高效液相色谱-质谱法分析菊芋叶中的绿原酸类化合物

建立了菊芋叶中绿原酸类化合物的高效液相色谱-紫外检测-质谱(HPLC-UV-MS)定性分析方法。液相色谱条件:Inertsil ODS-3色谱柱(250 mm×4.6 mm,5 μm);甲醇和水(含1%乙酸)梯度洗脱,流量1.0 mL/min;柱温35 ℃;检测波长327 nm。质谱条件:Thermo公司TSQ三级四极杆质谱仪;电喷雾电离(ESI)接口;负离子检出模式。采用该方法得到了菊芋叶提取物的紫外检测的色谱图、负离子监测的总离子流图以及相应色谱峰的紫外光谱图和一级、二级质谱图,对其进行解析,鉴别出菊芋叶中的7个绿原酸类成分。该方法简便、快速、灵敏度高,可以很好地对菊芋叶中的绿原酸类化合物进行定性分析。     

美白化妆品中杜鹃醇的超高效液相色谱荧光检测及质谱确证

采用超高效液相色谱结合荧光检测建立了美白化妆品中杜鹃醇的分析方法,并采用液相色谱-串联质谱法进行确证。化妆品试样以5%三氯乙酸-乙腈混合溶液(70∶30)超声提取15 min,离心过膜后,采用通用型的反相C18色谱柱进行分离,以0.1%甲酸水-乙腈(75∶25)为流动相,荧光检测器(λex/λem=280nm/315 nm)检测,外标法定量;质谱确证采用水(含0.01%氨水)和乙腈作为流动相梯度洗脱,电喷雾负离子模式电离,多反应监测模式检测。结果显示,杜鹃醇在0.05~1.0 mg/L范围内线性关系良好,相关系数为0.999 6,方法的定量下限为2.5 mg/kg。面膜、乳霜、乳液和爽肤水等样品在加标浓度为5.0,10,25 mg/kg时的回收率为86.5%~103.4%,RSD(n=6)为1.1%~3.4%。该方法简便、灵敏,加标回收率和重现性良好,可用于化妆品中杜鹃醇的检测及其含量水平的普查。     

高效液相色谱-电感耦合等离子体质谱联用技术测定花茶中砷形态

应用高效液相色谱-电感耦合等离子体质谱(HPLC-ICP-MS)联用技术,建立了花茶中6种砷形态:亚砷酸根、砷酸根、一甲基砷酸、二甲基砷酸、砷胆碱、砷甜菜碱的分析方法。样品在真空条件下采用水-磷酸进行提取,用Hamilton PRP-X100阴离子交换柱,以碳酸铵溶液和硝酸铵+磷酸氢二铵作为流动相进行梯度洗脱,电感耦合等离子体质谱进行定性和定量分析。方法学验证表明:在0.5～50μg/L范围内各砷形态线性良好,线性相关系数(r2)都大于0.999,定量限为0.5μg/L,加标回收率在89.9%～104.1%之间,相对标准偏差(RSD)在1.4%～4.2%之间。方法适用于各类花茶中的6种砷形态分析。     

高效液相色谱光化学在线衍生技术在11种磺胺药物残留检测中的应用

建立了磺胺药物残留的高效液相色谱-光化学在线衍生-荧光检测方法,并应用于猪肉的检测。样品经过乙腈提取,色谱柱分离后,通过在线光化学衍生后,用荧光检测器进行直接检测。优化后的色谱条件:Eclipse Plus C18柱(250 mm×4.6 mm,5.0μm),流动相为均含0.2%甲酸的乙腈、甲醇和水梯度洗脱,检测激发波长为248 nm,发射波长为350和412 nm。各种磺胺在各自浓度范围内线性相关系数R2>0.999,回收率在85.7%~101.1%之间,RSD为1.9%~6.6%(n=6),各磺胺的检出限(S/N=3)为0.2~3.0μg/kg,定量限(S/N=10)为0.5~10.0μg/kg。     

