Solid-phase extraction of vinblastine and vincristine from plasma and urine: variable drug recoveries due to non-reproducible column packings

A sensitive and selective high-performance liquid chromatographic (HPLC) method for the determination of vinblastine and vincristine in plasma and urine is described. The drugs are isolated from 1.0 ml of the biological fluid with a solid-phase extraction column (Bond-Elut Diol). The HPLC method was combined with electrochemical detection at +850 mV versus an Ag/AgCl reference electrode. The detection limit is 100 pg for vinblastine and 250 pg for vincristine with a signal-to-noise ratio of 3, which permits the determination of these compounds in biological fluids at the nanogram level. Evaluation of the isolation method revealed that the drug recoveries and the reproducibility of the extraction procedure depend on the batch number of the solid-phase extraction column used.     

The chromatographic assay of 4‐hydroxynonenal as a biomarker of diseases by means of MEPS and HPLC technique

The aim of this study was to develop and validate a new analytical method for the determination of 4‐hydroxy‐2‐nonenal (4‐HNE) in biological samples while applying microextraction by packed sorbent as a sample preparation method and HPLC with UV–vis detection. Various microextraction by packed sorbent (MEPS) sorbents like C₂, C₈, C₁₈, M1 (80% C₈ and 20% SCX) and silica were used to separate 4‐HNE from biological samples. The highest affinity of 4‐HNE was observed for sorbents like C₁₈. The extraction efficiency was in the range from 47.4 to 89.2% dependent on the concentration of 4‐HNE. Lower efficiency of 4‐HNE extraction was obtained with use of MEPS packings such as C₈ and M1. The extraction efficiency was in the range from 35.2 to 66.3% for packing C8 and from 34.2 to 64.3% for packing M1, respectively. The limit of detection and lower limit of quantitation for UV–vis detection were respectively 4.5 and 9.0 nmol/mL. The proposed method can be used for the evaluation of extraction efficiency of 4‐HNE in biological sample because the values of lower limit of quantitation are lower than the determined amounts of the analyte in samples. The method yields excellent performance of quantification and identification in analysis of inflammation biomarkers. Copyright © 2014 John Wiley & Sons, Ltd.     

HPLC determination of neopterin in biological liquids for clinical purposes

A HPLC method is proposed for determining neopterin in biological liquids. The method was realized using a standard chromatographic instrumentation. Neopterin was isolated from blood serum and urine by solid-phase extraction on cartridges containing 30 mg of supercrosslinked polystyrene. The separation was carried out on an Irica chromatograph (Japan) equipped with means of UV (350 nm) and fluorimetric (es350-em430 nm) detection. The degree of extraction was 96–113%, and the sensitivity of UV and fluorimetric detection was 0.1 and ～0.03 ng, respectively (at signal-to-noise ratio 3). It is shown that the method is suitable for use in routine clinical analysis of neopterin in biological liquids.     

超声液相萃取-GC/MS-SIM法定量检测唾液中苯丙胺类毒品

建立了一种人体唾液中苯丙胺(AM)、甲基苯丙胺(MAM)、 3, 4-亚甲二氧基苯丙胺(MDA)、 3, 4-亚甲二氧基甲基苯丙胺(MDMA)毒品的超声波液液萃取-气相色谱/质谱-选择离子检测方法. 对萃取溶剂、萃取时间等参数进行了考查, 确定了乙酸乙酯为萃取溶剂, 在超声波下液液萃取2 min. 用该溶剂对添加毒品的唾液进行提取, 采用气相色谱/质谱-选择离子检测法(GC/MS-SIM)检测, 获得了良好线性, 相对标准偏差在15%内, 准确性均在80%～115%之间, 最小检测限可达0.05 μg/mL. 该方法未对毒品进行衍生化处理, 可用于缴获毒品及嫌疑吸毒者人体生物检材中苯丙胺类毒品的分析.     

Rapid HPLC measurement of buflomedil in plasma in poisoning cases

A rapid high-performance liquid chromatographic method for the determination of buflomedil in human plasma is described. It requires a single liquid-liquid extraction step from 1 mL of plasma with diethyl ether followed by chromatography on a Nova Pak C(18) reversed-phase column and detection by ultaviolet light. Metoclopramide was used as internal standard. The method is sensitive with a quantification limit at 500 ng/mL. It was used for the determination of buflomedil in biological fluids in poisoning cases.     

