小白菜中残留虫酰肼的超临界流体萃取条件的研究

将超临界流体萃取(supercritical fluid extraction,SFE)技术与高效液相色谱分析相结合,建立了特异性杀虫剂虫酰肼的萃取分离方法。SFE对虫酰肼的萃取条件:压力48.3 MPa(7000 psi),温度60 ℃,静态萃取时间20 min,CO2体积10 mL,改性剂甲醇添加量0.04 mL/g,丙酮为收集溶剂。在此条件下,SFE对虫酰肼的萃取率为100.75%,所得样品可直接用于高效液相色谱分析。色谱条件：紫外-二极管阵列检测器(检测波长为245 nm),C18键合色谱柱,乙腈     

Simultaneous determination of L-693,612, a topical carbonic anhydrase inhibitor, and two potential metabolites in human whole blood by ion-pair high-performance liquid chromatography

A method for the simultaneous determination of a topical carbonic anhydrase inhibitor, L-693,612, and two of its potential metabolites in human whole blood is described. The analytes are isolated from the matrix via liquid-liquid extraction with a mixture of toluene, ethyl acetate and isopropanol (49:50:1, v/v/v). The analytes are then back extracted into dilute phosphoric acid prior to injection into the HPLC system. A cyano column (Zorbax SB-CN, 150 × 4.6 mm) with a mobile phase of phosphoric acid(0.085%)-acetonitrile (73.5:26.5) containing 10 mM sodium decane sulfonate and adjusted to pH 3 is used for the analysis. Detection is based on UV absorbance at 252 nm. The assay was found to be linear in the concentration range of 5–500 ng/ml for each analyte when 1-ml aliquots of whole blood were extracted.     

Determination of β-artemether and its main metabolite dihydroartemisinin in plasma employing liquid-phase microextraction prior to liquid chromatographic-tandem mass spectrometric analysis

A method for the determination of artemether (ART) and its main metabolite dihydroartemisinin (DHA) in plasma employing liquid-phase microextraction (LPME) for sample preparation prior to liquid chromatography-tandem mass spectrometry (LC-MS-MS) was developed. The analytes were extracted from 1 mL of plasma utilizing a two-phase LPME procedure with artemisinin as internal standard. Using the optimized LPME conditions, mean absolute recovery rates of 25 and 32% for DHA and ART, respectively, were achieved using toluene-n-octanol (1:1, v/v) as organic phase with an extraction time of 30 min. After extraction, the analytes were resolved within 5 min using a mobile phase consisting of methanol-ammonium acetate (10 mmol L⁻¹, pH 5.0, 80:20, v/v) on a laboratory-made column based on poly(methyltetradecylsiloxane) attached to a zirconized-silica support. MS-MS detection was employed using an electrospray interface in the positive ion mode. The method developed was linear over the range of 5-1000 ng mL⁻¹ for both analytes. Precision and accuracy were within acceptable levels of confidence (<15%). The assay was applied to the determination of these analytes in plasma from rats treated with ART. The two-phase LPME procedure is affordable and the solvent consumption was very low compared to the traditional methods of sample preparation.     

纤维素键合手性固定相拆分6种萘满酮衍生物对映体

使用Chiralpak IC（纤维素-三（3,5-二氯苯基氨基甲酸酯）共价键合硅胶）手性柱,建立了采用手性固定相高效液相色谱拆分6种 α -芳基萘满酮类衍生物对映体的方法。考察了流动相中有机改性剂的种类和比例、柱温和流速对对映体分离的影响。结果显示6种化合物在异丙醇为改性剂的条件下均可获得较高的对映体分离度。热力学研究表明6种化合物对映体的手性拆分过程均受焓驱动影响,且低温有利于对映体分离。最终推荐分离化合物Ⅰ对映体的流动相是正己烷-异丙醇（90：10,v/v）;分离化合物Ⅱ、Ⅲ、Ⅳ对映体的流动相是正己烷-异丙醇（99：1,v/v）;分离化合物Ⅴ对映体的流动相是正己烷-异丙醇（85：15,v/v）;分离化合物Ⅵ对映体的流动相是正己烷-异丙醇（80：20,v/v）。柱温为25℃,流速为1.0 mL/min。6种化合物对映体均可在Chiralpak IC手性固定相上得到完全分离,证明该色谱柱对6种化合物具有较高的对映体选择性。     

