反相硅胶整体柱离子对色谱法快速测定吡啶离子液体阳离子

建立了整体柱离子对色谱-紫外检测法梯度淋洗快速分离测定4种吡啶离子液体阳离子的方法。分离采用C18反相硅胶整体柱,以离子对试剂(用柠檬酸调节pH值)-乙腈为淋洗液,并采用多级梯度洗脱程序。实验考察了色谱柱、离子对试剂、乙腈浓度、色谱柱温度及流速对吡啶阳离子保留的影响,并讨论了其保留规律。咪唑阳离子的保留符合碳数规律。最佳色谱条件是:在流速3.0 mL/min,柱温30℃下,以1.0 mmol/L庚烷磺酸钠(pH 4.0)(A)+乙腈(B)为淋洗液进行梯度洗脱。淋洗梯度为0～2.0 min,10%B;2.0～2.5 min,10%～15%B;2.5～4.0 min,15%B;4.0～4.5 min,15%～20%B;4.5～10.0 min,20%B。在此条件下,4种吡啶阳离子可在7 min内基线分离。所测阳离子的检出限(S/N=3)为0.05～0.17 mg/L;峰面积的相对标准偏差(n=5)小于0.6%。将本方法用于实验室合成的离子液体样品和污水样品的分析,加标回收率在95.7%～99.0%之间。本方法准确、快速,具有较好的实用性。     

Determination of Boanmycin in Pharmaceutical Preparations by a Simple and Rapid Ion-pair LC Method

An ion-pair HPLC method with UV detection is described for the determination of boanmycin in freeze-dried pharmaceutical preparations. Chromatographic separation was achieved on a 5 μm Agilent Eclipse XDB-C₁₈ column (150 × 4.6 mm). The mobile phase contained methanol, acetonitrile, 055 M sodium hexanesulfonate and 0.08 M acetic acid in water. UV detection was at 291 nm. The assay was validated over a linear concentration range from 0.05 to 120 μg mL^?1. The method was applied to determine the content of BAM in freeze-dried powders.     

Rapid Determination of Polar and Non-Polar Pesticides in Human Serum, Using Mixed-Mode C-C18 Monolithic Spin Column Extraction and LC–MS/MS

Organophosphates and carbamates are pesticides whose acute toxicities are caused by inhibition of acetylcholinesterase. A liquid chromatography–mass spectrometry/mass spectrometry method was developed and validated for the quantification of 16 organophosphate and carbamate insecticides in human serum. Nonpolar and polar pesticides were simultaneously extracted from serum samples using a simple and fast monolithic spin column procedure using mixed-mode C-C₁₈ cartridges. Recovery was achieved in the range 11.9–99.2 %. Chromatography was carried out on an InertSustain^® C₁₈ HP 3 μm analytical column with gradient elution. Mass spectrometric analysis was performed using an Agilent 6410 Triple Quad Tandem mass spectrometer coupled with an electrospray ionization source in the positive ion mode. The assay was validated over a large concentration range and the limits of detection for all compounds ranged from 0.1 to 50 ng mL^?1. The precision for both intra- and inter-day determination of all analytes was found to be acceptable (< 12.9 %) and no significant matrix effect was observed. The developed method was effectively applied to clinical samples from patients presenting at hospital with symptoms of acute intentional organophosphate or carbamate poisoning, demonstrating its applicability to diagnostic applications.     

Simple and Sensitive Assay of Torasemide in Human Plasma by High-Performance Liquid Chromatography Using a Monolithic Silica Column

A rapid and sensitive method to assay torasemide in plasma was developed using a simple liquid-liquid extraction technique followed by high-performance liquid chromatography. Torasemide and the internal standard furosemide were extracted from 0.5 mL of plasma using ethyl acetate in the presence of 0.1M HCl. The analysis of the extracts was performed on a monolithic silica column with ultraviolet spectrophotometric detection. The calibration curve was linear over the concentration range of 0.05-5 μg mL^?1 in plasma. Recoveries were reasonable for routine analyses (>80%); the limit of quantification was 0.05 μg mL^?1 with a signal-to-noise ratio of 5. The coefficient of variation of the assay precision was less than 6.1%, and the accuracy exceeded 98%. This method was used to measure the torasemide concentration in plasma from healthy subjects after a single 20-mg oral dose of torasemide. This method provides a very simple, sensitive, and accurate way to determine torasemide concentrations in plasma.     

