微柱高效液相色谱与火焰光度检测器联用研究

报道了微柱高效液相色谱（micro-column HPLC）与火焰光度检测器（FPD）在线联用系统的研究,目的是发展一种不经复杂前处理步骤即可直接测定有机锡化合物的方法。三丁基锡氯化物（TBT）等经HPLC微柱分离后,通过毛细管连接引入特制的燃烧头,通过火焰光度检测器进行检测,对系统有关参数进行了优化和讨论。所建方法可以直接测定各种水样中的三丁基锡氯化物。     

Minimizing UV noise in supercritical fluid chromatography. I. Improving back pressure regulator pressure noise

Pressure fluctuations and resulting refractive index changes, induced by the back pressure regulator (BPR) can be a significant source of UV detector noise in supercritical fluid chromatography (SFC). The refractive index (RI) of pure carbon dioxide (CO(2)) changes ≈0.2%/bar at the most commonly used conditions in supercritical fluid chromatography (SFC) (40 °C and 100 bar), compared to 0.0045%/bar for water (CO(2) IS 44× worse). Changes in RI cause changes in the focal length of the detector cell which results in changes in UV intensity entering the detector. The change in RI (ΔRI/bar) of CO(2) decreases 8-fold at 200 bar, compared to 100 bar. A new back pressure regulator (BPR) design representing an order of magnitude improvement in the state of the art is shown to produce peak to peak pressure noise (PN(p-p)) as low as 0.1 bar, at 200 bar, and 20Hz, compared to older equipment that attempted to maintain PN(p-p)<1bar, at <5Hz. With this lower PN(p-p), changes in baseline UV offsets could be measured as a function of very small changes in pressure. A pressure change of ±1 bar at 100 bar, common with some older BPR's, produced a UV baseline offset >0.5 mAU. A pressure change of ±0.5 bar representing the previous state-of-the-art, resulted in a UV offset of 0.3m AU. Baseline noise <0.05 is required to validate methods for trace analysis. The new BPR, with a PN(p-p) of 0.1 bar, demonstrated UV peak to peak noise (N(p-p))<0.02 mAU with a >0.03 min (10Hz) electronic filter under some conditions. This new low noise level makes it possible to validate SFC methods for the first time.     

Investigating the performance characteristics of the barrier discharge ionization detector and comparison to the flame ionization detector for the gas chromatographic analysis of volatile and semivolatile organic compounds

Abstract

The response behavior and performance characteristics of the recently introduced barrier discharge ionization detector (BID) for gas chromatography (GC-BID) were investigated by analyzing different classes of organic compounds such as alcohols, alkanes, cycloaliphatic compounds, polycyclic aromatic hydrocarbons (PAHs), and others. The results obtained by GC-BID were compared with those of gas chromatography with flame ionization detection (GC-FID), aiming to demonstrate the particular merits of the new BID detector over the well-established FID. The response of the BID not only was found to be strongly dependent on the detector settings, but also shows a high dependence on the analyte class and the individual analyte. The sensitivity of the BID detector compared to the FID was higher by a factor of ca. 4 on average when considering all compounds analyzed. The relative standard deviation (RSD) was better than 5% for the majority of the cases. The BID detector showed better precision (lower RSD) in comparison with the FID for the investigated compounds. Linear calibrations were obtained for the analytes over more than four orders of magnitude with coefficients of determination typically higher than 0.999 and the limits of detection varied from 0.04 to 1.48?ng/s for the GC-BID.     

Dynamic control of split flow in packed column supercritical fluid chromatography using dual resistively heated restrictors

Remote control of the vent/detector split flow ratio in packed column supercritical fluid chromatography (pSFC) with flame ionization detector (FID) is demonstrated using a dual heated restrictor method. Restrictors stemming from a Tee at the separation column outlet were, respectively, fixed into an FID and a vent port, and their individual temperatures were controlled using resistively heated wires. Subsequently, both system pressure and split flow could be manipulated. For example, for applied restrictor temperatures examined up to 600°C, corresponding vent/FID split flow ratios between 2 and 7 were observed depending on the port heated. As well, column pressures around 16–23 MPa were also achievable over the same range. Conversely, isobaric altering of the split flow ratio was possible when opposing positive and negative temperature gradients were applied at the two restrictors. Under these conditions, the system pressure varied less than 1% RSD over a 10 min period. As an application, the method was used to establish stable detector operation in the analysis of n‐alkanes under pSFC‐FID conditions that initiated flame instability. Results indicate that this technique could be a relatively simple and inexpensive means of controlling system pressure and detector split flow ratios in pSFC‐FID.     