Determination of benzimidazole fungicides in soil samples using microwave-assisted micellar extraction and liquid chromatography with fluorescence detection

A simple and fast analytical method was developed for the determination of benzimidazole fungicides (benomyl, carbendazim, thiabendazole, and fuberidazole) in soil samples. The analytes were extracted from the soil samples by means of conventional microwave-assisted extraction, using the non-ionic surfactants polyoxyethylene 10 lauryl ether (POLE) and oligoethylene glycol monooalkyl ether (Genapol X-080) as extractants. Determinations were made by using liquid chromatography with direct fluorescence detection. The use of an analytical column Symmetry C-18 offered short retention times of analytes without the need of any pH regulators with mobile phase methanol-water (50 + 50, v/v). The best results were obtained using 5% (v/v) POLE as extractant with recoveries of the fungicides in spiked soil samples between 71 and 105%. The results were compared with those obtained when Soxhlet extraction was applied to the same soil samples.     

Supercritical fluid chromatography of metoprolol and analogues on aminopropyl and ethylpyridine silica without any additives

Metoprolol and a number of related amino alcohols and similar analytes have been chromatographed on aminopropyl (APS) and ethylpyridine (EPS) silica columns. The mobile phase was carbon dioxide with methanol as modifier and no amine additive was present. Optimal isocratic conditions for the selectivity were evaluated based on experiments using design of experiments. A central composite circumscribed model for each column was used. Factors were column temperature, back-pressure and % (v/v) of modifier. The responses were retention and selectivity versus metoprolol. The % of modifier mainly controlled the retention on both columns but pressure and temperature could also be important for optimizing the selectivity between the amino alcohols. The compounds could be divided into four and five groups on both columns, with respect to the selectivity. Furthermore, on the aminopropyl silica the analytes were more spread out whereas on the ethylpyridine silica, due to its aromaticity, retention and selectivity were closer. For optimal conditions the column temperature and back-pressure should be high and the modifier concentration low. A comparison of the selectivity using optimized conditions show a few switches of retention order between the two columns. On aminopropyl silica an aldehyde failed to be eluted owing to Schiff-base formation. Peak symmetry and column efficiency were briefly studied for some structurally close analogues. This revealed some activity from the columns that affected analytes that had less protected amino groups, a methyl group instead of isopropyl. The tailing was more marked with the ethylpyridine column even with the more bulky alkyl substituents. Plate number N was a better measure than the asymmetry factor since some analyte peaks broadened without serious deterioration of symmetry compared to homologues.     

Ion chromatography tandem mass spectrometry for simultaneous confirmation and determination of indandione rodenticides in serum

This paper describes a simple method for the simultaneous determination and confirmation of the indandione rodenticides in serum. After samples were extracted with 10% (v/v) methanol in acetonitrile and cleaned by solid‐phase extraction, chromatographic separation was performed on an IonPac® AS11 analytical column (250 × 4.0 mm) using gradient KOH eluent with 10% (v/v) methanol as organic modifier. Confirmation was depended on the extensive fragmentation of the indandione molecule under MS/MS conditions which provides sufficient structural information. Quantification was performed by negative electrospray ionization in multiple reaction monitoring mode. All the method parameters were validated. It was confirmed that this method could be used in clinical diagnosis and forensic toxicology. Copyright © 2009 John Wiley & Sons, Ltd.     

Optimization and validation of a fast ultrahigh‐pressure liquid chromatographic method for simultaneous determination of selected sulphonamides in water samples using a fully porous sub‐2 μm column at elevated temperature

High temperature in HPLC is considered a valuable tool helping to overcome the increase in the column backpressure when using small packing particles such as sub‐2 μm, as it allows reduction in the mobile‐phase viscosity. In this study, a fast analytical method based on HPLC‐UV was developed using a sub‐2 μm column at elevated temperature for the simultaneous determination of nine sulphonamides. Owing to the lower viscosity of the mobile phase, the separation could be achieved in 3 min at 60°C for all analytes. The effect of temperature, the organic modifier percentage and the flow rate on the retention time was studied. The method developed was used for the determination of selected sulphonamides in surface and wastewater samples. Sample preparation was carried out by solid‐phase extraction on Oasis HLB cartridges. The method developed was validated based on the linearity, precision, accuracy, detection and quantification limits. The recovery ranged from 70.6 to 96 % with standard deviations not higher than 4.7%, except for sulphanilamide. Limits of detection ranged from 1 to 10 μg/L after optimization of all analytical steps. This method has the highest performance in terms of analytical speed compared with other published HPLC‐UV methods for the determination of sulphonamides in water.     

