无机流动相低压离子色谱分离-化学发光在线检测痕量锰

以0.09 mol/L KCl和0.01 mol/L HCl的混合溶液作流动相,低压离子色谱(LPIC)分离,鲁米诺-H2O2化学发光(CL)在线检测Mn2+。研究了分离条件、化学发光条件及二者匹配方式和干扰离子等因素对分离和检测的影响。测定Mn2+的线性范围为1×10-9~4×10-8g/L,检出限为1×10-9g/L。该法用于测定血清、尿液、嘉陵江水样中的Mn2+。     

柱前手性荧光衍生反相高效液相色谱法分离甲状腺素对映体

以R(-)-4-N,N-二甲基磺酰胺-7-(3-异氰酸吡咯烷)-2,1,3-苯并氧杂咪唑（R(-)-DBD-PyNCS）为手性荧光衍生化试剂,成功地拆分了甲状腺素对映体D,L-四碘甲状腺原氨酸（T4）和L-三碘甲状腺原氨酸(T3)。在反应温度为40 ℃、反应时间为20 min时,R(-)-DBD-PyNCS在碱性介质中可与甲状腺素对映体生成稳定的非对映体衍生物。该衍生物在以乙腈-水-醋酸(体积比为60∶40∶1)为流动相,流速为1.0 mL/min,色谱柱为Intersil-ODS-3 C18柱(150 mm×4.6 mm,5 μm)的色谱条件下得到了充分的分离。采用荧光检测器在激发波长460 nm、发射波长550 nm下检测。D,L-T4和L-T3分别在0.016～0.30 μg/μL和0.0067～0.22 μg/μL范围内,峰面积与浓度呈良好的线性关系(r＞0.999)。D,L-T4和L-T3的最低检出限分别为0.02 μg/mL和0.85 μg/mL(S/N=3)。在D-T4、L-T4、L-T3质量浓度分别为0.10 μg/μL下测得峰面积的相对标准偏差分别为3.40%,1.63%,3.30%(n=7)。该方法成功地应用于甲状腺片中T4和T3的含量测定。     

固相萃取-离子色谱法测定饮用水中的痕量卤代乙酸

建立了固相萃取-离子色谱(SPE-IC)测定饮用水中痕量卤代乙酸(HAAs)(包括一氯乙酸、二氯乙酸、三氯乙酸、一溴乙酸和二溴乙酸)的方法。固相萃取采用LiChrolut EN SPE柱来进行痕量待测物的预浓缩（25倍）和基体杂质的消除,用NaOH(10 mmol/L)洗脱;色谱分离采用亲水性、高容量、氢氧化物选择型阴离子交换柱Dionex IonPac AS16(250 mm×4 mm i.d.),以NaOH为流动相进行浓度梯度淋洗,淋洗速度为0.8 mL/min,电导检测,进样量为500 μL。结果表明,用SPE-IC法测定HAAs,一溴乙酸的检测限为12.5 μg/L,其余4种HAAs的检测限为0.38~1.69　μg/L。该法可实现对饮用水中痕量卤代乙酸的测定。     

高效液相色谱手性流动相添加剂法拆分氯噻酮对映体

应用反向高效液相色谱,以羟丙基-β-环糊精(HP--βCD)作为手性流动相添加剂,拆分了氯噻酮(Chlorthalidone)对映体。对主要的影响因素如羟丙基-β-环糊精浓度、流动相pH值、三乙胺(TEA)、甲醇、柱温、流速等进行了系统研究,建立了羟丙基-β-环糊精流动相添加剂法拆分氯噻酮对映体的方法。使用HarbonLichrospher-C18色谱柱(5μm,150 mm×4.6 mm),流动相为V(甲醇)∶V(水相)=20∶80(水相含30 mmol/L HP--βCD0、.1 mol/L Na2HPO4、体积分数2%的TEA、pH5),流速为0.8 mL/min,室温下拆分,氯噻酮对映体可得到良好分离。     

固相萃取-超高效液相色谱/串联质谱法检测人体血清中邻苯二甲酸二(2-乙基已基)酯代谢物

建立了固相萃取-超高效液相色谱/串联质谱法检测人体血清中邻苯二甲酸二(2-乙基已基)酯(DEHP)代谢物.血清样品中加入乙酸钠溶液及内标13C4邻苯二甲酸单乙基已基酯(13C4MEHP)后,在37℃条件下用β-葡萄糖醛苷酶酶解提取12h,提取液经MAX固相萃取小柱净化并浓缩到纯水中.以甲醇5 mmol/L乙酸铵溶液为流动相,经Waters UPLC(R)HSS T3色谱柱分离后,在电喷雾离子源负离子模式下,以多反应监测(MRM)方式进行扫描,内标法定量.DEHP代谢物在1.0～100.0 μg/L范围内线性关系良好,检出限均为0.1 μg/kg,回收率89.6％～103.2％.该方法灵敏度高,准确度好,可作为监测人群内暴露的重要技术支撑.     

