Determination of catecholamines by CE with direct chemiluminescence detection

A rapid and sensitive method to detect three catecholamines, isoprenaline, epinephrine, and dopamine, by CE coupled with direct luminol-potassium periodate chemiluminescence (CL) detection is described. The conditions for CE separation and CL reaction were systematically optimized. Under the optimum conditions, the baseline separation of three catecholamines was achieved within 6.5 min. The LODs obtained in standard solution were 5.3 x 10(-8 )mol/L for isoprenaline, 4.7 x 10(-8 )mol/L for epinephrine, and 1.5 x 10(-7 )mol/L for dopamine. The RSD of the migration time and peak area were less than 1.8 and 3.6% (n = 5), respectively. The present method was applied to the determination of the dopamine in urine samples of cigarette smokers and nonsmokers. The results obtained indicate that there is a close relationship between the content of dopamine in human urine and the amount of cigarettes smoked daily; the level of dopamine in smokers is higher than in nonsmokers.     

Determination of PCR products by CE with contactless conductivity detection

The use of CE with contactless conductivity detection for the determination of PCR products is demonstrated for the first time. The separation of specific length PCR products according to their size could be achieved using 5% PVP as a sieving medium in a separation buffer consisting of 20 mM Tris and 20 mM 2‐(cyclohexylamino)ethansulphonic acid (pH 8.5). A fused silica capillary of 60 cm length and 50 μm id and an applied separation voltage of –15 kV were employed and separations could be completed within 20–50 min. PCR amplified DNA fragments of different sizes obtained from different bacterial plasmid templates as well as a fragment from genomic DNA of genetically modified soybeans could be successfully identified.     

Determination of olive oil acidity by CE

In this work, a CE method for the determination of olive oil acidity was proposed. The method was based on an ethanolic extraction (at 60 degrees C) of the oil long-chain free fatty acids (LC-FFAs) components followed by CE determination in pH 6.86 phosphate buffer at 15 mmol/L concentration containing 4 mmol/L sodium dodecylbenzenesulfonate (SDBS), 10 mmol/L polyoxyethylene 23 lauryl ether (Brij 35), 2% v/v 1-octanol and 45% v/v ACN under indirect UV detection at 224 nm. Although this electrolyte promoted baseline separation of myristic acid (C14:0) (internal standard (IS)) and olive oil major components (palmitic acid (C16:0), oleic acid (C18:1c) and linoleic acid (C18:2cc)) in less than 8 min, after a few injections, the electropherogram profiles were severely altered (peak broadening, migration time shifts, etc.) and the current increased substantially. An adsorption study was conducted revealing that the dissolution of the capillary external polyimide coating during the electrophoretic run caused the detrimental effect. After removal of the capillary tip coating, ten consecutive injections could be performed without any disturbances and this simple procedure was, therefore, implemented during quantitative purposes. The reliability of the proposed method was further investigated by the determination of acidity of an extra virgin olive oil sample in comparison to the established methodology (AOCS method Ca 5a-40, alkaline volumetric titration (AVT)). No statistical differences were found within 95% confidence level. A % acidity of 0.39 +/- 0.02 was found for the olive oil sample under consideration.     

高效液相色谱-蒸发光散射检测器测定五种甾醇含量

建立了一种采用高效液相色谱－蒸发光散射检测器分离、测定五种甾醇含量的方法。该方法采用Supecol Discovery C18色谱柱，以甲醇作流动相，在75－5920ng/L范围内，甾醇峰面积的对数值与其含量对数值间有良好的线性关系，相关系数r的0.9983以上，相对标准偏差RSD小于0.45%，甾醇的平均回收率为98.3%－101％。该法简便，快速，准确可靠。     

Determination of medroxyprogesterone acetate residues by CE immunoassay with chemiluminescence detection

A rapid and simple method is developed for the determination of medroxyprogesterone acetate (MPA) by CE immunoassay with chemiluminescence (CL). This method is based on the competitive reactions between horseradish peroxidase (HRP)-labeled MPA (MPA-HRP) and free MPA with anti-MPA antiserum. The influencing factors on the electrophoresis and CL detection were studied completely and the optimal conditions of separation and determination were obtained. The linear range was 2.0-50 nmol/L and the LOD for MPA was 0.9 nmol/L. The present method was applied to the analysis of pork tissues.     

毛细管电泳脉冲伏安电化学分离检测胺类化合物

电化学检测高效毛细管电泳自 80年代末问世以来 ,已迅速发展为一种重要的分析方法 ,但是具有许多优点的现代电分析化学方法在毛细管电泳检测中的应用还不多 .扫描伏安电化学检测是继安培检测方法之后应用较多的一种方法 ,它除具有安培检测方法的优点外 ,还能得到被测物质的电流随电压变化的伏安特性 [1～ 5 ] ,但由于在电极电位的扫描过程中会产生较大的充电电流 ,进而影响检测的灵敏度和检出限 .脉冲安培检测可获得较高的灵敏度和低的检出限 ,并减少电极的污染 ,因而被应用于高效液相色谱 [6,7] 和毛细管电泳 [8,9] 中检测有机化合物 .目前…     

Determination of Pyromellitic Acid in Aqueous Matrices by CE

An analytical method for the capillary electrophoresis determination of pyromellitic acid in aqueous media used as “food simulants” has been developed and is described in this paper. The proposed method determined the pyromellitic acid at ppb levels and is based on a capillary zone electrophoresis separation using coated fused-silica capillary column with a carbonate running buffer and a UV-Vis detector. The method herein developed has been applied to the determination of pyromelitic acid residues leached from plastic bottles. The amount of pyromellitic acid determined in different batch of polyethyleneterephthalate bottles is 2.18%, while the limit of detection is 2.30 ng mL^?1 with a relative standard deviation of 4.40%.     

