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.     

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 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.     

LC Analysis of Hexafluorophosphate on a Monolithic Column: Application to the Analysis of Ionic Liquids

A silica-based monolithic column with tetrabutylammonium hydroxide–phthalic acid–acetonitrile as mobile phase has been used for LC analysis of hexafluorophosphate with direct conductivity detection. The effects of mobile phase composition, column temperature, and flow rate on retention of hexafluorophosphate were investigated and the optimum chromatographic conditions were selected. Common anions and tetrafluoroborate did not interfere with analysis of hexafluorophosphate. The detection limit (S/N = 3) for hexafluorophosphate was 6.2 mg L^?1. Relative standard deviation (n = 5) for peak area was 0.1%. The method was successfully used for analysis of hexafluorophosphate in ionic liquids.     

Simple Free Amino Acid Separation by Reversed-Phase Ion-Pair Liquid Chromatography Using Column Switching Technique

Abstract

Reversed-phase ion-pair liquid chromatography with copper (II) ions (RP-IPC-Cu) was applied to develop a high speed separation of free amino acids. Dynamic gradient elution in RP-IPC-Cu could not achieve this purpose due to base line shift, therefore a column switching technique was used with a combination of different alkyl-bonded silica gel columns under isocratic elution. The flexibility of eluent components makes it easy to realize a rapid separation of a mixture of targeted amino acids.     

反相离子对色谱法测定油菜籽（饼）中的硫苷

 用反相离子对色谱法直接测定油菜籽（饼）中原 始硫苷成分,在样品预处理中加入抗氧化剂以防止吲哚类硫苷的氧化分解。研究了主要色 谱参数对硫苷组分保留值和选择性的影响,采用烯丙基硫苷或苯甲酸作内标,对硫苷的6种 组分进行了定性定量的测定。     

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%。     

以吡啶离子液体作为流动相添加剂的液相色谱法分析三氟乙酸根与三氟甲磺酸根

发展了用吡啶离子液体作为流动相添加剂的反相液相色谱分离和间接紫外检测三氟乙酸根和三氟甲磺酸根的分析方法。研究了吡啶离子液体、咪唑离子液体、对氨基苯酚盐酸盐和氯化四丁基铵作为流动相添加剂对三氟乙酸根和三氟甲磺酸根的影响,考察了吡啶离子液体的浓度、有机溶剂和检测波长等因素,并讨论了离子液体的作用、保留规律和相关机理。吡啶离子液体在分离检测中起到离子对试剂和紫外吸收试剂的作用。采用反相C_(18)色谱柱,以甲醇-0.3 mmol/L溴化N-己基吡啶水溶液(体积比10∶90)为流动相,在柱温30℃,流速1.0 m L/min,紫外检测波长250 nm条件下,三氟乙酸根和三氟甲磺酸根在12 min内完全分离,检出限分别为0.09、0.18 mg/L。将此法应用于离子液体中三氟乙酸根和三氟甲磺酸根阴离子的测定,加标回收率为96.0%~101%。该方法简单、准确,具有实用价值。     

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.     

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。     

Rapid Determination of Simple Polyphenols in Grapes by LC Using a Monolithic Column

The development of a rapid, reliable and reproducible LC method for the determination and quantification of 13 polyphenols (gallic acid, protocatechuic aldehyde, gentisic acid, catechin, vanillinic acid, caffeic acid, vanillin, epicatechin, syringaldehyde, p-coumaric acid, ferulic acid, sinapic acid and resveratrol) in grapes and derived products is reported. The polyphenols were separated in less than 8 min. Employed was an RP-18e (100 mm × 4.6 mm) monolithic type column. A gradient method with the following solvents was utilised for the chromatographic separation: A: 90% water, 2% acetic acid in methanol, and B: 90% methanol, 2% acetic acid in water. Two detectors in series were employed: a UV–Vis detector and a fluorescence excitation/emission detector. Influence of temperature (15–40 °C) and solvent flow rate (2–5 mL min^?1) on the separation were studied, and 25 °C and 2.5 mL min^?1 were found to be the optimum conditions. The relative standard deviations of the resulting peak areas, for both intra- and inter- experiments, were less than 2.4 and 2.6%, respectively. Finally, the developed method has been utilised for the quantification of the polyphenols in real samples.     

Determination of Pyridinium Ionic Liquid Cations by Reversed Phase Ion-Pair Chromatography Using Gradient Elution

Four pyridinium ionic liquid cations (N-ethyl-pyridinium, N-butyl-pyridinium, N-butyl-4-methyl-pyridinium, N-hexyl-pyridinium) were separated and determined by reversed phase ion-pair chromatography with ultraviolet-visible detection. The effects of ion-pair reagent, acetonitrile concentration and column temperature on the retention and separation of the cations were evaluated. Then the four pyridinium cations could be separated at baseline within 13 min. The detection limits (S/N = 3) were 0.30–0.70 mg L^?1, and relative standard deviations (n = 5) for peak areas were 0.18–0.58%. The method was applied to analyze surface water with recoveries of 99.5–104.0%, which is accurate, reliable and practical.     

