反相高效液相色谱法同时测定血清、尿液中尿酸、肌酐的含量

建立了同时测定人体血清、尿液中肌酐、尿酸含量的高效液相色谱分析方法。采用Hypersil ODS C18色谱柱,甲醇(A)-20 mmol/L乙酸铵(B)为流动相,梯度洗脱,流速1.0 mL/min,UV检测,检测波长235 nm。血清中肌酐、尿酸含量在2~20μg/mL范围内线性关系良好,尿液中肌酐、尿酸在5~1000μg/mL范围内线性关系良好;平均加标回收率在86.7%~99.0%,RSD小于5%。选择甲醇-乙酸铵作为流动相进行血清/尿液中肌酐、尿酸含量测定具有快速简便的特点,方法应用于健康人和糖尿病病人血清/尿液样本的测定,可以对临床病人进行快速监测。     

超高效液相色谱-串联质谱法测定蜂蜜中胆碱和乙酰胆碱

建立了超高效液相色谱-串联质谱同时测定蜂蜜中胆碱和乙酰胆碱的分析方法.试样采用水-乙腈(体积比2:3)溶液提取,乙腈-水(体积比8:2)稀释后以0.22μm滤膜过滤上机测定.采用ACQUITY UPLC BEH HILIC(100 mm×2.1 mm,1.7μm)色谱柱分离,以10 mmol/L乙酸铵(含0.1％乙酸)...     

反相高效液相色谱法测定藜芦混碱中藜芦定的含量

建立测定藜芦混碱中藜芦定的反相高效液相色谱方法.方法:采用Di-amonsil-C18色谱柱(250 mm×4.6 mm,5 μm),以甲醇-0.1 mol/L乙酸铵(60:40)为流动相,流速1.0 mL/min,检测波长220 nm;柱温30℃.藜芦定在0.96～9.6μg线形关系良好,r=0.9999,藜芦定平均加样回收率为96.4%,RSD为1.6%(n=3).试验结果表明,该方法准确、简便,重现性好.     

固相萃取/~(18)O标记高氯酸根稀释高效液相色谱-串联质谱法测定水果中的高氯酸盐

建立了水果中高氯酸盐的高效液相色谱-串联质谱分析检测方法。样品采用1%乙酸提取,C18固相萃取柱净化,Waters IC-Pak Anion HR(4.6 mm×75 mm)色谱柱洗脱,流动相为乙腈-100 mmol/L乙酸铵溶液(体积比60∶40),流速0.7 m L/min;液相色谱-三重四极杆质谱联用技术-电喷雾负离子监测模式检测,采用18O标记高氯酸根离子作为内标进行基质校正,内标法定量。结果表明:高氯酸盐在0.1~10.0μg/L范围内线性关系良好,定量下限为1.0μg/kg;在1.0,2.0,10μg/kg 3个加标水平下的回收率为92.5%~110%,相对标准偏差(RSD)为1.4%~5.4%。实际样品检测表明该方法准确可靠,适合于水果中高氯酸盐的测定。     

高效液相色谱-质谱联用法检测免疫抑制剂及其合并用药

建立高效液相色谱-质谱联用法同时测定人血浆中免疫抑制剂及合并用药12种药物浓度的方法.选用Kromasil-C18色谱柱(50 mm× 4.6 mm×5 μm),以甲醇-乙腈-1mmol/L乙酸铵溶液为流动相,采用梯度洗脱进行分离,样本用甲醇沉淀蛋白后进样,流速:1.1 mL/min;柱温:35℃;进样量:20μL.选用3200QTrap型液相色谱-串联质谱仪的多反应监测(MRM)扫描方式进行检测.12种药物的线性范围为0.2～1000μg/L;定量下限为0.2 μg/L.准确度与精密度结果显示方法日间、日内RSD均小于15％;相对偏差-13％～9.33％,稳定性较好.本方法快速、灵敏,专属性强、重现性好,可用于人体血浆中免疫抑制剂及其常用合并用药共12种药物浓度的测定.     

