用二维色谱技术测定聚合反应气体组成

介绍一种无阀切换的二维气相色谱分析方法。采用两根不同性质的色谱柱并联连接，样品分别经两根色谱柱分离后汇合在一起进入同一检测器。一次进样可同时测定Ｈ２、Ｏ２、Ｎ２及Ｃ１～Ｃ３的组分。     

高效液相色谱柱切换系统中系统峰受色谱条件的影响及其干扰的避免

在建立茶碱高效液相色谱(HPLC)柱切换方法测定的预试验过程中,发现在不进样及不进任何空白样的情况下,空切换后,在所收集的色谱图上有一些正峰或负峰存在,文献中称这些正峰或负峰为系统峰^[1]。这些峰的存在在一定程度上对被测样品峰产生干扰。对于因样品直接进样产生的系统峰,国外有较多报道^[2,3],而关于HPLC柱切换系统     

离子色谱-柱切换技术同步测定饮料中的三氯蔗糖、葡萄糖、果糖和蔗糖

建立了一种离子色谱-柱切换-安培检测技术同步测定饮料中三氯蔗糖、葡萄糖、果糖和蔗糖的方法。以CarboPac PA10阴离子交换保护柱和分析柱进行分离,用水和250 mmol/L NaOH梯度淋洗,脉冲安培检测。弱保留糖类在25 mmol/L NaOH流动相淋洗下分离检测,通过柱切换将保护柱切换至分析柱后,同时切换至250 mmol/L NaOH淋洗,三氯蔗糖仅通过较短的保护柱分离,4种糖类能够得到同步检测。4种糖类在0.01~20 mg/L范围内有良好的线性关系和较低的检出限,重复性好,样品测定的回收率分别为90.38%~102.88%（三氯蔗糖）、95.56%~102.75%（葡萄糖）、101.66%~114.33%（果糖）和105.03%~106.49%（蔗糖）。该方法可广泛应用于食品中强保留物质的测定。     

单泵柱切换离子色谱法分析复杂基体中痕量阴离子

本文通过离子色谱与柱切换技术联用实现了高浓度样品基体中的痕量阴离子检测.分别研究了不同类型基体的处理方法,使用商品化离子排斥柱和自制的聚合物色谱柱实现多种样品基体中痕量阴离子的检测.同时开发一种简化的单泵柱切换系统,利用抑制器将KOH淋洗液转化为水作为前处理柱的淋洗液,在同一个色谱系统中产生两种淋洗液,实现色谱分离与前...     

反相高效液相色谱法及电喷雾离子阱质谱法分析中药复方制剂肾宝片

建立了一种反相高效液相色谱梯度洗脱,以检测波长切换方法,同时测定中药复方制剂肾宝片中5种主要成分的含量。采用Alltima C18柱,以乙腈-水为流动相,用检测波长切换法,将5种主要成分分离测定,并采用高效液相色谱与电喷雾离子阱质谱(MS^3)联用,成功分离和鉴别了该制剂中的20种成分。本文建立的方法简便、灵敏、准确、可靠,可用于中药制剂肾宝片的质量控制。     

阀切换-离子色谱法测定分析纯硫酸钠中痕量氯离子

建立了阀切换-离子色谱法测定分析纯硫酸钠固体中痕量氯离子含量的方法。ICS-2100离子色谱系统,配置十通阀,用IonPac AS18色谱柱将硫酸钠固体样品中的氯离子和硫酸根离子预分离后,以IonPac TAC-ULP1为富集柱,将氯离子富集后在相同的IonPac AS18色谱柱上进行定量分析。同时以淋洗液发生器产生的不同浓度的KOH作为淋洗液,以抑制型电导检测器测定氯离子的含量。结果表明,阀切换-离子色谱法测定分析纯硫酸钠固体中的痕量氯离子,检出限为10 μg/L,线性相关系数(r2)大于0.999,实际样品的加标回收率为98.0%～103.0%,具有分离度和灵敏度高,选择性好,操作简单等特点。该方法能够准确测定硫酸钠固体中痕量氯离子的含量,适用于高纯化学试剂中痕量氯离子的分离测定。     

二维液相色谱阀切换接口技术的发展及应用

在复杂样本分析中,一种分离模式往往不能提供足够的分离度,组合不同的分离模式构建二维液相色谱系统是解决这一问题的有效途径。阀切换接口是二维液相色谱柱切换技术的核心,接口技术影响系统的分离度和灵敏度。传统的接口技术在生物、药学、食品、环境等领域得到了广泛应用,近20年发展了众多新型的接口技术来解决二维液相色谱中正交组合溶剂不兼容问题。本文综述了柱切换接口技术的原理和应用,并总结了近5年利用柱切换二维液相分析技术的进展,期望为二维液相色谱技术的发展和应用提供借鉴。     

