氯甲基苯乙烯包夹硅基单柱强阴离子固定相的制备及应用

用氯甲基苯乙烯包夹硅胶基质制备出一种新型强阴离子色谱柱填料,该填料具有良好的色谱性能,可以较好地分离常见的一些无机阴离子;另外,该填料可以对油田中用作驱油剂的单、双石油磺酸盐进行较好的分离。     

Quantitative determination of toxic mono- and non-ortho polychlorinated biphenyls in cod liver oil after selective liquid chromatographic separation

Summary By application of chromatographic column filled with Supelclean ENVI-Carb/Celite and elution with three solvents of different polarity three PCB fractions were obtained. Fraction A contained poly-ortho PCBs, Fraction B mono-ortho PCBs, and Fraction C non-ortho PCBs. The Supelclean ENVI-Carb/Celite column was used in combination with a sample preparation procedure for pre-cleaning of acid-stable chlorinated hydrocarbons such as DDT and its metabolites, HCH isomers, and regulation-relevant PCB congeners. The method was optimized using standard solutions of 55 PCB congeners, 8 chlorinated pesticides and contaminated cod liver oil samples. The influence of traces of remaining matrix on the elution profile of the organochlorine compounds on Supelclean ENVI-Carb/Celite was observed. Quantitation was carried out by GC-ECD with fused silica capillary columns of different polarity.     

Determination of diquat herbicide by selective enrichment by column chromatography on imprinted polymer immobilised on silica gel

Summary A silica gel-bound, imprinted polymer for selective recognition of the diquat herbicide: 5,6-dihydropyrazino [1,2,3,4-lmn]-1,10-phenanthrolinium dichloride, is reported. It was used in the solid-phase extraction procedure, following liquid chromatography-differential pulse, adsorptive-stripping voltammetric (LC-DPAdSV) technique. The operational conditions for 100% retention of the diquat herbicide on a chromatographic column (13.0×1.4 cm, adsorbent bed 1.0g) were realized at pH 6.9 and a flow rate of 5.0 mL min⁻¹. The adsorbent used could be regenerated during elution with 5.0 mL MHCl within 20 min. The limit of detection was 0.65 nM (0.18 ppb) with an enrichment factor as high as 99-fold.     

Utilization of a Crown Ether/Amine‐Type Rotaxane as a Probe for the Versatile Detection of Anions and Acids by Thin‐Layer Chromatography

A crown ether/amine‐type [2]rotaxane was synthesized and utilized as a probe for the detection of acids and anions. The addition of acids to the amine‐type [2]rotaxane solution generated corresponding crown ether/ammonium‐type [2]rotaxanes, which were purified by silica gel column chromatography as ammonium salts. The isolated yields of the [2]rotaxanes, possessing a variety of anions, depended on the acidity and polarity of the counter anions. The behaviours of the ammonium‐type [2]rotaxanes on thin‐layer chromatography (TLC) silica gel reflected the properties of the counter anions. The treatment of the amine‐type [2]rotaxane with acids afforded the corresponding ammonium‐type [2]rotaxanes bearing several different anions. The ammonium‐type [2]rotaxanes behaved similarly to the purified [2]rotaxanes on the TLC silica gel. Furthermore, we succeeded in the analysis of anions using mixtures of the amine‐type [2]rotaxane and salts in an appropriate solvent. We demonstrated the detection of anions by the combination of TLC and the utilization of the [2]rotaxane probe.     

Determination of monensins A and B in the fermentation broth ofStreptomyces cinnamonensis by high performance liquid chromatography

Summary High performance liquid chromatography on an octadecyl silica column has been used to determine both the monensin A: monensin B ratio and by the method of standard addition, the concentration of both in the fermentation broth ofStreptomyces cinnamonensis. Refractive index detection was preferred to ultraviolet owing to the presence of UV-absorbing components which could not be completely separated from the substances of interest. A linear relationship was obtained from the calibration data. The coefficients of variation for the estimation both of the ratio and the concentrations of the compounds were better then 5%. The estimated limit of detection for both substances was about 1 g/ml. The results obtained from the determination of the ratios of monensins were compared with those obtained by chemical ionization mass spectrometry. Chromatographic separation of monensins on the silica gel column is also described.     

Preparation and characterization ofp-tert-butyl-calix[6]arene-bonded silica gel stationary phase for high-performance liquid chromatography

Summary For the first time calix[6]arene has been chemically combined with silica gel via a longer spacer to prepare calix[6]arene-bonded silica gel stationary phase for high-performance liquid chromatography (HPLC). The separation of positional isomers and polycyclic aromatic hydrocarbons on the calix[6]arene-bonded phase was achieved with methanol-water as mobile phase. Some nucleosides were also separated on the bonded phase. The reversed-phase chromatographic performance of the bonded phase was studied. The results showed that the calix[6]arene-bonded phase was highly hydrophobic. A possible separation mechanism has been proposed.     