高效液相色谱-电喷雾飞行时间质谱分析娑罗子中皂苷类成分

采用高效液相色谱/电喷雾飞行时间质谱联用技术(HPLC/ESI-TOF/MS),研究4种七叶皂苷的分子结构与裂解规律间的关系,并对娑罗子中的七叶皂苷类化合物进行鉴定。实验采用反相C18色谱柱,以乙腈-0.2%乙酸溶液为流动相,二元线性梯度洗脱,通过与电喷雾飞行时间质谱联用获得娑罗子中各皂苷成分的精确分子量和分子式;采用质谱碰撞诱导解离技术获得各化合物碎片裂解信息,结合文献对娑罗子中的14种皂苷类化合物进行了初步鉴定。研究表明,高效液相色谱-电喷雾飞行时间质谱联用技术是娑罗子中皂苷类化合物鉴别的有效工具。     

超高效液相色谱/高分辨质谱法测定木质素氧化降解产物中单酚类化合物

建立了木质素氧化降解产物中单酚类产物的超高效液相色谱/高分辨质谱联用(UPLC/HRMS)检测方法。采用反相C18色谱柱,柱温30℃,0.1%(V/V)甲酸溶液-10%(V/V)甲醇乙腈溶液为流动相二元梯度洗脱,流速为0.2 mL/min,280 nm波长下紫外检测,可实现木质素氧化降解获得的9种单酚类化合物的有效分离,结合电喷雾离子源超高分辨飞行时间质谱(ESI-Q-TOF)正离子模式进行检测,对单酚类降解产物进行准确定性分析;通过高分辨质谱精确离子流抽提,面积外标法定量分析。本方法的线性范围为5.0~10000μg/L,线性相关系数大于0.9998,相对标准偏差(RSD)小于1.7%,检出限(LOD)和定量限(LOQ)分别为0.1~0.3μg/L和0.3~0.5μg/L,平均加标回收率为98.9%~105.1%。结果表明,酸性流动相体系下的正离子模式进行单酚类产物的质谱分析,具有较好的色谱分离效果和较高灵敏度。     

超高效液相色谱法同时测定洋常春藤中8种成分含量

建立了同时测定洋常春藤中绿原酸、隐绿原酸、芦丁、烟花苷、常春藤皂苷C、常春藤皂苷D、常春藤皂苷B和α-常春藤皂苷8种成分的超高效液相色谱法(UHPLC)。以80%甲醇为溶剂,将药材粉末于85℃、料液比1∶100条件下水浴回流1 h,制备供试品溶液;采用Agilent ZORBAX Eclipse Plus-C_(18)(2.1 mm×100 mm,1.8μm)色谱柱,以乙腈-0.05%磷酸溶液为流动相进行梯度洗脱。结果表明,上述8种成分均获得良好的分离度;仪器精密度、方法重复性的相对标准偏差(RSD)均小于3.0%;样品溶液在室温条件下24 h内稳定;8种成分在对应质量浓度范围内线性关系良好(r≥0.999 5),检出限为0.40～10.58μg·mL~(-1),定量下限为1.31～34.61μg·mL~(-1),平均回收率为97.3%～108%,RSD(n=6)为0.51%～3.2%。该方法适用于洋常春藤中上述8种化学成分的定量分析。     

高效液相色谱-质谱法快速鉴定复方毛冬青冲剂中三萜皂苷活性成分

建立了高效液相色谱-质谱法(HPLC-MS)快速鉴定复方毛冬青冲剂中三萜皂苷活性成分的方法.以甲醇为萃取剂超声萃取复方毛冬青冲剂30 min.采用高效液相色谱-离子阱质谱(HPLC-IT-MS)和高效液相色谱-飞行时间质谱(HPLC-TOF-MS)对萃取液进行分析,选用Agilent Zorbax Eclipse XDB C18色谱柱(250 mm×4.6 mm, 5 μm),以水(含0.1 %甲酸)-乙腈为流动相进行梯度洗脱,柱后流出液采用电喷雾离子阱质谱(ESI-IT-MS)和电喷雾飞行时间质谱(ESI-TOF-MS)的正、负离子模式进行检测.检测结果经离子阱一级质谱(IT-MS1)、离子阱二级质谱(IT-MS2)和分析时间质谱(TOF-MS)信息分析,并与相关文献报道进行比较,鉴定出1种三萜酸和8种三萜皂苷成分,并推测了其它3种可能的三萜皂苷化学成分,通过对照品对比分析,三萜酸确证为Ilexgenin A,其中一种三萜皂苷确证为Ilexsaponin A1.本方法无需对照品即可快速有效地鉴定出复方毛冬青冲剂中的三萜皂苷活性成分,为建立冲剂的质量标准提供了依据.     

