固相萃取-高效液相色谱法测定化妆品中的鞣花酸含量

建立了固相萃取-高效液相色谱法测定化妆品中鞣花酸的含量。样品用甲醇-水(1+1)溶液提取,超声提取10min,以10 000r·min-1转速离心5min,移取5.00mL上清液,经MAX固相萃取柱处理,用甲酸-甲醇(5+95)溶液洗脱。MG C18柱(250mm×4.6mm,5μm)为固定相,以0.2%(体积分数)磷酸-乙腈(18+82)溶液为流动相进行洗脱,检测波长为254nm。线性范围为0.5~100mg·L-1,测定下限(10S/N)为20mg·kg-1,应用该方法对化妆品中鞣花酸的含量进行检测,加标回收率在83.5%~100%之间。     

液相色谱-串联质谱法同时测定化妆品中的16种激素

建立了同时测定化妆品中糖皮质激素、雌激素、雄激素、孕激素等各类共16种激素的液相色谱-串联质谱分析方法。不同形态的化妆品样品以甲醇为提取溶剂进行超声提取,样品提取液高速离心处理,上清液以Oasis HLB固相萃取柱净化,经Agilent ZORBAX XDB-C8(250mm×4.6mm,5μm)反相色谱柱分离后进行LC/MS/MS多反应监测模式下的定性及定量分析。其中糖皮质激素、雄激素和孕激素采用正离子扫描方式,雌激素采用负离子扫描方式进行质谱分析。16种激素的方法检出限为1~13μg/kg,在10~100μg/kg的3个添加水平范围内的平均回收率为72.8%~93.4%,相对标准偏差均小于10.2%。     

不同前处理方式结合超高效液相色谱-串联质谱法测定当归中30种禁用农药残留量北大核心CSCD

当归样品经QuEChERS法和固相萃取法处理,浓缩后用60%(体积分数)乙腈溶液稀释,采用超高效液相色谱-串联质谱法(UHPLC-MS/MS)同时测定30种禁用农药残留量。以Agilent ZORBAX SB-C_(18)色谱柱(100 mm×2.1 mm,3.5μm)为固定相,以含5 mmol·L^(-1)甲酸铵的0.1%(体积分数)甲酸溶液-乙腈为流动相体系进行梯度洗脱;质谱分析中以电喷雾离子源正离子模式扫描,多反应监测模式检测。用基质匹配法绘制工作曲线,外标法定量。结果显示:除涕灭威外,其余农药几乎都存在基质效应;30种禁用农药的质量浓度在一定范围内与其对应的定量离子对峰面积呈线性关系,检出限为0.13~15.06μg·kg^(-1)(QuEChERS法),0.13~14.77μg·kg^(-1)(固相萃取法);基质匹配混合标准溶液中30种禁用农药测定值的相对标准偏差(n=6)为1.4%~12%(QuEChERS法),1.0%~13%(固相萃取法);阴性样品中30种禁用农药的加标回收率为60.4%~140%(QuEChERS法),61.0%~144%(固相萃取法);方法用于23批当归样品中禁用农药残留情况筛查,有2批样品中检出禁用农药甲拌磷亚砜,检出量为0.0160~0.0197 mg·kg^(-1),并且QuEChERS法和固相萃取法处理后的测定结果基本一致。     

分散固相萃取净化/液相色谱-串联质谱法测定化妆品中7种氨基苯甲醚

建立了同时测定化妆品中7种氨基苯甲醚类化合物(邻氨基苯甲醚、间氨基苯甲醚、对氨基苯甲醚、2,4-二氨基苯甲醚、2,5-二氨基苯甲醚、3,4-二氨基苯甲醚、3,3'-二甲氧基联苯胺)的分散固相萃取净化液相色谱-串联质谱(LC-MS/MS)分析方法。样品用甲醇-水(1∶1,含0.1%甲酸)溶液提取,经PSA分散固相萃取净化后,样液经Welch Ultimats XB-C_(18)(4.6 mm×150 mm,5μm)色谱柱分离,多反应监测(MRM)模式检测,以保留时间和特征离子对定性,外标法定量。结果表明,7种氨基苯甲醚类化合物在0.10~200.0μg/L浓度范围内线性关系良好,相关系数均大于0.998;方法检出限(S/N=3)为0.4~10.9μg/kg。样品日内回收率为64.7%~98.1%,相对标准偏差(RSD,n=6)为1.2%~10.6%;日间精密度(n=5)为2.3%~9.8%。对30个不同水剂类化妆品检测发现,其中1个样品检出3,3'-二甲氧基联苯胺,含量为5.3μg/kg。该方法准确可靠,适用于化妆品中7种氨基苯甲醚的同时测定。     