Enantiomeric resolution of anti-HIV agents on a cellulose derivative chiral stationary phase. Note II

Summary A series of enantiomeric 1H,3H-thiazolo[3,4-a] benzimidazoles with anti-HIV activity has been stereospecifically analyzed.The enantiomeric resolution has been carried out by means of an HPLC method using a column of cellulose tris-(4-methyl-phenylbenzoate) ester adsorbed on macroporous silica gel (Chiralcel^R OJ).     

采用新型固相萃取柱快速测定食用植物油中苯并［a］芘

研究了Bond Elut ENV新型固相萃取柱在食用植物油中苯并[a]芘快速检测中的应用,建立了快速测定食用植物油样品中苯并[a]芘残留量的固相萃取/液相色谱/荧光检测法。样品用正己烷溶解,固相萃取净化,SUPELCOSILTMLC-PAH(25 cm×4.6 mm,5μm)色谱柱分离,以乙腈-水(95∶5)为流动相,荧光检测(λex=297 nm,λem=408 nm),外标法定量。苯并[a]芘的检出限为0.3μg/kg,在1.0～50.0μg/L范围内线性关系良好,相关系数为0.999 6,方法的回收率为79%～102%,相对标准偏差不高于9.4%。该方法准确、实用、简便、快速,在食用植物油的苯并[a]芘残留量检测方面有广泛的应用前景。     

Dependence of the retention volumes of additional streaming current responses and of the column void volume on mobile phase composition

Summary The influence of the alcohol content of the mobile phase and water, acetic acid and aniline as mobile phase additives on the generation and shape of two additional changes of the streaming current, generated inside the liquid chromatography column by injection of any sample and recorded before the responses of retained solutes, was studied in a normal-phase system using silica gel as the stationary phase. The mobile phases were based on a n-heptane-1-propanol mixtures. Under the same conditions the relationships between the column interparticle volume, the column void volume and the total liquid volume in the column and the retention volumes of these two streaming current responses, having the form of chromatographic peaks, were studied. The column void volume was identified with the retention volume of n-octane. The total liquid volume in the column (column hold-up) was calculated from the weight loss of the column wetted with water at first and then dried in nitrogen stream. The retention volume of the first streaming current response equals the column interparticle volume disregarding the mobile phase composition. If the 95∶5 n-heptane-1-propanol mobile phase contains water up to 80% of its saturated concentration (up to 0.114% by vol.), the retention volume of the second response agrees with the total volume of the liquid in the silica gel column, with a precision better than 2%. At a higher relative water saturation the retention volume of the second response increases, while the column void volume decreases. Both changes are explained by the spontaneous formation of a highly polar stagnant liquid in the pores of the silica gel.     

A sensitive column-switching HPLC method for aripiprazole and dehydroaripiprazole and its application to human pharmacokinetic studies

A simple and sensitive column‐switching HPLC‐UV method was developed for the simultaneous determination of aripiprazole, a novel atypical antipsychotic drug, and its active metabolite, dehydroaripiprazole in human plasma. Aripiprazole, its active metabolite and 7‐[5‐[4‐(3‐chloro‐2‐methylphenyl)‐1‐piperazinyl]pentyloxy]‐3,4‐dihydro‐2(1H)‐quinolinone (OPC‐14558) as an internal standard were extracted from 1 mL of plasma using a mixture of chloroform/n‐heptane (3:7, v/v), and the extract was injected into a column I (TSK BSA‐ODS/S precolumn, 5 μm) for cleanup and column II (C₁₈ STR ODS‐II analytical column, 5 μm) for separation. Peaks were detected with an UV detector set at a wavelength of 254 nm, and the total time for chromatographic separation was ～20 min. Mean absolute recoveries were 74.0 and 74.7% for aripiprazole and dehydroaripiprazole, respectively. Intra‐ and inter‐day CVs were less than 7.5 and 7.1% for aripiprazole concentrations ranging from 2 to 600 ng/mL, and 9.2 and 4.5% for dehydroaripiprazole concentrations ranging from 2 to 160 ng/mL. The validated concentration ranges for this method were 1–500 ng/mL and the limits of detection were 0.5 ng/mL for both aripiprazole and dehydroaripiprazole. This method was applied to pharmacokinetic study in human volunteers and patients taking aripiprazole.     

Separation and identification of chiralN-acylcalix[4]arene amino acid derivatives by use of reversed-phase HPLC

Summary This work focuses on the separation and identification of p-tert butyl calix[4]arene derivatives. An isocratic mixture of 65% (v/v) acetonitrile and 35% (v/v) water with 0.1% (v/v) phosphoric acid was used as the mobile phase. A Bio-Rad Bio-Sil ODS-5S (250 mm×4 mm) column was used as the stationary phase with UV detection of the analytes at 274 nm. The reversed-phase high performance liquid chromatographic method which was developed provided baseline separation of five p-tertbutyl calix[4]arene derivatives in twenty minutes.     

