时间分辨后化学发光同时测定林可霉素和卡那霉素

根据林可霉素、卡那霉素在过氧化单硫酸盐(PMS)-鲁米诺(Luminol)体系中的化学发光反应动力学性质的明显差异,建立了时间分辨后化学发光同时测定林可霉素和卡那霉素的新方法.在PMS-鲁米诺体系中林可霉素化学发光反应较快,0.8s达到最大值,峰尖锐;卡那霉素化学发光反应较慢,54.8s后达到最大值,峰平缓,且其动力学曲线呈现出随时间分开的两个独立的发光峰,互不干扰.该方法测定林可霉素、卡那霉素的线性范围分别为4.0×10-9～8.0×10-7 g/mL、4.0×10-7～8.0×10-5 g/mL,对8.0×10-8 g/mL的林可霉素溶液和8.0×10-6 g/mL的卡那霉素溶液进行测定,其相对标准偏差(RSD,n=11)分别为4.6％和3.3％,测定林可霉素和卡那霉素的检出限分别为1.0×10-9 g/mL和1.0×10-7 g/mL.     

荧光素-牛血清白蛋白的化学发光反应研究

研究了在碱性介质和阳离子表面活性剂CTMAB存在下,NaClO氧化荧光素-牛血清白蛋白的化学发光行为和化学发光反应的条件,提出了反相流动注射化学发光测定牛血清白蛋白的新方法.该法测定牛血清白蛋白的线性范围为0.02～6.4 μg/mL,检出限为0.005μg/mL.     

Ce(Ⅳ)-罗丹明6G化学发光体系与毛细管电泳联用同时测定氯丙嗪和异丙嗪

提出了一种毛细管电泳化学发光联用技术同时测定氯丙嗪和异丙嗪。在酸性条件下,氯丙嗪和异丙嗪能被Ce(Ⅳ)氧化,然后将能量转移给荧光发射体-罗丹明6G,并以化学发光形式释放能量。基于此,结合流动注射技术,以10 mmol/L KH2PO4/H3PO4(pH3.5)为运行缓冲液,实现了两种药物的分离。方法的线性范围分别为4.0×10-8~2.0×10-6g/mL和2.0×10-8~2.0×10-6g/mL,检出限分别为5.6 ng/mL和3.4 ng/mL,对2.0×10-6g/mL异丙嗪平行测定了9次,相对标准偏差为2.8%。方法可用于同时测定人血清中的氯丙嗪和异丙嗪。     

高效液相色谱-荧光法同时测定人体尿液中的酪氨酸和色氨酸

建立了高效液相色谱-荧光检测法同时测定人体尿液中的酪氨酸(Tyr)和色氨酸(Typ)。采用Diamonsil C18柱(250×4.6mm,5μm),以水-乙腈(80∶20,V/V)为流动相,流速1.0mL/min,荧光检测波长为λex=260nm、λ_(em)=340nm。Tyr和Typ的含量分别在0.10~6.0μg/mL及0.050~6.0μg/mL范围内与色谱峰面积呈良好的线性关系(r=0.9993),检测限分别为0.05μg/mL和0.02μg/mL。在三个添加水平的回收中,两种氨基酸的平均回收率在86.3%~122.3%之间,相对标准偏差(RSD)小于8.51%。将所建立的方法应用于健康人、普通病人和癌症患者晨尿检测,结果发现:癌症患者尿样中色氨酸的水平与健康人和普通病人相比偏低。     

Ce(Ⅳ)-吐温40-色氨酸化学发光体系的研究与应用

实验观察到在酸性条件下,色氨酸能够增强Ce(Ⅳ)和吐温40的化学发光反应,其发光强度的增加与色氨酸含量在一定的范围内呈线性关系,据此建立了测定色氨酸的化学发光分析新方法.采用顺序注射技术进样,将试样和试剂的消耗降至微升范围内,明显提高了分析速度.考察了各种实验参数的影响和可能的反应机理,此反应的发光体为Tween 40的中间氧化产物.在试样体积70 μL、吐温40浓度为5%、试剂Ce(Ⅳ)体积80 μL、浓度为1.0 mmol/L、检测流速为1.8 mL/min的条件下,线性范围为2.0×10-7～1.4×10-5 mol/L; 检出限(3σ)为8.8×10-8 mol/L; 对6.0×10-6 mol/L色氨酸进行9次测定的相对标准偏差为1.3%.啤酒和血清中色氨酸含量测定的回收率为91.2%～102%.     