Sol-gel methyl coating in capillary microextraction hyphenated on-line with high-performance liquid chromatography Counterintuitive extraction behavior for polar analytes

A sol-gel coating with anchored methyl groups was developed for capillary microextraction hyphenated on-line with high-performance liquid chromatography (HPLC). This was accomplished by using methyltrimethoxysilane as the sol-gel precursor. The methyl group on the sol-gel precursor ultimately turned into a pendant group on the created sol-gel coating and was primarily responsible for the extraction of nonpolar analytes. A 40-cm segment of 0.25mm I.D. fused silica capillary containing the sol-gel methyl coating on the inner surface was installed as a sampling loop in an HPLC injection port. The analytes were extracted by the coating when an aqueous sample containing the analytes was passed through this capillary. The extracted analytes were then transferred to the HPLC column using isocratic elution with an acetonitrile/water mobile phase. This capillary demonstrated excellent extraction capability for polycyclic aromatic hydrocarbons and ketones. Unexpectedly, this coating also provided good extraction for polar analytes, including aromatic phenols, alcohols, and amines. Considering the fact that the methyl group is nonpolar in nature, such an extraction behavior of sol-gel methyl coating toward polar analytes is counterintuitive. Thus, sol-gel sorbents with short alkyl side chains have the potential to offer a polymer-free alternative to traditional sol-gel capillary microextraction (CME) media commonly prepared with the use of polymers in the sol solution. Elimination of polymers from the sol-gel coating solution is conducive to improving thermal stability and solvent tolerance of the created sol-gel extracting phase. This also makes the preparation of sol-gel coatings facile and cost-effective. Possessing excellent solvent stability, such sol-gel coatings offer the opportunity for effective on-line hyphenation of capillary microextraction with HPLC and other liquid-phase separation techniques that employ organo-aqueous mobile phases.     

Separation of phenolic compounds and corresponding glucuronides by coupled-column micellar reversed-phase liquid chromatography

Summary An isocratic HPLC technique for separation of phenolic compounds and corresponding glucuronides in urine is developed. Sample pre-treatment, often a tedious and rate-limiting factor, was eliminated by use of a coupled column system. Spiked urine samples were injected directly into a C₄ precolumn and a selected fraction was transferred on-line from the precolumn to a silanized C₁₈ analytical column in the backflush mode. Analyte peak enrichment was attained by employing mobile phases of different elution strengths. The weaker mobile phase (7% v/v acetonitrile) was used to strongly retain the analytes on the precolumn while most of the polar endogenous compounds were washed to waste. Elution and transfer of the trapped analytes from the precolumn to the analytical column was achieved by introducing a stronger mobile phase (20% v/v acetonitrile) with the aid of a switching valve. The use of cetyltrimethylammonium bromide as counter ion and micellar agent in the mobile phase involved a high selectivity for the analytes relative to the urine matrix components and allowed simultaneous analysis of the glucuronides and parent compounds without the need of gradient elution. The system demonstrated a good repeatability on spiked urine samples. Who passed away July 21, 1996     

Selenium speciation by high-performance liquid chromatography with on-line detection by atomic absorption spectrometry