高效液相色谱法测定化妆品中9种对氨基苯甲酸及其酯类防晒剂

利用反相高效液相色谱法建立了同时测定不同种类化妆品(膏霜、油状、粉饼)中9种对氨基苯甲酸及其酯类防晒剂含量的方法。样品用乙腈进行溶解,超声提取30 min,以Diamonsil C18柱(250 mm×4.6 mm,5μm)为分离色谱柱,甲醇和0.5%(V/V)甲酸水溶液为流动相,梯度洗脱,以311nm为检测波长进行定性,外标法定量。各组分在0.5~1000 mg/L范围内成线性关系,相关系数>0.99,在质量分数为0.1%,1%,5%3个添加水平下平均回收率在85.67%~108.38%,检出限为8~100μg/g。相对标准偏差(n=6)为1.3%~5.1%。     

基于分子印迹磁性复合材料的基质分散-固相萃取/液相色谱法测定海水中的氯酚类污染物

建立了一种快速、高效、灵敏的基质分散-磁性固相萃取/液相色谱(d MSPE-HPLC)方法,用于海水中5种氯酚类(CPs)污染物残留量的测定。样品用五氯酚分子印迹氨基功能化磁性复合材料富集,在C8反相液相色谱柱(250 mm×4.6 mm×5.0μm)上分离,以甲醇-5 mmol/L乙酸铵水溶液(体积比70∶30)为流动相,230 nm处检测。考察了样品p H值、萃取时间和洗脱剂的种类与用量对CPs富集回收率的影响。结果表明,在最佳实验条件下,5种CPs在1~5 000 ng/L浓度范围内呈良好的线性关系,相关系数(r2)均大于0.998 9;平均回收率为86.5%~98.8%,相对标准偏差(RSDs)为0.8%~8.6%;检出限(LODs)为0.18~1.20 ng/L,定量下限(LOQs)为0.6~4.0 ng/L。方法可用于海水中CPs类化合物的快速筛查和确证分析。     

高效液相色谱法同时测定化妆品中多种美白祛斑剂

建立了化妆品中8种美白祛斑剂高效液相色谱分析方法。采用Zorbax Eclipse XDB C18色谱柱(250 mm×4.6 mm,5.0μm)为固定相,0.02 mol/L磷酸二氢钾溶液(pH 6.95)和甲醇溶液为流动相,梯度洗脱,流速为1.0 mL/min,柱温为25℃,二极管阵列检测器,检测波长为270 nm,外标法定量。结果显示:8种美白祛斑剂线性关系良好,线性范围分别为:曲酸3.0~60 mg/L,维生素C磷酸酯镁、烟酰胺、苯酚为5.0~100 mg/L,熊果苷、氢醌、树莓苷、甘草酸二钾为10.0~200 mg/L。相对标准偏差(n=6)为0.22%~2.6%,平均回收率为95%~105%。     

稳定同位素稀释气相色谱-质谱联用测定化妆品中5种磷酸三酯类化合物

根据不同化妆品的基质特性探讨优化不同的提取净化方法,建立了稳定同位素稀释气相色谱-质谱联用测定化妆品中5种磷酸三酯类化合物(OPEs)的方法。膏霜乳液类和蜡基类化妆品经溶剂提取后,采用ENVI-Carb固相萃取柱净化;粉剂类和水剂类化妆品经溶剂提取、浓缩后直接检测。样液经DB-5MS(30 m×0.25 mm×0.25μm)色谱柱分离,GC-MS的选择离子监测(SIM)模式检测,以保留时间和特征离子丰度比定性,稳定同位素稀释内标法定量。在优化的实验条件下,5种磷酸三酯类化合物在各自的线性范围内相关系数大于0.9995,方法检出限为1.0~30μg/kg,平均回收率为89.5%~105%,相对标准偏差(n=6)为2.9%~9.1%。本方法净化效果好,可有效消除基质效应,且有较好的回收率,可用于不同类型的化妆品基质中磷酸三酯类化合物的测定。     

