Application of poly(methacrylic acid-ethylene glycol dimethacrylate) monolith microextraction coupled with capillary zone electrophoresis to the determination of opiates in human urine

A novel poly(methacrylic acid-ethylene glycol dimethacrylate) (MAA-EGDMA) monolith microextraction method coupled with CZE was proposed for rapidly determining a mixture of opiates comprising heroin, 6-monoacetylmorphine, morphine, codeine, papaverine, and narcotine in human urine. The extraction device contained a regular plastic syringe, the poly(MAA-EGDMA) monolithic capillary tube (530 microm id x 3 cm) and a plastic pinhead, which connected the monolithic capillary tube and the syringe without leakage. In the polymer monolith microextraction, the sample solution was ejected via the monolithic capillary tube by a programmable syringe pump, followed by desorption with an aliquot of appropriate solution, which was collected into a vial for the subsequent analysis by CZE. The best separation was achieved using a buffer composed of 0.1 M disodium hydrogen phosphate (adjusted to pH 4.5 with 1 M hydrochloric acid) and 20% methanol v/v with temperature and voltage of 25 degrees C and 25 kV, respectively. By applying electrokinetic injection with field-enhanced sample stacking, detection limits of 6.6-19.5 ng/mL were achieved. Excellent method of reproducibility was found over a linear range of 80-2000 ng/mL.     

Identification and determination of effective components in Euphrasia regelii by capillary zone electrophoresis

A capillary zone electrophoresis (CZE) method has been developed for simultaneous determination of eukovoside, cinnamic acid and ferulic acid in Euphrasia regelii for the first time. The electrophoresis buffer was 20 mmol/L sodium borate containing 10% (v/v) methanol (pH 8.50). The effects of concentration of borate and electrolyte pH on electrophoretic behavior and separation were studied. Regression equations revealed linear relationships (correlation coefficients 0.9995-0.9998) between the peak area of each analyte and the concentration. The levels of analytes in the different parts of Euphrasia regelii were easily determined with recoveries ranging from 95.5 to 104.2%.     

Separation of Hydroxybenzoic Acid Isomers by Capillary Zone Electrophoresis

Abstract

Capillary zone electrophoresis is a highly efficient analytical technique that has been shown to be particularly useful for the analysis of isomers. Using a cathodic injection and anodic detection scheme, ortho-, meta- and para-hydroxybenzoic acids were separated in a fused-silica capillary column with a phosphate buffer at pH 10.3 (25.0 mmol/1 phosphate + 0.20 mmol/1 cetyltrimethylammonium bromide (CTAB) + 10% (v/v) 1-propanol with an applied voltage of 10 KV followed by direct UV detection. The use of CTAB as electroosmotic flow modifier allows the rapid separation of the three isomers by reversing the direction of electro-osmotic flow. The influence of pH, CTAB concentration and organic solvents on the migration behaviour of the solutes were also studied.     

毛细管区带电泳分离硝基苯胺位置异构体的研究

采用毛细管区带电泳(CZE)技术,在极端pH值条件下分离了邻、间、对硝基苯胺位置异构体;研究了背景缓冲溶液、pH值、分离电压、温度及进样时间等因素对分离的影响,得出了3种样品的标准曲线、线性范围及加样回收率。在选定的实验条件下15min内实现了上述3种苯胺类化合物的分离。该方法快速,准确,重现性好。     

毛细管区带电泳分离测定邻、对、间氯代苯酚

通过改变电泳条件,用毛细管区带电泳成功地分离了邻、对、间氯代苯酚,并检测到废水中样品的含量。研究了缓冲溶液种类、浓度、pH值、电泳电压以及内标物的选择,并得出了三种样品的标准曲线、线性范围以及加样回收率,为环境样品的监测提供了依据。     

子窗口分析法用于偶氮染料GC-MS重叠峰的解析

 将子窗口因子分析法 (SWFA)应用于GC MS联用检测数据分析 ,并以两种偶氮染料 3,3′ 二氯联苯胺和 4,4′ 次甲基 双 (2 氯苯胺 )重叠图谱为例进行了解析。结果表明 ,此方法可直接进行目标组分的质谱分辨 ,得到目标组分的质谱图 ,进而得到该组分的色谱图。其结果准确、可靠。与窗口因子分析相比 ,子窗口的选择更加容易 ,人工干预少 ,解析速度快。     

有机改性剂对氯代酚毛细管区带电泳分离的影响

在分离19种氯代酚的过程中,考察了不同的有机添加剂对其毛细管区带电泳分离的影响,发现除了缓冲溶液的pH值外,缓冲溶液添加剂对氯代酚的电泳分离也有较大影响。这种影响与添加剂和氯代酚形成氢键的能力有关。     

Capillary zone electrophoresis of basic drugs in non-aqueous acetonitrile with buffers based on a conventional pH scale

Summary The pK _a ^* values of 10 nitrogen-containing basic drugs in non-aqueous acetonitrile were determined from the pH^* dependence of their electrophoretic mobilities. The pH^* scale in the organic solvent was established using background electrolytes with known conventional pK _a ^* values, making further calibration with reference pH electrodes unnecessary. In acetonitrile the pK _a ^* values of analytes (or their conjugated cation acids, BH⁺, respectively) were 5.2±8.9 pK units>those in water. The observed change in pK _a ^* values of cationic analytes was, however, much less than the known respective change for neutral acids type HA. From the pK _a ^* values and the actual mobilities, it is possible to predict pH^* conditions to enable separation of analytes, and this was demonstrated for two pairs of common drugs.     

pH对毛细管电泳分离多肽的影响

设计了一个针对高年级本科生的毛细管电泳分离实验,用以研究pH对生物小分子多肽分离的影响。5种多肽包括Bradykinin、[Hyp3]-bradykinin、Angiotensin I、Leucine Enkephalin和[Met5]-Enkaphalin,被用于毛细管电泳的分离实验。研究了毛细管电泳生物分析实验中最重要的2个因素即电渗流和样品吸附随pH的变化以及对于分离的影响。在pH=10的条件下,酸性多肽几乎没有吸附,少量的碱性多肽有吸附。在pH=6的条件下,碱性多肽具有非常强的吸附从而导致非常差的分离效果,在pH=2.3的条件下,5种多肽都能被很好地分离,由于多肽此时都带有正电荷因此几乎没有吸附。而在此pH,电渗流消失。对具有一定分析化学基础理论知识的学生而言,这是一个非常好的生物分析实验,有助于学生充分理解相关环境因素对仪器分析的重要影响。     

Determination of various inorganic anions and organic acids in the atmospheric particulate matter using capillary zone electrophoresis with indirect UV detection

Capillary zone electrophoresis with indirect UV detection was developed for the simultaneous analysis of inorganic anions and organic acids using a mixed solution of 2,6-pyridinedicarboxylic acid and cetyltrimethylammonium hydroxide as the background electrolyte (BGE). The parameters which influence the separation, such as indirect UV detection wavelength, BGE conditions, applied voltage and extraction conditions were investigated. Thirteen inorganic anions and organic acids were detected within 20 min. The calibration curves of each analyte were linear with correlation coefficients greater than 0.991. The relative standard deviations (n = 10) of the peak areas ranged from 0.6% to 3.3%. The detection limits for these species ranged from 0.4 to 1.4 mg/L at a signal-to-noise ratio of 3. The recovery rate of each analyte was more than 80% under optimised extraction conditions, except for nitrite. The proposed method was applied towards the analysis of inorganic anions and organic acids in the atmospheric particulate matter using an Andersen sampler. The particle size of the particulate matter was determined, but not the size of the anions.