Methylmercury determination in biological samples by derivatization,solid-phase microextraction and gas chromatography with microwave-induced plasma atomic emission spectrometry

A method for the extraction and gas chromatographic determination of methylmercury in biological matrices is presented. By combining the advantages of two extraction techniques-microwave-assisted extraction (MAE) and solid-phase microextraction (SPME)--the separation of methylmercury from biological samples is possible. Specifically, the procedure involves microwave extraction with 3 M hydrochloric acid, followed by aqueous-phase derivatization with sodium tetraphenylborate and headspace SPME with a silica fibre coated with polydimethylsiloxane (PDMS). For optimization of the derivatization-SPME procedure, a central composite experimental design with alpha = 1.682 and two central points was used to model gas-chromatographic peak areas as functions of pH, extraction temperature and sorption time. A desirability function was then used for the simultaneous optimization for methylmercury and Hg(II). The optimal derivatization-SPME conditions identified were close to pH 5, temperature 100 degrees C, and sorption time 15 min. The identification and quantification of the extracted methylmercury is carried out by gas chromatography with microwave-induced plasma atomic emission spectrometry detection. The validity of the new procedure is shown by the results of analyses of certified reference materials.     

生物样品中多氯联苯的微波皂化萃取气相色谱法测定

以KOH－甲醇－正己烷为皂化萃取溶剂,利用微波皂化萃取－气相色谱法测定了生物样品中的多氯联苯（PCBs）,实现了在皂化的同时对待测物的萃取。方法的检出限为质量分数6.25×10     

Solid-phase extraction with supercritical fluid elution as a sample preparation technique for the ultratrace analysis of flavone in blood plasma.

A new sample preparation technique, solid-phase extraction with supercritical fluid elution, was developed for the selective isolation of ultratrace levels of drugs from plasma. Plasma samples spiked with a drug were applied to octadecylsilane cartridges and the cartridges were then washed, briefly dried and directly fitted into cells for subsequent supercritical fluid elution. The absolute recovery was studied by using a radiolabeled model compound. The extraction selectivity was examined by chromatographing the extracts with a reversed-phase high-performance liquid chromatographic method with ultraviolet detection. The effects of extraction pressure and the length of capillary restrictors on drug recovery were examined in order to determine the optimal conditions for supercritical fluid elution. The performance of the method was compared to that of conventional solid-phase extraction in terms of recovery, selectivity, precision and accuracy of analysis. Flavone was used as the model compound and dog plasma as the biological matrix for these studies.     

Determination of remoxipride in plasma and urine by reversed-phase column liquid chromatography

A reversed-phase column liquid chromatographic method for the determination of remoxipride, a novel antipsychotic drug, in biological fluids is described. A simple one-step extraction is used followed by liquid chromatography on a 3-microns octadecylsilica column and ultraviolet absorbance detection. The method is accurate and precise for clinical remoxipride levels in both plasma and urine. For situations where a higher sensitivity is necessary a two-step extraction and a modified mobile phase are used. With this modification plasma concentrations down to 2 nM can be determined with acceptable precision.     

高效液相色谱-串联质谱法检测生物样品中6种雌激素

建立了雌酮、雌二醇、雌三醇、己烯雌酚、己烷雌酚和炔雌醇6种雌激素在生物体中的HPLC-MS/MS分析方法.采用加速溶剂萃取、固相萃取技术进行提取、富集及净化,有效降低了基质的干扰.以甲醇-0.1％氨水溶液为流动相,以C18色谱柱进行分离,质谱采用电喷雾负离子扫描模式,6种雌激素的回收率为88％～104％,相对标准偏差在1.3％～8.3％之间.雌酮、雌二醇、雌三醇在生物体中的方法检出限0.35ng/g;己烯雌酚、己烷雌酚、17α-乙炔基雌二醇在生物体中的方法检出限为0.13ng/g.方法适用于生物体内雌激素的分析和检测.     

加压毛细管电色谱法高效分离分析葛根多糖中的单糖

葛根多糖具有抗氧化、抗肿瘤等众多生物活性,对葛根多糖进行单糖组成分析对其活性研究具有重要意义。该研究利用响应面分析法考察了超声辅助提取法中液料比、超声温度、超声时间和超声功率对葛根多糖提取率的交互影响,并拟合数据得到多元二次回归方程。同时建立了柱前衍生加压毛细管电色谱检测糖类的方法,对分离8种中性单糖的色谱条件进行了探索与优化,并将此方法应用于两种葛根实际样品的单糖组成测定。响应面分析结果表明,4个试验因素中,超声温度对两种葛根多糖提取率的影响程度最大,其次为液料比,超声时间和超声功率影响程度较小。结合软件预测分析得到的最佳条件及设备实际情况,确定葛根多糖的最佳提取工艺条件为：超声温度90℃,粉葛多糖液料比20 mL/g,柴葛多糖液料比40 mL/g,超声时间30 min,超声功率180 W。优化后的色谱分离条件为：采用Halo-2.7 μm核壳型C18填料毛细管色谱柱,以乙腈-50 mmol/L pH 4.1的醋酸铵水溶液（18：82,v/v）为流动相,在250 nm波长下检测,施加电压-20 kV。在此条件下可以实现24 min内对葡萄糖等8种中性单糖衍生物的快速分离,相比传统液相色谱方法大大提升了分离检测速度和分离柱效。方法学考察表明此方法具有较好的线性关系和良好的重复性。对实际样品分离鉴定表明,粉葛多糖主要由葡萄糖、甘露糖、鼠李糖和岩藻糖组成,4种单糖物质的量之比为1.00：0.16：0.14：0.07;柴葛多糖主要由葡萄糖和甘露糖组成,2种单糖物质的量之比为1.00：0.70。该研究为单糖化合物快速高效分离检测提供了新方法,并为葛根多糖单糖组成分析提供了参考。     

