5-磺酸钠间苯二甲酸二甲酯的高效液相色谱法分析

提出了用离子对反相高效液相色谱分析５－磺酸钠间苯二甲酸二甲酯的方法,色谱柱为ＨｙｐｅｒｓｉｌＢＤＳＣ１８,５μｍ,２５０ｍｍ×４．６ｍｍ,流动相为Ｖ（甲醇）∶Ｖ（水）＝６０∶４０（甲醇中含四丁基磷酸二氢铵１０ｍｍｏｌ／Ｌ）,柱温为３０℃,流速为０．８ｍＬ／ｍｉｎ,进样体积为２０μＬ,检测波长为２２０ｎｍ。用外标法进行了定量,相对标准偏差和回收率分别为０．２６％和９８．１％～９９．６％。     

HPLC法测定中成药制剂中10-羟基-2-癸烯酸的含量

采用ＳｐｈｅｒｉｓｏｒｂＣ１８柱,以甲醇∶水∶磷酸（４５∶６５∶０．５）为流动相,以ＵＶ２１０ｎｍ为检测波长,测定中成药制剂中１０－羟基－２－癸烯酸（１０－ＨＤＡ）的含量,１０－ＨＤＡ浓度在０．００６～０．０３０ｇ／Ｌ范围内线性关系良好（ｒ＝０．９９９９,ｎ＝５）,检测限为０．２ｍｇ／Ｌ（Ｓ／Ｎ＝３∶１）。方法具有定量准确、快速及主峰和杂质分离度高等特点。     

高效液相色谱-间接光度检测法测定体液中西梭霉素

采用高效液相色谱－间接光度检测法（ＨＰＬＣ－ＩＰＤ）,在流动相中加入具有紫外检测响应的检测剂烟酰胺,用紫外检测器直接测定体液中无紫外吸收的西梭霉素含量。固定相为ＳｐｈｅｒｉｓｏｒｂＣ１８,流动相为甲醇－乙腈－水（２０∶１０∶７０）,内含磷酸０．０５ｍｏｌ／Ｌ、烟酰胺０．５ｍｍｏｌ／Ｌ、庚烷磺酸钠５ｍｍｏｌ／Ｌ。血清样品中西梭霉素平均回收率为９６．９２％±４．６３％,日内和日间变异系数分别为４．７５％和５．６５％。     

邻苯二甲醛-尿素柱前衍生高效液相色谱法快速检测枸杞中牛磺酸

干枸杞经粉碎、匀浆、离心后,通过阳离子交换柱脱去样品中其它氨基酸,再通过Ｚｏｒｂａｘ－Ｃ８柱进行柱前衍生分离。衍生剂：Ａ．４％ＯＰＡ甲醇溶液;Ｂ．尿素∶磷酸钠盐缓冲液（ｐＨ６．８）＝１∶３（Ｗ／Ｖ）。流动相：甲醇∶０．０１ｍｏｌ／Ｌ乙酸钠溶液（ｐＨ６．８）＝３５∶６５（Ｖ／Ｖ）。紫外检测波长３３０ｎｍ。牛磺酸浓度在０．１～１．０ｍｍｏｌ／Ｌ范围内可被定量测定。回收率可达１００．３１％±１．９８％,变异系数（ＣＶ）为１．９４％。     

气相色谱/质谱法测定大鼠脑中5-羟色胺的含量

采用气相色谱／质谱法（ＧＣ／ＭＳ）测定了正常大鼠和服药大鼠脑组织中５－羟色胺（５－ＨＴ）的浓度。大鼠脑组织制成匀浆后,先将５－ＨＴ酰化,酰化物经乙酸乙酯提取后,再经七氟丁酸酐衍生化,用ＧＣ／ＭＳ测定。ＭＳ采用电子捕获负离子化学电离（ＥＣＮＩＣＩ）模式。方法的线性范围为０．５０～５０．０μｇ／Ｌ,回归方程为Ｙ＝０．１３４８Ｘ－０．０７９９５（ｒ＝０．９９９６）;平均回收率为９８．２％±３．８％（ｎ＝１０）;检测限为０．５μｇ／Ｌ;相对标准偏差小于１０％。     