超高效液相色谱-电雾式检测器测定福建产绞股蓝中绞股蓝皂苷XLVI和LVI北大核心CSCD

该研究利用超高效液相色谱-电雾式检测器(UHPLC-CAD)建立了福建产绞股蓝中绞股蓝皂苷XLVI和LVI含量的测定方法。首先利用超高效液相色谱-四极杆-飞行时间质谱(UHPLC-Q-TOF/MS)结合UHPLC-CAD鉴定了福建产绞股蓝的主要成分,其中绞股蓝皂苷XLVI、LVI以及二者相应的含丙二酰基酸性皂苷为其主成分,因此在含量测定时先进行碱水解预处理将酸性皂苷转化为对应的去丙二酰基中性皂苷,再利用UHPLC-CAD测定碱水解后绞股蓝皂苷XLVI和LVI的含量。将绞股蓝样品粉末在乙醇-水-氨水(50∶46∶4,v/v/v)和料液比1∶150(g∶mL)条件下超声提取30 min,静置24 h后,在Waters ACQUITY UPLC BEH C18色谱柱(100 mm×2.1 mm,1.7μm)上分离,采用0.1%(v/v)甲酸水溶液和乙腈作为流动相进行梯度洗脱,流速0.5 mL/min,柱温40℃,电雾式检测器检测。结果表明,绞股蓝皂苷XLVI和LVI分别在9.94~318.00μg/mL和12.78~409.00μg/mL范围内具有良好的线性关系,相关系数(r)分别为0.9993和0.9995。方法精密度、重复性和24 h稳定性试验的相对标准偏差(RSD)均小于2.0%(n=6),绞股蓝皂苷XLVI与LVI的加标回收率分别在100.2%~107.2%与97.9%~104.2%范围内,RSD值分别为2.4%与2.6%。16批绞股蓝样品含量测定结果显示:绞股蓝皂苷XLVI含量占0.57%~2.57%,绞股蓝皂苷LVI含量占0.66%~2.99%。该方法灵敏度高,重复性好,可用于福建产绞股蓝的质量研究和质量控制。     

反相高效液相色谱测定依替巴肽注射液中氨基酸的含量

采用异硫氰酸苯酯为柱前衍生化试剂,结合反相高效液相色谱技术,建立了定量分析依替巴肽注射液中氨基酸组分的检测方法。优化色谱条件,选用Agilent XDB-C18色谱柱(5μm,150 mm×4.6 mm),以0.1 mol/L醋酸钠(冰醋酸调至pH 6.0)-乙腈(90∶10)为流动相A,乙腈为流动相B,梯度洗脱方式,检测波长为254 nm,流速为1.0 mL/min,进样体积为5μL,柱温为30℃。结果表明,在优化条件下,各氨基酸能实现有效分离,且在1.23～3.68 mmol/L浓度范围内,各氨基酸的线性关系良好,相关系数(r)为0.999 1～0.999 6。该方法显示了良好的准确性、重复性、稳定性及选择性,能对依替巴肽注射液中的氨基酸实现准确定量分析。     

Simultaneous determination of phenolic acids and flavonoids in rice using solid-phase extraction and RP-HPLC with photodiode array detection

