HPLC-MS法快速检测平喘类保健食品中非法添加的化学物质

针对平喘类保健食品中非法添加化学物质的现象,建立HPLC-MS法快速检测平喘类保健食品中12种非法添加化学物质。待测样品经甲醇提取,采用液相色谱-电喷雾离子肼质谱联用法测定。色谱条件:Thermo Hypersil GOLD C18色谱柱(4.6×250mm,5μm);梯度洗脱:流动相A为甲酸铵溶液;流动相B为乙腈;质谱条件:扫描方式:正离子扫描;雾化气压:35psi,去溶剂气温度:350℃,去溶剂气流量:10L/min;离子扫描范围:50~1000m/z;通过对照品与样品一级、二级质谱图的对比,定性鉴别样品中非法添加的化学物质。在10批样品中,检测到有9批样品中含有化学物质。结果表明该方法简便、快捷,准确性及灵敏度均可满足定性检查的要求。     

气相色谱-质谱法测定鱼肉中丁香酚的残留

研究建立一种鱼肉中丁香酚(eugenol)残留量的固相萃取-气相色谱-质谱检测方法.样品采用正己烷提取,硅胶柱净化,乙酸乙酯洗脱,气相色谱-质谱测定,内标法定量.丁香酚的响应值与其质量浓度在0.005~0.5 mg·L-1范围内的线性关系良好,相关系数为0.999 8;10~200μg·kg-1添加浓度的日内和日间平均回收率为80.6%~93.2%,相对标准偏差为3.47%~8.47%;检出限为5μg·kg-1,最低定量限为10μg·kg-1.该方法适用于鱼肉中丁香酚残留的检测.     

高效液相色谱-串联质谱测定化妆品中2,4,6-三氯苯酚和五氯苯酚

本试验建立了化妆品(爽肤水和润肤乳)中禁用的含氯苯酚(2,4,6-三氯苯酚和五氯苯酚)的超高效液相色谱-串联质谱测定方法,采用Q1多离子监测模式。1.0g爽肤水和1.0g润肤乳样品经10mL正己烷超声辅助提取后,取正己烷层45℃氮吹至近干,甲醇定容,经液相色谱分离、质谱测定,外标法定量。2,4,6-三氯苯酚在添加水平200μg/kg和800μg/kg时,方法的回收率范围为81.6%-94.5%,五氯苯酚在添加水平50μg/kg和200μg/kg时回收率范围为65.3%-74.3%,相对标准偏差小于6%。爽肤水中2,4,6-三氯苯酚和五氯苯酚的检出限分别为20μg/kg和3μg/kg,定量限分别为50μg/kg和10μg/kg;润肤乳中2,4,6-三氯苯酚和五氯苯酚的检出限分别为30μg/kg和5μg/kg,定量限分别为100μg/kg和20μg/kg。该方法可用于爽肤水和润肤乳中2,4,6-三氯苯酚和五氯苯酚的快速筛查和定量分析。     

超高效液相色谱-串联质谱法测定4种麻痹性贝类毒素

建立了超高效液相色谱-串联四极杆质谱法测定贝类中4种麻痹性贝类毒素的方法。样品均质后经乙酸水溶液提取,HLB固相萃取柱净化,超高效液相色谱分离,串联四级杆质谱检测,外标法定量。STX、dcSTX、neoSTX、dcneoSTX在10.0～50.0μg/kg的添加范围内的平均回收率为77.4%～90.8%,相对标准偏差为3.87%～6.37%,定量检出限均为10.0μg/kg。该方法分析速度快、灵敏度高、重现性好,可广泛适用于贝类中麻痹性贝类毒素的测定。     

离子色谱-串联质谱法测定茶叶中的氯酸盐和高氯酸盐

利用离子色谱-串联质谱技术测定茶叶中氯酸盐、高氯酸盐的含量,通过优化提取条件和色谱-质谱等参数,在茶叶经纯水提取,固相萃取净化后,用离子色谱-质谱负离子模式进行定性、内标法定量分析。结果表明,氯酸盐在0.08～200 ng/m L、高氯酸盐在0.04～100 ng/m L范围内线性良好,相关系数均大于0.999,氯酸盐、高氯酸盐检出限分别1.0、0.5μg/kg,定量限分别为4.0、2.0μg/kg,加标回收率为80.0%～107.9%,相对标准偏差为0.47%～12.3%。所建方法检出限低,精密度良好,可准确定性和定量茶叶中氯酸盐和高氯酸盐的含量,为我国茶叶的风险监测提供了一种有力的技术手段。     

