HPLC测定食品中脂溶性维生素A、D、E

本文讨论了用反相液相色谱法测定食品中脂溶性维生素A、D、E的方法。样品经皂化处理,乙醚抽提后,经μBondapak C_(18)柱分离,流动相为甲醇-水(98:2),样品中维生素A、D、E完全分离并定量测定。回收率为82.3～100.9％,相对标准偏差小于3.1％,线性相关系数优于0.9977。方法简便,用途广泛。     

高效液相色谱测定牛肉中己烯雌酚残留量方法的探讨

目的:建立固相萃取高效液相色谱法检测牛肉中己烯雌酚的含量。方法:牛肉中的己烯雌酚用甲醇溶解,超声提取后用HLB固相萃取小柱净化,流动相为甲醇:水(70∶30),流速1.0 m L/min;检测波长:230 nm;色谱柱:Hypsersil C18柱(250 mm×4.6 mm×5μm)作为分析条件。结果:与国标相比优化了流动相的条件,使流动相配制更为简便,且己烯雌酚在C18柱上分离较好,利用HLB固相萃取小柱有效的净化牛肉中的干扰杂质,标准曲线线性良好,相关系数0.9998,检出限为20μg/kg,回收率在92.0%~94.4%,均优于国标。结论:该方法具有准确性强、灵敏度高等优点,适合测定牛肉中己烯雌酚含量。     

液相色谱法测定花生酱中植物生长调节剂

采用固相分散萃取-高效液相色谱法同时测定花生酱中的吲哚乙酸(IAA)、吲哚丁酸(IBA)和α-萘乙酸(NAA)三种植物生长调节剂。无水硫酸钠作分散剂、甲醇作萃取剂。色谱条件:Diamonsil C18柱;甲醇-水(55:45,V/V,甲酸调PH=3.0)为流动相;流速:1.0mL/min;检测波长:272nm。在0.50～100μg/mL范围内线性良好。方法检出限均为1.25μg/g,平均回收率为98.97%、86.41%和84.24%,相对标准偏差为2.23%、1.75%和1.90%。     

HPLC及SEP-PAK C_(18)小预柱法测定复方甘草片中吗啡的含量

本文介绍了用SEP—PAK C_(18)小预柱固相萃取技术和反相高效液相色谱法测定复方甘草片中微量吗啡含量的方法。对固相萃取条件进行了研究,选择出以10％甲醇溶液为淋洗溶液,以70％甲醇溶液为洗脱溶液。这样基本消除了干扰组分对测定的影响,色谱图背景吸收小,基线平稳。色谱柱为μBondapak C_(18)柱,以0.1mol/L NaH_2PO_4溶液—甲醇(5:1)为流动相,检测波长为280nm。平均回收率为(101.2±1.5)％,RSD小于2％。该方法简便、快速、准确,重现性好,可用于药品质量控制。     

高效液相色谱法测定桶装水及水桶中双酚A含量

该文建立固相萃取/高效液相色谱测定桶装水及水桶中双酚A含量的方法。桶装水样品经C18固相萃取柱富集,水桶用二氯甲烷溶解甲醇提取双酚A;采用C18色谱柱,以乙腈-水(V/V,60:40)为流动相,检测波长224 nm,高效液相色谱法测定双酚A含量。在最优检测条件下,双酚A在0.4～10μg/mL浓度范围内线性关系良好(r2=0.999 8),方法的检出限为0.069μg/mL,定量限为0.23μg/mL,平均回收率为98.3%。该方法简便、灵敏、重现性好,所抽取桶装水中并未检测到双酚A的存在,水桶材质中检测出双酚A的含量为37.1μg/g。     

液相色谱串联质谱法测定植物油中复硝酚钠的含量

建立了液液萃取结合分散固相萃-液相色谱串联质谱(UPLC-MS/MS)技术同时测定植物油中3种复硝酚钠(5-硝基愈创木酚钠、对硝基苯酚钠、邻硝基苯酚钠)残留量的检测方法.样品经甲醇提取,C18粉净化,采用BEH C18柱(2.1 mm×100 mm,2.5μm)分离,以甲醇和水为流动相进行梯度洗脱,电喷雾负离子多反应监...     

