液相色谱-串联质谱法测定大鼠血浆中福斯克林

建立了测定大鼠血浆中福斯克林的液相色谱-串联质谱法(LC-MS/MS).血浆样品经液-液萃取后,以V(甲醇):V(10 mmol/L 醋酸铵):V(甲酸)=75:25:0.1为流动相,用Hypersil ODS柱分离,流速0.8 mL/min(柱后分流50%),通过电喷雾离子化四极杆串联质谱,以多反应监测方式(MRM)检测.用于定量分析的离子分别为m/z 428/375(福斯克林)和m/z 494/369(格列本脲,内标).福斯克林血浆浓度测定方法的线性范围为0.8～800 μg/L; 日内、日间精密度(RSD)均小于10%;准确度(RE)小于±9%.每个样品测试时间4.5 min.应用此法测试了大鼠口服或静注福斯克林后的血药浓度.     

奶粉中高氯酸盐的液相色谱-串联质谱测定

建立了奶粉中高氯酸盐的液相色谱-串联质谱(LC-MS/MS)测定方法.奶粉样品用水-乙腈(体积比1:2)超声波振荡提取2次,于4 000 r/min离心后,上清液经Oasis HLB固相萃取小柱净化;采用离子交换色谱分离,色谱柱为METROSEP A Supp 5(150 mm×4.0 mm)阴离子交换柱,流动相为0.2 mol/L乙酸铵溶液-乙腈(体积比1 : 1),流速0.7 mL/min;电喷雾负离子模式电离,质谱多反应选择离子检测(MRM),检测离子对为 m/z 99→83和m/z 101→85,其中m/z 99→83为定量离子对.方法的相对标准偏差为3.59%,回收率为91% ～106%,检出限为1.0 μg/kg,定量下限为5.0 μg/kg.结果表明,该法简便快速、准确可靠,也适用于鲜牛奶、酸牛奶等其他乳制品中高氯酸盐的测定.     

液相色谱-电喷雾串联质谱法测定人血浆中的艾芬地尔

建立了测定人血浆中艾芬地尔的液相色谱-串联质谱方法。血浆样品用乙酸乙酯液-液提取后,以甲醇-6 mmol/L乙酸铵溶液(pH 7.40)(体积比为90∶10)为流动相进行分离。在Q TRAPTM串联质谱仪上,以选择性反应离子监测(SRM)方式进行定量分析,用于监测的离子为m/z 326.1→308.2 (艾芬地尔)和m/z 531.0→82.1 (酮康唑,内标)。在6 min内完成了艾芬地尔的检测,工作曲线的线性范围为0.25～50 μg/L,日内、日间精密度分别小于2.7%和6.5%,平均回收率为101.3%～105.0%,检测限为0.08 μg/L。本方法灵敏度高,特异性好,可以用于临床试验的血浆样品的检测。     

高效液相色谱-质谱联用技术测定鼻腔给药后人血浆中佐米曲普坦的含量

建立了经鼻腔给药后人血浆中佐米曲普坦的液相色谱-质谱联用测定方法。血浆样品经乙酸乙酯-二氯甲烷(体积比4∶1)液-液提取后,以Hypersil BDS C6H5柱(4.6 mm×250 mm,5μm)为色谱柱,流动相为乙腈(含1%甲酸)-0.02 mol.L-1醋酸铵(体积比30∶70),流速为0.6 mL.m in-1,柱温:25℃,进样量:40μL,在Agilent 1100 LC/MSD XCT离子阱质谱仪上,以选择离子监测(SIM)方式进行定量分析,用于监测的离子为m/z288(佐米曲普坦)和m/z296(舒马普坦,内标物)。佐米曲普坦的定量下限为0.30μg.L-1,线性范围为0.30~25μg.L-1,方法回收率在82%~87%之间(n=5),精密度与准确度符合生物样品分析要求。该法操作简便、快速、灵敏度高,可用于佐米曲普坦临床血药浓度和药代动力学研究。     

超高效液相色谱-串联质谱法测定乳制品中三聚氰胺的残留量

建立一种用超高效液相色谱-电喷雾质谱联用技术测定乳制品中三聚氰胺残留量的方法.样品经含5%乙酸铅的三氯乙酸溶液提取,离心分离后经PCX-C18混合填料固相萃取柱净化.色谱分离采用Agilent ZORBAX-CN柱(250 mm×4.6 mm i.d.,5 μm),以10 mmol/L V(乙酸铵)∶V(乙腈)＝10∶90混合溶液为流动相.采用电喷雾离子源,正离子多反应监测(MRM)模式检测.该方法在1～1000 ng/mL范围内线性关系良好.在添加水平为10,30,45 μg/kg时,回收率在78.5%～92.6%之间,相对标准偏差在3.5%～8.6%之间,检出限为10 μg/kg.该方法适合于乳制品中三聚氰胺残留量的检测.     