Critical appraisal of the flame photometric detector in petroleum analysis

Summary This paper summarises experience gained at the British Petroleum Limited Research Centre, Sunbury-on-Thames, with sulphur selective gas chromatography (GC) detectors. A single flame photometric detector (SFPD) has been in use for three years for research and routine applications. Three areas of interest are described demonstrating in turn different characteristics of the detector. Firstly, a determination of trace levels of individual organo-sulphur compounds in the 15–65°C cut of crude oils illustrates the complexity of using an SFPD in a rigorously quantitative manner. Secondly, the use of an SFPD as a qualitative tool for the comparison of the sulphur distribution of crude oils up to the temperature limit of GC is cited. Finally, a third section describes the properties of a dual flame photometric detector (DFPD) which are compared and contrasted with those of the SFPD.     

高效离子交换色谱-电化学检测法测定药物合成中间体中的6-磷酸甘露糖

在制备6-磷酸甘露糖过程中,将6-磷酸甘露糖与磷酸根杂质分开是纯化过程和建立质量标准的重要环节。本文建立了6-磷酸甘露糖和磷酸根的离子色谱分离-电化学检测方法。样品经溶解、过滤后进行色谱分析,以IonPac AG18离子交换柱(50 mm×4 mm)为保护柱,在Ionpac AS18离子交换色谱柱(250 mm×4 mm)上分离,以25 mmol/L氢氧化钾溶液为流动相,等度淋洗,流速1.0 mL/min,安培检测器和电导检测器串联检测,外标法定量。先使用安培检测器检测,在碱性条件下,6-磷酸甘露糖在安培检测器上被选择性检出;后使用电导检测器检测,经ASRS型抑制器抑制背景电导后,6-磷酸甘露糖和磷酸根同时被电导检测器检出,二者分离度良好。采用安培检测器检测时,进样量为25 μL, 6-磷酸甘露糖的线性范围为0.06～10.00 mg/L,相关系数为0.9998,回收率为92.1%～103.1%,相对标准偏差均小于3%,检出限(以信噪比为3计)为0.02 mg/L。该方法灵敏度高,无杂质干扰,前处理简便,可用于原料药合成中间体的检测,结果令人满意。     

Aufbau und Überprüfung eines neuen Photoionisationsdetektors für die Fluidchromatographie

Zusammenfassung Diese Arbeit beschreibt die Entwicklung eines druckfesten Photoionisationsdetektors (PID) und überprüft seine Anwendung in der Fluidchromatographie (SFC). L?sungen von Benzol in Methanol wurden als Testl?sungen gebraucht. Drei Modelle wurden nacheinander konstruiert und mit Kohlendioxid sowie Argon als mobile Phase getestet. Es zeigten sich grunds?tzlich drei Typen von Problemen: Druckbest?ndigkeit, elektrische Isolation und Anordnung der UV-Lampe (10.2 eV). Obwohl bei einem druckfesten PID die mit der Entspannung des überkritischen Gases verbundenen Probleme wegfallen, bietet er mit Kohlendioxid als mobile Phase wegen seiner geringen Empfindlichkeit und seiner hohen Nachweisgrenze nicht die erhoffte Alternative zu den bisher in der SFC verwendeten Detektoren. Diese kleine Empfindlichkeit ist auf die Lichtabsorption von Kohlendioxid bei dieser Wellenl?nge (121 nm) und haupts?chlich auf einen Quenching-Effekt zurückzuführen.

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Construction and testing of a new photoionization detector for supercritical fluid chromatography

Summary This work describes the development of a pressure resistant photoionization detector (PID) and examines its use in supercritical fluid chromatography (SFC). Solutions of benzene in methanol were used as test solutions. Three models were constructed and tested with carbon dioxide and argon as mobile phase. Three types of problems were principally encountered: pressure resistance, electrical insulation and positioning of the UV-lamp (10.2 eV). Although all problems arising from pressure reduction could be avoided with each PID studied, these “high pressure” PID cannot be used for SFC instead of other usual detectors. With supercritical carbon dioxide as the mobile phase, the sensitivity was too low and the detection limit was too high. this could be explained by light absorption at the emitted wavelength (121 nm) and mainly by a quenching effect by this gas.

     

气相色谱分析中是否一定要用质谱检测器？

The detector, as well as being an essential supporting device for the gas chromatography (GC) has also played a critical role in the development of the technique as a whole. The mass spectrometer (MS) is still the commonly praised detector as before. In fact, the information of fragmentation patterns is seldom used in practice, and the GC-MS instrument is even more expensive. For today’s analytical problems, it seems that element specific detectors can and should be used for many applications rather than GC-MS.     