基于氨基功能化石墨烯磁性材料的磁固相萃取-高效液相色谱法分析海水中的氯酚类污染物

本文采用氨基功能化石墨烯磁性材料富集海水中的5种氯酚类(CPs)污染物,建立了一种快速、高效、灵敏的磁固相萃取-高效液相色谱(MSPE-HPLC)法,用于其残留量的测定。实验优化了磁固相萃取的条件,考察了样品pH值、富集时间和洗脱剂的种类与用量等对CPs回收率的影响。样品经富集后在C8反相液相色谱柱(250×4.6mm i.d.,5μm)上分离,以体积比为70∶30的甲醇-5mmol/L NH_4Ac溶液为流动相,紫外检测波长为230nm。结果表明,5种CPs的富集倍数可达250倍;CPs浓度在1~2 000ng/L范围内呈现良好的线性关系,线性相关系数(R)均大于0.9995;平均回收率为92.6%~101.2%,相对标准偏差为0.6%~7.2%;检出限为0.15~1.06ng/L,定量限为0.5~3.2ng/L。采用本方法对5个实际海水样品中的CPs进行了定量检测,结果其中一种样品含有2,4,6-三氯苯酚,浓度为6.5ng/L。     

纳米纤维固相萃取-高效液相色谱-荧光检测麻辣烫汤液中喹诺酮类药物

建立了固相萃取-高效液相色谱-荧光检测麻辣烫汤液中5种喹诺酮类抗生素的分析方法。麻辣烫汤液样品经EDTA-Mcllvaine缓冲溶液(pH 4)提取后,以HCX固相萃取小柱净化富集,用水淋洗,2%氨化甲醇洗脱。采用高效液相色谱-荧光检测器(HPLC-FLD),于激发波长280 nm,发射波长450 nm处进行检测,流动相为甲醇-水-磷酸(25∶75∶0.1,V/V,三乙胺调至pH 2.8)。麻辣烫汤液样品中氟罗沙星、诺氟沙星、沙拉沙星、环丙沙星、奥比沙星5种喹诺酮类抗生素加标回收率为72.1%~110.3%;日内相对标准偏差(RSD)为1.6%~4.3%,日间相对标准偏差为2.0%~4.3%;检出限(LOD)为1.2~5.4μg/L;定量限(LOQ)为3.9~18μg/L。本方法能够满足实际麻辣烫汤液样品的分析要求。     

Gels from a semifluorinated n-alkane in fluorinated solvents as a probe for intermolecular interactions

Diblock semifluorinated n-alkanes can form aggregates and gels in fluorinated solvents. We have investigated the thermal behavior of binary mixtures comprising F(CF₂)₈(CH₂)₁₆H and fluorinated solvents. The solvents were perfluorohexane, perfluoroheptane, perfluorooctane, perfluorooctyl bromide, perfluorodecalin, and perfluorotributylamine. The phase diagrams were used to calculate the activity coefficients of the two components and the main excess thermodynamic functions. The solubility and self-assembly behavior of F₈H₁₆ in the fluorinated solvents are related to the different solute–solvent dispersion interactions that depend on the polarizabilities and ionization potentials of the interacting species, and on the structural properties of the solvent.     

Studies on the Formation of Catalytically Active PGM Nanoparticles from Model Solutions as a Basis for the Recycling of Spent Catalysts

The paper presents basic studies on the precipitation of platinum, palladium, rhodium, and ruthenium nanoparticles from model acidic solutions using sodium borohydride, ascorbic acid, and sodium formate as reducing agents and polyvinylpyrrolidone as a stabilizing agent. The size of the obtained PGM particles after precipitation with NaBH₄ solution does not exceed 55 nm. NaBH₄ is an efficient reducer; the precipitation yields for Pt, Pd, Ru, Rh are 75, 90, 65 and 85%, respectively. By precipitation with ascorbic acid, it is possible to efficiently separate Pt, Rh, and Ru from Pd from the two-component mixtures. The obtained Pt, Pd, and Rh precipitates have the catalytic ability of the catalytic reaction of p-nitrophenol to p-aminophenol. The morphological characteristic of the PGM precipitates was analyzed by AFM, SEM-EDS, and TEM.     