HPLC-ICP-MS法测定水样中的甲基汞、乙基汞和无机汞

建立了高效液相色谱(HPLC)和电感耦合等离子体质谱(ICP-MS)联用测定环境水样中的甲基汞、乙基汞和无机汞的方法。实验使用的高效液相色谱流动相为含有0.06mol/L乙酸氨,20μg/LBi,0.1%(V/V)2-巯基乙醇的5%(V/V)甲醇-水溶液,色谱柱为C18反相柱(5μm,2.1mm×50mm),经前处理的水样在液相色谱中分离后,进入电感耦合等离子体质谱检测其甲基汞、乙基汞和无机汞的浓度。甲基汞、乙基汞和无机汞检出限分别为0.05μg/L、0.10μg/L和0.10μg/L。     

反相高效液相色谱法测定维生素B_1的含量

建立了测定维生素B1含量的高效液相色谱(HPLC)方法。方法采用ultimate C18柱(300×4.6mm,5μm)色谱柱,流动相为0.2%磷酸氢二钾水溶液(含5%甲醇,用磷酸调pH 2.6),检测波长245nm。维生素B1在0.002～2.0mg/mL范围内与峰面积呈现良好的线性关系(r=0.9968)。所建立的方法简单、准确、重现性好,可用于制剂中维生素B1含量的测定。     

2-噻吩乙酸的HPLC分析测定

建立了一种2-噻吩乙酸的反相高效液相色谱-紫外检测法.研究了流动相的组成、流速及色谱柱温度等因素对测定的影响.采用色谱柱为VARIAN C18(250 mm×4.6 mm,5μm)反相色谱柱,流动相为甲醇-水(V∶V=70∶30),流速1.0 mL/min,柱温为室温,紫外检测波长235 nm,在6 min内可完成分析.该方法的回收率为98.4%~99.8%,RSD<1%.其优点为2-噻吩乙酸与其同分异构体3-噻吩乙酸得到较好的分离,明显不重叠,且操作简单、快速和准确可靠,用于2-噻吩乙酸产品的纯度测定,结果令人满意.     

二氯喹啉酸的高效液相色谱法测定

建立了二氯喹啉酸的高效液相色谱(HPLC)快速检测方法。二氯喹啉酸俗称快杀稗,属激素型喹啉羧酸类除草剂。用高效液相色谱法测定除草剂中二氯喹啉酸的含量,通过改变高效液相色谱的检测波长、流动相的配比,确定测定二氯喹啉酸的最佳测定条件,以甲醇+水+冰乙酸(85:15:0.1)为流动相,采用C18柱(250 mm×4.6 mm×5μm)分离,在uV238 nm检测,外标法定量。以SPD-10AVP型检测器对试样中的二氯喹啉酸原药进行分离和定量分析。结果表明,二氯喹啉酸的线性相关系数为R=0.9998;标准偏差为0.29;变异系数为0.36;回收率82%～94%。     

Ion-pair chromatographic separation of water-soluble gold monolayer-protected clusters

We demonstrate the efficacy of ion-pair chromatography for separations of samples of charged, polydisperse, water-soluble gold nanoparticles protected by monolayers of N-acetyl-l-cysteine and of tiopronin ligands. These nanoparticle mixtures have 1-2-nm-diameter Au core sizes as estimated from UV-visible spectra of the separated components. This size range encompasses the transition from bulk metal to molecular properties. The nanoparticle mixtures were resolved, the smallest nanoparticles eluting first, on an octadecylsilyl (C18) column using isocratic elution with a methanol/water mobile phase containing tetrabutylammonium fluoride (Bu4N+F-) and phosphate buffer. The column retention increases with Bu4N+F- concentration, lowered pH, and decreasing methanol volume fraction. The retention mechanism is dominated by ion-pairing in either the mobile phase or at the stationary/mobile-phase interface. Size exclusion effects, used in many previous nanoparticle separations, are insignificant.     