Response of CZT drift-strip detector to X- and gamma rays

The drift-strip method for improving the energy response of a CdZnTe (CZT) detector to hard X- and gamma rays is discussed. Results for a 10×10×3 mm³ detector crystal demonstrate a remarkable improvement of the energy resolution. The full width at half maximum (FWHM) is 2.18 keV (3.6%), 2.45 keV (3.0%), 2.86 keV (0.8%) and 3.89 keV (0.6%) at 60, 80, 356 and 661 keV, respectively. The resolution is limited by electronic noise below 100 keV.     

Metal selective flame ionization detection after supercritical fluid chromatography

This work describes the construction and operation of a flame ionization detector for the selective detection of metal-containing compounds after capillary supercritical fluid chromatography. Using optimal conditions for achieving metal sensitive flame ionization responses which have been established for the detector after capillary gas chromatography, initial evaluation of the detector after SFC proved promising. Like the carbon sensitive FID, it appears that the metal sensitive FID is compatible with SFC when pure carbon dioxide is used as the mobile phase. Response characteristics were found to be similar to those observed when the detector is used in gas chromatography.     

Microwave-induced plasma emission spectrophotometer combined with a photodiode array monitor for capillary column gas chromatography

A microwave-induced plasma emission spectrophotometric detector (MIPD) was used as an element-specific detector for capillary column gas chromatography. The atmospheric pressure microwave helium plasma generated with an original device called a SURFATRON was used as an atomization and excitation source. Combining a photodiode array spectrophotometer with the above system made the emission spectrophotometric detector very powerful. A wide range of spectra could be instantly monitored without any mechanical device. However, the spectrum of atmospheric helium emission plasma was complicated by the presence of air around the plasma discharge. An on-line background correction scheme was developed to handle such complicated spectra.     

高效毛细管电泳紫外检测器光路的特殊性及其优化

紫外检测器用于高效毛细管电泳（ＨＰＣＥ）的主要难题在光路中,ＨＰＣＥ中熔融石英毛细管（内径通常在５０μｍ左右）直接放在光路中,一方面光程短,另一方面,光在透镜及毛细管界面上的折射与反射使光程常比毛细管内径短,甚至可能绕过毛细管内腔［１,２］．本文编制...     

超高效超临界色谱分析聚合物制品中的7种添加剂

采用超高效超临界色谱(UPSFC)-二极管阵列检测器(PDA)建立了快速分析高分子材料中7种常用聚合物添加剂的方法。在检测波长为220 nm条件下,通过考察样品的稀释溶剂、流动相添加剂、柱温、背压、柱流速对分离的影响,最终确定7种添加剂分离的最优化条件：采用正己烷/异丙醇(1/1,v/v)为稀释溶剂,流动相添加剂为甲醇/乙腈(1/1,v/v),流速2 mL/min,柱温50 ℃,背压12.41~13.79 MPa条件下,7种聚合物添加剂能够在5 min之内达到完全基线分离。利用微波辅助萃取方法对实际样品中的添加剂进行提取,经UPSFC-PDA分析,7种添加剂的回收率为69.9%~118.9%,相对标准偏差(RSD,n=9)低于10%。该方法简便、快速,选择性强,能够准确快速地分析聚合物制品中的添加剂。     

HPLC-ELSD法测定生物柴油中的游离甘油

采用液液萃取及高效液相色谱-蒸发光散射检测技术,建立了生物柴油中游离甘油含量的测定方法.待测生物柴油经乙腈-水(75:25)抽提并离心分离后,取部分下层水相进行分析.优化的色谱条件为:色谱柱Inertsil NH2 (250 nun ×4.6 mm,5μm );流动相为乙腈-水(75:25);流速1.0 mL/min;...     

应用高效液相色谱-二极管阵列检测器-蒸发光散射检测器联用技术同时测定清开灵注射液中的五类有效成分

建立了复方清开灵注射液中5类主要有效成分的定量测定方法。应用高效液相色谱-二极管阵列检测器-蒸发光散射检测器联用技术(HPLC-DAD-ELSD),根据各类成分紫外吸收光谱的差异,分别在240,254,280和330 nm波长下检测栀子苷、核苷(包括尿苷和腺苷)、黄芩苷和有机酸(包括绿原酸和咖啡酸)等4类成分,同时使用ELSD测定胆酸、熊去氧胆酸和猪去氧胆酸等3种甾体化合物,从而实现了清开灵注射液中5类有效成分(共9个化合物)的同时分离和定量测定。用该法测定了3个不同厂家的19批清开灵注射液成品。该法快速、准确,操作相对简单,为中药复方复杂体系的多组分定量测定和质量控制提供了一种可靠、合理且简便、易行的方法模式。     

Characterization of the flame photometric detector in the sulphur mode

Summary The effect of experimental conditions such as gas flow rates, detector and column temperatures on sulphur response are discussed. It is concluded that the response of the flame photometric detector is affected by the O/H ratio and the total gas flow. Column temperature has an important influence upon S₂ emission. It is shown that the sulphur response of the FPD is dependent on the compound containing the sulphur.     