未衍生高效液相色谱法测定螺旋藻粉中γ-亚麻酸含量

建立了未衍生高效液相色谱法测定螺旋藻粉中γ－亚麻酸（ＧＬＡ）的方法。采用Ｃ８反相柱,以乙腈：四氢呋喃：水（含０．４％乙酸）＝６２：３：３５（Ｖ／Ｖ／Ｖ）为流动相,示差折光检测器检测,测定了同一批螺旋藻粉中ＧＬＡ含量为１．３９％,标准偏差０．０４３２,变异系数３．１１％,回收率为９３．９０％￣９８．９３％,本方法快速,重现性及准确度均令人满意。     

2-羟基-3-羧基-5-磺酸基苯基重氮氨基偶氮苯与铊反应的分光光度法研究

于ｐＨ１０．０～１１．０的ＮＨ３－ＮＨ４Ｃｌ缓冲介质中，在ＴｒｉｔｏｎＸ－１００存在下，铊（Ⅲ）与２－羟基－３－羧基－５－磺酸基苯基重氮氨基偶氮苯（ＨＣＳ－ＤＡＡ）形成组成比为１∶３的红色配合物，其最大吸收波长和对比度分别为５１０ｎｍ和８０ｎｍ，表观摩尔吸光系数为１．５２×１０５Ｌ·ｍｏｌ－１·ｃｍ－１，线性范围为０～０．７０ｍｇ／Ｌ，室温下显色反应立即完成，配合物至少稳定２ｈ。方法用于水样、烟叶和煤灰中痕量铊的分析，回收率为９０．０％～１０１．４％，５次测定的相对标准偏差不大于４．６％。     

钴－5－（4－硝基苯偶氮）－8－（4－甲苯磺酰氨基）－喹啉配合物的极谱波研究

钴（Ⅱ）在ＨＡｃ－ＮａＮＯ＿２－吐温－８０－ＮＰＴＳＱ体系中有一灵敏的阴极极化导数波，其峰电位－１．００Ｖ（ｖｓ．ＳＣＥ），钴浓度在４．０×１０￣（－９）～３．０×１０￣（－７）ｇ／ｍＬ范围内与峰电流有良好的线性关系。本文讨论了测定钴（Ⅱ）的最佳实验条件，对极谱波的性质进行了初步探讨，并作了维生素Ｂ＿（１２）中钴的测定，测定结果的相对标准偏差为３．７４％，回收率为９６～１０８％。     

山药中尿囊素的高效液相色谱分析方法研究

建立了山药中尿囊素的高效液相色谱分析方法。样品用甲醇－水（９０：１０,Ｖ／Ｖ）提取,在氨基柱上进行高效液相色谱分析,紫外检测波长２２４ｎｍ,流动相为甲醇－水（８０：２０,Ｖ／Ｖ）,相对标准偏差为２．０％（ｎ＝５）,尿囊素的回收率为９８．８％（ｎ＝４）。     

5-氨基水杨酸锌及相关物质的高效液相色谱分析研究

对５－氨基水杨酸锌及相关物质５－氨基水杨酸、水杨酸、对氨基苯酚和５－苯偶氮基水杨酸的高效液相色谱法（ＨＰＬＣ）的分离条件进行了优化研究,结果表明,采用ＣＬＣ－ＯＤＳ（１５０ｍｍ×６．０ｍｍｉ．ｄ．,１０μｍ）作为分离柱,１％（Ｖ／Ｖ）ＨＡｃ－ＭｅＯＨ（４∶６）作为流动相,在流速为１ｍＬ／ｍｉｎ的情况下,上述５种物质在１０ｍｉｎ内可以达到基线分离,保留时间的日内和日间的变异系数分别小于２％和５％,在一定浓度范围内,浓度与峰面积的线性关系良好。     

Determination of phenolic compounds in water using membrane inlet mass spectrometry

Two membrane inlet mass spectrometric (MIMS) methods for determining phenolic compounds in water are described and compared, namely direct analysis and analysis after acetylation of the phenolic compounds. Direct analysis of phenolic compounds in water is a very simple and rapid method and detection limits are relatively low (from 30 mug 1(-1) for phenol to 1000 mug 1(-1) for 4-nitrophenol). Analysis of phenolic compounds after aqueous acetylation is also a very simple and rapid method, and the detection limits are even two orders of magnitude lower than in the direct analysis. For example the detection limit of phenol acetate is 0.5 mug 1(-1) and that of 4-nitrophenol is 10 mug 1(-1). The acetylation method was also tested in the analysis of phenolic compounds from contaminated surface water samples.     