An analytical method based on an optimized solid-phase extraction procedure and followed by high-performance liquid chromatography (HPLC) separation with diode array detection was developed and validated for the simultaneous determination of phenolic acids (gallic, protocatechuic, 4-hydroxy-benzoic, vanillic, caffeic, syringic, p-coumaric, ferulic, sinapic, and cinnamic acids), flavanols (catechin and epicatechin), flavonols (myricetin, quercetin, kaempferol, quercetin-3-O-glucoside, hyperoside, and rutin), flavones (luteolin and apigenin) and flavanones (naringenin and hesperidin) in rice flour (Oryza sativa L.). Chromatographic separation was carried out on a PerfectSil Target ODS-3 (250 mm × 4.6 mm, 3 μm) column at temperature 25°C using a mobile phase, consisting of 0.5% (v/v) acetic acid in water, methanol, and acetonitrile at a flow rate 1 mL min(-1) , under gradient elution conditions. Application of optimum extraction conditions, elaborated on both Lichrolut C(18) and Oasis HLB cartridges, have led to extraction of phenolic acids and flavonoids from rice flour with mean recoveries 84.3-113.0%. The developed method was validated in terms of linearity, accuracy, precision, stability, and sensitivity. Repeatability (n = 5) and inter-day precision (n = 4) revealed relative standard deviation (RSD) <13%. The optimized method was successfully applied to the analysis of phenolic acids and flavonoids in pigmented (red and black rice) and non-pigmented rice (brown rice) samples.     

Droplet microfluidics based microseparation systems

Lab on a chip (LOC) technology is a promising miniaturization approach. The feature that it significantly reduced sample consumption makes great sense in analytical and bioanalytical chemistry. Since the start of LOC technology, much attention has been focused on continuous flow microfluidic systems. At the turn of the century, droplet microfluidics, which was also termed segmented flow microfluidics, was introduced. Droplet microfluidics employs two immiscible phases to form discrete droplets, which are ideal vessels with confined volume, restricted dispersion, limited cross-contamination, and high surface area. Due to these unique features, droplet microfluidics proves to be a versatile tool in microscale sample handling. This article reviews the utility of droplet microfluidics in microanalytical systems with an emphasize on separation science, including sample encapsulation at ultra-small volume, compartmentalization of separation bands, isolation of droplet contents, and related detection techniques.     

乙酸镍吡啶配合物催化的分子氧氧化反应研究

Ni(OAc)2结合吡啶和叔丁基过氧化氢(TBHP)实现了苄基C-H与苄基醇类化合物在温和条件下(80～90℃,O21 atm)的选择性催化分子氧氧化反应.研究了过氧化物添加剂,配体,溶剂和温度的影响,得到了优化的反应条件.在苄基C-H的氧化中显示了很高的酮/醇选择性.用ESR法进行了Ni(III)的检测,证实了反应机理.竞争实验说明羰基化合物的生成不是因为醇继续氧化.酮可被解释为过氧化氢中间体受金属催化分解的产物.     

Changes in the proteome of extracellular vesicles shed by rat liver after subtoxic exposure to acetaminophen

To identify changes in extracellular vesicles (EVs) secreted by the liver following drug-induced liver injury (DILI), rats were treated with a subtoxic dose (500 mg/kg) of the analgesic drug, acetaminophen (APAP). EVs were collected by liver perfusion of sham and APAP-treated rats. Changes in EVs morphology were examined by transmission electron microscopic analysis of negatively stained vesicles. Results from morphometric analysis of EVs revealed striking differences in their size and distribution. Proteome composition of EVs collected by liver perfusion was determined by mass spectrometry using methods of sample preparation that enabled better detection of both highly hydrophobic proteins and proteins with complex post-translational modifications. The collection of EVs after liver perfusion is an approach that enables the isolation of EVs shed not only by isolated hepatocytes, but also by the entire complement of hepatic cells. EVs derived after DILI had a lower content of alpha-1-macroglobulin, ferritin, and members of cytochrome 450 family. Fibronectin, aminopeptidase N, metalloreductase STEAP4, integrin beta, and members of the annexin family were detected only in APAP-treated samples of EVs. These results show that the present approach can provide valuable insights into the response of the liver following drug-induced liver injury.     