Low-Cost Detection of Methane Gas in Rice Cultivation by Gas Chromatography-Flame Ionization Detector Based on Manual Injection and Split Pattern

Rice cultivation is one of the most significant human-created sources of methane gas. How to accurately measure the methane concentration produced by rice cultivation has become a major problem. The price of the automatic gas sampler used as a national standard for methane detection (HJ 38-2017) is higher than that of gas chromatography, which greatly increases the difficulty of methane detection in the laboratory. This study established a novel methane detection method based on manual injection and split pattern by changing the parameters of the national standard method without adding any additional automatic gas samplers. The standard curve and correlation coefficient obtained from the parallel determination of methane standard gas were y = 2.4192x + 0.1294 and 0.9998, respectively. Relative standard deviation (RSD, <2.82%), recycle rate (99.67–102.02%), limit of detection (LOD, 0.0567 ppm) and limit of quantification (LOQ, 0.189 ppm) of this manual injection method are satisfying, demonstrating that a gas chromatography-flame ionization detector (GC-FID), based on manual injection at a split ratio (SR) of 5:1, could be an effective and accurate method for methane detection. Methane gases produced by three kinds of low-methane rice treated with oxantel pamoate acid, fumaric acid and alcohol, were also collected and detected using the proposed manual injection approach Good peak shapes were obtained, indicating that this approach could also be used for quantification of methane concentration.     

石墨炔修饰的ZnO薄膜紫外探测器

制备了石墨炔修饰的金属-半导体-金属结构的ZnO紫外探测器,研究了不同旋涂次数的石墨炔修饰对探测器性能的影响。实验结果表明,石墨炔修饰的探测器比未修饰器件的光电流提高4倍,暗电流降低2个数量级,同时探测器的响应度和探测率也明显提高,其中旋涂2次的石墨炔修饰的器件特性为最优。在10 V偏压下,旋涂2次的石墨炔修饰的探测器响应度高达1759 A·W⁻¹,探测率高达4.23× 10¹⁵ Jones,这是迄今为止报导过的溶胶-凝胶法制备的ZnO紫外探测器的最高值。经过对探测器各项性能的测试分析可知,石墨炔修饰的ZnO探测器性能的提高归因于石墨炔良好的空穴传输特性。暗环境下ZnO与石墨炔界面处形成p-n结,使探测器的暗电流大幅降低;光照条件下光生空穴在石墨炔中聚集,减少了电子空穴对的复合,有效提高了器件的光电流。由于石墨炔修饰减少了ZnO表面的氧分子吸附和解吸附过程,器件的响应速度也明显加快。     

常规离子色谱系统-电容耦合非接触式电导检测器的构建

通过考察电极长度及电极间距、检测管管径及材质、激励信号频率、电压和波形等参数对信噪比的影响,研制了一种适用于常规型离子色谱系统的电容耦合非接触式电导检测器（C⁴D）。在抑制模式下,该检测器对常见无机阴离子（F^-、Cl^-、NO₂^-、Br^-、NO₃^-和SO₄^2-）的检出限（信噪比=3）为0.02~0.08 μmol/L;峰面积的相对标准偏差<1.8%（n=6）;在0.1~10 μmol/L范围内上述6种无机阴离子线性关系良好,相关系数（R²）>0.999。自制C⁴D的主要性能参数与商品化接触式电导检测器相当。该检测器具有结构简单、成本低廉、无电极污染等优点,有利于拓展离子色谱的应用范围。     

Determination of the sulfur components of gasoline streams by capillary column gas chromatography with sulfur chemiluminescence detection

A method using a sulfur chemiluminescence detector (SCD) has been developed for the qualitative and quantitative determination of sulfur components in stabilized gasoline-range process streams, including blended gasolines containing between 1 and > 4000 ppm total sulfur. The detection limit per sulfur component was approximately 50 ppb. On-column injection was employed for optimum precision and accuracy. A new probe material was found which did not soften under FID operating conditions. A new method, using a hydrogen sulfide permeation tube, was developed for rapid alignment of the probe in the FID.