Determination by LC of Polyphenols in Italian Red Wine

A reversed-phase liquid chromatographic method, optimised for the separation of trans-, and cis-resveratrol, catechin, epicatechin, quercetin and rutin, is reported. Separation was achieved using a C18 column and a gradient elution with acetonitrile and 5% formic acid aqueous solution. The analyses required an equilibration period of 10 min and a run time of 25 min for completion. Identification was based on retention characteristics and by relative UV spectra, obtained by photodiode array detector and were compared with commercial standards. Analyses were performed without any sample pre-treatment. Detection was carried out by UV–Vis detector at three different wavelengths. The detection limit ranged from 0.16 μgm L⁻¹ (cis-resveratrol) to 1.5 μgm L⁻¹ (+)-catechin. Investigation was extended to quantitative determination of phenol compounds in Italian red wine and to investigate the stability of the six antioxidants.     

Rapid Determination of Trifluoromethanesulfonate and p-Toluenesulfonate by Ion-Pair Chromatography Using a Reversed-Phase Silica-Based Monolithic Column: Application to the Analysis of Ionic Liquids

A method of ion-pair chromatography was developed on a reversed-phase silica-based monolithic column for the fast and simultaneous determination of trifluoromethanesulfonate (CF₃SO₃ ⁻) and p-toluenesulfonate (C₇H₇SO₃ ⁻). The analysis was performed using a mobile phase of tetrabutylammonium hydroxide + citric acid + acetonitrile on the Chromolith Speed ROD RP-18e column with direct conductivity detection. The effects of the eluent, column temperature and flow rate on the retention of the anions were investigated. The experimental phenomenon was discussed according to hydrophobic interaction and ion-exchange mechanism in the separation. The optimized chromatographic conditions were selected. The optimized eluent for the separation consisted of 0.2 mmol L⁻¹ tetrabutylammonium hydroxide + 0.10 mmol L⁻¹ citric acid + 9% acetonitrile (pH 5.5). The flow rate was set at 6.0 mL min⁻¹. The column temperature was 25 °C. Under the optimal conditions, the better separation of CF₃SO₃ ⁻ and C₇H₇SO₃ ⁻ was achieved without any interference by other anions (Cl⁻, Br⁻, I⁻, NO₃ ⁻, SO₄ ²⁻, ClO₃ ⁻, BF₄ ⁻ and PF₆ ⁻). The detection limit (S/N = 3) was 0.28 and 0.71 mg L⁻¹ for CF₃SO₃ ⁻ and C₇H₇SO₃ ⁻, respectively. The method has been applied to the determination of CF₃SO₃ ⁻ and C₇H₇SO₃ ⁻ in ionic liquids. The spiked recoveries of CF₃SO₃ ⁻ and C₇H₇SO₃ ⁻ were 101.1 and 100.2%, respectively.

     

Rapid Determination of Trifluoromethanesulfonate and p-Toluenesulfonate by Ion-Pair Chromatography Using a Reversed-Phase Silica-Based Monolithic Column: Application to the Analysis of Ionic Liquids

A method of ion-pair chromatography was developed on a reversed-phase silica-based monolithic column for the fast and simultaneous determination of trifluoromethanesulfonate (CF₃SO₃ ^?) and p-toluenesulfonate (C₇H₇SO₃ ^?). The analysis was performed using a mobile phase of tetrabutylammonium hydroxide?+?citric acid?+?acetonitrile on the Chromolith Speed ROD RP-18e column with direct conductivity detection. The effects of the eluent, column temperature and flow rate on the retention of the anions were investigated. The experimental phenomenon was discussed according to hydrophobic interaction and ion-exchange mechanism in the separation. The optimized chromatographic conditions were selected. The optimized eluent for the separation consisted of 0.2?mmol?L^?1 tetrabutylammonium hydroxide?+?0.10?mmol?L^?1 citric acid?+?9% acetonitrile (pH 5.5). The flow rate was set at 6.0?mL?min^?1. The column temperature was 25???C. Under the optimal conditions, the better separation of CF₃SO₃ ^? and C₇H₇SO₃ ^? was achieved without any interference by other anions (Cl^?, Br^?, I^?, NO₃ ^?, SO₄ ^2?, ClO₃ ^?, BF₄ ^? and PF₆ ^?). The detection limit (S/N?=?3) was 0.28 and 0.71?mg?L^?1 for CF₃SO₃ ^? and C₇H₇SO₃ ^?, respectively. The method has been applied to the determination of CF₃SO₃ ^? and C₇H₇SO₃ ^? in ionic liquids. The spiked recoveries of CF₃SO₃ ^? and C₇H₇SO₃ ^? were 101.1 and 100.2%, respectively.     

