High performance liquid chromatography-mass spectrometry based chemometric characterization of olive oils

In this study the effective discrimination of extra virgin olive oils is described using HPLC-MS, combined with chemometric evaluation. The presented method is simple since the diluted oil sample is directly injected into the system, without any preliminary chemical derivatization or purification step. Separation of diacylglycerols, triacylglycerols and sterols occurs within 20 min and is achieved using an octadecyl-silica column. Detection is performed by positive APCI mass spectrometry which provided sensitivity to detect over 50 compounds in the sample. After extraction of data, stepwise discriminant function analysis is used to select the variables with the highest discriminative power. These variables are used to perform linear discriminant analysis and classify/predict the samples. One-hundred per cent classification and 99% prediction rate was achieved for olive oils obtained from Nocellara, Biancolilla and Cerausola cultivars. Reliability of prediction was tested by cross validation.     

超高效液相色谱-串联质谱法同时测定尿样中4种痕量的乌头类生物碱

建立了超高效液相色谱-串联质谱(UPLC-MS/MS)结合中空纤维微萃取(HF-LPME)同时检测尿样中痕量的乌头碱、次乌头碱、新乌头碱和滇乌头碱等4种生物碱的方法。采用HF-LPME对尿样进行提取、纯化和富集,富集倍数达102～301。同时采用电喷雾电离(ESI)、多反应监测(MRM)进行含量测定,显著提高了尿液中乌头类生物碱的检测灵敏度,4种乌头类生物碱的定量限达到0.01～0.1 ng/L,可大大延长中毒患者尿样中乌头类生物碱的检测时间窗。方法验证结果表明,尿液中乌头碱、新乌头碱和滇乌头碱在0.01～10 ng/L、次乌头碱在0.1～100 ng/L范围内线性关系良好,提取回收率为80.2%～109%,相对标准偏差小于4.6%。该方法适用于乌头类生物碱中毒案件的检测,为痕量乌头类生物碱分析提供了灵敏的分析方法。     

Analysis of tropane alkaloids with thermospray high-performance liquid chromatography-mass spectrometry

A thermospray high-performance liquid chromatography-mass spectrometry method for analysis of hyoscyamine and scopolamine in plant cell culture samples is described. The alkaloids were separated on a polymeric reversed-phase column with an alkaline ammonium acetate buffer-acetonitrile eluent. Selected-ion recording of the protonated molecular ions was used for quantitation of the compounds. The compounds were fragmented by discharge-assisted ionization and elevated thermospray capillary temperatures or ion repeller potentials.     

High performance liquid chromatography-mass spectrometric analysis of sulphonated dyes and intermediates

This paper reports our results in the analysis of polysulphonated anionic dyes and their intermediates using high-performance liquid chromatography-mass spectrometry (HPLC-MS). Negative-ion electrospray ionization is the most suitable ionization technique for the molecular mass determination of polysulphonated dyes or other dyes carrying a negative charge. From the series of [M-xH]x- ions and their sodiated adducts [M-(x + y)H+yNa]x-, the molecular mass and the number of sulphonic and carboxylic groups can be determined. The mobile phase should be compatible with the mass spectrometric detection, which rules out non-volatile tetraalkylammonium salts usually used as ion-pair mobile phase additives for the HPLC of sulphonated compounds. Some mono- and disulphonated dyes and intermediates can be separated with aqueous-organic mobile phases containing 5 mM ammonium acetate, which is the most suitable additive as far as compatibility with MS detection is concerned. However, the retention of compounds with two or more sulphonic groups is too low for a successful separation both with this mobile phase additive and with ion-pair additives with short alkyl chains. The dihexylammonium acetate ion-pairing reagent offers a reasonable compromise in terms of sufficient volatility and adequate retention and separation selectivity for the HPLC-MS analysis of polysulphonated dyes.     

High performance liquid chromatography-mass spectrometry analysis for rat metabolism and pharmacokinetic studies of lithospermic acid B from danshen

Metabolism and pharmacokinetic studies on rat were conducted for lithospermic acid B, one of the components from Radix Salviae Miltiorrhizae (danshen) that shows many bioactivities. Liquid chromatography-electrospray ionization mass spectrometry method was applied for the determination of lithospermic acid B and its metabolites in samples from in vitro and in vivo metabolism studies. Rat plasma samples collected after intravenous administration were analyzed for obtaining pharmacokinetic data of lithospermic acid B. Four O-methylated metabolites, namely one monomethyl-, two dimethyl- and one trimethyl-lithospermic acid B, were detected when lithospermic acid B was incubated in rat hepatic cytosol. These four metabolites were also detected in rat bile, plasma and feces samples after intravenous administration of lithospermic acid B. The in vitro and in vivo results indicate that the methylation is the main metabolic pathway of lithospermic acid B. The danshen component and its methylated metabolites were excreted to rat bile and feces.     

