新型微填充柱－毛细管柱色谱操作条件的优化及灰色关联分析

 通过正文设计实验方法优化了新型微填充柱。毛细管柱色谱操作条件，并利用灰色关联分析方法考察了操作条件与柱效的相关程度，对实验能起一定的指导作用。     

XDA-1树脂对茶多酚的吸附及吸附柱放大研究

研究了XDA-1树脂对茶多酚的吸附及吸附柱放大规律。建立了XDA-1树脂柱吸附茶多酚过程的传质模型，并根据该模型分别计算了不同操作条件下相应的物质总传质系数及传质区长度．结果表明，在实验操作的流速范围内，过程属于外扩散控制．按照操作线速度相等的原则进行固定床设备的放大，传质区长度的放大误差在10％左右，实验所得传质区长度的结果可作为吸附柱设计的基础．     

不依赖于统计模型的手性毛细管电泳分离多指标同时优化

考虑到手性毛细管电泳分离机理的复杂性，提出了不依赖于统计模型的二进制编码遗传算法多目标优化策略。根据实验参数的多少及其重要性，采用均匀设计安排完成初步实验。并用Derringer功效函数作为多指标同时优化的评价指标，以取得较高的分离度和较快分离速度；通过对实验参数给予编码，转化为二进制字符串，根据得到的总功效函数值大小进行遗传算法操作，产生新的一组实验条件。重复上述过程直到得到最佳分离条件为止。此方法成功地应用于华法令对映体的毛细管电泳分离条件优化。     

电沉积非晶态铁—铬合金镀层的研究

本实验通过控制镀液组成和操作条件获得了非晶态铁－铬合金镀层，实验分析了ＰＨ值，电流密度以及镀层中铬含量对所形成镀层的非晶态结构的影响，阳极极化曲线测量结果表明，与晶态层相比，非晶态度层具有较高的耐蚀性。     

对白磷燃烧实验的改进

由于白磷的燃点低,在自然条件下能够与氧气发生剧烈的氧化反应,使得通过白磷的燃烧来研究物质燃烧的条件操作困难,任何不慎操作都会使实验失败甚至威胁到实验人员的安全。因此设计了将白磷放置于可控制氧气流速的实验装置中,人工控制氧气的流速并能确定反应温度,较好地解决了上述操作难题,该方法直观、简便、危险性小,并能使学生容易推导出物质燃烧的条件。     

学生实验操作受挫的心理因素及其矫正对策

实践证明：学生在实验操作时,常常遇到困难或出现一些问题,不仅阻碍了实验的进展,还会影响实验效果。这除了受实验条件、知识和能力素质的影响外,由心理因素引起的操作受挫占有很大的比重。因此,心理因素对学生实验操作的影响不容忽视,这是全面提高学生实验素质不可缺少的研究课题。     

TiCl4/Al体系中低价钛诱导下的硝基苯还原偶联反应实验

设计了以铝粉为还原剂还原TiCl4形成TiCl4／Al的新体系，并成功地用于硝基苯的还原偶联反应，具有还原剂易得、条件温和、选择性好、收率较高等优点。这一实验涉及到有机化学的一个基本反应——还原偶联反应，在不同条件下经还原得到多种产物，并可实施产物间相互转化。合成也涉及到多种基本实验操作，并可根据实验结果及分析数椐推测反应过程。     

灰熔聚射流流化床适宜操作条件及几何结构

在３００×５０×２６００ｍｍ带有流化分离柱的灰熔聚冷模流化床中，选用具有实际意义的焦粉／灰球体系，通过考察不同操作条件及不同几何结构时灰球的分离效率及分离速率的变化特征，以确定这一射流流床的适宜操作及几何条件。证明了对分离操作而言，射流分离分隔式的流化床具有操作弹性大的优点。基于实验结果及理论分析，指出流出分离柱高／宽比小于３．７时可获得稳定分离操作，并给出分离柱高效分离操作时的气速变化范围。本文     

从双多阶程升保留时间预测恒温保留指数可行性研究

由于程序升温保留值受多种操作条件的影响，缺乏数据的共用性，作者提出了根据组分双多阶程序升温保留时间预测其恒温保留指数的方法。以烃类化合物对象，从理论和实验两方面论证了该法的可行性。     