Sample preparation for planar chromatography

High-performance thin-layer chromatography has favorable properties for high-throughput separations with a high matrix tolerance. Sample preparation, however, is sometimes required to control specific matrix interferences and to enhance the detectability of target compounds. Trends in contemporary applications have shifted from absorbance and fluorescence detection to methods employing bioassays and mass spectrometry. Traditional methods (shake-flask, heat at reflux, Soxhlet, and hydrodistillation) are being challenged by automated instrumental approaches (ultrasound-assisted and microwave-assisted solvent extraction, pressurized liquid extraction, and supercritical fluid extraction) and the quick, easy cheap, efficient, rugged, and safe extraction method for faster and streamlined sample processing. Liquid-liquid extraction remains the most widely used approach for sample clean-up with increasing competition from solid-phase extraction. On-layer sample, clean-up by planar solid-phase extraction is increasingly used for complex samples and in combination with heart-cut multimodal systems. The automated spray-on sample applicator, the elution head interface, biological detection of target and non-target compounds, and straightforward mass spectrometric detection are highlighted as the main factors directing current interest toward faster and simpler sample workflows, analysis of more complex samples, and the determination of minor contaminants requiring high concentration factors.     

Determination of arsenic and antimony in biological materials by solvent extraction and neutron activation

Arsenic and antimony in digested biological samples can be extracted with pyrrolidinecarbodithioate at pH 1 into chloroform and stripped with nitric acid for neutron-activation analysis (NAA). The extraction method eliminates interferences from matrix species, including Br and Na, making the accurate determination of low levels of As and Sb in biological materials feasible. The detection limits under the experimental conditions used are 0.005 and 0.006 mug/g for arsenic and antimony, respectively. A comparison of the results obtained for As and Sb in NBS biological standards by this method and by non-destructive instrumental neutron-activation analysis (INAA) is also given.     

新型纳米纤维固相萃取柱制备及其用于组织样品中柔红霉素测定研究

研制出一种新型纳米纤维固相萃取柱,并将其用于大鼠心、肝、脾、肺、肾组织及血浆中柔红霉素的净化、浓缩处理,建立了生物样品中柔红霉素的高效液相荧光检测法.以10%(V/V)HClO4为溶剂,对组织样进行匀浆和离心处理,上清液用纳米纤维小柱净化富集,以50 μL含1%(V/V)冰醋酸的甲醇洗脱,进样20μL检测.流动相为甲醇...     

Rapid and selective determination of urinary lysozyme based on magnetic molecularly imprinted polymers extraction followed by chemiluminescence detection

A rapid, low cost and selective chemiluminescence method coupled with magnetic molecularly imprinted polymers extraction was developed to detect lysozyme in human urine samples. Compared with traditional solid-phase extraction, this method could achieve selective extraction for the lysozyme, avoid the time consuming elution from a column or centrifugation steps, and then showed great potential in the high-throughput screening of clinical samples. The parameters affecting the performance of extraction and chemiluminescence were investigated. Under optimal conditions, the whole analytical procedure was completed within 12 min and spiked recovery ranged from 90.1% to 103.7% (R.S.D.≤6.7%). The limit of quantitation was 5 ng mL(-1). Furthermore, the results obtained by the proposed method were linearly correlated to those by commercial lysozyme detection kit (r=0.9595). Finally, the validated method was used to measure the urinary lysozyme of renal disease patients and healthy controls. The results confirmed the reliability and practicality of the protocol and revealed a good perspective of this method for biological sample analysis.     

Specific assay for unconjugated dehydroepiandrosterone in human plasma by capillary gas chromatography with electron-capture detection.