PMDA-BPDA-HAB聚苯并噁唑的合成及耐热性

PMDA-BPDA-HAB聚苯并噁唑的合成及耐热性;均苯四甲酸二酐;联苯四羧酸二酐;二羟基联苯胺;聚酰亚胺;聚苯并噁唑;耐热性     

HCOO在Cu(110)、Ag(110)和Au(110)表面的吸附

采用密度泛函理论(DFT)以及广义梯度近似方法(GGA)计算了甲酸根(HCOO)在Cu(110)、Ag(110)和Au(110)表面的吸附. 计算结果表明, 短桥位是最稳定的吸附位置, 计算的几何参数与以前的实验和计算结果吻合. 吸附热顺序为Cu(110)(-116 kJ·mol-1)>Ag(110)(-57 kJ·mol-1)>Au(110)(-27 kJ·mol-1), 与实验上甲酸根的分解温度相一致. 电子态密度分析表明, 吸附热顺序可以用吸附分子与金属d-带之间的Pauli 排斥来关联, 即排斥作用越大, 吸附越弱. 另外还从计算的吸附热数据以及实验上HCOO的分解温度估算了反应CO2+1/2H2→HCOO的活化能, 其大小顺序为Au(110)>Ag(110)>Cu(110).     

Transition metal complexes of the tripodal ligand 4-(2′-pyridylmethyl)-4-azaheptane-1,7-diamine. Crystal structures of [CuLCl]ClO4 and [NiL(MeCN)2](ClO4)2

The tripodal ligand 4-(2′-pyridylmthyl)-4-azaheptane-1,7-diamine has been prepared by reaction of 2-aminemethyl pyridine with acrylonitrile, followed by the reduction of the nitrile groups. Copper(II), nickel(II), zinc(II), cobalt(III) and chromium(III) complexes of the ligand have been prepared and characterized and the crystal structures of the complexes [CuLCl]ClO₄ and [NiL(MeCN)₂](ClO₄)₂ determined. The copper complex is five coordinate with approximate square pyramidal stereochemistry with the apical position occupied by a primary amine donor. The nickel complex is octahedral with the pyridine nitrogen donor lying trans to an acetonitrile ligand.     

SYNTHESIS AND CHARACTERIZATION OF METAL COMPLEXES WITH AMPICILLIN

Abstract

The reaction, in water, of Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) ions with sodium ampicillinate at room temperature has allowed isolation of dimers with the following general formula [M(amp)Cl]₂ × nH₂O (n = 1.5?3.2). The complexes were characterized by elemental analyses, conductivity measurements, magnetic susceptibilities and spectroscopic methods (IR, Raman, EPR and UV-Visible). A dinuclear structure based on octahedrally coordinated metal ions is proposed.     

Magnetism of metal-nitroxide compounds involving bis-chelating imidazole and benzimidazole substituted nitronyl nitroxide free radicals

Coordination compounds based on imidazole and benzimidazole substituted nitronyl nitroxide radicals with transition metal ions and trivalent lanthanide ions are described from the perspective of their magnetic properties.For the transition metal compounds the crystal structures show various metal-nitroxide dimensionalities including mononuclear (0D), one-dimensional (1D) and two-dimensional (2D) complexes. The mononuclear complexes were isolated with most metal ions of the first transition series. One copper(II) complex shows a copper(II)-radical ferromagnetic coupling (J = +75 cm⁻¹) while for the other mononuclear compounds, mainly with manganese(II), the metal-radical interactions are antiferromagnetic. The one-dimensional and two-dimensional complexes are manganese(II) compounds which show canting effects leading to weak ferromagnetism.For the trivalent lanthanide ions [La(III), Gd(III) and Eu(III)], three series of mononuclear complexes were obtained in which the metal center is bound to four, two or one nitroxide radicals depending on the counter ions and ancillary ligands. Unexpectedly, in most gadolinium(III) complexes, the Gd(III)-radical interactions were found to be antiferromagnetic in contradiction with other foundings and previous theoretical models. In support to the magnetic studies, the optical properties of the lantanide complexes have also been investigated and are briefly described.     

具有聚集诱导发光性质的近红外荧光染料

聚集诱导发光(AIE)现象的发现为解决传统有机荧光分子在高浓度和聚集形态下存在的荧光猝灭问题提供了最佳方案,并实现了在光电器件、化学传感、生物成像和靶向治疗等众多领域的广泛应用.随着对AIE 发光机理研究的不断深入,AIE 分子体系得到了极大的扩展.其中,一类具有给体-受体结构的AIE分子能够显著降低分子能隙,使发光分...     