气相色谱热导池定量法中的某些问题

本文讨论了各种操作条件对热导池鉴定器定量的影响,并用实验结果验证,同时讨论了各种定量方法与测量方法的优缺点,并对操作条件控制范围和仪器设计提出了要求。     

猪毛水解母液中氨基酸的反相高效液相色谱分析

A new method for separation and quantification of amino acids by pre-column derivatization withphenylisothiocyanate(PITC ) and reversed-phase HPLC is described. Seventeen amino acids were separatedin 30 min at room temperature.The method has been successfully applied to the determination of amino acidcomposition in the solution which was prepared by hydrolyzing pig hair and extration of cystine.     

Derivatization of ephedrine with o-phthaldialdehyde for liquid chromatography after treatment with sodium hypochlorite

The usefulness of the reaction with NaClO followed by derivatization with o-phthaldialdehyde (OPA) and N-acetyl-L-cysteine (NAC) has been investigated for the chromatographic analysis of ephedrine. The influence of parameters affecting the two-stage reaction has been evaluated, including concentration of NaClO, time of reaction, temperature and pH. On the basis of these studies, conditions for the pre-column and (automated) post-column determination of ephedrine are presented. The described conditions have been applied to the measurement of ephedrine in the concentration intervals 0.2-20.0 microg/ml and 2.0-50.0 microg/ml for the pre-column and post-column methods, respectively. The possibility of applying the NaClO/ OPA-NAC method to other primary, secondary and tertiary derivative amphetamines has also been evaluated.     

Coupled LC-GC: Evaporation rates for partially concurrent eluent evaporation using an early solvent vapor exit

Partially concurrent eluent evaporation presupposes an eluent evaporation rate in the GC pre-column that approaches the LC flow rate. Discharging the vapors through the whole GC column, evaporation rates reach 10–30 μl/min, i.e. are suitable just for LC flow rates typical for packed capillary LC columns. With an early vapor exit, evaporation rates are increased to 100–200 μl/min (under extreme conditions to some 800 μl/min), thus fitting the LC flow rates of 2 mm i.d. columns. Evaporation rates were measured for a standard set of pre-columns and conditions. The dependence of the evaporation rate on temperature, inlet pressure, carrier gas, and internal diameter of the retaining pre-column are discussed in order to allow the design of a GC system producing a desired evaporation rate.     

柱前衍生高效液相色谱法测定四氢噻唑-2-硫酮-4-羧酸的光学纯度

用苯胺对四氢噻唑-2-硫酮-4-羧酸(TTCA)进行柱前衍生,将其衍生物在手性固定相上拆分,通过二极管阵列紫外检测器和在线旋光检测仪对其衍生物进行检测,建立了一种拆分TTCA消旋体、测定TTCA光学纯度的新方法。以正己烷和乙醇或异丙醇为流动相,在DNB-Leucine手性固定相上对TTCA衍生物进行了拆分,并考察了流动相组成和柱温对其衍生物分离的影响,获得较优分析条件,分离因子大于1.2。非手性试剂苯胺柱前衍生化法测定(R)-TTCA的光学纯度与旋光度方法比较,结果一致,相对偏差小于1.34%。     

二维色谱柱效的支持向量回归预测

以有效塔板数作为二维色谱的柱效指标,根据二维色谱在不同影响因素(包括预柱柱温、主柱柱温、柱间压差和主柱间的放空量)下的有效塔板数实测数据集,应用基于粒子群算法(PSO)寻优的支持向量回归(SVR)方法,建立了二维色谱柱效的SVR预测模型,并与BP神经网络(BPNN)模型进行了比较.结果表明:基于相同的训练样本和检验样本,二维色谱的SVR模型的平均绝对百分误差(MAPE, 13.3%)比其BPNN模型的MAPE小4%;增加训练样本数有助于提高支持向量回归(SVR)模型的泛化性能;基于留一交叉验证法(LOOCV)的SVR模型预测的平均绝对误差(MAE, 196.79 m-1)和MAPE(1.6%)均为最小,明显优于BPNN模型(2397.98 m-1, 17.3%)或SVR模型(1849.95 m-1, 13.3%)的预测效果.因此,SVR是一种预测二维色谱柱效的有效方法.     