Determination of organic acids by CE and CEC methods

A comprehensive overview of the analysis of low-molecular-mass organic acids employing electromigration methods in the capillary format is given. This review includes papers published since 2003 and can be seen as an update of the review paper published by Galli et al. in 2003. Tables included in this review contain application papers describing the determination of organic acids from a variety of fields like the analysis of food and beverages, environmental samples, samples from clinical origin, and from natural products.     

测定锗的二极管阵列检测-流动注射分光光度法

研究了在溴化十六烷基三甲铵（ＣＴＭＡＢ）存在下，锗与２，３，７－三羟基－９－小杨基荧光酮－６（ＳＡＦ）的显色反应，采用二极管阵列检测器，建立了检测微量锗的流动注射分光光度法。将该法应用于食品和中草药中锗的测定，取得了满意的结果。锗在０～３．０ｍｇ／Ｌ范围内线性良好，检出限为０．０１２ｍｇ／Ｌ，样品加标回收率为８１．０％～９８．５％，相对标准偏差小于８．４％。实验表明，该法灵敏、快速，准确度高、精密     

Determination of vigabatrin in human plasma by means of CE with LIF detection

A method has been developed for the quantitation of the antiepileptic drug vigabatrin (VGB) in human plasma. It is based on CE with LIF detection. The effect of the pH of the buffer and of N-methylglucamine (GLC) as BGE constituent was investigated. The final BGE consisted of 50 mM borate buffer, pH 9.0, with 100 mM GLC and enabled separation within 12 min at 20 kV voltage. An SPE procedure was used for the pretreatment of biological samples, based on mixed-mode lipophilic-cation exchange cartridges, followed by a derivatization step with 6-carboxyfluorescein-N-succinimidyl ester (CFSE). Fluorescence was excited by an Ar-ion laser (lambda(exc) = 488 nm). Linearity was observed in the 10-120 microg/mL plasma concentration range. Extraction yield was >96%, precision (expressed as RSD) <6.7% and accuracy (recovery) was between 97.0 and 101.6%. The method has been successfully applied to the analysis of VGB in plasma of epileptic patients undergoing therapy with the drug.     

Determination of peptide hormones of brain and intestine by CE with ESI-MS detection

A new method for the determination of the peptide hormones of brain and intestine based on CE coupling with a DAD and ESI-MS was established. Several electrophoretic and ESI-MS parameters were investigated in detail, such as electrolyte nature and concentration, organic solvent and sheath liquid compositions, nebulization gas pressure and the ESI capillary voltage. Optimized conditions were achieved with 25 mM formic acid-ammonium formate (pH 2.9) as the optimal electrolyte, 2 mM formic acid in 80% methanol in water as the sheath liquid, and 20 kV applied voltage. Under the optimized conditions, four protonated peptides were separated by CE and selectively detected by a quadrupole mass spectrometer with a sheath flow ESI interface. LODs for the four peptides (neurotensin hexapeptide, neurotensin, cholecystokinin tetrapeptide, and pentagastrin) were in the range of 0.10-0.60 micromol/L at an S/N of 3. The RSDs (n = 8) of the method were 0.70-1.5% for migration times and 1.6-6.1% for peak areas. This method is simple, rapid, and selective compared with RIA and ELISA techniques, and has been applied to the analysis of rat hypothalamus tissue.     

微流蒸发光散射检测器与加压毛细管电色谱联用测定川贝枇杷糖浆中6种有效成分的含量

建立了同时测定川贝枇杷糖浆中6种有效成分(桔梗皂苷D、贝母辛、齐墩果酸、西贝素、贝母甲素和贝母乙素)含量的微流蒸发光散射检测器(μELSD)与加压毛细管电色谱(p CEC)联用检测方法。搭建p CEC-μELSD联用平台,采用C18毛细管色谱柱(EP-150-15-3-C18),流动相为乙腈(A)-10 mmol·L-1甲酸-三乙胺水溶液(p H 11.0)(B),梯度洗脱,柱流速为1.02μL·min-1,施加电压为+10 k V,雾化载气流速为0.4 L·min-1,蒸发温度为40℃。川贝枇杷糖浆中6种有效成分可在10 min内得到分离检测,6种有效成分的线性范围可达4个数量级,检出限均在pg水平,加标回收率为97.9%~103.0%。所建立的p CEC-μELSD联用方法精密度、重复性和稳定性良好,且简便、快速、可靠,可用于川贝枇杷糖浆中6种有效成分的含量测定。     