离子交换色谱法检测离子液体中阴离子

建立了用阴离子交换分离柱、化学抑制模式、电导检测测定系列离子液体中BF4^-阴离子及其他杂阴离子（F^-、Cl^-、Br^-）含量的方法，并用于在线监控离子液体合成工艺中阴离子杂质含量。确定淋洗液组成为1．6mmol／L Na2CO3＋3．9mmol／L NaHCO3，流速为0．6mL／min。本方法对所测阴离子检出限分别为50μg／L（F^-、Br^-）和80μg／L（BF4^-）；线性范围在3个数量级以上；r〉0．999；回收率在98％～102％之间。方法用于对离子液体小试工艺样品分析及过程监控时，结果满意，样品的RSD小于2．6％（n=6）。     

反相离子对高效液相色谱法测定心肌组织中的三磷酸腺苷

 采用反相离子对高效液相色谱法测定心肌组织中三磷酸腺苷 (ATP)的含量。样品经高氯酸溶液沉淀蛋白 ,上清液用KOH溶液中和后用反相离子对高效液相色谱法分离测定。色谱柱为SpherisorbODS2柱 ,流动相为甲醇 KH2 PO4缓冲液 (内含 5mmol/LIPR A离子对试剂 ) ,在 2 59nm波长处检测。方法最低检测限为 2mg/L,在 5mg/L～ 1 0 0 mg/L范围内有良好的线性关系 (r=0 9998) ,方法的回收率为 97 8%～ 1 0 4 % ,日内精密度 <4 85% ,日间精密度 <8 81 %。方法准确、灵敏、快速 ,适用于动物和人心肌组织中ATP含量的测定。     

离子交换色谱法检测离子液体中阴离子

建立了用阴离子交换分离柱、化学抑制模式、电导检测测定系列离子液体中BF-4阴离子及其他杂阴离子(F-、Cl-、Br-)含量的方法,并用于在线监控离子液体合成工艺中阴离子杂质含量.确定淋洗液组成为1.6 mmol/L Na2CO3+3.9 mmol/L NaHCO3,流速为0.6 mL/min.本方法对所测阴离子检出限分别为50 μg/L(F-、Br-)和80 μg/L(BF-4);线性范围在3个数量级以上;r＞0.999;回收率在98%～102%之间.方法用于对离子液体小试工艺样品分析及过程监控时,结果满意,样品的RSD小于2.6%(n＝6).     

Determination of Amphotericin-B in Human Plasma by Reversed-Phase High Performance Liquid Chromatography Using a Short Octyl Column

Abstract

Amphotericin-B is a polyene antifungal antibiotic used for the treatment of severe systemic fungal infections. For effective treatment of urinary fungaria and the prevention of significant adverse-effects, monitoring the concentration of Amphotericin-B in biological samples of humans (ingesting the drug) is required. In this experiment, Amphotericin-B was isolated from plasma endogenous substances by adding 200 μL of acetonitrile in 800 μL of plasma. This mixture was vortex mixed, 20 mg of zinc sulfate and 10 mg of monobasic potassium phosphate was added to the mixture. This mixture was again vortex mixed and followed by centrifugation. The supernatant was filtered through a 0.45 μm membrane and a 100 μL aliquot of this solution was injected onto the chromatographic system. A short column of 60 mm × 4.6 mm packed with 3 μm octyl particles was used with an isocratic elution of 50/50, acetonitrile/0.01M KH₂PO₄ (v/v). The pH of the mobile phase mixture was adjusted to 3.5 with H₃PO₄. The intact drug molecule (parent drug) was monitored by a W-visible detector at 410 nm and 0.10-0.005 A.U.F.S. The limits of detection of the method were 0.03 μg/mL for 100 μl injection volume at signal-to-noise ratio of 3.     

离子色谱-直接电导检测法测定离子液体的阴离子p-甲苯磺酸根

建立了离子液体阴离子p-甲苯磺酸根的离子色谱-直接电导检测分析方法。采用Shim-pack IC-A3季铵型阴离子交换色谱柱,考察了流动相种类和色谱柱温度对分离测定p-甲苯磺酸根的影响。确定最佳色谱条件为:以1.2 mmol/L柠檬酸-15%乙腈混合水溶液(pH 5.0)为流动相,流速1.0 mL/min,柱温45℃。在此条件下,p-甲苯磺酸根与常见无机阴离子(氟离子、氯离子、溴离子和硝酸根)可以获得很好的分离。该方法测定p-甲苯磺酸根的线性范围为4～100 mg/L,检出限(S/N=3)为1.22 mg/L,保留时间和峰面积的相对标准偏差(n=5)分别为0.42%和1.8%。将方法用于离子液体中p-甲苯磺酸根的测定,加标回收率为99.6%。     

反相离子对高效液相色谱法快速分离和定量测定食品中的甜蜜素

采用反相离子对高效液相色谱法快速分离和测定食品中的甜蜜素。在ODS柱上,以V（甲醇）：V（水,含离子对试剂）=30：70的溶液为流动相进行分离,分别考察了流动相中离子对试剂和甲醇浓度对甜蜜素保留行为的影响。检测波长为205nm;采用外标法定量,测得甜蜜素在0．5～2．5g／L范围内具有良好的线性关系;回收率在96．9％～101．7％之间;检测限为0．05g／L。