Simultaneous determination of 2-nitrophenol and 4-nitrophenol based on the multi-wall carbon nanotubes Nafion-modified electrode

In this work, multi-wall carbon nanotubes (MWNT) were conveniently dispersed into Nafion-ethanol solution, and the MWNT-Nafion-modified glassy carbon electrode (GCE) was described for the simultaneous determination of 2-nitrophenol and 4-nitrophenol. At pH 4.0 phosphate buffer, the reduction peak currents of 2-nitrophenol (at -0.8 V) and 4-nitrophenol (at -1.0 V) increase significantly at the MWNT-Nafion-modified GCE, in comparison with that at the Nafion-modified GCE and the bare GCE. The experimental parameters, such as solution pH of phosphate buffer, accumulation potential and time, and the amounts of MWNT-Nafion onto the GCE surface, were optimized. The reduction peak currents are linear with the concentration of 2-nitrophenol from 5 x 10(-8) to 1 x 10(-5) mol L(-1) and with that of 4-nitrophenol from 1 x 10(-7) to 1 x 10(-5) mol L(-1). The detection limits after 3-min accumulation are 1 x 10(-8) mol L(-1) for 2-nitrophenol and for 4 x 10(-8) mol L(-1) for 4-nitrophenol. This modified electrode was applied to direct determination of 2-nitrophenol and 4-nitrophenol in lake water samples.     

Trace level determination of phenols as pentafluorobenzyl derivatives by gas chromatography-negative-ion chemical ionization mass spectrometry.

A method for the trace level determination of 11 phenols as pentafluorobenzyl (PFB) derivatives by gas chromatography-mass spectrometry (GC-MS) with negative-ion chemical ionization (NICI) is described. First, the conditions for the PFB derivatisation of phenols were optimized and were found to be reaction temperature 80 degrees C and reaction time 5 h. Second, the detection limits using selected ion monitoring (SIM) were compared between trimethylsilylated (TMS) derivatives in the electron ionization (EI) mode and PFB derivatives in the NICI mode. The responses for the PFB derivatives in the NICI mode were 3.3-61 times higher than those of the TMS derivatives in the EI mode. The instrumental detection limits using NICI-SIM ranged from 2.6 to 290 fg. This method was applied to the analysis of phenols in river water using solid-phase extraction. The recoveries of the phenols from a river water sample spiked with standards at 100 ng l-1 with 2-chlorophenol, 4-chloro-3-methylphenol and pentachlorophenol and at 1000 ng l-1 with phenol, 2,4-dimethylphenol, 2,4-dichlorophenol, 2-nitrophenol, 2,4,6-trichlorophenol and 4-nitrophenol were 81.2-106.3% (RSD 5.1-8.0%), except for 2-methyl-4,6-dinitrophenol and 2,4-dinitrophenol, for which the recoveries were 5.8 and 4.2%, respectively, because water contained in the acetone eluate interfered with the derivatisation of these compounds with two electrophilic nitro groups.     

