleophilic arene rings to render the quinolinone skeleton. Alternatively, under the same reaction conditions, N-para-methoxyphenylamides afford pyrrolidinone derivatives through an olefin amidohydroxylation process. 相似文献
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Agata Zaremba Katarzyna Waszkowiak Dominik Kmiecik Anna Jdrusek-Goliska Maciej Jarzbski Krystyna Szymandera-Buszka 《Molecules (Basel, Switzerland)》2022,27(10)
This study aimed to determine the use of selected vegetables (pumpkin, cauliflower, broccoli, carrot) as carriers of potassium iodide (KI) and potassium iodate (KIO3) by determining changes in iodine content under various conditions of impregnation as the degree of hydration, impregnated sample temperature, and impregnation time. The influence of these conditions on iodine contents in vegetables after their fortification and storage (21 °C/230 days) was analyzed. The results showed that all selected vegetables could be efficient iodine carriers. However, the conditions of the impregnation process are crucial for fortification efficiency, particularly the degree of hydration and the temperature of the impregnated samples before drying. The results showed that the lowest iodine content was in samples fortified at 4 °C and 1:4 hydration. On the other hand, the highest reproducibility of iodine was for the following fortification conditions: temperature of −76 °C and hydration of 1:1. The studies confirmed the higher stability of iodine in KIO3 form compared to KI. To increase recovery of the introduced iodine in the product after drying, using the conditioning step at 4 °C is not recommended. We recommend freezing vegetables immediately after the impregnation process 相似文献
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In studies of metabolism using serum albumin labelled with iodine (I131 and I125) the question of the biological equivalence of the labelled material is of decisive importance. Changes of the chemical and biological characteristic of various proteins after iodination have been found by a number of workers [1–4], especially with reference to chromatographic behaviour, rate of metabolism in the organism and content of thiol. Oxidation of sulphhydryl groups can lead to interchain disulphide bridge-linkage and the formation of molecule aggregates. 相似文献
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A reliable method for direct synthesis of β‐dichlorosubstituted acetanilides is reported. The key transformation involves the oxidative and catalytic cleavage of a carbon‐carbon bond in the presence of iodine trichloride (ICl3). In this protocol ICl3 is used not only as the catalyst but also as the oxidant which widely broadens the scope of its application in organic synthetic chemistry. 相似文献
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An effective and environmentally benign benzylic oxidation for transition of alkylarenes into the corresponding carbonyl compounds was reported.Alkylarenes were mixed and stirred with potassium bromide,m-chloroperbenzoic acid and a catalytic amount of iodobenzene in water at 60 8C for several hours,a series of the corresponding carbonyl compounds was obtained in moderate to good yields.In the reaction,iodobenzene was first oxidized by m-chloroperbenzoic acid into the hypervalent iodine intermediate which then reacted with potassium bromide to form the key radical initiator for the benzylic oxidation. 相似文献
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H. Herzmann 《Isotopes in environmental and health studies》2013,49(2):45-52
Radioaktiv markierte Präparate haben in denletzten Jahren in schnell zunehmendem Maße Eingang in die klinische Medizin gefunden. Sie sind beieiner Reihe von Indikationen schon jetzt außerordentlich wertvolle Hilfsmittel bei der Diagnose, besonders bei der Prüfung von Organfunktionen. 相似文献