基质固相分散-高效液相色谱分析奶粉中残留的左旋咪唑和甲苯咪唑

研究了奶粉中左旋咪唑和甲苯咪唑药物残留的高效液相色谱分析方法。将基质固相分散与液液萃取相结合,对牛奶中的残留物进行提取净化,反相高效液相色谱进行测定。流动相为V(甲醇)∶V(0.005 mol/L KH2PO4溶液pH 6.0)=70∶30溶液,等度洗脱,紫外检测器检测,柱温为室温时于230 nm波长处以外标法测定。结果表明,左旋咪唑和甲苯咪唑分别在0.18~0.90μg/mL和0.12~0.60μg/mL浓度范围内线性关系良好,左旋咪唑和甲苯咪唑的检测限分别为0.09和0.06μg/mL。分析的添加回收率为69.5%~80.1%。方法具有处理简单、检测快速、准确的特点。     

离子对色谱法测定万乳康注射液中淫羊藿苷和盐酸左旋咪唑含量

建立了反相离子对色谱法同时测定万乳康样品中淫羊藿苷和盐酸左旋咪唑的含量。本法使用Shim-pack VP-ODS色谱柱(250×4.6 mm,5μm),该流动相为65%甲醇(V/V),10.0 mmol/L的十二烷基磺酸钠,pH=3.0;等度洗脱样品中的淫羊藿苷和盐酸左旋咪唑。紫外检测波长270 nm。结果表明:淫羊藿苷测定的线性范围为2.73~54.58μg/mL,加标回收率为99.45%~100.69%,理论塔板数达6 641;盐酸左旋咪唑测定的线性范围为26.23~524.54μg/mL,加标回收率为99.58%~100.23%,理论塔板数5 564。该方法可用于淫羊藿提取物和万乳康样品中的淫羊藿苷和盐酸左旋咪唑的测定。     

超高效液相色谱-串联质谱法测定牛奶和奶粉中残留的左旋咪唑

建立了一种专属、灵敏的超高效液相色谱-串联质谱(UPLC-MS/MS)测定牛奶和奶粉中左旋咪唑残留量的方法。在碱性环境下用乙酸乙酯超声波提取试样中的左旋咪唑,再经稀盐酸反提取、强阳离子交换(SCX)固相萃取柱净化,采用BEHC18超高效液相色谱柱、乙腈-0.1%甲酸(体积比为15∶85)流动相分离,以电喷雾离子源正离子检测方式进行质谱分析。实验结果表明,在2.0～100.0 μg/L浓度范围内左旋咪唑呈良好的线性关系,其相关系数r=0.997。在低、中、高3个浓度添加水平下,左旋咪唑的回收率为64.5%～102.0%,相对标准偏差小于13.1%。牛奶中左旋咪唑检出限为0.4 μg/kg,奶粉中左旋咪唑检出限为2.0 μg/kg。     

饮料、甜橙、药片和尿液中维生素C的流动注射分析——2,6-二氯吲哚酚光度法

流动注射2,6-二氯吲哚酚光度法测定维生素C具有灵敏,快速的特点,检出限为0.5μg/ml,分析速度120样/h,取Vc 40μg/ml时测量的相对标准偏差为±0.5％。测定各类样品中Vc含量获得较好的结果。     

微孔膜气体扩散分离流动注射光度法测定废水中氰化物

研究了利用吡啶-巴比妥酸显色体系反应的中间产物,采用微孔膜气体扩散分离流动注射分析技术测定工业废水中氰化物,该法具有简便、快速并能消除某些干扰的特点。进样频率为65个样/h,检出限为0.02μg/ml,取氰化物2.5μg/ml时测量的相对标准偏差为0.3％(n=20),测定实际样品结果令人满意。     

固相萃取-高效液相色谱法测定鱼/虾生物体中甲苯咪唑及代谢物的残留

建立了同时测定鱼、虾生物体中甲苯咪唑及代谢物-氨基甲苯咪唑和羟基甲苯咪唑残留的分析方法。样品以水和乙酸乙酯提取,正己烷去脂、MCX固相萃取柱净化,高效液相色谱-紫外检测器测定。重点研究了样品前处理方法,并对各种不同的固相萃取柱的净化效果和准确度进行了研究。甲苯咪唑及代谢物在5～200μg/kg的添加水平下回收率为81.4%～95.3%,相对标准偏差为1.9%～8.6%,方法线性范围为10～2000ng/mL。方法检测限为甲苯咪唑:5μg/kg,羟基甲苯咪唑:5μg/kg,氨基甲苯咪唑:10μg/kg。     