Determination of sertraline and N-desmethylsertraline in human plasma by CE with LIF detection

A method has been developed for the analysis of the antidepressant drug sertraline together with its main metabolite N-desmethylsertraline (DMS) in human plasma. It is based on CE with LIF detection (lambda = 488 nm). A SPE procedure is employed for biological sample pretreatment, followed by a derivatization step with FITC; reboxetine was the internal standard. The effect of CD, acetone and N-methyl-D-glucamine (GLC) as constituents of the BGE for analyte separation was investigated. The final BGE consisted of 20 mM carbonate buffer, pH 9.0, with 2.5 mM heptakis(2,6-di-O-methyl)-beta-CD, 50 mM GLC and 20% v/v acetone. With 30 kV applied voltage, the electrophoretic run is completed in 7.5 min. Linearity was observed in the plasma concentration range from 3.0 to 500 ng/mL for sertraline and 4.0 to 500 ng/mL for DMS. Extraction yield was >97.1%, precision - expressed as RSD% - was <3.7, accuracy (recovery) was >95.6%. Due to its sensitivity and selectivity, the method was suited for the analysis of plasma samples from patients undergoing therapy with sertraline.     

电磁感应加热与原子荧光光谱联用测定海产品中的无机汞和有机汞

研制了电磁感应加热装置和磁感应加热柱,并将其应用于有机汞的在线氧化。与冷蒸汽发生-原子荧光光谱法联用,在线测定了海产品中的无机汞和有机汞。样品溶液与K2S2O8在线混合后流经磁感应加热柱,在较低功率(15W)时快速升温将有机汞氧化为无机汞,测定总汞含量;加热柱为室温时,测定无机汞含量,二者之差为有机汞。对各种实验参数和干扰情况进行了详细研究。无机汞的检出限为0.036μg/L;样品分析精密度(RSD)为2.4%(n=11);有机汞的检出限为0.043μg/L,样品分析精密度(RSD)为3.6%(n=11)。     

气相色谱/电子捕获检测法测定键合态糖苷的研究

该文建立了GC/ECD法测定键合态糖苷的分析方法,采用N-甲基-双(三氟乙酰胺)(MBTFA)对目标物进行衍生,并优化了反应温度和时间.结果表明在60℃下反应50 min时,衍生效果最好.该衍生反应在产物中引入氟元素,可用GC/JECD法进行测定.以苯氧基葡萄糖苷为典型目标物进行线性研究,方法在0.05～200 mg/...     

气相色谱-电子捕获检测器法检测水中氟乐灵

建立了气相色谱仪检测水中氟乐灵的方法. 分别采用液液和固相两种萃取浓缩的方式进行样品预处理,两种方法均能满足要求. 液液萃取操作简单,节约时间. 固相萃取能实现自动化处理,节省劳力. 浓缩后使用HP-5色谱柱分离,电子捕获检测器进行测定. 试验结果表明,当水中氟乐灵的质量浓度在0.05~1.0 μg/L范围内,其工作曲线回归方程的相关系数高于0.999,方法检出限(3 S/N)为0.02 μg/L. 在两种不同浓度水平条件下对方法的回收率和精密度进行了试验,其回收率在84.0%~98.0%之间,相对标准偏差在3.0%~5.8%之间.     

高效液相色谱–光电二极管阵列法测定虾青素的含量

建立虾青素含量测定的高效液相色谱–光电二极管阵列法。采用Purospher STAR RP 18(4.6 mm×250mm,5μm)色谱柱,以甲醇–水(体积比为95∶5)为流动相,流速1.0 mL/min,检测波长为482 nm,柱温为30℃,进样量为20μL。在所选定的液相色谱条件下,虾青素主峰与其它杂质峰分离良好,虾青素在0.2~16μg/mL范围内线性良好,线性相关系数r=0.999 9,检出限为0.01μg/mL,测定结果的相对标准偏差为0.42%(n=6),平均回收率为100.4%。该法分析快速准确、灵敏度高、重现性好。     

Effective Separation and Simultaneous Determination of Four Fluoroquinolones in Milk by CE with SPE

A simple and sensitive capillary electrophoresis method with solid phase extraction was developed for the determination of sarafloxacin, ciprofloxacin, enrofloxacin and flumequine in milk. Solid-phase extraction with Oasis HLB cartridge column was used for the isolation of four fluoroquinolones in raw milk from a farm and fresh milk sample. Separation conditions of CE, including running buffer, voltage and temperature, were investigated and optimized. Baseline separation was achieved for the four fluoroquinolones under the developed conditions. Correlation coefficients greater than 0.9998 were obtained for all fluoroquinolones with a dynamic range from 1 up to 100 mg L^?1. The intra-day precision was less than 5%, and the inter-day precision was less than 6%. The method recoveries of four fluoroquinolones were in the range of 70.9–90.6%. The detection limits for sarafloxacin, ciprofloxacin, enrofloxacin and flumequine was 19.8, 15.2, 13.3 and 15.9 μg kg^?1, respectively, which allows positive detection of the fluoroquinolones at the targeted maximum residue levels in milk samples.