Determination of melengestrol acetate in bovine tissues by automated coupled-column normal-phase high-performance liquid chromatography

A method has been developed for the determination of melengestrol acetate in bovine tissues at lower levels than previously reported. Liquid-liquid extraction of tissue homogenates provided crude clean-up while final isolation, screening, and quantification was done on-line with an automated, normal-phase, coupled-column high-performance liquid chromatographic system. The chromatographic system included phenyl and silica analytical columns for the purposes of isolation and final separation, respectively. These columns provided a large difference in selectivity when operated under normal-phase conditions which allowed for the efficient isolation of melengestrol acetate from the complex tissue extracts. Mobile phases were composed of hexane and dichloromethane modified with methanol and water. Transfer and enrichment of the analyte from the primary phenyl column to the silica column was via a short (12 mm x 4 mm I.D.) silica column. Regeneration and equilibration of the phenyl column was performed after the injection of each tissue extract and was accomplished simultaneously while analytical separation occurred on the final silica column. Routing of the mobile phases and regeneration solvent was performed with automated switching valves. The total time required for each analysis was 12 min. Quantification is demonstrated using external standards with UV detection at 287 nm. The overall recovery of the method was 86% with a coefficient of variation of 9.84% at the 10 ppb [the American billion (10(9] is used in this article] level in bovine liver extracts.     

A particle size distribution analysis of used HPLC column packing material

Summary Particle size distribution analysis and scanning electron microscopy (SEM) were carried out on eight used HPLC columns containing either irregular silica based, spherical silica based or spherical polymer based packing material. Particle size distributions of the used irregular silica based columns were at least bimodat at the outlet ends and either biomodal or log-normal at the inlet ends with regular progressions between the two extremes through the column. A new ODS-3 column showed log-normal size distributions from the inlet to the outlet ends. Spherical silica based column particle size distributions showed distinct shoulders on large central distribution peaks in most column sections with various degrees of shoulder erosion. The spherical resin based column showed a broader inlet particle size distribution progressing to a very narrow outlet distribution. SEMs of both irregular and spherical silica based columns revealed a larger number of undersized particles and debris at the outlet than inlet ends which could have resulted from stationary phase degradation, since this was not seen in the new ODS-3 column. While several SEMs of the spherical silica based columns revealed hollow spheres and twins, the spherical resin based column packing showed stress fractures or wrinkle lines resulting from use or dehydration.Presented in part as a poster at the HPLC '92, 16^th Symposium on CLC, Baltimore, MD, USA.     

HPLC method for the simultaneous analysis of valproic acid and other common anticonvulsant drugs in human plasma or serum

Summary The derivatizing procedure of Moody et al. [20] for valproic acid has been simplified and applied to the simultaneous HPLC determination of valproic acid (VPA), barbital (B), primidone (PRM), phenobarbital (PB) and carbamazepine (CBZ) in serum or plasma of epileptic patients. The sample is deproteinized with acetonitrile containing esterification agents and an aliquot of the supernatant is heated to 70°C for 15 min with 4-bromophenacyl bromide. The reaction mixture is analysed on a C18 column at ambient temperature, with gradient elution and with detection at 205 nm. The time required for the chromatographic analysis is 13 min; identification is based on retention time and quantification is by peak area determination with an internal standard. The calibration curves show good linearity in the range 6.25 to 100 mg/L. The detection limits at a signal: noise ratio 3, ranged from 1 mg/L for B and CBZ to 2–3 mg/L for PRM, PB and VPA. The method described for the simultaneous determination of the five drugs in the same plasma pool, correlated well with isocratic HPLC methods specific for each drug. The simultaneous procedure described allows a reproducible (CVs6.5% within run) and rapid (25 min for sample preparation: 13 min for chromatographic run) therapeutic monitoring of patients treated with VPA and two or more antiepileptic drugs.     

Determination of Biodiesel and Triacylglycerols in Diesel Fuel by LC

A high performance liquid chromatographic method was developed for quantifying blends of biodiesel (simple alkyl esters of fatty acids) in petrodiesel. The method uses a silica column with an isocratic mobile phase consisting of hexane and methyl t-butyl ether. Separated components were quantitated using either an evaporative light scattering detector (ELSD) or UV detector. Precision of injection and linearity of response of the ELSD and UV detectors over a range of biodiesel-petrodiesel blends [1–30 v/v %] were established by use of standards. The method also can be used for quantitating similar levels of oils or fats (triacylglycerols) in petrodiesel.     