Several approaches to the determination of selenomethionine, selenocystine, selenite and selenate by high-performance liquid chromatography with online detection by atomic absorption spectrometry are described. The N?2,4-dinitrophenyl derivatives of selenomethionine, selenoethionine, selenocystine and phenylmercury(II) cystineselenoate were recovered from aqueous solution, separated on a Nucleosil 5-NO₂ reversed-phase HPLC column with a methanolic mobile phase containing acetic acid and triethylamine, and detected with a quartz thermochemical hydride-generating interface–atomic absorption spectrometry (AA) system. The restriction of having to perform chromatography with an organic mobile phase (to support the combusion process) was overcome with a new interface design capable of operation with either organic or aqueous HPLC mobile phases. Using aqueous acetic acid (0.015% v/v) containing 0.1% (w/v) ammonium acetate delivered at 0.5cm³ min^?1, selenate, selenite, selenomethionine, selenocystine and selenoethionine were separated virtually to baseline on a cyanopropyl-bonded phase HPLC column. Other selenium compounds which were investigated included methane seleninic and methane selenonic acids as well as the crude oxidation product mixtures resulting from the treatment of selenomethionine and selenocystine with hydrogen peroxide. A procedure for extracting selenate, selenite, selenomethionine, selenocystine and selenoethionine from spiked water or ground feed supplement into liquefied phenol resulted in acceptable recoveries for the latter four analytes but was unacceptably low for selenate.     

Simultaneous determination of peimine and peiminine in rat plasma by LC‐ESI‐MS employing solid‐phase extraction

A simple and reliable LC‐ESI‐MS method for the determination of peimine and peiminine in rat plasma was developed for the first time. The method was proven to be specific and sensitive by carrying out validation. The analytes were extracted from rat plasma via solid‐phase extraction on Waters Oasis MCX cartridges. Chromatography separation was achieved on a C₁₈ column using 10 mM ammonium acetate (adjusted to pH 3.0 with glacial acetic acid)–acetonitrile (85:15, v/v) as mobile phase. The linear range was 1–100 ng/mL for peimine and peiminine. Intra‐ and inter‐day precisiond were less than 10%. Accuracies were within 85–115% of their nominal concentrations. The limit of quantification was 1 ng/mL for both analytes. The developed assay was successfully applied to pharmacokinetic study of peimine and peiminine in rats orally administered the alkaloids extracts from Bulbus Fritillariae, demonstrating a possible broader spectrum of applications of this method. Copyright © 2009 John Wiley & Sons, Ltd.     

高效液相色谱法测定化妆品中11种二苯酮类紫外线吸收剂

建立了化妆品中11种二苯酮类紫外线吸收剂的高效液相色谱分析方法。采用四氢呋喃-甲醇-水或二氯甲烷-水体系提取化妆品中二苯酮类紫外线吸收剂,经离心(5000 r/min),上清液过0.22 μm滤膜后,进入高效液相色谱分析。采用C18色谱柱进行分离,以0.1% (体积分数)甲酸水溶液(含10 mmol/L乙酸铵)为流动相A,以0.1% (体积分数)甲酸甲醇为流动相B,梯度洗脱。方法加标回收率(n=7)为93.4%~103.8%,相对标准偏差为0.1%~4.2%,方法的检出限为4.0~30 μg/g,方法的定量限为15~100 μg/g。采用该方法对42种市售化妆品检测分析发现,有5种二苯酮类紫外线吸收剂被检出,其中防晒隔离液中二苯酮-3和香水中二苯酮-2的检出量分别为2785 μg/g和2106 μg/g。研究结果表明,所建立的方法具有良好的回收率、重现性和较高的灵敏度,可用于化妆品中多种二苯酮类紫外线吸收剂的分析。     

高效液相色谱法测定土壤中香豆素类灭鼠药残留

建立了测定土壤中杀鼠灵、杀鼠醚、溴敌隆、氟鼠灵、溴鼠隆5种香豆素类灭鼠药残留量的柱后衍生荧光检测高效液相色谱方法。样品在加入内标物氯杀鼠灵后用丙酮-氨水-甲醇（体积比为100：3：100）混合液提取,浓缩的提取液用5 mL正己烷-氯仿（体积比为3：1）混合液溶解,NH₂固相萃取小柱净化,用15 mL 50 mmol/L四丁基磷酸二氢铵甲醇溶液洗脱分析物,移除溶剂,用甲醇-0.25%（体积分数）乙酸水溶液（体积比为3：2）混合液溶解,过滤后,经高效液相色谱分离,以甲醇-氨水-水（体积比为1：1：8）混合液为衍生试剂进行柱后衍生,采用荧光检测器检测。杀鼠灵、杀鼠醚、溴敌隆、氟鼠灵、溴鼠隆5种鼠药在0.02～10.00 mg/L范围内线性关系良好,相关系数均大于0.999,定量限（LOQ,S/N=10）为2.2～18.5 μg/L。在0.1～0.3 mg/kg添加水平内,5种灭鼠药的回收率为94.6%～118.0%,相对标准偏差（RSD）为0.8%～10.2% （n=3）。实验结果表明该方法灵敏、准确,重复性好。     