固相萃取-高效液相色谱法测定婴幼儿米粉中烟酸和烟酰胺

建立了以EDTA-NaCl混合溶液为提取液,使用亲水亲脂平衡(HLB)固相萃取柱净化,以甲酸铵(pH 4.5)为流动相,Atlantis T3色谱柱上梯度洗脱分离,在261 nm检测紫外吸收的液相色谱方法。方法的线性范围为0.3～30.0 mg/L,检测限为0.3 mg/kg,定量限为1.0 mg/kg,回收率在93.3%～102.5%范围内。方法可应用于各种婴幼儿米粉中烟酸与烟酰胺的测定。     

固相萃取富集高效液相色谱法测定烟草及烟草添加剂中的重金属元素

报道用固相萃取富集,高效液相色谱法测定烟草及烟草添加剂中镍、铜、锡、铅、镉、汞的方法。样品用微波消化,消化液中的镍、铜、锡、铅、镉、汞用四-(对甲氧基苯基)-卟啉(T4MPP)柱前衍生．用C18固相萃取小柱萃取富集镍、铜、锡、铅、镉、汞的T4MPP络合物,然后用甲醇和四氢呋喃为流动相梯度洗脱,Waters Xterra^TMRP18色谱柱分离二极管阵列检测器检测。镍、铜、锡、铅、隔、汞的捡出限在2～4ng／L之间,方法相对标准偏差为1．8％～2．4％,加标回收率为96％～103％。     

咪唑离子液体用于反相色谱流动相添加剂分析苯甲酸和山梨酸

开展了咪唑离子液体用于反相色谱流动相进行苯甲酸和山梨酸分析的研究。考察了咪唑离子液体种类与浓度、甲醇浓度、紫外检测波长等因素对分离、检测苯甲酸和山梨酸的影响,并探讨了2种分析物的保留规律。建立了以咪唑离子液体为流动相添加剂的反相色谱测定苯甲酸和山梨酸的分析方法。采用Agilent ZORBAX ODS反相色谱柱,以甲醇-0.2 mmol/L氯化1-丁基3-甲基咪唑水溶液(40∶60,体积比)为流动相,紫外检测波长230 nm,流速1.0 mL/min,色谱柱温度35℃时,可在7.0 min内实现苯甲酸和山梨酸的分离和检测。苯甲酸和山梨酸的线性范围为1.0～100.0 mg/L,相关系数(r)高于0.999 5,检出限均为0.02 mg/L。将方法应用于饮料样品中苯甲酸和山梨酸的测定,加标回收率为93.9%～104%,相对标准偏差(RSD)不大于4.0%,满足定量分析的要求。     

手性流动相添加剂高效液相色谱法分离苯基琥珀酸对映体

以七(2,3,6三-O-甲基)-β-环糊精(TM-β-CD)作为手性流动相添加剂,反相高效液相色谱研究苯基琥珀酸(PSA)对映体拆分;在Nova—pak C18色谱柱上,采用0．30mmol/L TM-β-CD、含0．05％三氟乙酸的乙腈一水(体积比16：84)为流动相,(R)-(-)-PSA和(s)-( )-PSA的容量因子分别为5．43和6．42,对映体分离因子为1．18,分离度为2．50;对比：PSA在β-CD手性流动相法和2,6-丁基化-β-CD涂渍C18柱的色谱行为,探讨环糊精分子对PSA的手性拆分机理：本法已用于测定L-脯氨酸化学拆分苯基琥珀酸对映体产品的光学纯度。     

手性流动相添加剂法拆分安妥沙星对映体

采用L-苯丙氨酸和CuSO_4作为手性流动相添加剂,建立液相色谱法拆分安妥沙星对映体的方法。考察了手性添加剂的种类、浓度及流动相pH等对安妥沙星对映体分离的影响。采用Welch Ultimate XBC_(18)色谱柱(4.6 mm×250 mm,5μm),优化流动相为8 mmol/L L-苯丙氨酸溶液(含4 mmol/L的CuSO_4,pH 3.5)-甲醇(80∶20,V∶V),流速:1.0 mL/min,检测波长:302 nm,结果左、右旋安妥沙星峰达到基线分离,分离度为6.6。     