Capillary electrochromatography using a strong cation-exchange column with a dynamically modified cationic surfactant

A novel mode of capillary electrochromatography (CEC), called dynamically modified strong cation-exchange CEC (DMSCX-CEC), is described in this paper. A column packed with a strong cation-exchange (SCX) packing material was dynamically modified with a long-chain quaternary ammonium salt, cetyltrimethylammonium bromide (CTAB), which was added to the mobile phase. CTAB ions were adsorbed onto the surface of the SCX packing material, and the resulting hydrophobic layer on this packing was used as the stationary phase. Using the dynamically modified SCX column, neutral solutes were separated with the CEC mode. The highest number of theoretical plates obtained was about 190,000/m, and the relative standard deviations (RSD's) for migration times and capacity factors of alkylbenzenes were less than 1.0% and 2.0% for five consecutive runs, respectively. The effects of CTAB and methanol concentrations and the pH value of the mobile phase on the electroosmotic flow and the separation mechanism were investigated. Excellent simultaneous separation of the basic and neutral solutes in DMSCX-CEC with a high-pH mobile phase was obtained. A mixture containing the acidic, basic, and neutral compounds was well separated in this mode with a low-pH mobile phase; however, peak tailing for basic compounds was observed in this mobile phase.     

Complete enantiomeric separation of phenylthiocarbamoylated amino acids on a tandem column of reversed and chiral stationary phases

The enantiomeric separation of phenylthiocarbamoyl derivatives of amino acids (PTC-AAs) was studied on a series of reversed phase HPLC columns coupled to the chiral phase HPLC columns. First, the five chiral phases (native, 0.2, 3.3, 7.5 and 16.9 phenylcarbamoylated/β-cyclodextrins, Ph/CD) were newly prepared by modification of β-cyclodextrin with phenyl isocyanate and were examined for the enantiomeric separation of PTC-AAs. Among them, the 3.3Ph/CD phase gave the best enantiomeric separation (α ≥ 1.04). However, the separation of the individual PTC-AAs was not sufficient. Next, these separations were investigated on various reversed phase HPLC columns, and octyl silica was selected in terms of the suitability of the mobile phase adopted for the enantiomeric separation mentioned above. The effects of the column temperature, the ion-pairing reagent, and the final content of methanol were also studied on the tandem column of octyl silica and the 3.3Ph/CD phase. Under the best conditions (100 mM ammonium acetate (pH 6.5) containing 1 mM butanesulfonate with 0-40% methanol as the mobile phase), all the individual PTC-AAs were well separated within 150 min. The applicability of the method was demonstrated by the sequence/configuration analysis of a peptide containing a d-amino acid ([d-Thr(2)]leucine enkephalin-Thr).     

Effect of the temperature and mobile phase composition on the retention behavior of nitroanilines on ligand-exchange stationary phase

This paper deals with the separation of isomers of nitroaniline by liquid chromatography using the ligand-exchange technique. The chromatographic separations were performed on the ligand-exchanger sporopollenin. The sporopollenin used as support of stationary phase was modified with carboxylated-ethylenediamine matrix and was loaded with cobalt(II) ions. Using the column packed with cobalt(II) loaded carboxylated diaminoethyl sporopollenin [Co(II)-CDAE-S], the retention behavior of 3- and 4-nitroanilines was investigated. The mobile phase used, was a mixture of 0.05 M NH(4)OH in ethanol-water. The resolution was strongly affected by the presence of ammonium hydroxide in the mobile phase and a concentration of 0.05 M was shown to be necessary for the separation of analytes. To study the effects of temperature on the resolution, column runs were also performed at various temperatures (15-60 degrees C). With increasing temperature, a decreased interaction between the solutes and the ligand-exchanger was observed. Consequently, the best results were obtained using a mixture of 0.05 M NH(4)OH in ethanol-water (10:90, v/v) as the mobile phase at a column temperature of 35 degrees C. Ligand-exchange chromatography on the Co(II)-CDAE-S could be a useful alternative method for the separation of nitroaniline.     

