量子点在分析检测中的应用进展

量子点是一类粒径在纳米尺度的荧光材料,因其独特而优良的光学性质已在化学、生物和医学的研究及应用方面取得了很大进展.本文综述了近年来量子点在重金属离子和有机分子的定量分析、药物分析以及生命分析等领域的应用进展.     

Quantitative HPTLC analysis of carboxylic acids in wine and juice

The need for quick and specific assay of carboxylic acids in wine and non-fermented beverages is explained. The method developed in this work is based on high performance thin-layer chromatography (HPTLC) followed by densitometric evaluation. Untreated samples, with the exception of red wines which were destained, were directly sprayed onto the cellulose layer. The chromatogram was developed with ethyl acetate-toluene-water-formic acid 60:20:20:15, then stained with xylose-aniline reagent. Densitometric scanning is by absorbance at 546 nm. The method is quick, sensitive, and has a wide dynamic range for the acids analyzed.     

TLC for pharmaceutical analysis in resource limited countries

This review article discusses the sustainability and robust advantages of planar chromatography that are critical to the successful performance of product quality assessments in resource limited areas including field applications. Because of the robustness and ease of use, the training required for successful performance of the high performance thin layer chromatography (HPTLC) assessments is much lower than that of other technologies with comparable reproducibility such as high performance liquid chromatography (HPLC). Some of the successful applications of planar chromatography in resource limited countries are presented. It should be noted that these planar chromatographic technologies have much lower plate counts and therefore separation power than column technologies such as HPLC and gas liquid chromatography (GLC). However in finished pharmaceutical products there are generally few active ingredients which are assessed making the HPTLC adequate for these analyses. In addition at this time there is a much wider array of detection technologies available for HPLC and GLC.     

Introduction of solid-phase microextraction as a high-throughput sample preparation tool in laboratory analysis of prohibited substances

A fully automated, high-throughput method based on thin-film solid-phase microextraction (SPME) and liquid chromatography-mass spectrometry was developed for simultaneous quantitative analysis of 110 doping compounds, selected from ten classes and varying in physical and chemical properties. Among four tested extraction phases, C18 blades were chosen, as they provided optimum recoveries and the lowest carryover effect. The SPME method was optimized in terms of extraction pH, ionic strength of the sample, washing solution, extraction and desorption times for analysis of urine samples. Chromatographic separation was obtained in reversed-phase model; for detection, two mass spectrometers were used: triple quadrupole and full scan orbitrap. These combinations allowed for selective analysis of targeted compounds, as well as a retrospective study for known and unknown compounds. The developed method was validated according to the Food and Drug Administration (FDA) criteria, taking into account Minimum Required Performance Level (MRPL) values required by the World Anti-Doping Agency (WADA). In addition to analysis of free substances, it was also shown that the proposed method is able to extract the glucuronated forms of the compounds. The developed assay offers fast and reliable analysis of various prohibited substances, an attractive alternative to the standard methods that are currently used in anti-doping laboratories.     

Performance of the linear ion trap Orbitrap mass analyzer for qualitative and quantitative analysis of drugs of abuse and relevant metabolites in sewage water

This work illustrates the potential of liquid chromatography coupled to a hybrid linear ion trap Fourier Transform Orbitrap mass spectrometer for the simultaneous identification and quantification of 24 drugs of abuse and relevant metabolites in sewage water. The developed methodology consisted of automatic solid-phase extraction using Oasis HLB cartridges, chromatographic separation of the targeted drugs, full-scan accurate mass data acquisition under positive electrospray ionization mode over an m/z range of 50–600 Da at a resolution of 30,000 FWHM and simultaneous MSⁿ measurements to obtain information of fragment ions generated in the linear ion trap. Accurate mass of the protonated molecule, together with at least one nominal mass product ion and retention time allowed the confident identification of the compounds detected in these complex matrices. In addition to the highly reliable qualitative analysis, Orbitrap analyzer also proved to have satisfactory potential for quantification at sub-ppb analyte levels, a possibility that has been very little explored in the literature until now. The limits of quantification ranged from 4 to 68 ng L⁻¹ in influent sewage water, and from 2 to 35 ng L⁻¹ in effluent, with the exception of MDA, morphine and THC that presented higher values as a consequence of the high ionization suppression in this type of samples. Satisfactory recoveries (70–120%) and precision (<30%) for the overall procedure were obtained for all compounds with the exception of meta-chlorophenylpiperazine, methylphenidate and ketamine. Isotope-labelled internal standards were added to sewage samples as surrogates in order to correct for matrix effects and also for possible losses during sample treatment. The methodology developed was applied to sewage water samples from the Netherlands (influent and effluent), and the results were compared with those obtained by LC–MS/MS with triple quadrupole. Several drugs of abuse could be identified and quantified, mainly MDMA, benzoylecgonine, codeine, oxazepam and temazepam. Orbitrap also showed potential for retrospective investigation of ketamine metabolites in the samples without the need of additional analysis.     