AuCl_4~--鲁米诺体系测定氨苄西林钠

在NaOH介质中, AuCl4-氧化鲁米诺产生化学发光, 氨苄西林钠显著增强该体系的发光. 据此, 建立了一种测定氨苄西林钠的流动注射化学发光新方法. 在优化的实验条件下, 该法测定氨苄西林钠的线性范围为0.01～10 μg/mL, 检出限为4.0 ng/mL, 对1.0 μg/mL 氨苄西林钠进行了11次测定, 其相对标准偏差为1.4%. 用于粉针剂、合成样品及尿样中氨苄西林钠的测定.     

毛细管电泳-化学发光联用新方法检测色氨酸

基于色氨酸对三(1,10-菲咯啉)钌(Ⅱ)[Ru(phen)32+]-Ce(Ⅳ)体系化学发光的增强作用,结合毛细管电泳分离技术,提出了一种毛细管电泳-化学发光检测色氨酸的新方法。在最优化的分离和检测条件下,该方法测定色氨酸的线性范围为5.0×10-7～2.0×10-5mol/L,检测限为7.6×10-8mol/L。将其应用于复方氨基酸注射液(18AA)中L-色氨酸含量的测定,结果满意。     

双波长双指示剂催化光度法同时测定Fe和Cu

研究了在Na2SO4介质中,痕量Fe(Ⅲ)和Cu(Ⅱ)催化H2O2氧化次甲基蓝和甲基橙褪色的指示反应,通过测量440和664 nm波长下,催化反应体系和非催化反应体系的吸光度,建立了双波长、双指示剂催化动力学光度法同时测定痕量Fe(Ⅲ)和Cu(Ⅱ)的新方法.同时测定Fe(Ⅲ)和Cu(Ⅱ)的线性范围分别为0.0050～0.50 μg/25 mL和0.0025～0.75 μg/25 mL,检出限分别为6.9×10-8 g/L和8.7×10-8 g/L.用于水样中痕量Fe(Ⅲ)和Cu(Ⅱ)的测定.     

HPLC／UV法对银鲫肌肉组织中甲苯咪唑及其代谢产物残留的同时测定

建立了一种用高效液相色谱同时测定银鲫肌肉组织中甲苯咪唑(MBZ)及其代谢物氨基甲苯咪唑和羟基甲苯咪唑的方法.银鲫肌肉组织用乙酸乙酯提取,萃取物旋转蒸发至干后用1 mL二甲基甲酰胺-0.05 mol/L磷酸盐缓冲液(体积比3 ∶ 7)定容.色谱条件:Waters symmetry C18反相色谱柱(250 mm×4.6 mm,5 μm);流动相:乙腈-0.05 mol/L磷酸二氢铵溶液(体积比33 ∶ 67);流速:0.8 mL/min;检测波长为298 nm;检测温度为室温.在10 ～120 μg/kg添加水平,MBZ、MBZ-NH2、MBZ-OH的回收率分别为81% ～86%、71% ～75%、86% ～93%.MBZ的检出限为2 μg/kg,MBZ-OH和MBZ-NH2检出限均为3 μg/kg.     

化学发光法测定氨苄西林钠

在NaOH介质中,KI04氧化鲁米诺产生化学发光,氨苄西林钠显著增强该体系的发光.据此,建立了一种简单、快速测定氨苄西林钠的流动注射化学发光新方法.在优化的实验条件下,线性范围为0.01～10 μg/mL,检出限为3.0 ng/mL,对1.0 μg/mL氨苄西林钠进行了11次平行测定,其相对标准偏差为1.4%.已用于粉针剂、合成样品及尿样中氨苄西林钠的测定.     

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.     

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.     

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.     

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.     

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.     

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.