Determination of phenols by flow injection and liquid chromatography with on-line quinine-sensitized photo-oxidation and quenched luminol chemiluminescence detection

An on-line quinine-sensitized photo-oxidation with quenched chemiluminescence (CL) detection method is developed for phenols using flow injection (FI) and liquid chromatography (LC). This detection method is based on the decrease of light emission from the luminol CL reaction due to the photo-oxidation of phenols that scavenge the photogenerated reactive oxygen species (e.g. singlet oxygen () and superoxide (O₂⁻)). On-line photo-oxidation is achieved using a coil photo-reactor made from fluoroethylene-propylene copolymer tubing ( mm i.d.) coiled around a mercury UV lamp. A buffer of pH 7 and a concentration of 350 μM for quinine sulfate are determined optimum for the sensitized photo-oxidation. Using a carrier system flow rate of 60 μl/min, calibration curves taken by FI for 10 phenolic compounds in aqueous solutions showed this decreasing sensitivity order: 4-chlorophenol, phenol, 4-nitrophenol, 3-hydroxy-l-kynurenine, 2-nitrophenol, salicylate, 3-nitrophenol, catechol, 2,4-dinitrophenol, and 2,4-dichlorophenol. This detection method using two tandem coil photo-reactors is also applied for the LC separation of phenol, 4-nitrophenol and 4-chlorophenol on an octadecyl (C18) silica LC column using acetonitrile-H₂O (40:60, v/v) as a mobile phase. The quenched CL detection limits (about 1 μM or 20 pmol) for phenol and 4-chlorophenol are comparable to those for UV detection at 254 nm. Some selectivity in the quenched CL detection is evident by no interference in the FI phenol response even when benzaldehyde and phenethanol concentrations are 8 and 15 times that of phenol.     

Universal screening method for the determination of US Environmental Protection Agency phenols at the lower ng l(-1) level in water samples by on-line solid-phase extraction-high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry within a single run

The applicability of a previously optimized method for the analysis of the US Environmental Protection Agency (EPA) regulations phenols, based on on-line solid-phase extraction coupled to liquid chromatography with mass spectrometric (MS) detection in different matrix loaded water samples is demonstrated. The comprehensive optimization of the mobile phase conditions and their influence on the ionization process in atmospheric pressure ionization is described in detail. In particular, MS detection of the weakly acidic phenols such as phenol, monochlorinated phenols and methylated phenols requires the absence of acidic mobile phase modifiers and buffers. Thus lower retention times and slight peak broadening of the more acidic dinitrophenols are obtained if the entire range of EPA phenols is analyzed within a single chromatographic run. The figures of merit for the method were determined and the applicability to real water samples was investigated. Limits of detection for phenols ranging from 40 to 280 ng l(-1) and relative standard deviations below 8% in SCAN mode are obtained for all phenols if only 10-ml river water samples with low dissolved organic carbon (DOC 5 mg C l(-1) concentrations are preconcentrated. The method was used to detect 2-nitrophenol and 4-nitrophenol in river water samples in the lower ng l(-1) range. The analysis of highly matrix-loaded samples (DOC 210 mg C l(-1)) requires a reduced enrichment volume resulting in decreased sensitivity. Still the method is capable of reaching excellent detection limits which demonstrates its excellent suitability for screening analysis.     

Evaluation of a new hypercrosslinked polymer as a sorbent for solid-phase extraction of polar compounds

A new hypercrosslinked polymer (HXLGp) with hydrophilic character due to the presence of hydroxyl moieties has been tested as a sorbent for the solid-phase extraction (SPE) of several polar compounds from water samples. This new sorbent enables the on-line extraction of 300 ml of sample with recoveries higher than 80% for polar compounds such as oxamyl, methomyl or desisopropylatrazine (DIA). The HXLGp has also been compared to other commercially available sorbents such as Oasis HLB (hydrophilic macroporous), to hydrophobic hypercrosslinked resins and to a previously synthesized sorbent based on N-vinylimidazole-divinylbenzene. The results are consistently better with the new synthesized sorbent. The method was successfully applied to the on-line SPE-HPLC of tap and river water samples. The validation with river water samples provided good linearity range and detection limits between 0.03 for methomyl and 4-nitrophenol (4NP) to 0.2 microg l(-1) for phenol (Ph).     

