高效液相色谱内标法检测鸡血浆中甲砜霉素的浓度

以氟甲砜霉素作内标,乙腈作为提取溶剂,采用高效液相色谱内标法检测鸡血浆中甲砜霉素的浓度。色谱柱为Shim-pack CLC-ODS(150 mm×6 mm,5μm),流动相为乙腈-水(体积比25∶75),流速为1.0 mL/min,检测波长为225 nm,柱温为40℃。在此色谱条件下,在0.25~32.00 mg/L浓度范围内,甲砜霉素浓度与甲砜霉素和氟甲砜霉素峰面积比呈线性关系,相关系数r为0.9999,最低检测浓度为0.1 mg/L;在高、中、低3个浓度水平下日内、日间精密度均大于6.1%(n=5),提取回收率大于98.68%,方法回收率为99.20%~100.25%。建立的方法符合生物样品的分析要求,可用于临床药代动力学研究。     

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。     

高效液相色谱-串联质谱法同时测定水产品中氯霉素、甲砜霉素和氟甲砜霉素的残留量

建立了水产品中氯霉素、甲砜霉素和氟甲砜霉素药物残留量同时测定的高效液相色谱-串联质谱方法。以氘代氯霉素做内标,选择乙酸乙酯提取,HLB固相萃取柱净化,洗脱液氮气吹干,采用LC-MS/MS选择反应监测(SRM)负离子模式进行定性、定量分析。结果表明:氯霉素的检出限(LOD)为0.01μg/kg,甲砜霉素和氟甲砜霉素检出限(LOD)为0.03μg/kg,检测结果的相对标准偏差为3.3%～9.7%(n=6),加标回收率达到78.6%～110.5%。该方法在水产品中氯霉素、甲砜霉素和氟甲砜霉素药物的残留测定中具有很好的应用前景。     

反相高效液相色谱同时测定五味子中五味子醇甲、五味子酯甲和五味子乙素的含量

本文建立了同时测定五味子中五味子醇甲、五味子酯甲和五味子乙素的反相高效液相色谱(RP-HPLC)方法。五味子先经超声提取后用高效液相色谱法测定。色谱柱为Kromasil C18柱(150×4.6 mm,5μm),流动相为甲醇-水(75∶25,V/V),紫外检测波长220 nm,柱温30℃,流速1.0 mL/min。结果显示,五味子醇甲在0.10~6.0μg范围内(r=0.9998),五味子酯甲在0.13~8.0μg范围内(r=0.9999),五味子乙素在0.03~2.0μg范围内(r=0.9999)线性关系良好。平均回收率五味子醇甲为98.6%,相对标准偏差(RSD)为1.4%(n=5);五味子酯甲为97.1%,RSD为1.6%(n=5);五味子乙素为97.7%,RSD为1.1%(n=5)。本法准确、快速、灵敏度高,可用于五味子中有效成分的定量分析。     

一种简便的双酚A高效液相色谱检测方法

建立了用紫外检测器高效液相色谱法(HPLC)代替荧光检测器HPLC法检测去除双酚A过程中,双酚A残留量的分析方法.采用Symmetry C18柱(5μm,4.6 mm i.d.×150 mm),以V(甲醇):V(水):V(乙腈):V(四氢呋喃)=40:44:8:8为流动相,流速为1.0 mL/min,紫外检测波长为276 nm,柱温为室温,进样量50μL.双酚A在0.500～20.0 mg/L范围内,峰面积与质量浓度呈良好的线性关系,相对标准偏差RSD为1.5%(n=6),回收率在99.98%～100.13%之间,该方法简便、准确、价廉,可用于去除环境中双酚A的跟踪检测.     

高效液相色谱法测定盐酸甲氯芬酯胶囊的含量

建立了用高效液相色谱测定盐酸甲氯芬酯胶囊含量的方法.采用Hypersil C18柱(5 μm,4.6 mm i.d.×200 mm),流动相为V(乙腈)∶V(0.12% NH4HCO3-0.50%三乙胺)溶液＝33∶67 (甲基磺酸调pH至3.0),流速: 1.0 mL/min,检测波长为225 nm.盐酸甲氯芬酯的线性范围为1.632～163.2 μg/mL,平均回收率为99.67%,RSD=1.8% (n=9).     