Simple,Selective, and Sensitive Spectrophotometric Method for Determination of Trace Amounts of Nickel（Ⅱ）, Copper （Ⅱ）, Cobalt （Ⅱ）, and Iron （Ⅲ） with a Novel Reagent 2-Pyridine Carboxaldehyde Isonicotinyl Hydrazone

A selective and sensitive reagent of 2-pyridine carboxaldehyde isonicotinyl hydrazone（2-PYAINH） was synthesized and studied for the spectrophotometric determination of nickel, copper, cobalt, and iron in detail. At a pH value of 7.0, 9,0, 9.0, and 8.0, respectively, which greatly increased the selectivity; nickel, copper, cobalt, and iron reacted with 2-PYAINH to form a 1：2 yellow-orange, 1：2 yellow-green, 1：2 yellow and 1：1 yellow complexes, with absorption peaks at 363, 352, 346, and 359 nm, respectively. Under the optimal conditions, Beer＇s law was obeyed over the ranges of 0.01-1.4, 0.01-1.5, 0.01-2.7, and 0.01-5.4 mg/L respectively. The apparent molar absorptivity and Sandell＇s sensitivities were 8.4×10^4, 5.2×10^4, 7.1×10^4, and 3.9×10^4 L·mol^-l·cm^-1, respectively, and 0.00069, 0.0012, 0.00078, and 0.0014 μg·cm2, respectively. The detection limits were found to be 0.001, 0.002, 0.003, and 0.01 mg/L, respectively. The detailed study of various interfering ions to make the method more sensitive was carried out and selective and several real samples were analyzed with satisfactory results.     

New Complexes of Ditopic Ligands with “d” and/or “s” Metal Ions

Abstract

The asymmetric compartmental macrocycles containing one N₂O₂ or N₃O₂ Schiff base and one O₂O₃ or O₂O₄ crown-ether like chamber, have been obtained by condensation reaction of the formyl precursors 3,3′-(3-oxapentane-1, 5-diyldioxy) bis (2-hydroxybenzaldehyde) or 3,3′-(3,6-dioxaoctane-1,8-diyldioxy)-bis(2-hydroxybenzaldehyde) with ethyl ethylenediamine (H₂L_A, H₂L_C), 1,5-diamino-3-azamethylpentane(H₂L_B, H₂L_D), also in the presence of metal ions as templating agents. These ditopic ligands, with dissimilar coordination sites, have been designed and used for the selective complexation of “d” and/or “s” metal ions, respectively into the Schiff base and the crown ether chamber. The selectivity of these processes strongly depends on the size and on the donor atom sets of the sites. The possibility to obtain mononuclear M(L)·nH₂O (M = Ni²⁺, Cu²⁺, Co²⁺), Mn(L)(CH₃COO)·nH₂O or Na(L) and hetero-dinuclear MNa(L)(CH₃COO) (M = Ni²⁺, Cu²⁺, Co²⁺) and MnNa(L)(CH₃COO)₂·nH₂O complexes has been successfully tested. The ligands and complexes have been characterized by ir, nmr, mass spectrometry and magnetic susceptibility measurements.

Two of the ligands used for the preparation of the solid samples, i.e., to H₂L_A and H₂L_B, have been employed to study complexation reactions of Co(II) and Na(I) in solution. In order to obtain information on the ligand preorganization effect toward the complex stabilities, a simpler open chain parent compound of H₂L_B (H₂L_E) has been also prepared and studied. FT-IR spectra show that H₂L_A is unable to complex Na⁺ in DMSO while the complexation reactions of Na⁺ by H₂L_B and of Co²⁺ by H₂L_A take place with slow kinetics. Therefore, thermodynamic data have been obtained only for the systems Co²⁺/H₂L_B and Co²⁺/H₂L_E. The thermodynamic parameters obtained for the complexation reactions show that the pre-organization of the donor atoms in H₂L_B does not add a significant contribution to the stabilities of the complexes. Both H₂L_B and H₂L_E form in DMSO 1:1, 1:2 and 1:3 = M:L complexes with very similar stabilities and almost equal enthalpies of formation. Physico-chemical studies suggest besides that the slow reaction of Na⁺ with H₂L_B is probably due to the formation of a 1:1 complex where the metal cation, initially occupying the O₃ cage of the ligand, slowly binds also the oxygens of the phenolic moieties. Spectral and calorimetric data on solutions containing H₂L_B and different Co²⁺: Na⁺ ratios evidence that in DMSO no stable heterodinuclear complexes form when the neutral ligand is considered.