Toxicological screening of human plasma by on‐line SPE‐HPLC‐DAD: identification and quantification of acidic and neutral drugs

A multi‐analyte screening method for the quantification of 50 acidic/neutral drugs in human plasma based on on‐line solid‐phase extraction (SPE)–HPLC with photodiode array detection (DAD) was developed, validated and applied for clinical investigation. Acetone and methanol for protein precipitation, three different SPE materials (two electro‐neutral, one strong anion‐exchange, one weak cation‐exchange) for on‐line extraction, five HPLC‐columns [one C₁₈ (GeminiNX), two phenyl‐hexyl (Gemini C₆‐Phenyl, Kinetex Phenyl‐Hexyl) and two pentafluorophenyl (LunaPFP(2), KinetexPFP)] for analytical separation were tested. For sample pre‐treatment, acetone in the ratio 1:2 (plasma:acetone) showed a better baseline and fewer matrix peaks in the chromatogram than methanol. Only the strong anion‐exchanger SPE cartridge (StrataX‐A, pH 6) allowed the extraction of salicylic acid. Analytical separation was carried out on a Gemini C₆‐Phenyl column (150 × 4.6 mm, 3 µm) using gradient elution with acetonitrile–water 90:10 (v/v) and phosphate buffer (pH 2.3). Linear calibration curves with correlation coefficients r ≥ 0.9950/0.9910 were obtained for 46/four analytes. Additionally, this method allows the quantification of 23 analytes for therapeutic drug monitoring. Limits of quantitation ranged from 0.1 (amobarbital) to 23 mg/L (salicylic acid). Inter‐/intra‐day precisions of quality control samples (low/high) were better than 13% and accuracy (bias) ranged from ?14 to 10%. A computer‐assisted database was created for automated detection of 223 analytes of toxicological interests. Four cases of multi‐drug intoxications are presented. Copyright © 2015 John Wiley & Sons, Ltd.     

中空纤维液相微萃取-高效液相色谱法测定水中残留的氨基甲酸酯类农药

应用中空纤维液相微萃取(HP-LPME)技术建立了水样中呋喃丹、西维因、异丙威和乙霉威的高效液相色谱分析方法。对影响HP-LPME的实验条件进行了优化。采用Accurel Q3/2聚丙烯中空纤维,以甲苯为萃取溶剂,于室温、搅拌速度为720 r/min条件下在4.5 mL样品溶液中萃取20 min,萃取物在室温下经氮气流吹干后用流动相溶解进样。采用Baseline C18分离柱(4.6 mm×250 mm,5.0 μm),以甲醇-水(体积比为60∶40) 为流动相,流速为1.0 mL/min。呋喃丹、西维因、异丙威和乙霉威的检测波长分别为200,223,200和208 nm。该方法对4种氨基甲酸酯类农药的富集倍数均大于45倍;4种氨基甲酸酯类农药在10~100 μg/L质量浓度范围内,其质量浓度与峰面积之间有良好的线性关系,相关系数均大于0.99;呋喃丹、西维因、异丙威和乙霉威的检出限(S/N=3)分别为5,1,5和3 μg/L;实际水样中的加标回收率为82.0%~102.2%,相对标准偏差为2.0%～6.2%(n=6)。     

Packed column supercritical fluid chromatographic separation and estimation of acetaminophen, diclofenac sodium and methocarbamol in pharmaceutical dosage forms