高效液相色谱手性流动相法拆分甲状腺素对映体

运用高效液相色谱手性流动相法（ＨＰＬＣ－ＣＭＰ）对影响甲状腺素对映体（Ｄ－,Ｌ－Ｔ４）分离方法的因素：三乙胺（ＴＥＡ）浓度,流动相ｐＨ值,铜离子（Ｃｕ２＋）浓度,Ｌ－脯氨酸（Ｌ－ｐｒｏ）浓度,柱温以及流动相的流速进行了系统的研究。同时,考察了色谱方法分离Ｔ４对映体的线性关系,精密度和准确度。线性响应范围为０．６～３．２　ｎｍｏｌ　（Ｄ－,Ｌ－Ｔ４）,线性相关系数为ｒＤ－Ｔ４＝０．９９８０,ｒＬ－Ｔ４＝０．９９９０,日内和日间的精密度分别为ＲＳＤ＜２．３％（ｎ＝６）,ＲＳＤ＜３．１５％（ｎ＝５）。结果表明本实验所得的色谱条件较文献报道的优越,分离条件简单,重现性好。ＨＰＬＣ－ＣＭＰ法测定甲状腺素对映体其意义在于该方法可为定量测定药品及人体血液中Ｄ－,Ｌ－Ｔ４两种异构体,为治疗药物监测（ＴＤＭ）和药物不良反应监测（ＡＤＲｓ）提供了依据。     

Hybridation of different chiral separation techniques with ICP-MS detection for the separation and determination of selenomethionine enantiomers: chiral speciation of selenized yeast

Enantioseparation and determination of selenomethionine enantiomers in selenized yeast was investigated using chiral separation techniques based on different principles, coupled on-line to inductively coupled plasma mass spectrometry (ICP-MS) for selenium-specific detection. High performance liquid chromatography (HPLC) on a beta-cyclodestrin (beta-CD) column, cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC), gas chromatography (GC) on a Chirasil-L-Val column, and HPLC on a Chirobiotic T column have been investigated as the chiral separation techniques. For HPLC separation on the beta-CD column, and also for CD-MEKC, selenomethionine enantiomers were derivatized with NDA/CN(-). For chiral separation by GC, selenomethionine enantiomers were converted into their N-trifluoroacetyl (TFA)-O-alkyl esters. The developed hybridation methodologies are compared with respect to enantioselectivity, sensitivity and analysis time. The usefulness of the best-suited method [HPLC (Chirobiotic T)-ICP-MS] was demonstrated by its application to the successful chiral speciation of selenium and D-and L-selenomethionine content determination in selenized yeast.     

Separation of the Enantiomers of Thyroxine by HPLC with Chiral Mobile Phases

A high-performance liquid chromatographic (HPLC) method has been developed for separation of the enantiomers of thyroxine (T4). A silica gel column was used in conjunction with a chiral mobile phase (CMP) comprising 35:65 (v/v) acetonitrile–water containing 0.1 mM copper(II) acetate, 0.2 mM L-proline, and 0.5 mM triethylamine (TEA), pH 5.42. The flow rate was 1.0 mL min^?1 and the analysis temperature 40 °C. L-T4 was eluted before D-T4 by mobile phase containing L-proline copper complex. Inversion of the chirality of the mobile phase resulted in reversal of this order of elution. A racemic mobile phase containing DL-proline copper complex resulted in no separation. The enantioseparation phenomenon is discussed. When the method was used to determine the concentration of T4 enantiomers in the serum of a patients with thyroid disease, different concentrations of T4 enantiomers were found in different patents.     

Sensitive procedure for the determination of reboxetine enantiomers in human plasma by reversed-phase high-performance liquid chromatography with fluorimetric detection after chiral derivatization with (+)-1-(9-fluorenyl)ethyl chloroformate

A sensitive and selective high-performance liquid chromatographic method for the determination of reboxetine enantiomers in human plasma was developed. Although two chiral centres are present in reboxetine, its stereospecific synthesis leads to two rather than four possible enantiomers. After extraction from plasma and reaction with (+)-1-(9-fluorenyl)ethyl chloroformate, reboxetine enantiomers were separated as diastereoisomeric derivatives by reversed-phase high-performance liquid chromatography (HPLC) and determined by fluorimetric detection. The HPLC analysis time was about 90 min. The linearity, precision, accuracy and limit of quantification of the method were evaluated. No interference from blank plasma sample was observed. The suitability of the method for in vivo samples was assessed by the analysis of plasma samples obtained from a healthy male volunteer who had received a single oral dose of 4 mg of reboxetine in tablet form.     

