超声波辅助分散液相微萃取-气相色谱联用分析菌核净

将超声波萃取(USE)与分散液-液微萃取(DLLME)联合,利用气相色谱-电子捕获检测(GC-ECD),建立了一种高灵敏度检测水体中菌核净的新方法。对萃取的条件进行优化,选定萃取条件为:在5 mL样品中,注入1 mL丙酮和0.1 mL的四氯化碳混合液,20 Hz超声10 min,振荡混匀后高速离心5 min,移出下层溶剂低温吹干以丙酮定容自动进样分析。在优化条件下,样品的富集倍数可达50倍,检出限为0.001μg/mL,对采于蔬菜地边的水样进行加标回收率实验,平均回收率在81%以上,相对标准偏差在4.3%~7.6%之间,方法可满足水样中菌核净农药残留的检测要求。     

液-液-液三相液相微萃取-高效液相色谱法检测尿样中的安非他明和氯胺酮

建立了液-液-液三相液相微萃取与高效液相色谱联用技术测定尿样中的安非他明和氯胺酮的方法。考察了萃取溶剂、料液相pH值、搅拌速度、萃取时间和接受相HCl浓度等因素对富集因子的影响,得到了萃取溶剂为300 μL甲苯,料液相pH值为11,接受相为1.0 μL 0.1 mol/L HCl,搅拌速度为600 r/min,萃取时间为50 min的最佳实验条件。在该条件下,获得了较高的富集因子;方法的线性范围为安非他明0.01～10 μg/mL,氯胺酮0.01～5 μg/mL,相对标准偏差均小于2%,检测限均为5 ng/mL (S/N=3)。建立的三相液相微萃取方法能有效地去除复杂基体的干扰,有机溶剂消耗少,萃取效率高,是一种有效、灵敏的样品前处理方法,适合于尿样中安非他明和氯胺酮的测定。     

顶空液液萃取-气相色谱-质谱法用于白术挥发性成分的分析

采用高温顶空液相萃取再转移的方法,对中药白术中挥发性成分进行萃取分离富集,采用顶空液液萃取/气相色谱-质谱(HS-LP-LPE/GC-MS)联用法进行测定,并与传统水蒸汽蒸馏法(SD)提取的挥发性成分进行对比。对各种测定条件和影响因素进行了考察,最佳萃取条件为:1.0 mL PEG 400为高温萃取剂,样品用量1.2 g,萃取温度120℃,萃取时间60 min,再将萃取剂用1.0 mL正己烷进行反萃取后进行GC-MS分析;采用HS-LP-LPE/GC-MS鉴定了33个组分,占总组分含量93.18%;SD鉴定了31个组分,占总组分含量97.12%。两种方法共同检测到的组分有29个,均以苍术酮(Atractylone)含量最高。结果表明,两种方法所提取的组分基本相同,可用于白术挥发性成分的测定。     

基于分子络合的分散液液微萃取与高效液相色谱联用检测环境水样中2种苯氧羧酸类除草剂

建立了基于分子络合的分散液液微萃取（DLLME）方法,以磷酸三丁酯为萃取剂,以甲醇为分散剂,与高效液相色谱联用检测了环境水样中麦草畏和2,4-二氯苯氧乙酸（2,4-D酸）2种苯氧羧酸类除草剂,对影响前处理效果的因素（包括水样的pH值、萃取剂的种类和体积、分散剂的种类和体积、反萃液的pH值、反萃液的体积和盐浓度等）进行了详细考察,在最佳萃取条件下（水样体积10 mL,水样的pH值为0~1.0、100 μL磷酸三丁酯萃取剂、1000 μL甲醇分散剂、0.01 mol/L的氢氧化钾反萃液的体积为80 μL）,2种苯氧羧酸类除草剂在0.50~1000 μg/L范围内具有良好的线性,相关系数不小于0.9985,麦草畏和2,4-D酸的检出限分别为0.44 μg/L和0.49 μg/L,富集倍数分别为85和90,在实际样品中的加标回收率为75.7%~104.0%。该方法基于分子络合反应机理,将新型萃取剂磷酸三丁酯应用于分散液液微萃取,与HPLC联用实现了麦草畏和2,4-D酸的富集与检测,为环境水样中苯氧羧酸类除草剂的检测提供了新的前处理方法。     

高效液相色谱法同时测定啤酒中4种老化味物质

建立了同时测定啤酒中5-羟甲基糠醛、糠醛、苯乙醛和反-2-壬烯醛4种主要老化味物质的高效液相色谱方法.确定了最佳梯度洗脱程序和时间变化波长检测程序,实现了30 min内对4种老化味物质的分离和检测;优化了样品前处理条件,使4种老化味物质得到了同时提取和富集.所建立的4种物质工作曲线相关系数良好(r为0.9996～0.9999),线性范围≥103,检出限为0.002～0.003μg/mL(S/N=3),样品加标平均回收率为87.1%～108%,相对标准偏差为2.6%～5.5%.     