气相色谱法测定车用汽油中含氧化合物和苯胺类化合物

利用中心切割技术和双毛细管色谱柱系统,采用两次进样的方式,建立了气相色谱测定车用汽油中含氧化合物和苯胺类化合物的分析方法。第一次进样分析,组分首先进入非极性DB-1色谱柱(30 m×0.32 mm×1.0μm),按沸点由低到高的顺序分离,通过电磁阀切换将沸点小于2-己酮的组分切割至强极性GS-OxyPLOT色谱柱(10 m×0.53 mm×10μm)或CP-Lowox色谱柱(10 m×0.53 mm×10μm),其余重烃组分通过阻尼柱进入FID检测器。在GS-OxyPLOT或CP-Lowox色谱柱上,烃类组分与含氧化合物分离并进入检测器检测,消除了大量的烃类组分对含氧化合物测定的影响。第二次进样分析,设定电磁阀切换时间为间-甲基苯胺从非极性色谱柱流出的时间,苯胺类化合物在GS-OxyPLOT或CP-Lowox色谱柱上与烃类和含氧化合物分离并进入检测器检测。以乙二醇二甲基醚为内标化合物进行内标法定量。实现了在一套系统上同时测定车用汽油中添加的甲基叔丁基醚(MTBE)、甲醇、甲缩醛、乙酸仲丁酯、乙酸乙酯、苯胺、邻/间/对-甲基苯胺和N-甲基苯胺的含量,各组分的检测范围为0.01%~10%(质量分数),回收率为86.0%~102.6%。该法可以为车用汽油的质量控制提供有效的检测手段。     

气相色谱法测定黑色PMMA燃烧产物中的一氧化碳和二氧化碳含量

利用气相色谱法检测黑色PMMA完全燃烧烟气中的常量二氧化碳和微量一氧化碳,建立了双气路双检测器的检测方法。恒定色谱柱温度,通过定量管进样,Poropak T色谱柱预分离后,采用阀切换及柱反吹技术使不同组分分别流入5A分子筛色谱柱和Poropak N色谱柱中。5A分子筛色谱柱用于分离一氧化碳,经Ni催化甲烷化转化后用FID检测器测定;Poropak N色谱柱分离二氧化碳后进入电导检测器测定。采用峰面积法建立标准曲线,一氧化碳和二氧化碳的线性相关系数分别为0.999 9和0.999 6。用该法测定标准气体,其测定值与标准值的相对误差小于2%,测定结果的相对标准偏差小于1%。该方法可用于烟气毒性的分析。     

离子色谱-柱切换法测定土壤浸出液中的氟离子

建立了离子色谱-柱切换测定土壤浸出液中氟离子的方法。使用柱切换技术,将样品通过高聚物反相色谱柱进行在线预处理,分离氟离子和小分子有机酸,同时除去水溶性有机杂质,采用收集环收集氟离子并进入分析系统分析,消除了测定氟离子时普遍存在的干扰问题。分析系统的淋洗液为KOH溶液,流速为1.0 mL/min,采用抑制性电导检测,外标法定量。氟离子的线性范围为0.05~10.0 mg/L,相关系数为0.9999,加标回收率为103.4%~105.3%,相对标准偏差为2.0%~2.1%,检出限 (S/N=3)为5.50 μg/L。该方法适用于测定复杂基体样品中的氟离子。     

The desalination of a mixed solution of an amino acid and an inorganic salt by means of electrodialysis with charge-mosaic membranes

A new electrodialysis with charge-mosaic membranes was proposed to achieve efficient desalination of a mixed solution of an amino acid and an inorganic salt. For such a mixed solution, the conventional electrodialytic desalination with both cation-and anion-exchange membranes had resulted in a considerable loss of the amino acid through the membranes. In this method, however, the amino acid in the desalination channel of the electrodialyzer migrates away from the membranes so that the permeation loss of the amino acid through the membrane can be prevented.

Batchwise desalination experiments by this method were carried out with a glutamic acid or arginine solution including NaCl under the condition of constant electric current density. Similar experiments by the conventional method were also carried out. As a result of comparing both methods, the amino acid loss in this method became much smaller than that in the conventional one. It was confirmed that this method was very useful for the desalination of an amino acid solution. The effects of operating conditions on the desalination process are also discussed.     

火焰原子吸收光谱法测定铜原矿尾矿中的镉

采用盐酸、氢氟酸、硝酸、高氯酸分步溶解的方式对具有硅、铁含量高等特性的铜原矿尾矿样品进行溶解。在体积分数为5%的盐酸介质中,利用原子吸收光谱法,采用扣除背景方式对样品溶液进行测定。样品溶解较完全,共存元素对镉的测定基本无干扰。方法重现性较好,准确度较高。相对标准偏差在2.3%~8.3%,加标回收率在96.7%~105%,标准样品分析结果与标准值基本一致。能满足日常分析检测的需要。     

Purification of domoic acid from toxic blue mussels (Mytilus edulis) and phytoplankton.