High throughput log D determination using liquid chromatography-mass spectrometry

A method has been developed which allows direct measurement of partition coefficients (log D, log P) using liquid chromatography-mass spectrometry (LC-MS). The high throughput, microtiter plate based protocol uses small quantities of 10 mM analyte in DMSO solution (5 microL) and is therefore amenable to standard archive and screening formats. Single Ion Monitoring (SIM) mass spectrometry is used to achieve optimal sensitivity. Experimental log D values for 34 known drugs have been determined, with partition coefficients ranging from -2 to 5, giving data very similar to literature values. In these analyses, deviations from known values average less than 0.3 log units. The sample handling and data processing have been significantly automated, and the protocol has been applied to over 800 in-house lead molecules to date. In its format, sensitivity, throughput, and amenability to automation, it represents significant progress in the direct measurement of partitioning behavior [1].     

Synthesis of protoberberine alkaloids

In this review an analysis is made of literature information on the synthesis of protoberberine alkaloids during 1980–1990.     

Synthesis of protoberberine alkaloids

In this review an analysis is made of literature information on the synthesis of protoberberine alkaloids during 1980–1990.Institute of Chemistry of Plant Substances, Uzbekistan Republic Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 449–468, September–October, 1992.     

Enantioselective analysis of methadone in saliva by liquid chromatography-mass spectrometry

Saliva was tested and evaluated as a biological matrix for methadone (Mtd) monitoring. Conventional method using a narrow bore C18 column, and an enantioselective method using a narrow bore alpha1-acid glycoprotein column, were developed using liquid chromatography coupled with a mass spectromeric (MS) detector. After optimisation of MS conditions by flow injection analysis, selected ion monitoring detection was used to enhance sensitivity. The total Mtd concentration and the enantiomeric ratio in saliva were validated using an experimental design. The methods were applied to samples provided by heroin addicts undergoing a Mtd treatment. Results on total Mtd determination showed a very poor correlation between saliva and serum, whereas the enantiomeric ratios of Mtd gave a very good one.     

HPLC-MS联用测定发酵液中的紫杉醇

用HPLC-MS测定发酵液中的紫杉醇,分别考察了实验条件下(+)ESI和(-)ESI方式的MS检测灵敏度,苯基柱和C18柱的分离效果,研究表明以(-)ESI方式的MS检测灵敏度较(+)ESI方式优,苯基柱的分离效果优于C18柱,本文报道的实验方法用于测定发酵液中的紫杉醇效果快速、准确、可靠.     

高效液相色谱-质谱联用测定胶原蛋白中的羟脯氨酸

建立了一种简单、快速地测定胶原蛋白中羟脯氨酸(HYP)的高效液相色谱-电喷雾质谱(HPLC-ESI/MS)方法。胶原蛋白经酸水解后,以乙腈-0.05%的三氟乙酸水溶液(体积比为5∶95)为流动相,以1.0 mL/min的流速在C8反相柱上进行分离。以茶氨酸为内标,利用质谱定性定量测定HYP。在电喷雾正离子模式下,对m/z 132和m/z 175离子进行选择离子监测。在11.7～117 mg/L范围内,HYP与内标物茶氨酸的峰面积比和HYP的质量浓度呈良好的线性关系,相关系数为0.9993。含量测定的相对标准偏差为1.87%,回收率为97.85%～101.76%。此方法流动相简单,分析时间短且无需衍生处理,抗干扰能力强,能准确快速地测定胶原蛋白中HYP的含量。     

高效液相色谱-质谱法测定发酵液中的喷司他丁

建立了测定发酵液中喷司他丁含量的反相高效液相色谱-质谱分析方法。采用的色谱条件: 色谱柱为Hypersil ODS2柱(250 mm×4.6 mm, 5 μm);流动相为甲醇/乙腈/10 mmol/L乙酸铵(pH 7.6)(2.5/2.5/95, v/v/v),流速为1.0 mL/min;检测波长为280 nm;柱温为40 ℃;进样量为10 μL。喷司他丁在1.0～100 mg/L范围内有良好的线性关系,相关系数为0.9999。该方法精密度好,稳定性高,能简便、快速、准确地测定发酵液中喷司他丁的含量。     

Matrix effects in pesticide multi-residue analysis by liquid chromatography-mass spectrometry

Three sample preparation methods: Luke method (AOAC 985.22), QuEChERS (quick, easy, cheap, effective, rugged and safe) and matrix solid-phase dispersion (MSPD) were applied to different fruits and vegetables for analysis of 14 pesticide residues by high-performance liquid chromatography with electrospray ionization-mass spectrometry (HPLC/ESI/MS). Matrix effect, recovery and process efficiency of the sample preparation methods applied to different fruits and vegetables were compared. The Luke method was found to produce least matrix effect. On an average the best recoveries were obtained with the QuEChERS method. MSPD gave unsatisfactory recoveries for some basic pesticide residues. Comparison of matrix effects for different apple varieties showed high variability for some residues. It was demonstrated that the amount of co-extracting compounds that cause ionization suppression of aldicarb depends on the apple variety as well as on the sample preparation method employed.     