Paternal genetic structure of Kyrgyz ethnic group in China revealed by high-resolution Y-chromosome STRs and SNPs

Kyrgyz ethnic group is one of the nomads in China, with the majority in Xinjiang and a small part of them living in Heilongjiang province. Historically, they have went through five migrations westward due to the wars. The name “Kyrgyz” means 40 tribes, originating from the primary groups of Kyrgyz. However, it is a largely understudied population, especially from the Y chromosome. In this study, we used a previously validated high-resolution Y-chromosome single nucleotide polymorphisms (Y-SNPs) and short tandem repeats (Y-STRs) system to study Kyrgyz ethnic group. A total of 314 male samples of Kyrgyz ethnic group were genotyped by 173 Y-SNPs and 27 Y-STRs. After data analysis, the results unveiled that Kyrgyz ethnic group was a population with high percentage of both haplogroup C2a1a3a1d∼-F10091 (91/134) and R1a1a1b2a2-Z2124 (109/134), which has never been reported. This implied that Kyrgyz ethnic group might have gone through bottleneck effects twice, with these two main lineages left. Mismatch analysis indicated that the biggest mismatch number in haplogroup C2a1a3a1d∼-F10091 was 10, while that of haplogroup R1a1a1b2a2-Z2124 was 20. This huge difference reflected the different substructure in two lineages, suggesting that haplogroup C2a1a3a1d∼-F10091 might have the least admixture compared to the other two lineages. After admixture modelling with other datasets, the conclusion could be drawn that Kyrgyz ethnic group had great genetic affinity with Punjabi from Lahore, Pakistan, which supported that Kyrgyz ethnic group in China was close to central Asian.     

TPD study of NH3 adsorption/desorption on the surface of V/Ti, V/Al based catalysts for selective catalytic reduction of Nox by ammonia 2. TPD test of commercial V/W/Ti, V/Al, Pd/V/Al catalysts

The effect of temperature on the adsorption/desorption of ammonia from the air mixture on the surface of commercial binary V/Al and ternary Pd/V/Al, V(0.65 wt.%) /W(6.73 wt.%) /Ti and V(1.8 wt.%) /W(7.3 wt.%) /Ti de-NO_x catalysts has been investigated by temperature-programmed desorption (TPD) method. The ability of the commercial catalysts to adsorb ammonia in the most stable surface species was shown to correlate well with their suppression of the NH₃ oxidation.     

Electroosmotic flow: From microfluidics to nanofluidics

Electroosmotic flow (EOF), a consequence of an imposed electric field onto an electrolyte solution in the tangential direction of a charged surface, has emerged as an important phenomenon in electrokinetic transport at the micro/nanoscale. Because of their ability to efficiently pump liquids in miniaturized systems without incorporating any mechanical parts, electroosmotic methods for fluid pumping have been adopted in versatile applications—from biotechnology to environmental science. To understand the electrokinetic pumping mechanism, it is crucial to identify the role of an ionically polarized layer, the so-called electrical double layer (EDL), which forms in the vicinity of a charged solid–liquid interface, as well as the characteristic length scale of the conducting media. Therefore, in this tutorial review, we summarize the development of electrical double layer models from a historical point of view to elucidate the interplay and configuration of water molecules and ions in the vicinity of a solid–liquid interface. Moreover, we discuss the physicochemical phenomena owing to the interaction of electrical double layer when the characteristic length of the conducting media is decreased from the microscale to the nanoscale. Finally, we highlight the pioneering studies and the most recent works on electro osmotic flow devoted to both theoretical and experimental aspects.     