高效液相色谱法测定叔丁基对苯二酚的含量

建立了HPLC测定叔丁基对苯二酚含量的方法:色谱柱:Shim-pack VpODS(150 mmt×4.6 mm,5μm)接C18保护柱(20 mm×4.6 mm,5μm);以V(乙腈):V(水)=32:68(含1%乙酸)作为流动相;流速:0.8 mL/min;检测波长:290 mm;柱温:25℃.结果表明TBHQ质量浓度在2×10-4～1.0 mg/mL范围内与峰面积线性关系良好r≥0.9999,最低检测限为4 ng,并建立了回收率及日内和日见精密度实验.     

高效液相色谱-串联质谱法同时测定蜂胶、蜂胶原料保健食品中的氯霉素、甲砜霉素与氟甲砜霉素

建立了同时测定蜂胶、蜂胶原料保健食品(片剂、硬胶囊、软胶囊3种剂型)中氯霉素、甲砜霉素和氟甲砜霉素残留的高效液相色谱-串联质谱(HPLC-MS/MS)方法。样品经0.1 mol/L盐酸溶解,涡旋混匀,超声提取后,通过HLB柱串接NH_2固相萃取柱净化。采用Waters ACQUITY UPLC~?BEH C_(18)(2.1 mm×100 mm,1.7μm)色谱柱进行分离,以0.1%甲酸水-乙腈为流动相梯度洗脱,经HPLC-MS/MS测定,电喷雾离子源负离子模式检测,外标法定量。结果表明3种目标分析物在0.10～20.0μg/L范围内线性关系良好,相关系数(r~2)均大于0.999;蜂胶原胶、片剂和软胶囊剂型中3种目标物的检出限(LOD)为0.037～0.083μg/kg,定量下限(LOQ)为0.12～0.28μg/kg;硬胶囊剂型中的LOD为0.39～0.47μg/kg,LOQ为1.28～1.57μg/kg;在2.5、5.0、10.0μg/kg加标水平下,3种目标物的回收率为66.6%～120%,相对标准偏差(RSD)为0.80%～11%。将该方法应用于45个实际样品检测,其中氯霉素的检出率为22.22%,最大残留量为14.32μg/kg;氟甲砜霉素的检出率为17.78%,最大残留量为21.62μg/kg。该方法操作简单、灵敏度高、适用性强,能够满足蜂胶、蜂胶原料保健食品中此类药物残留的检测要求。     

SPE-RP-HPLC法测定羊肉组织中胺菊酯和三氟氯氰菊酯残留量

建立了羊肉组织中胺菊酯和三氟氯氰菊酯的固相萃取-反相高效液相色谱测定法。采用氟罗里硅土固相萃取柱(1000 mg/6 mL)进行固相萃取。以Shim-pack VP-ODS(200 mm×4.6 mm)柱为分析柱,流动相为甲醇:水=95:5(V/V),流速为0.7 mL/min。胺菊酯和三氟氯氰菊酯分别在0.01～6.40μg/mL(r=0.9999)和0.068～7.20ug/mL(r=0.9998)范围内与峰面积呈良好线性关系,检出限分别为0.001μg/mL和0.002μg/mL,胺菊酯和三氟氯氰菊酯的回收率为90.2%～101.4%,相对标准偏差为2.3%～4.0%。该方法可作为羊肉组织中胺菊酯和三氟氯氰菊酯含量监测的控制方法。     

二维液相色谱法在线检测哈茨木霉发酵液中2460A含量

建立了在线检测哈茨木霉发酵液中微量2460A的二维液相色谱方法。利用Ultimate 3000双三元液相色谱仪,采用阀切换二维色谱技术,组合3根色谱柱实现2460A的在线净化、富集和含量检测。净化柱采用资生堂MF C8柱(10 mm×4.6 mm,5.0μm),富集柱采用资生堂MGC18柱(20 mm×4.6 mm,5.0μm),以水-甲醇为流动相,梯度洗脱,流速2.0 m L/min;二维分析柱采用Thermo Hypersil GOLD C18柱(250 mm×4.6 mm,5.0μm),以水-甲醇为流动相,梯度洗脱,流速1.0 m L/min;进样量1.0 m L;柱温40℃;检测波长424 nm。方法验证结果显示,2460A的线性范围为0.0025~10.0 mg/L(r=0.9981,n=8),检出限为1.2μg/L;定量限为2.5μg/L;方法回收率为88.0%~104.4%。     

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.     

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.     

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.     

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.     

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.