固相萃取-高效液相色谱法快速测定生活用水中痕量苯并[a]芘

针对国家标准GB/T 5750.8(9.1)-2006生活用水中苯并[a]芘测定方法进行改进,采用固相萃取-高效液相色谱荧光检测法,通过全自动盘氏固相萃取仪对生活用水中的苯并[a]芘进行富集,可以快速准确测定其含量.实验结果表明苯并[a]芘在0.00μg/L～5.00μg/L的浓度范围内呈现良好的线性关系,相关系数为0...     

高效液相色谱荧光法测定贵阳市市售腊肉中苯并[a]芘含量

建立高效液相色谱法测定腊肉中苯并[α]芘(简称BaP)的测定方法。通过先超声提取,后皂化的处理,采用迪马C18色谱柱(250mm×4.6mm,5μm);乙腈-水为流动相;荧光检测器,激发波长为385 nm;检测波长为405nm;苯并[a]芘在(0.005-1.0μg/mL)范围呈线性,其线性回归方程为:Y=1.8×107x+11012;相关系数R=0.9992;苯并[a]芘在0.0035、0.0070、0.0105μg 3个添加浓度水平上的回收率为(83.08%、88.67%、84.54%)。本法色谱条件易于掌握,测得数据重复性好,线性关系好,精密度和准确度均能满足分析要求。同时本文对贵阳市主要市售腊肉中苯并[α]芘(BaP)含量进行了测定,结果含量在1.04~4.16μg?kg之间,表明传统的油炸食品安全性使人的健康受到不同程度的影响。     

高效液相色谱法测定辣条中苯并[a]芘的含量

使用C18反相色谱柱,高效液相色谱检测仪,甲醇与水的混合溶液作为流动相,比例为90∶10,流速2.0 mL/min,检测波长260 nm,进样量为20μL,紫外检测器对样品中苯并[a]芘的含量进行定量检测。检出限为36.04μg/L,辣条中苯并[a]芘的平均加标回收率为102.5%,实验相对标准偏差为1.20%(n=9)。方法步骤简单、溶剂与试样消耗少、样品分析时间短,具有良好的精密度以及高回收率,适合于对辣条中苯并[a]芘浓度的有效检测。     

离子液体-中空纤维膜液相微萃取-高效液相色谱法快速测定卷烟烟气中的苯并[a]芘

将中空纤维膜液相微萃取技术与高效液相色谱-荧光检测器相结合,建立卷烟烟气中苯并[a]芘的分析检测新方法.以疏水性离子液体1-辛基-3-甲基咪唑六氟磷酸盐([OMIM]PF6)作萃取剂,十一烷酸乙腈溶液作为液膜支持相溶剂,在最佳实验条件下,萃取平衡可在3 min内完成.苯并[a]芘浓度在0.1~20.0ng/mL范围内与其色谱峰面积呈良好的线性关系,相关系数R2=0.999 4,检出限为0.05ng/mL.该方法已成功应用于卷烟烟气中苯并[a]芘的分析检测,回收率为93.6%~102.4%,相对标准偏差为2.7%~4.8%.     

GPC-气相色谱质谱法测定卷烟主流烟气中的苯并[a]芘

建立了用凝胶渗透色谱(GPC)联用GC-SIM-MS法测定卷烟主流烟气中苯并[a]芘的方法.卷烟烟气样品经环己烷超声萃取,GPC系统分离纯化后,经浓缩后用GC-SIM-MS分析测定.与经固相萃/R(SPE)分离纯化的样品相比,通过GPC系统处理后,卷烟烟气样品的干扰烽大大减小,样品谱图干净.该方法测定苯并[a]芘的线性范围为:10.00ng/mL～130.00ng/mL;相关系数R2为O.999 1,检出限为0.99ng/mL,加标回收率为91.70%-103.40%.GPC系统在处理卷烟烟气样品上有独特的优势,该方法适宜应用于卷烟主流烟气中苯并[a]芘含量检测.     