Enantiomeric Separation and Quantitative Determination of Atenolol in Tablets by Chiral High-Performance Liquid Chromatography

The separation and quantitative determination of atenolol isomers by chiral high-performance liquid chromatography (HPLC) are described. Atenolol isomers were separated using a Chiralcel OD® column (250 × 4.6 mm,10 μm); the mobile phase was hexane-ethanol-diethylamine (75:25:0.1 v/v/v); ultraviolet detection was at 276 nm; and flow rate was 0.7 ml/min. The coefficient of variation and average recovery of (R)-isomer were 0.60% and 100.37%, respectively, for sample A and 0.69% and 100.63%, respectively, for sample B. The coefficient of variation and average recovery of (S)-isomer were 0.59% and 100.33%, respectively, for sample A and 0.63% and 99.78%, respectively, for sample B.     

Enantiomeric separation and quantitative determination of atenolol in tablets by chiral high-performance liquid chromatography

The separation and quantitative determination of atenolol isomers by chiral high-performance liquid chromatography (HPLC) are described. Atenolol isomers were separated using a Chiralcel OD® column (250 × 4.6 mm,10 μm); the mobile phase was hexane-ethanol-diethylamine (75:25:0.1 v/v/v); ultraviolet detection was at 276 nm; and flow rate was 0.7 ml/min. The coefficient of variation and average recovery of (R)-isomer were 0.60% and 100.37%, respectively, for sample A and 0.69% and 100.63%, respectively, for sample B. The coefficient of variation and average recovery of (S)-isomer were 0.59% and 100.33%, respectively, for sample A and 0.63% and 99.78%, respectively, for sample B.     

等度高效液相色谱测定大豆异黄酮中大豆甙元和金雀异黄酮

本文介绍了等度高效液相色谱(HPLC)测定大豆异黄酮中二种主要成份:大豆甙元(Daidzein)和金雀异黄酮(Genistein)的方法。采用Atlantis C18色谱柱和EasyGuard C18,保护柱;以甲醇:0·1%醋酸(pH3·11)=51·5:48·5(v/v)为流动相;检测波长λ=254nm;流速1mL/min。在测定范围内(10-200ng)峰面积与质量浓度线性关系良好。大豆甙元和金雀异黄酮的相关系数分别为0·9984,0·9997·两组份回收率为97·0—102·92%·     

Capillary electrochromatography for separation of peptides driven with electrophoretic mobility on monolithic column.

A mode of capillary electrochromatography for separation of ionic compounds driven by electrophoretic mobility on a neutrally hydrophobic monolithic column was developed. The monolithic column was prepared from the in situ copolymerization of lauryl methacrylate and ethylene dimethacrylate to form a C12 hydrophobic stationary phase. It was found that EOF in this hydrophobic monolithic column was very poor, even the pH value of mobile phase at 8.0. The peptides at acidic buffer were separated on the basis of their differences in electrophoretic mobility and hydrophobic interaction with the stationary phase; therefore, different separation selectivity can be obtained in CEC from that in capillary zone electrophoresis (CZE). Separation of peptides has been realized with high column efficiency (up to 150,000 plates/meter) and good reproducibility (migration time with RSD <0.5%), and all of the peptides, including some basic peptides, showed good peak symmetry. Effects of the mobile phase compositions on the retention of peptides at low pH have been investigated in a hydrophobic capillary monolithic column. The significant difference in selectivity of peptides in CZE and CEC has been observed. Some peptide isomers that cannot be separated by CZE have been successfully separated on the capillary monolithic column in this mode with the same buffer used.