整体柱离子对色谱快速分析高氯酸盐

研究了用硅胶整体柱和直接电导检测的离子对色谱快速分析高氯酸盐的方法。实验采用Chromolith Speed ROD RP-18e色谱柱,以氢氧化四丁铵(离子对试剂) 邻苯二甲酸 乙腈(有机改进剂)为淋洗液,讨论了离子对试剂浓度、有机改进剂浓度、pH、色谱柱温度和流速对ClO4-保留时间的影响。确定最佳色谱条件为:0.25mmol/L氢氧化四丁铵 0.18mmol/L邻苯二甲酸 7%乙腈(pH5.5)作为淋洗液,柱温30℃,流速6.0mL/min。在此条件下,ClO4-的保留时间在1min之内。其它常见阴离子(Cl-、NO3-、SO42-和I-)不干扰测定。方法的检出限为1.56mg/L;工作曲线的线性范围是2.4~100mg/L;峰面积的相对标准偏差(RSD,n=5)为1.9%。将本方法应用于测定加标果汁和加标地下水中的ClO4-,加标回收率分别为98.2%和97.6%。     

Rapid Determination of Polyphenols in Tobacco by MLC

A rapid, simple and reliable analytical procedure has been developed for the determination of polyphenols, including chlorogenic acid, rutin and scopoletin, in tobacco samples. After extraction, the polyphenols were analyzed by micellar liquid chromatography coupled with UV detection at 340 nm without sample preparation step. The compositions of the micellar mobile phase for the separation of these polyphenols were selected adequately by a chemometric method. The optimal resolution and satisfactory peak shapes were achieved with 0.022 mol L^?1 sodium dodecyl sulfate and 0.45% (volume fraction) 1-propanol solution at pH 5.0 using Eclipse XDB-C18 (250 mm × 3.0 mm, 5 μm) column. The limits of detection for chlorogenic acid, rutin and scopoletin were 0.15, 0.29 and 0.22 μg mL^?1, respectively. This validated method was successfully applied to qualitatively and quantitatively analyze the polyphenols in tobacco in less than 10 min.     

Rapid Analysis of Nitrate and Nitrite by Ion-Interaction Chromatography on a Monolithic Column

Ion-interaction chromatography with direct conductivity detection has been used for analysis of nitrate and nitrite. Chromatographic separation was performed on a monolithic silica-based C₁₈ column dynamically modified with tetrabutylammonium (TBA⁺). Using the optimized mobile phase, containing 2.0 mmol L^?1 TBA⁺ and 0.8 mmol L^?1 citrate (pH 6.0), delivered at a flow rate of 6.0 mL min^?1, separation of five anions (chloride, nitrite, bromide, nitrate, and sulfate) was achieved in only 40 s at a column temperature of 30 °C. The detection limits for nitrate and nitrite were 0.74 and 0.92 mg L^?1, respectively. The relative standard deviation (RSD, n = 5) of the retention times of nitrate and nitrite was 0.1% and RSD of chromatographic peak areas were 0.4 and 0.2%, respectively. The method was successfully used for analysis of the anions in groundwater. Recovery of nitrate and nitrite was 99.1 and 105%, respectively.     

Determination of Imidazolium Ionic Liquid Cations by Ion-Pair Chromatography Using a Monolithic Column and Direct Conductivity Detection

Determination of four imidazolium ionic liquid cations by ion-pair chromatography was carried out using direct conductivity detection. Chromatographic separations were performed on a silica-based monolithic column with 1-heptanesulfonic acid sodium + acetonitrile + citric acid as eluent. Carbon number rule and influence of acetonitrile on the retention of imidazolium cations were discussed. Detection limits (S/N = 3) for the cations were 2.1–55.9 mg L^?1. Relative standard deviations (RSD, n = 5) for peak areas were less than 3.0%. The method has been successfully applied to the determination of two ionic liquids synthesized by organic chemistry lab.     

整体柱离子相互作用色谱快速分析无机阴离子

研究了用硅胶整体柱和直接电导检测的离子相互作用色谱快速分析常见无机阴离子的方法。实验采用氢氧化四丁铵和邻苯二甲酸为淋洗液,讨论了包括淋洗液浓度、流速和pH对分离的影响。当以1.5 mmol/L氢氧化四丁铵和1.1 mmol/L邻苯二甲酸为淋洗液(pH 5.5),流速6 mL/min时,可以在1 min内分离Cl-、NO2-、Br-、NO3-、ClO3-、SO42-和I-7种阴离子。方法的检出限为0.3~1.9 mg/L,峰面积、峰高的相对标准偏差(RSD,n=5)分别为0.4%~2.2%和0.1%~1.5%。将该法用于测定矿泉水和地下水中的阴离子,加标回收率在97.9%~100.3%之间。     

Simple and Rapid Determination of Benzoylphenylurea Pesticides in River Water and Vegetables by LC–ESI-MS