Quantitative determination of clenbuterol enantiomers in human plasma by high-performance liquid chromatography using the macrocyclic antibiotic chiral stationary phase teicoplanin

We report a method for the high-performance liquid chromatographic (HPLC) chiral separation of racemic clenbuterol in human plasma. Human plasma was spiked with stock solutions of clenbuterol hydrochloride and practolol as the internal standard. Following a liquid-liquid extraction procedure with 10% (+/-)-2-butanol/isopropyl ether under alkaline conditions, the dried samples were reconstituted in methanol and chromatographed using a macrocyclic antibiotic chiral stationary phase (CSP) known as Chirobiotic T(trade mark) (teicoplanin). The mobile phase composition was methanol:acetonitrile (70:30, v/v), containing 0.3% (v/v) acetic acid and 0.2% (v/v) triethylamine. The resulting chromatogram achieved baseline separation for the clenbuterol enantiomers. Calibration curves (peak area ratio vs plasma concentration, n = 10) were constructed for the (-)-R-and (+)-S-clenbuterol enantiomers with a plasma concentration range of 0. 25-10 microM. The correlation coefficient (r) range was 0.99988-0. 99999 (mean = 0.99999). The lowest concentration measured was 0.25 microM. Inter- and intra-assay variation was determined for the lowest, medium and highest plasma concentration (0.25, 2 and 10 microM) by calculating the analytical recoveries with a range of 96-104%. The percentage recoveries for the clenbuterol enantiomers were 88.4-102% over the concentration range used. Detailed methodology is presented.     

Enatiomeric analysis of simendan by CE with beta-CD as chiral selector compared with CMPA-HPLC

The chiral separation of simendan enantiomers using capillary electrophoresis was studied with beta-cyclodextrin (beta-CD) as chiral selector. The influences of the concentration and pH of borate buffer solution, beta-CD concentration and methanol content in the background electrolyte were investigated. These factors were compared with those in an HPLC with beta-CD as chiral mobile phase additive (CMPA-HPLC). The quantification properties of the developed CE method were examined. A baseline separation of simendan enantiomers was achieved in the background electrolyte of 20 mmol/L borate buffer (pH 11.0) containing 12 mmol/L beta-CD-methanol (50:50 in volume ratio). The CE method is comparable with CMPA-HPLC in chiral resolution, although the optimal pH in CE (11.0) is much higher than that (6.0) in CMPA-HPLC. This chiral CE method is applicable to the quantitative ananlysis and enantiomeric excess value determination of L-simendan.     

Chiral separation of the β2‐sympathomimetic fenoterol by HPLC and capillary zone electrophoresis for pharmacokinetic studies

The development of methods for the separation of the enantiomers of fenoterol by chiral HPLC and capillary zone electrophoresis (CZE) is described. For the HPLC separation precolumn fluorescence derivatization with naphthyl isocyanate was applied. The resulting urea derivatives were resolved on a cellulose tris(3,5‐dimethylphenylcarbamate)‐coated silica gel column employing a column switching procedure. Detection was carried out fluorimetrically with a detection limit in the low ng/mL range. The method was adapted to the determination of fenoterol enantiomers in rat heart perfusates using liquid–liquid extraction. As an alternative a CE method was used for the direct separation of fenoterol enantiomers comparing different cyclodextrin derivatives as chiral selectors. Copyright © 2010 John Wiley & Sons, Ltd.     

Liquid chromatographic separation of the enantiomers of metoprolol and its alpha-hydroxy metabolite on Chiralcel OD for determination in plasma and urine.

The two enantiomers of metoprolol and the four enantiomeric forms of alpha-hydroxymetoprolol were separated by liquid chromatography on a Chiralcel OD column containing a cellulose tris(3,5-dimethyl-phenylcarbamate) chiral stationary phase. The column efficiency was strongly dependent on the flow-rate and the enantioselectivity was influenced by temperature. Of utmost importance for the chiral separation was the water content of the mobile organic phase. The separation system was used for the separation and determination of the enantiomers in plasma and urine samples. The metoprolol enantiomers could be determined by fluorescence down to 10 nmol/l of each in plasma with a relative standard deviation of less than 15%.     

Enantioseparation of four cis and trans diastereomers of 2',3'-didehydro-2',3'-dideoxythymidine analogs, by high-performance liquid chromatography and capillary electrophoresis

Compounds 1-4 are the four stereoisomers of a synthetic new potential antiviral agent (d4T analog) containing two chiral centers and a base (uracil). Both high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE) techniques were used to separate and quantify enantiomers with high resolution. The determination of enantiomeric purity of the compounds was developed using both amylose chiral stationary phase by HPLC and anionic cyclodextrins (highly S-CD) as chiral selectors in CE. The HPLC method was found to be superior in sensitivity to the CE method.