Rapid,simple and selective determination of 2,4-dinitrophenol by molecularly imprinted spin column extraction coupled with fluorescence detection

A rapid, simple and selective method based on molecularly imprinted, spin column extraction coupled with fluorescence detection was successfully established for the determination of 2,4-dinitrophenol in serum samples. The 2,4-dinitrophenol imprinted polymers exhibited highly selective recognition for the template molecule and the maximum adsorption capacity was 138.9 mg/g. The results indicated that when water is used as the loading solution, only 2,4-dinitrophenol could be adsorbed on the spin column without the remaining structural analogs（2-nitrophenol, 4-nitrophenol and phenol）. After eluting with acetonitrile/acetic acid（9/1, v/v）, 2,4-dinitrophenol in serum samples could be determined by using the fluorescence spectrometer, based on the fluorescence enhancement of fluorescein by the template molecule. Under the optimal conditions, the spiked recovery ranged from 95.8% to 103.4% and the detection limit was 1 nmol/L. The results confirmed the reliability and practicality of the protocol and revealed a good perspective of this method for biological sample analysis.     

Determination of phenols in waters by stir membrane liquid-liquid-liquid microextraction coupled to liquid chromatography with ultraviolet detection

A simple and rapid method for the determination of eleven phenols in water samples is presented. The target analytes are isolated by stir membrane liquid-liquid microextraction working under the three-phase mode. An alkaline aqueous solution is used as extractant phase while octanol is selected as supported liquid membrane solvent. The target analytes are separated and determined by liquid chromatography (LC) with ultraviolet detection (UV). All the variables involved in the extraction process have been studied in depth. Low detection limits (in the range from 82.1 ng/L for phenol to 452 ng/L for 2,4,5-trichlorophenol) were obtained. The repeatability, expressed as relative standard deviation (RSD), varied between 1.3% (for 4-nitrophenol) and 8.0% (for 4-chlorophenol). The enrichment factors were in the range from 168 (for 2,4,5-trichlorophenol) to 395 (for 3-chlorophenol). The proposed procedure was applied for the direct determination of the eleven phenols in some real water samples including river, well and tap waters. The accuracy was evaluated by means of a recovery study, the results being in the range of 87-120%.     

Pulsed amperometric detection with poly(dimethylsiloxane)-fabricated capillary electrophoresis microchips for the determination of EPA priority pollutants

A miniaturized analytical system for separation and detection of three EPA priority phenolic pollutants, based on a poly(dimethylsiloxane)-fabricated capillary electrophoresis microchip and pulsed amperometric detection is described. The approach offers a rapid (less than 2 min), simultaneous measurement of three phenolic pollutants: phenol, 4,6-dinitro-o-cresol and pentachlorophenol. The highly stable response (RSD = 6.1%) observed for repetitive injections (n > 100) reflects the effectiveness of Au working electrode cleaned by pulsed amperometric detection. The effect of solution conditions, separation potential and detection waveform were optimized for both the separation and detection of phenols. Under the optimum conditions (5.0 mM phosphate buffer pH = 12.4, detection potential: 0.7 V, separation potential: 1200 V, injection time: 10 s) the baseline separation of the three selected compounds was achieved. Limits of detection of 2.2 microM (2.8 fmol), 0.9 microM (1.1 fmol), and 1.3 microM (1.6 fmol) were achieved for phenol, 4,6-dinitro-o-cresol and pentachlorophenol, respectively. A local city water sample and two over-the-counter sore-throat medicines were analyzed in order to demonstrate the capabilities of the proposed technique to face real applications.     

Solid-phase microextraction of phenol compounds using a fused-silica fiber coated with beta-cyclodextrin-bonded silica particles.

A novel solid-phase microextraction (SPME) fiber was prepared by coating an HPLC beta-cyclodextrin bonded silica stationary phase (CDS) on the surface of a fused-silica fiber. The fiber was evaluated for the determination of five phenol compounds (phenol, 2,4-dimethylphenol, 4-nitrophenol, 3-chlorophenol, 4-methylphenol). Compared with commercially available polymer coatings, the CDS coating showed high sensitivity and fast velocity of mass transfer for phenol compounds because of its porous structure and a unique molecular structure of beta-cyclodextrin. In addition, the CDS coating was proved to be very stable at a relatively high temperature (up to 300 degrees C). The method was suitable for the determination of phenol compounds in aqueous samples. The determination of 4-nitrophenol in soil by microwave-assisted extraction (MAE) coupled to solid-phase microextraction was also investigated.