Rapid analysis of methylated xanthines in teas by an improved high-performance liquid chromatographic method using a polyvinylpolypyrroridone pre-column.

We have developed a new high-performance liquid chromatography (HPLC) method for the analysis of methylated xanthines in tea by removing polyphenols using a polyvinylpolypyrroridone (PVPP) pre-column. The PVPP pre-column was connected with the upstream of analytical column to remove catechins in tea extract. Using this pre-column, caffeine and theobromine in tea, which belong to methylated xanthines, could be rapidly determined in less than 10 min with an isocratic solvent system. RSDs of standard solutions of caffeine and theobromine were about 0.3 and 0.3% for the retention time, and were about 1.6 and 2.5% for the peak area. The quantitation curves of caffeine and theobromine were linear from 5 to over 1000 ng.     

手性固定相HPLC法拆分3-叔丁基己二酸对映体

用苯胺对3-叔丁基己二酸对映体进行柱前衍生后,在CHIRALCEL OD-H手性固定相上拆分,并通过二极管阵列紫外检测器和在线旋光检测器对其衍生物进行检测,首次建立了一种拆分3-叔丁基己二酸消旋体和测定3-叔丁基己二酸光学纯度的新方法。考察了流动相组成、柱温和流速对该对映体衍生物分离的影响。结果表明,3-叔丁基己二酸衍生物对映体在正己烷-异丙醇(体积比90∶10)为流动相,流速为1.0 mL.min-1,柱温为30℃时,分离效果最佳。在优化的实验条件下,分析在10 min内完成,分离因子和分离度均大于1.5。在质量浓度为2~160 mg/L范围内,(+)-3-叔丁基己二酸衍生物和(-)-3-叔丁基己二酸衍生物的回归方程分别为y1=2 116.4x1-3 541.3(r12=0.999 4)和y2=2 097.6x2-4 774.1(r22=0.999 1)。该方法操作简单、重复性好,可用于3-叔丁基己二酸对映体的质量控制。     

Amino acid analysis by derivatization with chromogenic 4-phenylazobenzyloxycarbonyl chloride (PAZ-Cl): Comparison of reversed-phases

Summary The chromogenic reagent 4-phenylazobenzyloxycarbonyl chloride (PAZ-Cl) was used for the automated pre-column derivatization of amino acids (AAs) at ambient temperature followed by liquid chromatographic separation of the derivatives formed.Since in previous investigations it was realised that the selectivity of a C-18 stationary phase decreased after 40 injections of PAZ-AAs the suitability of 12 reversedphases distinguished by silica modification, carbon content, and particle characteristics was tested. Among these columns only a polymer-coated C-18 stationary phase furnished satisfactory repeatability of retention times for 250 analyses.     

花生油中游离脂肪酸的HPLC-FLD分析

采用柱前衍生-高效液相色谱荧光检测法(HPLC-FLD)分析了花生油中的游离脂肪酸.用荧光衍生试剂2-(11 H-苯[a]咔唑)乙基对甲苯磺酸酯(BCETS)作为柱前衍生化试剂对11种脂肪酸标准品(9种不饱和脂肪酸和棕榈酸、硬脂酸)进行衍生,经梯度洗脱实现了11种游离脂肪酸BCETS衍生物的完全分离,使用外标法定量,建...     

Quantitative HPLC Analysis of Plasma Amino Acids as Orthophthaldialdehyde/Ethanethiol Derivatives

Abstract

A reverse phase high performance liquid chromatographic method for the analysis of plasma amino acids is described. The method employs pre-column derivatization with o-phthaldialdehyde using ethanethiol as the reducing agent. The analysis shows good linearity and reproducibility. An average overall difference of 12% was seen for results obtained by the HPLC method versus those obtained with an amino acid analyzer. The chromatographic parameters of buffer concentration and column temperature were also examined.