超高效液相色谱-串联质谱法测定食品中4种罂粟壳生物碱

建立了超高效液相色谱-串联质谱法(UPLC-MS/MS)测定食品中可卡因、可待因、吗啡、盐酸罂粟碱的检测方法.样品经氨化甲醇提取,采用Capcell Pak C_(18)(250 mm×2.0 mm,MGⅡ 5μm)色谱柱,以色谱纯乙腈为流动相A,以20 mmol/L乙酸铵和0.1%甲酸缓冲液为流动相B,进行梯度洗脱.在优选条件下,可待因、吗啡方法线性范围为5.0~50.0μg/L,可卡因、盐酸罂粟碱的方法线性范围为1.0~20.0μg/L,相关系数均大于0.999,方法检出限在0.1~0.8μg/kg之间,平均回收率为76.0%~111.2%,相对标准偏差RSD低于10%.     

高效液相色谱法测定食品中的富马酸二甲酯

采用高效液相色谱法测定食品中的富马酸二甲酯.样品中的富马酸二甲酯经甲醇提取后,以甲醇-乙酸铵溶液(体积比为55∶45)为流动相,C18色谱柱分离,二极管阵列检测器检测,检测波长为210 nm,外标法定量.方法的线性范围为1～16μg/mL(r=0.99987),检出限为0.1μg/g,测定结果的相对标准偏差为0.54%...     

反相液相色谱法测定农药中氯菊酯

建立反相液相色谱法测定农药中氯菊酯含量的方法.采用C18反相色谱柱(250 mm×4.6 mm,5μm),以甲醇–水溶液(体积比为9:1)为流动相,流量为0.8 mL/min,检测波长为230 nm,柱温为35℃,进样体积为10μL,以外标法测定农药中氯菊酯的含量.氯菊酯的质量浓度在1～200μg/mL范围内与色谱峰面...     

HPLC-ICP-MS法检测化妆品中的硫柳汞和苯基汞

建立了化妆品中硫柳汞和苯基汞的高效液相色谱分离,电感耦合等离子体质谱法(ICP-MS)测定的检测方法。方法采用SB C18反相色谱柱(4.6×150mm,5μm)分离,流动相为甲醇-60 mmol/L乙酸铵溶液(含0.1%L-半胱氨酸),经过梯度洗脱,ICP-MS测定组份中的202Hg,以保留时间定性,外标法定量。结果表明,在此条件下,硫柳汞和苯基汞在0～100μg/L范围内线性良好,两种有机汞的检出限分别为5.76μg/L和4.41μg/L,不同类型化妆品中硫柳汞和苯基汞的平均回收率在82.0%～118.7%范围内。方法适用于化妆品中硫柳汞和苯基汞的测定。     

超高效液相色谱串联质谱法测定蜂蜜中氯霉素、氟甲砜霉素、甲砜霉素、甲硝唑

建立液相色谱串联质谱法测定蜂蜜中氯霉素、氟甲砜霉素、甲砜霉素和甲硝唑的分析方法。试样经乙酸乙酯提取,MCX固相萃取柱净化,选择Kinetex C_(18)型(100 mm×2.1 mm,2.6μm)色谱柱,以乙腈与5 mmol/L乙酸铵溶液(含0.05%甲酸)流动相进行梯度洗脱,流量为0.4 mL/min,进样体积为10μL。采用多反应监测(MRM)模式检测,以氯霉素-D_(5)和甲硝唑-D_(4)为内标,采用超高效液相色谱–串联质谱法测定。4种抗生素的质量浓度在0.25-10μg/L范围内与各自的色谱峰面积线性关系良好,线性相关系数均大于0.995,检出限为0.08μg/L。测定结果的相对标准偏差为3.7%-8.9%(n=6),平均加标回收率为90.2%-105.7%。该方法适用于蜂蜜中氯霉素、氟甲砜霉素、甲砜霉素、甲硝唑的检测。     

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%.     

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.     

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.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

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.