在线净化-超高效液相色谱同位素稀释串联质谱法检测蜂蜜中硝基咪唑类及其代谢物的残留

建立了在线净化( TurboFlow, TF)-超高效液相色谱同位素稀释串联质谱法检测蜂蜜中硝基咪唑类及其代谢物(甲硝唑,羟基甲硝唑,二甲硝咪唑,羟基二甲硝咪唑,洛硝哒唑,异并硝唑,羟基异并硝唑,奥硝唑)的方法。以0.1％甲酸溶解样品后,进入TF-超高效液相色谱-串联质谱系统分析,以内标法定量。对影响净化的条件如TF净化柱、流动相、洗脱溶液等进行优化。确定以Cyclone-P为净化柱,Hypersil GOLD aQ为分析柱,乙腈-0.1％甲酸溶液为流动相,电喷雾正离子选择反应监测模式( ESI+)检测。结果表明,在0.1~50μg/L范围内,目标化合物线性关系良好(相关系数均大于0.997),其定量限如下：奥硝唑、异并硝唑为0.1μg/kg;甲硝唑、羟基甲硝唑、二甲硝咪唑、洛硝哒唑和羟基异并硝唑为0.2μg/kg;羟基二甲硝咪唑为1.0μg/kg。本方法在4个水平的添加回收率为73.7％~116.4％,RSD为1.1％~9.1％。本方法简便、快速、结果准确可靠,并成功应用于实际样品中硝基咪唑及其代谢物残留的测定。     

无火焰非色散原子荧光法测定头发,尿及指甲中微量汞

本文研究了无火焰非色散原子荧光法测定头发、尿及指甲中微量汞的方法。方法简便快速、灵敏。在选定的条件下,方法检出限为:头发0.0025μg/g Hg,尿0.0023μg/ml Hg,指甲0.0020μgHg/g。工作曲线线性范围0.001～0.100μg/2ml Hg。相对标准偏差(n=16)小于4％;标准回收率95％～106％。36种共存元素其含量低于允许存在量,不干扰汞的测定。     

两次液液萃取-气相色谱-质谱联用法测定动物肝脏中左旋咪唑残留

建立了液液萃取-气相色谱-质谱联用法测定动物组织中残留左旋咪唑的方法。在碱性溶液中将左旋咪唑盐酸盐转化为左旋咪唑,以乙酸乙酯进行提取;分别以HCl水溶液、氢氧化钾-二氯甲烷体系进行两次液液萃取净化,依次消除提取液中的脂溶性杂质和水溶性杂质,最后进入气相色谱-质谱系统,在选择离子监测模式下,以m/z 148、176、204为定性离子,m/z 204为定量离子进行结构确证和定量检测。结果表明: 左旋咪唑含量在0.25～3.0 mg/L范围内方法的线性关系良好(相关系数为0.999);定量限为5 μg/kg,低于当前国际最低限量标准;在鸡肝、鸭肝、兔肝和猪肝样品中的加标回收率在76%～106%范围内,相对标准偏差(RSD)小于9%。该法简便、稳定性好,无需对样品进行复杂的预处理即可实现对动物肝脏中左旋咪唑残留的快速准确测定。     

直接荧光分光光度法测定天然水中微量铈

采用荧光法测定稀土氧化物中的微量铈,近年来研究得较多。本文提出直接荧光分光光度法测定天然水中微量铈,方法简便、快速、灵敏度较高,检测限可达0.004μg/10ml。在2N盐酸中,最大激发波长为256nm,最大发射波长为358nm。对于高、中、低三个浓度的样品溶液作精密度测定,分别测定12次的变异系数,0,005μg铈/10ml是10.0％,0.121μg铈/10ml是3.0％,1.185μg铈/10ml是2.3％。作质量控制图,各点均在警戒线内。水中常见离子和其他稀土离子不干扰测定,含铁量高的水样可用加三氯化钛溶液(其中钛约为1mg/ml)来消除铁的干扰。对河水、井水样品测定,平均回收率达90％以上。     

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.     

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.     

关于"对‘燃料电池物理及化学性能的有限时间热力学分析方法'的讨论”答复

把有限时间热力学理论用于化学过程的研究,将会得到一系列新的结论,开展这方面的研究是很有意义的.文献[1]以燃料电池为例,在同时考虑化学反应及传热不可逆性的情况下,研究了燃料电池的性能界限,文献[2]指出了文献[1]计算化学反应及传热不可逆性而引起系统与有关环境的总熵产生率的错误以及由此而导致的结论所存在的问题,并进行了富有启发性的分析与讨论.但文献[2]对于系统与有关环境的总熵产生率的计算也是不正确的,由此得到的其它结论自然不能成立.本文将就此情况下系统与有关环境的总熵产生率的计算再次进行讨论,并给出电池功率和效率的有限时间热力学性能界限.     