超声辅助低密度溶剂分散液液微萃取-气相色谱-三重四极杆质谱法检测生物样品中的8种毒品

建立了生物样品中8种毒品的超声辅助分散液液微萃取-气相色谱-三重四极杆串联质谱检测方法,采用密度比水低的有机溶剂甲苯作为萃取溶剂,萃取过程中不需要任何分散剂。对影响萃取富集效率的因素进行优化:将100 μL甲苯萃取剂加入到1 mL样品溶液中,超声波剧烈振荡使甲苯充分分散到样品溶液中进行萃取,离心分层后,抽取上层萃取剂供气相色谱-三重四极杆串联质谱分析检测。在优化条件下,分析物在各自的线性范围内具有良好的线性关系,线性相关系数在0.9984~0.9994之间;检出限为0.05~0.40 μg/L (S/N=3);样品加标回收率在79.3%~100.3%之间,RSD<5.7%。本方法具有操作简单、灵敏度高和重现性好等优点,可应用于生物样品中多种毒品的分析检测。     

基于脂肪酸的漂浮液滴固化分散液液微萃取-高效液相色谱法联用测定酒类样品中的4-乙基苯酚和4-乙基愈创木酚

建立了基于脂肪酸的漂浮液滴固化分散液液微萃取（FA-DLLME-SFO）方法,与高效液相色谱联用检测了酒类样品中的4-乙基苯酚和4-乙基愈创木酚。该方法萃取时间仅需4 min,仅需脂肪酸、氨水和硫酸3种对环境友好的试剂。对影响方法萃取效率的因素（包括样品的体积、萃取剂的种类和用量、氨水和硫酸的体积以及盐的加入量）进行了详细的考察。在最佳萃取条件下（10 mL样品,100 μL辛酸萃取剂,110 μL 25%～28%（质量分数）的氨水,0.8 mL 98%（质量分数）的浓硫酸,3.0 g NaCl）,4-乙基苯酚和4-乙基愈创木酚在0.02～1.0 mg/L范围内呈良好的线性关系,相关系数分别为0.9997和0.9999,相对标准偏差（n=3）分别为6.2%和3.5%,检出限分别为6.33和5.81 μg/L,富集倍数分别为79和86。在啤酒和白葡萄酒样品中,加标回收率为81.4%～108.7%,相对标准偏差（n=3）小于8.9%。该方法简单、对环境友好,可用于酒类样品中4-乙基苯酚和4-乙基愈创木酚的检测。     

超声辅助离子液体分散液液微萃取/高效液相色谱法测定新型抗艾药ACC007

该文提出了一种基于超声辅助离子液体分散液液微萃取/高效液相色谱(HPLC)测定血清及药片中ACC007含量的新方法。在超声辅助下,无需分散剂即可将疏水性离子液体1-辛基-3-甲基咪唑六氟磷酸盐([C8mimPF6])形成的细小液滴分散于样品溶液中,从而有效萃取ACC007,萃取率在94.0%以上。实验对萃取剂种类、萃取剂用量、溶液pH值、萃取时间、冷却和离心时间等萃取条件进行了考察。在优化条件下,ACC007的线性范围为0.20~10.0μg/mL,检出限分别为0.062μg/mL(药片)和0.068μg/mL(血清)。采用该方法对药片和血清中ACC007进行测定,加标回收率为90.5%~103%,相对标准偏差为2.9%~5.1%,结果令人满意。     