Domoic acid was the primary neurotoxin in blue mussel (Mytilus edulis) that caused poisoning in humans. Further research showed that the algae, Nitzschia pungens, was the source of this toxin. In this study, a method for the extraction and purification of domoic acid from contaminated mussels and phytoplankton was developed. Domoic acid was extracted from these sources by treatment with a mixture of chloroform and methanol (1:2, v/v). The resulting extract was subjected to ultrafiltration through a PM1 Millipore filter, followed by repeated high-performance liquid chromatography on a reversed-phase column. The purity and yield of domoic acid prepared by this method are compared with two previously described methods of extraction. The current method is relatively simple, rapid, and results in improved recovery with comparable purity of domoic acid.     

从叔醇制备叔硫醇

实验室中合成叔硫醇缺少简便方法。用叔醇和氢溴酸与硫脲直接反应是目前采用的方法。Lee和Akerstrom曾用此法合成了叔硫醇,但碳原子数没超过七个。Sprague及Kresze分别用干燥氯化氢及盐酸代替氢溴酸也合成了叔硫醇,但产率不高。本文提出了用叔醇、硫酸与硫脲反应来制备叔硫醇的方法,并合成了六个叔硫醇。     

毛细管电泳法分离测定小麦根中的有机酸

研究了毛细管电泳法分离测定草酸、乌头酸、苹果酸、柠檬酸等有机酸的条件。在pH7．8的磷酸钠缓冲溶液中中加入表面活性剂溴化十六烷基三甲铵作为电泳溶液体系,紫外检测波长214nm,可以有效地分离检测以阴离子形式存在的上述有机酸：将该法应用于铝胁迫下培育的小麦根样品中有机酸的分析,结果表明：随着培养基中铝浓度的增加,苹果酸被诱导增加,与报道的HPLC法的测定结果一致,本法可在植物化学研究中使用。     

Analysis of the fatty acid from Bupleurum Chinense DC in China by GC-MS and GC-FID

Fatty acid of the root of the medicinal plant of Bupleurum Chinense DC in China has been investigated by gas chromatography combined with mass spectroscopy. After methyl-esterification, eight fatty acid compositions were identified by GC-MS. A simple and rapid determination of the fatty acid has been firstly developed by GC-FID. The derivatization condition was investigated in order to validate this method. Palmitic acid, palmitoleic acid, oleic acid and linoleic acid were analyzed simultaneously by internal standard method. The validity of method has been examined both experimentally with good recovery, intra-assay precisions and linearity. The quick and accurate method of capillary gas chromatography could be used for the analysis of the fatty acid from Bupleurum Chinense DC.     

草酸电解合成乙醛酸连续化工艺研究

针对传统草酸电解生产乙醛酸工艺只能间歇循环的缺陷,本文提出模拟连续化实验方案,并分别设计阴极冷却反应器和阴极冷却固定床反应器,探讨连续化实验的可行性.另外还考察了草酸饱和度和温度工艺参数对反应的影响.实验表明,保持草酸过饱和和利用变温操作可在反应停留时间(30m in)内于连续化反应过程中得到分别含有3.76%和3.66%乙醛酸的反应液,因此阴极冷却固定床反应器可望实现草酸电解还原乙醛酸的连续化生产.     

酶法生产L-苯丙氨酸体系的液相色谱-质谱联用分离分析

通过对高效液相色谱各主要分离条件以及质谱分析条件的优化,建立了一种有效的液质联用方法分析酶法生产L-苯丙氨酸体系中3种主要成分:L-天冬氨酸,丙酮酸和L-苯丙氨酸.该方法抗干扰能力强,简单、快速、准确、灵敏且重现性好,适用于定性及定量分析实际样品,为生产工艺优化和生产过程研究提供了依据.     

Analysis of total propionic acid in feed using headspace solid-phase microextraction and gas chromatography

A method is described to analyze total propionic acid content (free propionic acid + sodium, ammonium, calcium salts, etc.) in feed, using headspace solid-phase microextraction (HS-SPME) of a feed suspension in salted and acidified water. Optimization of the extraction variables was done by simplex method after choosing a polyacrilate fiber to enhance the response of this acid. Separation was made by capillary gas chromatography (GC), using a special free fatty acid phase (FFAP) column for acids and a flame ionization detector (FID). Some of the chromatograms were also done, injecting the SPME fiber in a GC-mass spectrometry (MS) system, working with some specific ions for propionic acid, to be selective enough to avoid confusing the propionic acid peak with interferences of those complex matrixes. The method was tested for linearity and repeatability. Detection and quantification limits were also calculated. The method was applied to commercial feed samples, very variable in composition, quantifying by standard addition method. No major interferences were observed.     

Determination of sorbic acid with sodium chlorite

A new method for the determination of sorbic acid is proposed, using sodium chlorite in hydrochloric add medium as reagent. In these conditions the hydrochloric acid is oxidized to chlorine which adds on to the double bonds of the sorbic acid. The addition is rapid (30-90 sec) and for this reason the determination is more rapid then others similar to it. Sorbic acid has been determined in foods by this method, after a preliminary solvent extraction or steam-distillation.