Simultaneous liquid-liquid extraction of dibenzyl disulfide, 2,6-di-tert-butyl-p-cresol, and 1,2,3-benzotriazole from power transformer oil prior to GC and HPLC determination

2,6-Di-tert-butyl-p-cresol (DBPC), dibenzyl disulfide (DBDS), and 1,2,3-benzotriazole (BTA) are additives that may be found concomitantly in the oil matrix of power transformer. DBPC and DBDS act as antioxidants while, BTA is a corrosion inhibitor that protects copper conductors inside the transformer unit from corrosion. A powerful analytical method is, therefore, required to determine these additives at trace levels in the transformer oil. This work describes a unique single liquid-liquid extraction pretreatment step prior to the determination of the components by gas chromatography (GC) and high-performance liquid chromatography (HPLC) techniques. The optimum volume ratio used in the pretreatment step was determined as 5:2:5 for mineral oil/n-hexane/acetonitrile, respectively. Relatively, the method is simple and quick with a minimal use of solvents. Analytical results indicate that the method is relatively sensitive, accurate, and precise for each of the three components in fresh and used mineral oil. The calibration curves for the three components demonstrate a significant increase in sensitivities. Detection limits found were, 100 mg L(-1) (0.01% w/v), 0.80 mg L(-1) , and 2.04 mg L(-1) for DBPC, DBDS, and BTA, respectively. The Student's t values determined at 95% confidence level indicate that there is no significant difference between the experimental means obtained by this method and the standard method for each component.     

Analysis of alendronate in human urine and plasma by magnetic solid-phase extraction and capillary electrophoresis with fluorescence detection

A simple, rapid and sensitive CE-fluorescence (FL) detection method for the analysis of alendronate (ALEN), a bisphosphonate drug, has been developed. Using a buffer solution of 20 mM sodium phosphate (pH 10.0) and a voltage of 24 kV, separation of ALEN in a 55-cm length (35-cm effective length) capillary was achieved in 5 min. FL detection of ALEN was performed via pre-column derivatization with 2,3-naphthalene dicarbox-yaldehyde (NDA). Linear correlation (r=0.9981, n=6) between FL intensity and analyte concentration was obtained in the range of 7-200 ng/mL ALEN. The developed CE-FL method was applied to the analysis of ALEN in human urine and plasma samples. In order to eliminate the interfering matrix components, SPE using magnetic Fe(3) O(4) @Al(2) O(3) nanoparticles as solid sorbents was employed to clean the biological fluids before CE-FL analysis. The linear ranges of ALEN in urine and plasma were 5-100 ng/mL (r = 0.9982, n = 7) and 5-70 ng/mL (r = 0.9954, n = 7), respectively. The LOD and LOQ in both urine and plasma samples were 1.5 and 5 ng/mL ALEN, respectively. Total analysis time including sample pre-treatment and CE separation was less than 1.5 h.     

盐酸氯丙嗪在聚L-苏氨酸/多壁碳纳米管修饰电极上的电化学行为

以玻碳电极为基底成功制备了聚L-苏氨酸poly(L-Threonine)/多壁碳纳米管(MCNTs)修饰电极(p-L-Thr/ MCNTs/GCE).研究了盐酸氯丙嗪在该修饰电极上的电化学行为.该修饰电极对盐酸氯丙嗪具有明显的电催化氧化作用,并对此电极进行显微表征.本研究将此修饰电极用于流动注射不可逆双安培(FL-IB)体系的构建,即利用盐酸氯丙嗪在p-L-Thr/MCNTs/GCE上的氧化和高锰酸钾(KMnO4)在另一支铂电极上的还原构建了双安培检测体系,成功的建立了在外加电压为0 V条件下流动注射双安培法直接测定盐酸氯丙嗪的方法.在0 V外加电压下,在1 mol/L pH6.8的磷酸盐缓冲溶液的载液中,氧化峰峰电流与盐酸氯丙嗪浓度在2.0×10-6mol/L～4.0×10-5 mol/L范围内呈良好的线性关系,其线性回归方程为i (nA)=9.73×107C-50(r=0.9993,n=6),在4.0×10-5mol/L～10-3 mol/L范围内呈线性关系,其线性回归方程为i (nA)=2.33×107C+4×103 (r=0.9984,n=7),方法检出限为4.0×10-7 mol/L (S/N=3).连续测定1.00×10-4mol/L的盐酸氯丙嗪标准溶液20次,电流值RSD为2.44%,进样频率为90样/h.该方法具有较高的选择性和灵敏度.对盐酸氯丙嗪片中的盐酸氯丙嗪的含量的测定,结果比较满意.