气相色谱-串联质谱检测烟草中10种酰胺类除草剂残留

采用固相萃取-气相色谱-串联质谱来测定烟草中10种酰胺类除草剂的残留量。烟草样品通过含1%乙酸的乙腈混合液提取,固相萃取净化,采用气相色谱分离,串联质谱多反应监测模式分析。10种酰胺类除草剂在0.01~1.0 mg/L线性范围内均呈良好线性关系,相关系数大于0.997,方法的检出限在0.2~4.7μg/kg之间。在10μg/kg,50μg/kg,100μg/kg等3个浓度水平下进行加标实验,其加标回收率在79.6%~101.4%之间,测定值的相对标准偏差(n=6)在1.6%~6.7%之间。建立的方法简便、快速、灵敏,为常见烟草中酰胺类除草剂残留的准确判断提供了可靠依据,适用于烟草中10种酰胺类除草剂的同时检测。     

超高效液相色谱-质谱联用法测定水产品中喹乙醇代谢物残留量

建立了水产品中喹乙醇代谢物残留量的超高效液相色谱-质谱联用测定方法。样品经乙酸乙酯提取、液液萃取净化后吹干,流动相定容,经超高效液相色谱分离后进入串联质谱检测器。采用电喷雾正离子,多反应监测(MRM)模式检测,内标法定量。方法的检出限为1μg/kg,浓度在2～100 ppb范围内,线性良好(r=0.999),添加浓度1～20μg/kg下,不同水产品基质的回收率在80%～100%之间,相对标准偏差(RSD)小于10%。     

液相色谱-质谱联用法检测鸡蛋中8种氟喹诺酮类药物残留

建立了一种液相色谱-质谱联用法(LC-MS/MS)快速测定鸡蛋中8种氟喹诺酮类药物残留的方法.样品经磷酸-乙腈提取,冷冻离心,旋转蒸发浓缩,初始流动相溶解,然后用正己烷脱脂,有效地去除杂质,随后进行LC-MS/MS定性定量分析.8种氟喹诺酮类药物含量在2~50μg/kg线性关系良好,相关系数R均大于0.995 6;添加量在5,10和20μg/kg时,该方法的加标回收率为65.4%~119.6%,相对标准偏差均小于7.52%.该方法的检出限为0.000 5~0.22μg/kg,定量限为0.02~0.74μg/kg,适用于鸡蛋中8种氟喹诺酮类药物残留的定性和定量检测.     

HPLC-MS-MS正负离子切换测定豆芽中4种植物生长调节剂残留量

建立了高效液相色谱-串联质谱法(HPLC-MS-MS)同时测定豆芽中4种植物生长调节剂(6-苄基腺嘌呤、赤霉酸、对氯苯氧乙酸、咪酰胺)残留的方法。样品加入少量无水硫酸钠后采用含1%(V/V)乙酸的乙腈溶液提取,Qu ECh ERS(PSA+C18)净化。在ESI源下进行正负离子切换扫描检测,以保留时间和特征离子对定性,外标法定量。结果表明4种待测物质在1.0-200μg/L范围内线性关系良好,定量离子对的相关系数大于0.9990。方法定量限(S/N=10)赤霉酸为20μg/kg,其余三种均为2.5-5.0μg/kg,方法回收率为81.3%-102.5%。本文提供了质谱中正负离子切换同时检测多个植物生长调节剂残留的方法,可满足一针进样同时测定,前处理方法简便,回收率高,可应用于豆芽中4种植物生长调节剂残留的日常检测。     

SPE-UPLC-MS/MS快速测定豆制品中的乌洛托品

建立了一种固相萃取-超高效液相色谱质谱联用(SPE-UPLC-MS/MS)测定豆制品中乌洛托品的分析方法。样品经粉碎后,采用乙腈提取,ProElut PXA小柱净化,Shim-pack XR-ODS色谱柱分离,在电喷雾正离子模式下用质谱仪进行MRM分析。结果表明:乌洛托品在0～160μg/kg范围内呈现良好的线性关系,线性相关系数为0.9998,该方法对应的检出限和定量限分别为0.3μg/kg和1μg/kg在5～100μg/kg添加水平下,乌洛托品回收率为88.4%～97.1%,相对标准偏差为5.39%～8.74%。该方法简便,快速,可成功应用于豆制品中乌洛托品的检测。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that