反相液液微萃取/高效液相色谱测定变压器油中糠酸的含量

以水为萃取剂,建立了变压器油中糠酸含量的反相液液微萃取/高效液相色谱测定方法。通过研究萃取剂的p H值、萃取剂体积、稀释剂用量、萃取时间及离心转速的影响,确定了最优的萃取条件。结果表明:在以中性水为萃取剂,萃取剂体积为150μL,稀释剂比例V油∶V正己烷为3∶1,涡旋萃取时间为5 min,离心转速为5 500 r/min的条件下,水萃取相直接用于高效液相色谱测定,变压器油中糠酸的浓度在0.05~5.00 mg·L-1范围内呈良好线性,相关系数(r)为0.999 9,方法的检出限为9.6μg·L-1,相对标准偏差(RSD,n=6)为1.4%,糠酸的富集倍数为13.6倍。实际老化样品测定的加标回收率为99.7%~105.1%,并对样品中的糠酸进行了HPLC-MS定性分析。该方法简捷有效,为变压器油纸绝缘老化特征量的研究提供了数据支持。     

低温富集液液萃取-气相色谱-串联质谱法测定水样中15种农药残留

利用低温冷冻条件下农药在水相和有机相之间达到新的传质平衡,建立了低温富集液液萃取-气相色谱-三重四极杆串联质谱法同时测定水样中15种有机磷、有机氯及菊酯类农药的方法。通过对样品前处理中的溶剂选择、冷冻温度及冷冻时间的优化,最终确定的样品前处理条件为:萃取溶剂为甲苯2.0 mL;冷冻温度-40℃;冷冻时间1h。15种农药的检出限(3S/N)在0.005~0.02μg·L-1范围,测定下限(10S/N)为0.02~0.07μg·L-1。方法用于水样中农药的分析,加标回收率在78.8%~124%之间,测定值的相对标准偏差(n=5)在0.9%~9.1%之间。     

Impact of solvent conditions on separation and detection of basic drugs by micro liquid chromatography-mass spectrometry under overloading conditions

In this study the impact of solvent conditions on the performance of μLC/MS for the analysis of basic drugs was investigated. Our aim was to find experimental conditions that enable high-performance chromatographic separation particularly at overloading conditions paired with a minimal loss of mass spectrometric detection sensitivity. A focus was put on the evaluation of the usability of different kinds of acidic modifiers (acetic acid (HOAc), formic acid (FA), methansulfonic acid (CH₃SO₃H), trifluoroacetic acid (TFA), pentafluoropropionic acid (PFPA), and heptafluorobutyric acid (HFBA)). The test mixture consisted of eleven compounds (bunitrolol, caffeine, cocaine, codeine, diazepam, doxepin, haloperidol, 3,4-methylendioxyamphetamine, morphine, nicotine, and zolpidem). Best chromatographic performance was obtained with the perfluorinated acids. Particularly, 0.010–0.050% HFBA (v/v) was found to represent a good compromise in terms of chromatographic performance and mass spectrometric detection sensitivity. Compared to HOAc, on average a 50% reduction of the peak widths was observed. The use of HFBA was particularly advantageous for polar compounds such as nicotine; only with such a hydrophobic ion-pairing reagent chromatographic retention of nicotine was observed. Best mass spectrometric performance was obtained with HOAc and FA. Loss of detection sensitivity induced by HFBA, however, was moderate and ranged from 0 to 40%, which clearly demonstrates that improved chromatographic performance is able to compensate to a large extent the negative effect of reduced ionization efficiency on detection sensitivity. Applications of μLC/MS for the qualitative and quantitative analysis of clinical and forensic toxicological samples are presented.     

离子液体作高效液相色谱流动相添加剂测定水杨酸

建立了以离子液体作反相高效液相色谱流动相添加剂测定水杨酸的方法.实验以ZORBAX ODS反相色谱柱为分离柱,采用紫外检测方法,研究了检测波长、离子液体烷基链长度、离子液体溶液的浓度以及pH值等对分离和测定的影响.优化的色谱条件为:以体积比60:40的甲醇-3.0 mmol/L1-丁基-3-甲基咪唑四氟硼酸盐溶液(乙酸...     

高效液相色谱法分离和测定小麦中的5种内源激素

建立了高效液相色谱法(HPLC)用于分离和测定小麦中的吲哚乙酸(IAA)、脱落酸(ABA)、赤霉素(GA₃)、玉米素(ZT)和水杨酸(SA)5种植物内源激素。经过条件优化,选用甲醇作为样品提取溶剂。然后,经石油醚和乙酸乙酯萃取,经Sep-Pak C18小柱纯化。液相色谱的分离采用Eclipse XDB-C₁₈ (250 mm×4.6 mm, 5 μm)反相色谱柱;流速为1 mL/min;进样量10 μL。检测器波长设置为254 nm; 14.5 min时切换到240 nm; SA洗脱后即18 min时切换回254 nm。流动相A为甲醇,B为乙酸溶液(pH 3.6)。梯度条件为0~7 min, 20%A; 7~10 min, 20%A~28%A; 10~17 min, 28%A; 17~19 min, 28%A~40%A; 19~35 min, 40%A。结果表明,小麦中各激素的分离效果理想,加标回收率达96.9%~98%,相对标准偏差在1.54%~2.29%之间。因此,该方法的建立为快速、准确地分离和测定小麦内源激素提供了可靠的方法。     