A specific and sensitive method for the determination of unconjugated dehydroepiandrosterone in plasma is described. After extraction and purification of the extracts on a Celite column, the iodomethyldimethylsilyl ether derivative of dehydroepiandrosterone was isolated on an aluminium oxide column and assayed by gas chromatography with electron-capture detection. The method is sensitive: sample volumes of 0.5-1 ml are sufficient for the determination of dehydroepiandrosterone in plasma of normal male and female subjects aged 1-80 years. The assay is highly specific and has the potential to be used as a reference method for the determination of unconjugated dehydroepiandrosterone in biological samples.     

HPLC Analysis of Cefmetazole and Nocardicins A and E in Human Serum and Urine Using Solid-Phase Extraction

Abstract

A method for extraction and quantification of cefmetazole and nocardicins A and E in serum and urine samples is described in this paper. Sample pretreatment is carried out using solid-phase extraction cartridges, resulting in very high extraction recoveries of these β-lactam antibiotics. The procedure, which prepares biological fluids for reversed-phase high-performance liquid chromatographic analysis is convenient, rapid and reproducible. An water-methanol-acetic acid mobile phase was used with benzotriazole as an internal standard. The detection limit was 0.2 μg/ml at 280 nm.     

Trace analysis of fullerenes in biological samples by simplified liquid-liquid extraction and high-performance liquid chromatography

Fullerene (C60) has several potential biomedical and industrial applications. While pure fullerene is not soluble in water, nanoparticles of the fullerene aggregates (nano-C60) can be prepared in water solutions. The concentration of nano-C(60) in biological media after systemic exposure could be very low and requires trace analytical methods to be developed for the toxicological and pharmacokinetic studies of the nanomaterial. A serious drop in extraction efficiency was observed when the concentration was under 0.5 microg/mL using traditional liquid-liquid extraction (LLE) protocols. The evaporation of the solvent extract to dryness was found to be the main reason for the efficiency drop and an improved evaporation method was proposed to overcome this problem. Optimal proportion of glacial acetic acid (GAA) was used to solublize the proteins and surfactants in the biological samples, so that the emulsion problem was eliminated during LLE. Magnesium perchlorate was used to destabilize the nano-C60 particles in the water solution and promoted the solvent extraction. A simplified LLE method was developed for high throughput while preserved the advantages of the traditional LLE. The developed method was used for trace analysis of fullerenes in protein containing media and tape-stripped skin samples. Under optimal experimental conditions, the detection limit was 0.34 ng/mL and the recovery was in the range of 94-100% (n=5) at a concentration of 10 ng/mL nano-C60 in the biological media.     

Determination of 36Cl in biological shield concrete using pyrohydrolysis and liquid scintillation counting

A method for the determination of 36Cl in biological shield concrete of nuclear reactors was developed. Cl in the concrete sample was extracted quantitatively by pyrohydrolysis at 900 degrees C and recovered in Na2CO3 solution for subsequent measurement of 36Cl by liquid scintillation counting. WO3 was used as an accelerator in the pyrohydrolysis. The Cl extraction procedure was optimized by investigating experimental conditions with the use of ion chromatography and its recovery was evaluated by the analysis of the geochemical reference samples. The detection limit of 36Cl was 0.02 Bq g(-1) for a sample weight of 2 g. The relative standard deviation was 3-7% for the samples containing 0.5 Bq g(-1) levels of 36Cl. The method was applied to determine 36Cl in biological shield concrete of the Japan Power Demonstration Reactor.     

Bio-compatible in-tube solid-phase microextraction capillary for the direct extraction and high-performance liquid chromatographic determination of drugs in human serum

A restricted access material (RAM), alkyl-diol-silica (ADS), was used to prepare a highly bio-compatible solid-phase microextraction (SPME) capillary for the automated and direct in-tube extraction of several benzodiazepines from human serum. The bifunctionality of the ADS extraction phase prevented fouling of the capillary by protein adsorption while simultaneously trapping the analytes in the hydrophobic porous interior. This the first report of a restricted access material utilized as an extraction phase for in-tube SPME. The approach simplified the required apparatus in comparison to existing RAM column switching procedures, and more importantly eliminated the excessive use of extraction solvents. The biocompatibility of the ADS material also overcame the existing problems with in-tube SPME that requires an ultrafiltration or other deproteinization step prior to handling biological samples, therefore further minimizing the sample preparation requirements. The calculated oxazepam, temazepam, nordazepam and diazepam detection limits were 26, 29, 22 and 24 ng/ml in serum, respectively. The method was linear over the range of 50-50 000 ng/ml with an average linear coefficient (R2) value of 0.9998. The injection repeatability and intra-assay precision of the method were evaluated with five injections of a 10-microg/ml serum sample (spiked with all compounds), resulting in an average RSD<7%. The ADS extraction column was robust, providing many direct injections of biological fluids for the extraction and subsequent determination of benzodiazepines.