气相色谱-质谱法测定脂肪酸含量

提出了气相色谱-质谱法测定棕榈酸、硬脂酸、油酸、亚油酸等4种脂肪酸含量的方法。脂肪酸样品与甲醇在硫酸介质中进行衍生化反应后的产物用正己烷定容。在气相色谱分离中用J&W DB-WAX毛细管柱为固定相,在质谱分析中采用全扫描和选择离子监测模式。4种脂肪酸在一定的质量浓度范围内与峰面积呈线性关系,检出限(3S/N)和测定下限(10S/N)分别在4.42～22.5mg.L-1和14.7～75.0mg.L-1之间。方法已用于油脚制备混合脂肪酸过程中主要脂肪酸成分的测定。     

自动顶空-气相色谱-质谱法测定血液中乙醇含量

提出了自动顶空-气相色谱-质谱联用检测血液中乙醇含量的方法。取一定量的血样或乙醇标准样品置于顶空瓶中(其中各加固定量的叔丁醇作为内标),在60℃及中速振摇的条件下平衡20 min,通过进样环定量地将一定量样品引入于气相色谱-质谱联用仪器中进行测定。乙醇和叔丁醇的保留时间分别为1.47 min和1.56 min。方法的线性范围为0.01~10.00 g.L-1,检出限(3S/N)为0.6 mg.L-1,测定下限(10S/N)为1.0 mg.L-1。乙醇的回收率在92%~105%之间,测定值的相对标准偏差(n=6)小于7%。     

氧弹燃烧-离子色谱法测定原油中氯和溴

采用氧弹燃烧法对原油样品进行燃烧,然后用碳酸钠-碳酸氢钠溶液作为吸收液进行吸收,并提出了离子色谱法分离测定原油中氯和溴的含量的方法。以Dionex IonPac AS23型分离柱为离子交换柱,以4.8mmol·L-1碳酸钠-1.0mmol·L-1碳酸氢钠溶液为淋洗液等度洗脱。氯和溴的质量浓度均在0.01～1mg·L-1范围内与其峰面积呈线性关系,方法的检出限(3S/N)分别为0.3mg·kg-1与0.7 mg·kg-1。方法用于原油样品分析,测定值的相对标准偏差(n=6)在3.5%～4.2%之间,回收率在91.8%～109%之间。     

高效液相色谱法测定保健食品中α-硫辛酸含量

提出了高效液相色谱法测定保健食品中α-硫辛酸含量的方法。样品用乙腈-水(4+6,预调至pH 3.5)混合液超声提取25min,以C18色谱柱为分离柱,以上述乙腈-水混合液为流动相,在波长210nm处进行测定。α-硫辛酸质量浓度在20.0~500mg·L-1范围内与峰面积呈线性关系,方法检出限(3S/N)和测定下限(10S/N)分别为0.80mg·L-1和2.7mg·L-1。以空白样品为基体进行加标回收试验,所得回收率在91.5%~98.7%之间,相对标准偏差(n=5)小于5.0%。     

气相色谱法测定离子液体中间体中N-甲基咪唑残留量

采用气相色谱法对离子液体中间体中N-甲基咪唑残留量进行测定。以N,N-二甲基苯胺作为内标,采用DB-FFAP石英毛细管色谱柱(30 m×0.32 mm,0.25μm)分离,用氮磷检测器测定。N-甲基咪唑的质量浓度在0.02~0.140 g.L-1范围内与其峰面积呈线性关系,检出限(3S/N)为6.52 mg.L-1,测定下限(10S/N)为21.73 mg.L-1。在两个浓度水平作回收试验,平均回收率(n=5)分别为96.4%,96.2%,测定结果的相对标准偏差(n=5)为0.88%。     

超高效液相色谱-串联质谱法快速测定化妆品中水杨酸

提出了超高效液相色谱-串联质谱法测定化妆品中水杨酸含量的方法。化妆品试样用甲醇溶解,振荡提取20 min,离心分离取上清液过ACQUITYTMBET C18色谱柱(2.1 mm×100 mm,1.7μm)并用乙腈和甲酸-水(0.3+99.7)溶液(体积比6比4)的混合溶液作为流动相进行分离,串联质谱法进行测定。采用正离子模式多反应监测,同位素内标法定量。水杨酸的线性范围为1.0~5.0×103μg.L-1,方法的检出限(3S/N)为0.15μg.L-1,测定下限(10S/N)为0.50μg.L-1。方法用于分析8种化妆品试样,回收率在97.3%~107.0%之间,相对标准偏差(n=5)在2.0%~3.8%之间。     

气相色谱法测定水样中三唑磷残留量

用气相色谱法对水样中残留的三唑磷的含量进行测定.水样经苯提取,采用HP-5毛细管色谱柱(30 m×0.32 mm,0.25 μm)分离,用氮磷检测器测定.三唑磷的质量浓度在0.0051.0 mg·L-1范围内与其峰面积呈线性关系,检出限(3S/N)为3.5 μg·L-1.方法的回收率在94.0%～97.5%之间,测定结果的相对标准偏差(n=6)小于3.7%.     

电感耦合等离子体原子发射光谱法测定铅锑合金中锑

采用电感耦合等离子体原子发射光谱法对铅锑合金中锑含量进行测定。样品经硝酸(1+1)溶液和200 g.L-1酒石酸溶液溶解,选择206.833 nm的谱线作为测定锑的分析线。锑的质量浓度在5.0~100.0 mg.L-1之间与其谱线强度呈线性关系。测定下限(10S/N)为0.179 mg.L-1。在优化的试验条件下,分析了两种铅锑合金样品,加标回收率分别为97.8%及98.6%,相对标准偏差(n=11)小于1.5%。     

顶空气相色谱法测定骨水泥中甲基丙烯酸甲酯释放量

提出了以乙酸乙酯为内标测定骨水泥中甲基丙烯酸甲酯(MMA)的释放量的顶空气相色谱法.对平衡温度、平衡时间进行了试验并对顶空条件予以优化.在0.3～15.0 mg·L-1的质量浓度范围内绘制标准曲线,同时加入1.05 mg·L-1内标溶液以提高测定的准确性.结果表明:在考察的浓度范围内线性关系良好,检出限(3S/N)为94.5 μg·L-1.样品中加入1.05 mg·L-1甲基丙烯酸甲酯标准溶液进行回收试验,平行测定5次,所得回收率为97.6%～101.8%,相对标准偏差小于2%.在模拟手术条件下,骨水泥中的甲基丙烯酸甲酯在20 min以后释放总量达到平衡.     

电感耦合等离子体原子发射光谱法测定易切钢中铅含量

采用电感耦合等离子体原子发射光谱法对易切钢中铅的含量进行测定,样品经硝酸-盐酸(1+1)混合酸溶解,选择220.353 nm波长为测定铅的分析线,铅的质量浓度在2.00～20.00 mg·L-1范围内与其谱线强度呈线性关系,测定下限(10S/N)为0.03 mg·L-1.该方法用于两个标准样品(GSBH 40064-93和GSBH 40061-93)中铅含量的测定,加标回收率在97.1%～99.1%之间,相对标准偏差(n=11)小于0.8%.     

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.