直链淀粉手性固定相法分离利阿唑对映体

建立了利阿唑对映体的高效液相色谱拆分方法。采用Chiralpak AD-H手性柱在正相条件下直接拆分利阿唑对映体,考察了流动相中有机极性调节剂的种类和浓度、酸碱的种类和含量、柱温及流速等对利阿唑对映体分离的影响。确定了最佳的拆分条件:流动相为正己烷-乙醇(含0.3%二乙胺和0.1%冰醋酸)(体积比为80∶20),流速0.6 mL/min;检测波长254 nm;柱温20 ℃。在此条件下利阿唑对映体的分离度为3.4。该法简单快速,重现性好。     

Simultaneous determination of artificial sweeteners, preservatives, caffeine, theobromine and theophylline in food and pharmaceutical preparations by ion chromatography.

A novel ion chromatographic method was proposed for the simultaneous determination of artificial sweeteners (sodium saccharin, aspartame, acesulfame-K), preservatives (benzoic acid, sorbic acid), caffeine, theobromine and theophylline. The separation was performed on an anion-exchange analytical column operated at 40 degrees C within 45 min by an isocratic elution with 5 mM aqueous NaH2PO4 (pH 8.20) solution containing 4% (v/v) acetonitrile as eluent, and the determination by wavelength-switching ultraviolet absorbance detection. The detection limits (signal-to-noise ratio 3:1) for all analytes were below the sub-microg/ml level. Under the experimental conditions, several organic acids, including citric acid, malic acid, tartaric acid and ascorbic acid, did not interfere with the determination. The method has been successfully applied to the analysis of various food and pharmaceutical preparations, and the average recoveries for real samples ranged from 85 to 104%. The levels of all analytes determined by this method were in good agreement with those obtained by the high-performance liquid chromatographic procedure. The results also indicated that ion chromatography would be possibly a beneficial alternative to conventional high-performance liquid chromatography for the separation and determination of these compounds.     

Determination of histidine and related compounds in rumen fluid by liquid chromatography

A liquid chromatographic procedure was developed for quantitative determination of histidine (His), histidinol (HDL), histamine (HTM), urocanic acid (URA), imidazolepyruvic acid (ImPA), imidazoleacetic acid (ImAA), and imidazolelactic acid (ImLA) in rumen fluid. The method is based on direct injection analysis by UV absorbance detection at 220 nm. The separation was performed under 2 different chromatographic conditions on a LiChrospher 100 NH2 column. In the first chromatographic system, the mobile phase used for isocratic elution was 67 mM potassium phosphate buffer (monobasic and dibasic) pH 6.45-90% acetonitrile in water (21 + 79); in the second system, an acetonitrile gradient in 63 mM potassium phosphate buffer (monobasic) pH 3.0, obtained by addition of 60 mM phosphoric acid, was used. Analyses of both systems were completed within 32 and 25 min, respectively. The limits of detection of these compounds were (microM): His, 2.8; HDL, 3.7; HTM, 4.0; URA, 0.75; ImPA, 4.7; ImAA, 1.2; and ImLA, 1.3. Recovery of these compounds added to rumen fluid was 97.4-103.0% within a 1-day study and 95.4-99.0% on different day studies. Detectable levels of His were found in the deproteinized rumen fluid of goats, with average concentrations of 16.10, 10.43, 11.14, and 13.62 microM in the rumen fluid collected before the morning feeding and 2, 4, and 6 h after feeding, respectively. HDL, HTM, URA, ImPA, ImAA, and ImLA were not detected in the rumen fluid before and after feeding. Trp, Phe, and Tyr were also identified in the rumen fluid, with average concentrations of 8.25, 29.04, and 12.6 microM, respectively, before the morning feeding.     