Liquid chromatography with electrospray mass spectrometry (LC–ESI-MS) instrumentation equipped with a single quadrupole mass filter has been used to determine several benzoylphenylurea insecticides (diflubenzuron, triflumuron, hexaflumuron, lufenuron and flufenoxuron). Chromatographic and MS parameters were optimised to obtain the best sensitivity and selectivity for all pesticides. Solid-phase extraction (SPE) using C₁₈ cartridges was applied for preconcentration of pesticide trace levels in river water samples. Recoveries of benzoylphenylurea pesticides from spiked river water (0.01 and 0.025 μg L⁻¹) were between 73 and 110% and detection limits were between 3.5 and 7.5 ng L⁻¹. The applicability of the method to the determination of benzoylphenylurea insecticides in spiked cucumber, green beans, tomatoes and aubergines was evaluated. Samples were extracted into dichloromethane without any clean-up step. The limits of detection ranged from 1.0 to 3.2 ng mL⁻¹ (0.68 and 2.13 μg kg⁻¹ in the vegetable samples). Mean recoveries ranged from 79 to 114% at spiking levels of 0.01 and 0.03 mg kg⁻¹. The method was applied to determine traces of benzoylphenylureas in both river water and vegetable samples with precision values lower than 10%. Interferences due to the matrix effect were overcome using matrix-matched standards.     

Determination of Lead Employing Simple Flow Injection AAS with Monolithic Alginate-Polyurethane Composite Packed In-Valve Column

A simple flow injection FlameAAS for lead determination with an alginate-polyurethane composite (ALG-PUC) monolithic in-valve column has been developed. The ALG-PUC monolithic rod was prepared by mixing methylene diphenyl diisocyanate with polyol and sodium alginate with the ratio of 2:1:1 by weight for a 5 min polymerization reaction. It was then put into a column (0.8 cm i.d × 11 cm length) situated in a switching valve for the FI set up. A single standard calibration could be obtained by plotting the loaded µg Pb²⁺ vs. FI response (absorbances). The loaded µg Pb²⁺ is calculated: μg Pb²⁺ = FR_load × LT × C_Pb²⁺, where the FR load is the flow rate of the loading analyte solution (mL min⁻¹), LT is the loading time (min), and C_Pb²⁺ is the Pb²⁺ concentration (µg mL⁻¹). A linear calibration equation was obtained: FI response (absorbances) = 0.0018 [µg Pb²⁺] + 0.0032, R² = 0.9927 for 1–150 µg Pb²⁺, and RSD of less than 20% was also obtained. Application of the developed procedure has been demonstrated in real samples.     

Rapid Separation of Proteins by Capillary HPLC on a Short Polymethacrylate-based Strong Cation-exchange Monolithic Column

A polymethacrylate‐based strong cation‐exchange capillary monolithic column was prepared by in‐situ copolymerization for the fast separation of proteins. Glycidyl methacrylate (GMA) was used as monomer, ethylenedimethacrylate (EDMA) as cross link agent and the mixture of 1‐propanol, 1,4‐butanediol and water as porogen solvent. The monolith was sulfonated using 1 mol/L Na₂SO₃ based on a ring opening of epoxides. The influences of the contents of the porogen solvent and GMA and the various concentration ratios of 1‐propanol to 1,4‐butanediol in the polymerization mixture on the morphology, porosity, globule size, stability and column efficiency were investigated. The morphology and pore size distribution of the monolith were characterized by SEM and mercury intrusion porosimetry, respectively. Using only 1.5 cm length of this monolithic capillary column, four kinds of proteins, trypsin, cytochrome C, lysozyme (egg white) and egg albumin, were successfully separated from each other in 5 min at a high flow rate of 110 mm/s.     

Determination of Ochratoxin A in Poultry Feed by High-Performance Liquid Chromatography with a Monolithic Column

A monolithic column with high-performance liquid chromatography coupled with an ultraviolet detector was investigated for the determination of ochratoxin A in poultry feed. A systematic study was performed using solid phase extraction with a C₁₈ cartridge for sample pretreatment with three solvent systems. Ethyl acetate:methanol:formic acid (95:5:0.5) was found to be the most suitable. Pretreated samples were injected separately into packed and monolithic columns. The effects of the mobile phases on the chromatographic figures of merits were evaluated. Better peak symmetry, improved separation, and more theoretical plates were observed using an acetonitrile:water:formic acid (99:99:2) mobile phase. The repeatability and accuracy of the method were statistically evaluated and found to be satisfactory with a limit of detection of 40 µg L^?1. The use of a monolithic column in conjunction with sample pretreatment provided good results for the determination of ochratoxin A in poultry feed.