Regiospecific synthesis of quercetin O-β-d-glucosylated and O-β-d-glucuronidated isomers

Quercetin, the polyphenolic compound, which has the highest daily intake, is well known for its protective effects against aging diseases and has received a lot of attention for this reason. Both quercetin 3-O-β-d-glucuronide and quercetin 3′-O-β-d-glucuronide are human metabolites, which, together with their regioisomers, are required for biological as well as physical chemistry studies. We present here a novel synthetic route based on the sequential and selective protections of the hydroxyl functions of quercetin allowing selective glycosylation, followed by TEMPO-mediated oxidation to the glucuronide. This methodology enabled us to synthesize the five O-β-d-glucosides and four O-β-d-glucuronides of quercetin, including the major human metabolite, quercetin 3-O-β-d-glucuronide.     

Cl+F2→ClF+F和F+ClF′→ClF+F′反应机理的密度泛函理论研究

用密度泛函理论(DFT)B3LYP方法, 在6-311G基组下,计算研究了反应Cl+F2→ClF+F和对称反应F+ClF′→ClF+F′的机理。求得前者的过渡态为三角形,活化能为15.57 kJ*mol-1;后者的过渡态为线形和三角形,活化能分别为11.52和196.25 kJ*mol-1。结果均经过振动分析和IRC计算验证。     

丙三醇浓溶液玻璃化转变与结构松弛参数DSC分析

In order to examine the effects of water contents and heating/cooling rates on the glass transition and the structure relaxation parameters of glycerol/water mixtures, five aqueous solutions (60%, 70%, 80%, 90% and 100%) were investigated using the differential scanning calorimetry. Four scanning rates (10, 15, 20, 25 K/min) were used to obtain the glass transition parameters. The fitting results of plasticization constants indicated that Gordon-Taylor relationship could not be used effectively without considering scanning rates and that point on calorimetric step was chosen as the glass transition temperature. The specific heat changes during glass transition processes were relative not only to water content but also to heating rates. With the increasing of water contents in glycerol aqueous solutions, the structure relaxation activation energies and dynamic fragilities were decreased. Since the thermodynamic fragilities were increased with the increasing of water content, so the dynamic fragility and thermodynamic fragility were changed inversely if the water contents were changed in glycerol/water mixtures.     

Deuterodehalogenation—a mild method for synthesising deuterated heterocycles

We report a mild and efficient method for introducing deuterium into a range of heterocycles by reacting readily available halide analogues in a deuterodehalogenation reaction using D₈-IPA or Et₃SiD under palladium-catalysed conditions.     

The conversion of 2-cyano cyanothioformanilides into 3-aminoindole-2-carbonitriles using triphenylphosphine

2-Cyano cyanothioformanilide 3a reacts with triphenylphosphine in the presence of water to give 2-(cyanomethyleneamino)benzonitrile 4a, 2-(cyanomethylamino)benzonitrile 5, 3-aminoindole-2-carbonitrile 2a and (2-cyanoindol-3-yl)iminotriphenylphosphorane 6a. In the presence of p-toluenesulfonic acid in MeOH the reaction between 2-cyano cyanothioformanilide 3a and triphenylphosphine (2 equiv) gives 3-aminoindole-2-carbonitrile 2a in 90% yield. Under the same conditions 2-(cyanomethyleneamino)benzonitrile 4a gives anthranilonitrile 8a, 3-aminoindole-2-carbonitrile 2a and N-(2-cyanophenyl)formamide 9. In addition, substituted 2-cyano cyanothioformanilides 3b-f react with triphenylphosphine and p-toluenesulfonic acid in MeOH to give 3-aminoindole-2-carbonitriles 2b-f in 63-75% yields. Under analogous conditions 2-cyano-4,5-dimethoxyphenyl cyanothioformanilide 2g gives only 4,5-dimethoxyanthranilonitrile 8g and 4,6,7-trimethoxyquinazoline-2-carbonitrile 14g, but in refluxing dry PhMe in the absence of p-toluenesulfonic acid 2-cyano-4,5-dimethoxyphenyl cyanothioformanilide 3g, (2-cyano-5,6-dimethoxyindol-3-yl)iminotriphenylphosphorane 6g and 2-(cyanomethyleneamino)-4,5-dimethoxybenzonitrile 4g are obtained. The structure of 2-(cyanomethyleneamino)-4,5-dimethoxybenzonitrile 4g is supported unambiguously via independent synthesis and comparison to the isomeric 6,7-dimethoxyquinazoline-2-carbonitrile 15. All new compounds are fully characterised and a tentative mechanism for the transformation of 2-cyano cyanothioformanilides to indoles is proposed.