Determination of acyclovir in dog plasma by HPLC using a column switching technique

Summary A new HPLC-UV method has been developed and validated for the pharmacokinetic linearity study of Telviran^? tablets containing 200, 400, and 800 mg acyclovir. RP-18 solid phase extraction has been developed for sample preparation. Guanosine (9-[β-D-ribofuranosyl]-guanine) was used as internal standard. The separation was carried out on an ODS Hypersil (5 μm, 200×4.5 mm) analytical column, supplied with a 20 mm guard column containing the same packing material. A column switching technique was applied for the elimination of the endogenous compounds eluting with longer retention times than the investigated compounds, so the analysis time was considerably shorter compared with the time of gradient elution. The eluent was 0.5% triethylamine in water, the pH was adjusted with orthophosphoric acid (85%) to pH5. The detection was performed at 254 nm. The calibration curve was linear in the concentration range 10–5000 ng mL⁻¹. The new bioanalytical method was successfully applied for a pharmacokinetic linearity study in dogs. Presented at Balaton Symposium on High Performance Separation Methods, Siófok, Hungary, September 1–3, 1999     

Dynamically coated silica monolith with ionic liquids for capillary electrochromatography

An ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) was introduced as dynamic coating of a silica monolithic column for capillary electrochromatography of phenols and nucleoside monophosphates. The run-to-run and column-to-column repeatability of migration time for six phenols were satisfactory on this column with relative standard deviation values less than 0.90 and 4.31%, respectively. Anodic electroosmotic flow (EOF) was observed, which increased with the increase of [BMIM][BF4] concentration within 120 mM and when [BMIM][BF4] concentration was above 120 mM, EOF leveled off due to the saturation of [BMIM][BF4] on the monolith. Efficient separation of phenols and nucleoside monophosphates on this dynamically coated monolithic column was obtained, compared with a dynamically coated fused-silica column and unmodified silica monolithic column. The retention behavior of uncharged phenols is mainly manipulated by hydrophobic interactions due to the presence of butyl groups, and that of nucleoside monophosphates is governed by the electrostatic attraction mechanism based on the interaction between positively charged [BMIM][BF4] moieties and negatively charged phosphate groups. In addition, silica matrix also contributes to the separation resolution.     

Microanalyses of beta-cyclodextrin in plasma by high-performance liquid chromatography

Procedures for the micro-determination of beta-cyclodextrin (beta-CyD) in plasma were investigated by four methods using high-performance liquid chromatography (HPLC). In methods A and B, underivatized beta-CyD was detected with a refractive index detector and determined by the absolute calibration graph method. An NH2-bonded silica/acetonitrile-water system was used in A and a C18-bonded silica/methanol-water system in B. In method C, the percarbanilate of beta-CyD was separated on a C8-bonded silica column with acetonitrile-water and determined using gamma-CyD as the internal standard with a UV detector at 231 nm. In method D, the per[1-14C]acetate of beta-CyD was fractionated on a silica column with n-hexane-ethanol containing 1% of water and the radioactivity of each fraction was measured with a liquid scintillation counter. gamma-CyD was used as the internal standard. Interfering plasma proteins were removed by centrifugal ultrafiltration with an MPS-1 micro-partition system. Method B was superior to the other methods with respect to ease of sample preparation, sensitivity and time required for analysis. The cumulative amount of beta-CyD in the mesenteric vein absorbed from the rat intestinal lumen after administration of phenobarbital-beta-CyD complex in a closed loop method was determined by the use of method B.     

Preliminary experiments for the analysis of tetrahydrotetrols of benz[a]anthracene and benzo[a]pyrene derived from their hemoglobin adducts using a coupled-column high-performance liquid chromatographic system

Improved technologies for the detection of polycyclic aromatic hydrocarbon adducts are required for human biomonitoring. Therefore, a coupled-column high-performance liquid chromatographic method, with system-integrated sample processing, has been developed and its applicability for determination of tetrahydrotetrols of polycyclic aromatic hydrocarbons in acid hydrolysates of human hemoglobin has been investigated. A novel column-switching technique applying ‘thermotransfer’ is used to separate tetrahydrotetrols of benzo[a]pyrene and benz[a]anthracene more efficiently. Derivatives of polycyclic aromatic hydrocarbons from blood hydrolysates are concentrated on a pre-column and then transferred to the analytical column by applying an electrical current to heat the solvent eluting the pre-column. This method allows for rapid and quantitative transfer of the analytes from the pre-column to the analytical column, after HPLC-integrated sample processing.     

含杯[4]芳烃毛细管固定相的制备与色谱性能

杯芳烃是由对位取代的苯酚在邻位通过亚甲基连接起来的环状化合物,由于具有可调节大小的空腔,不仅能络合无机离子,而且还可络合有机分子,在分析分离方面有极好的应用前景［１,２］．杯芳烃已用于气相色谱［３,４］、离子选择性萃取［５,６］、液相色谱［７,８］和...