ICP－AES中无机酸效应与OH带强度相关性研究

本文用干扰因子法对ＩＣＰ－ＡＥＳ中无机酸的非光谱干扰进行了讨论，特别是对元素干扰因子与ＯＨ带干扰因子之间的相关性作了较深入探讨。由此建立了元素干扰因子与ＯＨ带干扰因子之间的线性回归方程，并以ＯＨ带作为通用内参比线来校正无机酸效应引起的干扰。为了验证此种校正方法是否可行，我们对不同酸浓度的人工合成样品进行校正，校正后的回收率在８０％—１２０％之间，基本符合痕量分析要求，证明此种校正方法是可行的。     

ICP－AES中内标法的应用研究 Ⅲ．用内标法校正基体干扰

通过观测基体对分析元素发射强度的干扰情况，分析干扰机制，从而确定用来校正基体干扰的内标元素与分析元素的匹配条件。实验结果表明，只要选择合适的内标元素，可以校正基体干扰。     

石墨炉原子吸收光谱法测定血铅的干扰校正

研究了用石墨炉原子吸收光谱法测定血铅的干扰校正方法。通过对测定过程中的干扰研究，建立了一种数学校正干扰的标准加入法基体匹配工作曲线。用本法分析健康儿童血铅及脐带血铅，线性范围为０￣９０ｎｇ／Ｌ，相关系数为０．９９９７，灵敏度为８．６ｐｇ／１％信号，检出限为４．８ｐｇ，与一般标准加入法工作曲线相比较，测定血铅线性斜率大，灵敏度高，准确性好。     

亚硝基红盐吸光光度法同时测定铜铁钴

研究在ＰＨ５时，以亚硝酸红盐为显色剂在同一份溶液中分别测定铜、铁、钴，７２０ｎｍ测定铁时钴不干扰，铜干扰用Ｋ系数校正，Ｆｅ－ＮＲＳ络合物在４７０－５６０ｎｍ无吸收，钴、铜测定波长选在５５０、４９０ｎｍ，用Ｋ系数相互校正干扰，方法简便快速，相对标准偏差≤６％，     

等离子体质谱法测定地质样品中痕量稀土元素的基体效应 …

采用模拟地质样品中稀土元素间天然组成比的基体匹配校正标准溶液进行外标校正,有效地抑制了地质样品分析中的基体效应,以＾１１５Ｉｎ－＾１０３Ｒｈ双内标元素校正,监控和校正分析信号的短期和长期漂移;通过单个稀土元素及钡的氧化物,氢氧化物的测定计算出等效的干扰浓度,进而校正了稀土元素分析中多原子离子干扰。建立了地质样吕吕痕量稀土元素测定中基体效应及多原子离子干扰的校正方法。通过对５个标准参考物质的分析,定     

光电二极管阵列等离子体原子发射光谱分析背景智能化实…

提出了用于光电二极管阵列等离子体原子发射光谱分析背景智能化实时校正的方法，采用二次微分结合原ＩＣＰ光谱法，在不经微分噪声过滤的基础上，实现快速准确的谱线识别，简单背景采用多项式模型，结构背景及翼展干扰采用概率统计模型，通过对高浓度Ｃａ存在下Ａｌ用Ｌａ的测定，表明本方法能够准确地校正背景干扰。     

ICP—AES中稀土元素Q数据的编辑与Q光谱的模拟

研究了一种将实验数据与计算机模拟相结合的方法，编辑Ｑ数据和模拟Ｑ光谱，从而预测和校正用ＩＣＰ－ＡＥＳ分析稀土元素时的光谱干扰，首先通过实验获得每一稀土元素的原始光谱数据，然后用光谱平均结合Ｋａｌｍａｎ平滑剔除噪声，并校正波长漂移，最后将处理的光谱数据转为Ｑ数据，用于光谱模拟和光谱干扰校正，讨论了光谱模拟和干扰校正中的一些基本问题，结果表明；当光谱干扰不很强时，Ｑ数据用于光谱干扰校正已足够准确，光谱     

浅析锡对电感耦合等离子体质谱法测定镉的干扰

在不同的工作条件下,分析了不同Sn(锡)/Cd(镉)比值下Sn对电感耦合等离子体质谱法(ICP-MS)测定Cd的干扰程度,并将经过在线干扰校正和离线干扰校正后的Cd浓度与标准值比较,实验结果表明:当样品中Sn浓度与Cd浓度比值在2以下时,Sn对Cd的干扰很小,Cd的测定值不用经过任何方式校正也比较接近标准值;当Sn浓度与Cd浓度比值在2~30时,采用离线校正和在线校正后的Cd测定值与标准值均比较接近;当Sn浓度与Cd浓度比值大于30时,采用离线校正才能获得更满意的结果。     

等离子体质谱法测定地质样品中痕量稀土元素的基体效应及多原子离子干扰的校正研究

采用模拟地质样品中稀土元素间天然组成比的基体匹配校正标准溶液进行外标校正,有效地抑制了地质样品分析中的基体效应;以¹¹⁵In-¹⁰³Rh双内标元素校正,监控和校正分析信号的短期和长期漂移;通过单个稀土元素及钡的氧化物、氢氧化物的测定计算出等效的干扰浓度,进而校正了稀土元素分析中多原子离子干扰.建立了地质样品中痕量稀土元素测定中基体效应及多原子离子干扰的校正方法,通过对5个标准参考物质的分析,定量测定限为0.0090.133μg·g^-1,RSD小于5%.     

原子荧光光谱法测定区域地球化学调查样品中硒的干扰校正

氢化物发生-原子荧光光谱法(HG-AFS)是测定土壤样品中硒(Se)的理想方法，常用SePb合金材质的空心阴极灯为激发光源，无色散系统的AFS测硒时存在铅的光谱干扰，但尚未引起广泛关注。本文研究了高浓度Pb对硒测定的影响，并提出一种干扰校正的方法，可对检测结果进行有效校正。同时对还原剂浓度和消解酸的比例进行了优化，在2~40 ng/mL范围内获得Se标准曲线r2=0.9989，检出限为0.0023 ug/g，方法精密度为2.9-9.8%，准确度ΔlogC小于0.035。对南疆铁门关区域地球化学调查样品进行了测定，校正后Se的检测结果合格率为94.0%。此方法具有操作简单、准确高效，能够有效的校正样品中高浓度Pb的干扰，适合于大批量区域地球化学调查样品的检测。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.