A reproducible and fast method has been developed for the assay of acetaminophen, methocarbamol, and diclofenac sodium in bulk and drug forms using packed column supercritical fluid chromatography employing internal standard method. The analytes were resolved by elution with supercritical fluid carbon dioxide doped with 11.1% (v/v) methanol on a Shendon-Phenyl (250x4.6 mm) 5 mum column with detection monitored spectrophotometrically at 225 nm. The densities and polarities of the mobile phase were optimised from the effects of pressure, temperature and modifier concentration on chromatograhic figures like retention time (t(R), min), retention factor (k(')) etc. Modifier concentration proved to be the most effective means for changing both retention and selectivity. Calibration data and recovery of the drug from spiked concentrations were determined to assess the viability of the method. The supercritical fluid chromatography (SFC) method was directly compared to an HPLC assay, developed in the laboratory, of the same analytes. With respect to speed and use of organic solvents SFC was found to be superior, while in all other aspects the results were similar to HPLC. The method has been successfully used for the assay of two formulations containing a combination of (A) acetaminophen and methocarbamol and (B) acetaminophen and diclofenac sodium. There was no interference from excipients. The present work validates the recent proposition that supercritical fluid chromatography using CO(2) and modifiers is a viable, faster alternative to reverse phase HPLC.     

四氮杂杯[2]芳烃[2]三嗪键合硅胶固相萃取-高效液相色谱法测定河水中硝基苯酚和己烯雌酚

基于四氮杂杯[2]芳烃[2]三嗪键合硅胶吸附剂（NC-Si）,构建了固相萃取-高效液相色谱法同时测定河水中3种硝基苯酚和己烯雌酚的新方法。考察并获得了固相萃取和液相色谱分离的优化条件：将样品溶液pH调至5,以5 mL/min上样,经自制固相萃取柱净化,2 mL氨水-甲醇（2：98,v/v）洗脱;在C8柱上以甲醇-0.1%磷酸溶液为流动相进行梯度洗脱。4种目标分析物的检出限（LOD,S/N=3）为0.03~0.3 μg/L,定量限（LOQ,S/N=10）为0.1~1.0 μg/L;加标回收率为75.5%~104.2%,相对标准偏差（RSD,n=5）小于6.3%。该方法准确、可靠,可用于河水中硝基苯酚及己烯雌酚的灵敏检测。     

Quantification of arecoline (areca nut alkaloid) in neonatal biological matrices by high-performance liquid chromatography/electrospray quadrupole mass spectrometry

A high-performance liquid chromatography (HPLC) method with mass spectrometric detection is described for determination of arecoline in newborn meconium, urine and cord serum, using pilocarpine as internal standard. The analytes were extracted from neonatal biological matrices with chloroform/isopropanol (95:5, v/v) at alkaline pH. Extracts were analyzed by HPLC coupled to an electrospray (ESI) interface and a quadrupole mass spectrometer. Chromatography was performed on a C(8) reversed-phase column using 10 mM ammonium acetate (pH 4.3)/acetonitrile (90:10, v/v) as mobile phase. The mass spectrometer was operated in selected ion monitoring mode. The method was validated over the concentration range 0.005-1.00 micro g/g meconium, 0.004-1.00 micro g/mL cord serum and 0.001-1.00 micro /mL urine. Mean recoveries ranged between 86.5 and 90.7% for arecoline in the different biological matrices, with precision always better than 10%. The quantification limits of arecoline were 0.005 micro g/g meconium, 0.004 micro g/mL cord serum, and 0.001 micro g/mL urine. The method was applied to the analysis of neonatal biological matrices to assess eventual fetal exposition to arecoline. Two newborns from Asian mothers who declared areca nut consumption presented arecoline in meconium with concentrations in the range 0.006-0.008 micro g/g; also the urine from one neonate tested positive for the drug.     

高效液相色谱-蒸发光散射检测法在烟用香精料液中水溶性糖及山梨醇分析中的应用

建立了高效液相色谱-蒸发光散射(HPLC-ELSD)同时检测烟用香精料液中6种水溶性糖及山梨醇的分析方法。方法选用Isolute ENV+固相萃取(SPE)小柱净化样品提取液,以Prevail Carbohydrate ES高效糖柱(250 mm×4.6 mm, 5 μm)作为分析柱,以乙腈和水(75:25, v/v)作为流动相,在1.0 mL/min流速下实现目标物的良好分离;蒸发光散射检测器漂移管温度为79 ℃,载气流速为2.0 L/min。方法针对各目标物建立双对数工作曲线,线性范围约为0.06～1.2 g/L,检出限为12～26 mg/L,样品加标回收率为88%～109%。针对蒸发光散射检测器的双对数工作曲线,通过实验进行分析对比,并结合前人的工作,指出目标物的物理化学性质及其在色谱柱上的保留状态和流动相的洗脱能力等都是影响检测信号的因素。