Purification of drugs from biological fluids by counter-current chromatography

Experiments were performed to demonstrate the potential of counter-current chromatography (CCC) for the isolation of drugs and their metabolites from biological matrices relevant to the metabolism studies of pharmaceutical research. Examples of typical drugs are spiked into biological media ex vivo to provide test samples for analysis. A mass spectrometer hyphenated to a CCC allows for the detection of small molecule drugs within the matrix through selected ion monitoring, and fraction collection can provide material for further structural elucidation by NMR.     

在线固相萃取-高效液相色谱法同时测定人血清中氯氮平、奎硫平和利培酮的含量

使用双梯度液相色谱系统紫外检测器,建立了在线固相萃取液相色谱法全自动、快速、同时测定人血清中氯氮平、奎琉平和利培酮的含量。本方法采用了反相系统,为了提高分离的互补性,使用Capcell MF Ph-1柱作为在线固相萃取柱,Acclaim C18柱作为分析柱。在线固相萃取柱以乙腈-水体系作为流动相,流速1 m L/min梯度洗脱;分析柱以乙腈-100 mmol/L醋酸铵溶液作为流动相,流速1 m L/min,梯度洗脱。样品溶液注入到在线固相萃取苯基柱中,根据此柱的限进机制,血清中的蛋白等大分子物质不被保留而排出,而氯氮平、奎琉平和利培酮等小分子化合物得到保留;通过阀切换使用双梯度液相色谱系统的分析泵将固相萃取柱上保留的氯氮平、奎琉平和利培酮等小分子化合物转移到分析柱中进行二次分离,采用外标法测定氯氮平、奎琉平和利培酮的含量,整个前处理和分析过程仅需18 min。氯氮平在10~1800μg/L浓度范围内相关系数为0.9996,低、中、高浓度的平均回收率分别为118.4%,105.0%和105.4%;奎琉平在3.6~640μg/L浓度范围内相关系数r为0.9997,低、中、高浓度的平均回收率分别为112.8%,101.1%和101.5%;利培酮在0.71~128μg/L浓度范围内相关系数为0.9995,低、中、高浓度的平均回收率分别为100.7%,97.2%和98.8%。结果表明,本方法可极大地提高样品分析效率,快速准确测定人血清中氯氮平、奎琉平和利培酮的含量。     

Hptlc Separation And Determination Of Amniotic Fluid Phospholipids

Abstract

High performance thin layer chromatography (HPTLC) under controlled relative humidity conditions was employed in order to separate phospholipids of amniotic fluid. Quantitative determination was accomplished after visualization by copper acetate/phosphoric acid (CA) and by phospho-molybdic acid (PMA). In both cases reflectance was found to follow the Kubelka-Munk theory in the Treiber and Pollak approximation. PMA gives fairly better results as it concerns reproducibility. A method of analysis is proposed that allows to use 500 μl or less of amniotic fluid. A complete phospholipid analysis can be performed in 40 min. Proposed method was tested on simulated and real samples and results compared with conventional spectrophotometry analysis.     

Systematic and statistical errors in quantitative evaluation using TLC and HPTLC. 2. Internal and external standard methods

The error propagation is given for routine analysis by in situ evaluation in TLC using the methods with internal or external standard. The internal standard method will need four different measurements of peak height or area, while the external standard method uses only two measurements. Therefore in the latter case the error of the spotting volume will cause errors in the determined concentration. By error propagation it can be shown, that the internal standard method gives better results, if the error in measuring peak height or area is less than the error of the spotting volume.     

平行入射式光谱电化学池的制作及分析应用

本工作制作了用于定量分析的平行入射式光谱电化学池,电极长度为2 cm,光束高度约为120μm。稳定的吸光度在较宽的浓度范围内具有良好的线性关系,最低检测限对氢醌为3×10~(-8)mol/L,而对邻甲联苯胺为2×10~(-8)mol/L。利用光谱电化学可以在四倍的多巴胺存在下测定抗坏血酸,而大量存在的抗坏血酸对多巴胺的测定无影响。