婴幼儿配方食品中生物素的高效液相色谱-质谱联用测定

采用高效液相色谱-质谱联用法测定了婴幼儿配方食品中生物素的含量.样品经前处理后以Dikma C18(4.6 mm×250 mm,5 μm)为色谱柱,流动相为甲醇(含体积分数为0.5%甲酸)-0.02 mol·L-1醋酸铵(含0.5%甲酸)(体积比40 ∶ 60)溶液,柱温:25 ℃,进样量:80 μL,流速为1.0 mL·min-1,柱后分流比为1 ∶ 3(体积比).在Agilent 1100 LC/MSD XCT离子阱质谱仪上,以多离子反应监测(MRM)方式进行定量分析,用于监测的离子为m/z 245.3→226.9.生物素在2.50 ～100.0 μg·L-1范围内线性关系良好,方法加标回收率为87% ～101%(n=5),检出限为0.35 μg·L-1;方法的检出限为0.7 ng/g.结果表明,该法操作简便、灵敏度高、重复性好,将其用于婴幼儿配方食品中生物素的测定,取得了良好的结果.     

反相离子对高效液相色谱法测定SD大鼠血浆中河豚毒素的含量

建立了大鼠血浆中河豚毒素(TTX)反相离子对高效液相色谱测定方法。血浆样品加水涡漩,再加沉淀剂V(乙腈)∶V(含0.5%HAc的甲醇液)=3∶1),旋涡离心后取上清液进样测定。色谱柱为Agilent ZorbaxSB C18柱(150 mm×4.6 mm×5μm);流动相为10?N-90%的8 mmol/L庚烷磺酸钠与0.005%TFA混合溶液,配好后调到pH5.0;紫外检测波长196 nm;流速1.0 mL/min;柱温为室温。本方法TTX标准品检出限为1.055 mg/L,血浆中TTX的检出限为0.1055 mg/L。血浆中TTX的线性范围为21.1~211 mg/L,r=0.9989。日内和日间精密度RSD均小于3%。本方该法准确、专属性强,适用于血浆中TTX的浓度测定。     

液相色谱－串联质谱法对小鼠血浆中远志皂苷元的测定

建立了小鼠血浆中远志皂苷元(senegenin,Se)的高效液相色谱-串联质谱(HPLC-MS/MS)测定方法.以RESTEK PinnacleⅡC18柱(100 mm×2.1 mm,5 μm)为色谱柱,乙腈-水(体积比51∶49)为流动相,流速200 μL·min-1;柱温20 ℃;质谱条件为气动辅助电喷雾离子源(ESI),检测方式为负离子多反应监测模式(MRM),用于定性分析的离子对为m/z 535/481和m/z 535/423,其中m/z 535/481为定量离子;生物样品采用固相萃取方法处理.远志皂苷元标准曲线的线性范围为0.5～1 000 μg·L-1,定量下限达0.5 μg·L-1,日内、日间相对标准偏差(RSD)均小于15%,回收率大于80%,精密度和准确度等均符合生物样品分析的要求.结果表明该法准确、灵敏、特异,适用于血浆中远志皂苷元的测定.该文还借助ABI4000 Q TRAP四极杆质谱仪特有的MS/MS/MS技术探讨了远志皂苷元碰撞活化裂解(collision-active dissociation,CAD)主要质谱碎片的产生机理.     

高效液相色谱-串联质谱法测定人血浆中消旋卡多曲活性代谢物含量

建立高效液相色谱-串联质谱法(HPLC-MS/MS)测定人血浆中消旋卡多曲活性代谢物Thiorphan(TP)的含量及S-Methyl-Thiorphan(MTP)的相对含量。采用Kromasil C18色谱柱(25mm×4.6mm,5μm),流动相为V(水)∶V(乙腈)=72∶28,甲酸调pH至2.8。加抗氧化剂的血浆样品经乙腈直接沉淀后进样、MRM模式外标法定量,TP和MTP检测离子对分别为m/z252/218和m/z266/218。TP在6.25~3200μg/L范围内线性关系良好(r=0.9998);方法回收率为97.1%~109.0%,批内批间RSD分别小于3.5%及6.0%。     

高效液相色谱法测定保健食品和饮料中的阿斯巴甜

建立了保健食品和饮料中的甜味剂阿斯巴甜的高效液相色谱快速测定方法.固体样品用纯水超声提取;饮料样品超声脱气.取适量提取液或饮料样品,经0.45 μm滤膜过滤后,取20 μL进样色谱柱分析.色谱条件:分离柱为C18柱(250mm×4.6 mm i.d.,10μm),柱温35℃,流动相为V(10 mmol/L KH2PO4,pH 3.50):V(乙腈)=80:20,流速1 mL/min,检测波长210 nm.本法线性范围为0～16 μg,最低检出量为0.0024 μg,回收率为92.3%～102%.相对标准差小于1.6%.本法准确度和精密度均能满足保健食品和饮料中阿斯巴甜测定的要求.     

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%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

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.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

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.