气相色谱-质谱法检测卷烟烟气中的苯并[a]芘

通过固相萃取方法去除卷烟烟气中杂质对分析物苯并[a]芘的影响,建立了气相色谱-选择离子(SIM)质谱方法分析卷烟烟气中有害物质苯并[a]芘的量,该方法的相对标准偏差为3.2%,回收率为96.3%,检测限可达到0.07ng/支卷烟.检测了国内外卷烟烟气中苯并[a]芘的量,结果显示国产烤烟型卷烟烟气中苯并[a]芘的量明显高于国外混合型卷烟.     

GC-MS/MS法快速测定卷烟主流烟气中苯并[a]芘的含量

建立了一种使用GC-MS/MS法测定卷烟主流烟气中苯并[a]芘含量的方法,以内标法定量.将捕集了20支卷烟主流烟气的总粒相物的剑桥滤片用40 mL含有内标物的环己烷振荡萃取,过滤后检测.苯并[a]芘的检出限、定量限分别可达0.056 4 ng/cig和0.094 0 ng/mL,线性相关系数达0.999 4;日内重复性和日间重现性分别为2.39%和3.97%;在3种不同添加浓度下,加标回收率分别在93.00%~109.00%之间.该方法操作简便、重复性好、分析通量大、受环境和人为因素干扰较小,可以作为一种准确、快速测定卷烟主流烟气中苯并[a]芘含量的改进方法加以推广.对无烟气烟草制品质量控制具有重要意义.     

高效液相色谱法测定间苯二甲醛含量在工业上的应用

建立了工业生产中测定间苯二甲醛含量的高效液相色谱方法.采用Kromasil C18(150mm×4.6mm,5μm);流动相:水-乙腈(65∶35按0.1%加入三氟乙酸);流速:1.0mL/min;在220nm波长处检测.间苯二甲醛在4.0～160.0μg/mL的浓度范围内呈线性关系,r=0.9999.高效液相色谱法简单、准确、快速,可精确测定间苯二甲醛的有效含量,适用于药品的出厂分析.     

液液萃取-高效液相色谱法测定水体中的阿特拉津

为建立检测水体中阿特拉津的高效液相色谱法,以Kromasil-C18(250 m×4.6 mm×5μm)为色谱柱,以甲醇∶水=7∶3为流动相,流速0.8 mL/min,采用紫外检测器,用外标法测定水体中阿特拉津含量。结果表明,方法线性范围为0.030~1.96μg/ml,相关系数达0.999 4;采样体积为100 mL时,方法的最低检测浓度为0.30μg/L;对不同加标浓度水样的回收率为87.9%~93.0%,相对标准偏差为1.2%~3.4%。该方法适用于水体中痕量和常量阿特拉津的测定。     

食用油中苯并[α]芘净化技术的优化及高效液相检测方法的建立

针对我国国标中食用油中苯并[a]芘检测方法的不足,建立高效液相色谱法-FLD检测方法,通过优化检测条件得到的最佳操作条件:检测波长:激发波长384nm,发射波长406nm;流动相为乙腈:水(梯度洗脱),在最佳实验条件下,苯并[a]芘得到良好的分离,对苯并芘标准溶液的检测分析的相对标准偏差小于5.5%,方法的检出限(3倍信噪比)和定量下限(10倍信噪比)分别为0.046μg/kg和0.155μg/kg。选用花生油、辣椒油、煎炸油为本底,通过比较中性氧化铝柱、HLB小柱、分子印迹技术、GPC凝胶色谱净化技术、QuEChERS提取净化几种不同前处理在三种食用油中苯并芘的提取效果,确定了食用油中苯并[a]芘检测的前处理技术,建立了分子印迹柱净化-效液相色谱仪联用的检测方法,优化分子印迹技术各影响因素。并考察了日常食用油和油炸油中苯并[a]芘含量情况。     

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