高效液相色谱柱后化学衍生法测定食品中的VB1及叶酸含量

研究柱后化学衍生荧光检测高效液相色谱分离测定食品中维生素B1和叶酸的方法。采用C18柱,以含有3．5％乙腈的pH5．0磷酸盐缓冲溶液(0．05mol／L)作为流动相反相分离。色谱流出液在柱后与0．4％的过二硫酸钾溶液在线汇合后流经—Teflon管化学反应器时,维生索B1和叶酸转化为强荧光产物,由荧光检测器测定。在最佳条件下,进样20μL,维生素B1和叶酸工作曲线的线性范围分别为0．21～4．2mg／L和0．10～2．0mg／L,峰面积的相对偏差均为2．0％,回收率及实际样品测定结果满意。     

柱前衍生反相高效液相色谱法测定小麦中氨基酸含量

以肌氨酸为内标物,邻苯二甲醛-9-芴甲基氯甲酸酯为柱前衍生剂,用ODS色谱柱在柱温40℃下,采用二元梯度洗脱,DAD检测器在338nm波长处检测,建立了一种利用反相高效液相色谱同时测定小麦籽粒中17种氨基酸的方法。氨基酸浓度在5～800μmol／L范围内,其峰面积与内标物峰面积的比值和氨基酸浓度的线性相关系数均大于0．996;17种氨基酸的加标回收率在97．5％～103．1％范围内。应用本方法对小麦籽粒中氨基酸含量进行测定,取得了较理想的结果。同时,本法还可应用于糙米和玉米等粮食中氨基酸含量的测定。     

氯甲酸2-(9-咔唑)乙基酯柱前衍生化HPLC法用于环境水中脂肪胺测定

利用一种新型的衍生化试剂氯甲酸2-(9-咔唑)乙基酯柱前衍生10种脂肪胺,建立了脂肪胺类化合物的梯度洗脱高效液相色谱分离分析方法,在紫外254nm条件下检测,线性检测范围为50-500μmol／L,检出(S／N=3)为9．5—25μmol／L;对海水及河水中脂肪胺的试验结果表明,建立的方法快速、灵敏度高,可以满足环境检测等方面的需要。     

柱后光化学反应荧光检测高效液相色谱法测定茶叶中的五种菊酯类农药残留

建立了柱后光化学反应荧光检测高效液相色谱法测定茶叶中菊酯类农药残留的方法。采用Hypersil ODS色谱柱，以乙腈／水为流动相、梯度洗脱进行分离。用自制的光化学反应器作为荧光衍生装置，优化了柱后光化学反应的实验条件，并用于茶叶样品中菊酯类农药残留的测定。方法的检出限为0．012～0．048μg／g(干重)；线性范围0．040～8．0μg／g，相对标准偏差3．4％～6．4％(0．1mg／L，n=8)。     

柱前衍生高效液相色谱法测定血清中克拉霉素的含量

建立了2，4-二硝基苯肼柱前衍生反相高效液相色谱紫外检测法测定血清中克拉霉素的含量，将在碱性条件下甲基叔丁基醚的血清萃取物，与2，4-二硝基苯肼在55％酸性条件下反应30min，然后用乙腈-0．05mol/LpH7．2磷酸盐缓冲液（48：52）在Alltima C18色谱柱上进行分离，在340nm检测衍生物。方法的线性范围为0．05～3．2mg／L（r=0．9993）；检出限为30μg/L，绝对回收率大于89％，相对标准差小于10％。本方法已用于克拉霉素在健康受试者中的药代动力学研究。     

柱前衍生化高效液相色谱荧光检测法测定桑叶中的1-脱氧野尻霉素

建立了芴甲氧酰氯(FMOC—Cl)柱前荧光衍生一高效液相色谱法测定桑叶中1-脱氧野尻霉素(DNJ)的方法。桑叶经0．05mol／L,盐酸提取,在pH8．5的硼酸盐缓冲溶液条件下,DNJ反应生成荧光产物,然后用高效液相色谱-荧光检测器测定。流动相为乙腈-0．1％醋酸(55：45,V/V)。线性范围为0．567～34mg／L(相关系数r=0．9999);检出限为0．03mg／L。实验测得桑叶中DNJ含量为0．24％;平均回收率为97．1％,RSD为1．35％(n=6)。     

毛细管区带电泳法对柱前衍生胆汁酸的高效分离研究

以7-氨基-1,3-萘二磺酸作为柱前衍生试剂,采用毛细管区带电泳-光二极管阵列检测器分离测定6种胆汁酸。实验综合考察了缓冲溶液浓度、pH值、温度及添加剂对胆汁酸衍生化产物分离效果的影响。在不加其它添加剂情况下,于25mmol/L的pH为9.5的硼酸盐缓冲溶液中,20℃,5kPa压力下进样,进样时间8s,13min可实现6种胆汁酸的快速高效基线分离。该方法检出限(3σ)为0.022～0.046μmol/L,线性范围为0.07～5μmol/L。     

反相高效液相色谱法测定人血浆中利培酮及其代谢物的质量浓度

建立了测定人血浆中利培酮及其活性代谢物9-羟利培酮质量浓度的反相高效液相色谱方法。用Zor－baxODSC18色谱柱,以V（甲醇）：V（水）：V（1mol／L醋酸铵）：V（3mol／L氨水）＝300：50：3：1为流动相,检测波长为280nm,流速为0．8mL／min。利培酮的线性范围为2～600μg／L（r＝0．996）,回收率为（98．2±3．5）％,日内与日间的标准偏差分别为4．12％和4．83％;9-羟利培酮的线性范围为2～800μg／L（r＝0．998）,回收率为（97．8±3．8）％,日内与日间的标准偏差分别为4．28％和4．81％。     

反相高效液相色谱法测定鼠胆汁中游离与结合型胆汁酸

建立了一种柱前衍生反相高效液相色谱荧光检测大鼠胆汁中游离与结合型胆汁酸的方法.以4-溴甲基-7-甲氧基香豆素为衍生剂,月桂酸为內标,Waters Nova C18色谱柱分离,采用甲醇/乙腈和水梯度洗脱,荧光激发波长(λex)330 nm,发射波长(λem)400 nm,內标标准曲线法定量.各胆汁酸在5-2 400μmol/L范围内线性良好,r为0.998 9-0.999 7.最低检出限为1.2-2.5μmol/L.精密度日内在1.05%-3.67%之间,日间在3.16%-6.83%之间.平均回收率为87.8%-106.7%.该方法灵敏、重复性好,分析时间短,线性范围宽,适合于科研工作中对鼠胆汁中各胆汁酸进行定量检测.     

建筑材料中甲醛含量的柱内衍生HPLC法测定

选用偏二甲肼作柱内衍生剂,利用甲醛与偏二甲肼能在适当的pH值条件下生成有较强紫外吸收的偏二甲腙的实验原理,建立了内墙涂料和胶牯剂中甲醛的柱内衍生高效液相色谱测定方法。实验讨论了甲醛与偏二甲肼反应的机理、pH值对亲核加成反应的影响,估算了流动相的pH值范围为2相似文献   

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.