Effect of chromatographic parameters and detector settings on the response of HILIC-evaporative light-scattering detection system using experimental design approach and multicriteria optimization methodology

Four polar compounds, i.e. pantothenic acid, inositol, taurine and caffeine were used as probe solutes in conjunction with chemometric methods to find out meaningful implications of chromatographic conditions and detector settings on the system performance. Putting a premium on the conditions of hydrophilic interaction liquid chromatography (HILIC) and settings of evaporative light-scattering detection (ELSD), we scrutinize the importance of certain factors on signal-to-noise ratio and its variability. The application of a central composite design reveals that caffeine, which sublimes, differentiates from the relatively thermosensitive pantothenic acid as well as from inositol and taurine, which are thermostable, do not sublime and have high melting points. It seems that prior knowledge of solute characteristics is critical to estimate the chromatographic response as a function of chromatographic conditions and detection settings. Reducing the responses to just one by combining them “ad hoc”, results in an overall desirability function, which brings out the global optimal chromatographic conditions and detector settings.     

Development of a bimodal polarimetric response model for improved quantitation of enantiomeric mixtures under conditions of poor chromatographic resolution

The combination of a chiral-selective separation mode with polarimetric detection was investigated in terms of its ability to quantitate enantiomeric mixtures of the dansylated derivatives of phenylalanine, threonine, and valine under conditions of poor chromatographic resolution. Using the difference between two Gaussian functions to model the bimodal response obtained using polarimetric detection and incomplete chiral resolution, correlation coefficients as high as 0.999 were obtained when actual enantiomeric fractions were plotted against observed enantiomeric fractions calculated from the fitting procedure. The methodology was evaluated at different levels of chromatographic resolution, and as a function of the sign and magnitude of the specific rotation of the model compounds. Limits of quantitation calculated at different levels of enantiomeric excess demonstrate the potential of the method to quantitate enantiomeric mixtures even under conditions of poor chromatographic resolution. Minimum measurable quantities (MMQ) at, or below the 1.0% enantiomeric excess (ee) level were obtained for the three amino acid derivatives tested under various conditions of chromatographic resolution when the polarimetric data were fit to the bimodal response model. Even under the lowest resolution conditions tested, the MMQ was determined to be at the 5% ee level.     

Determination of fifteen bioactive components in Radix et Rhizoma Salviae Miltiorrhizae by high-performance liquid chromatography with ultraviolet and mass spectrometric detection

A high-performance liquid chromatographic (HPLC) method coupled with ultraviolet (UV) and electrospray ionization time-of-flight mass spectrometry (ESI-TOF/MS) was established for simultaneous qualitative and quantitative determination of nine phenolic acids and six diterpenoids in Radix et Rhizoma Salviae Miltiorrhizae (RRSM). The optimal chromatographic conditions were achieved on a Zorbax C(18) column by gradient elution with 0.1% (v/v) aqueous formic acid and acetonitrile as mobile phase at the flow rate of 1.0 mL/min. The detection wavelength at 281 nm was chosen to determine the 15 bioactive components, namely danshensu (1), protocatechuic acid (2), protocatechuic aldehyde (3), caffeic acid (4), rosmarinic acid (5), lithospermic acid (6), salvianolic acid B (7), salvianolic acid A (8), salvianolic acid C (9); dihydrotanshinone I (10), cryptotanshinone (11), tanshinone I (12), methylene tanshiqunone (13), tanshinone IIA (14) and miltirone (15). Additionally, LC-ESI-TOF/MS was used to make definite identification of the constituents in samples in comparison with those reference compounds. The validation of the method included tests of linearity, sensitivity, repeatability, stability and recovery. The proposed method was successfully applied to quantify the 15 components in 21 samples; significant variations were demonstrated in the contents of the samples from diverse species and origins. The developed method could be used to effectively and comprehensively evaluate the quality of RRSM for its clinical safety and efficacy.     

麻疯油转酯化产物的高效液相色谱分析

建立了高效液相色谱法同时测定麻疯油转酯化产物中4种主要脂肪酸甲酯的分析方法。样品经膜处理后用丙酮溶解,采用Hypersil ODS(C18)色谱柱进行分离。以乙腈为流动相进行等度洗脱,内标法定量,同时对色谱条件进行优化。结果表明,在优化的色谱条件下4种脂肪酸甲酯在10 min内得到良好的分离,标准曲线的线性相关系数均达到0.999以上,平均回收率为96%~98%,重现性相对标准偏差为7.2%~10.2%,重复性相对标准偏差为0.31%~2.02%。与气相色谱法相比,该方法具有较高的灵敏度,可用于麻疯油转酯化产物中脂肪酸甲酯含量的测定,为麻疯油转酯化反应制备生物柴油的定性定量分析提供了参考依据。