Simultaneous analysis of protoberberine, indolequinoline and quinolone alkaloids in coptis-evodia herb couple and the Chinese herbal preparations by high-performance liquid chromatography-electrospray mass spectrometry

A new and sensitive method has been developed for analysis of protoberberine, indolequinoline and quinolone alkaloids in coptis-evodia herb couple and the Chinese herbal preparations by using HPLC in combination with electrospray mass spectrometry (ESI-MS). Different LC and cone voltages have been optimized prior to this in order to obtain better results and sensitivity. The method was carried out by using a spherigel C₁₈ analytical column with a gradient solvent system of acetate buffer-acetonitrile-methanol. The contents of alkaloids were measured by pseudomolecule ion on the selective ion recording (SIR) mode. Linearity of around three orders in the magnitude of concentration was generally obtained and limits of detection for these compounds were in the range of 9-30 pg.     

State-of-the-art in liquid chromatography-mass spectrometry.

Impressive progress has been made in the technology and application of combined liquid chromatography-mass spectrometry (LC-MS) in the past decennium. From a technique, that could only be used by a specialist, it has developed into a routinely applicable technique. LC-MS has become the method-of-choice of analytical support in many stages of drug development within pharmaceutical industries and has found its way into environmental, biochemical and other laboratories. This paper provides a perspective on the current technology, principles and applications of LC-MS.     

液相色谱-质谱法研究附子生物碱的煎煮减毒机理

建立了基于液相色谱-质谱分析的附子中生物碱指纹分析方法,并将其应用于附子煎煮减毒的机理研究。基于质谱特征鉴定了生物碱标准品在加热回流过程中产生的6种降解产物,确定了双酯型生物碱的煎煮条件降解规律。在此基础上研究了附子饮片煎煮不同时间条件下生物碱的指纹变化,结果表明,长时间煎煮可明显降低双酯型生物碱和生物脂碱的浓度,为附子的安全用药提供了科学依据。     

Sequence analysis of derivatized peptides by high-performance liquid chromatography-mass spectrometry

N-Acetyl-N,O,S-permethylated derivatives of oligopeptides were analyzed by high-performance liquid chromatography-mass spectrometry (HPLC-MS) using a moving belt interface. A heated-gas nebulizer was employed for sample deposition, thus permitting the effective use of a water-methanol gradient covering the range from 5% to 95% water at mobile phase flow-rates of 0.5 ml/min. We demonstrate in this paper that it is possible to sequence the octapeptide derived from the C-chain of glucagon by HPLC-MS analysis of a permethylated enzymatic hydrolysate of this peptide using overlap information from the mass spectral patterns. Moreover, it is shown that peptides not readily amenable to analysis by gas chromatography-MS can be analyzed using this approach. Preliminary results suggest that N-acetyl-methyl ester derivatives of oligopeptides may in specific cases also be a useful alternative for HPLC-MS analysis of complex oligopeptide mixtures.     

超高效液相色谱-质谱联用法监测人心房钠尿肽的化学合成

多肽作为神经递质、激素、受体等参与和调节许多重要的生命过程。随着对多肽结构与功能认识的深入,化学合成多肽在生物医药、生命分析等领域显示了重要价值。人心房钠尿肽(ANP)是一种由28个氨基酸组成的多肽类激素,其含量和代谢异常与心血管疾病、癌症等密切相关。针对ANP重要的生理功能,该文开展了ANP化学合成及其过程的监测与优化,设计了集固相合成线性直链多肽和液相氧化成环为一体的策略。基于高效液相色谱的分离性能和多级质谱的结构鉴定能力,建立了超高效液相色谱-串联质谱(UHPLC-MS/MS)分析新方法,对固相合成产物进行了分离分析,并对液相氧化方法进行了筛选和优化,最终分离纯化得到了目标多肽,为人心房钠尿肽的高效化学合成及氧化成环反应提供借鉴。     

Determination of isotopically labelled monoesterphthalates in urine by high performance liquid chromatography-mass spectrometry

A method of analysis for monoesters of phthalic acid ('monoesterphthalates') in human urine has been developed. The method was needed to determine the hydrolysis and excretion efficiency of isotopically-labelled phthalate diesters ('phthalates') when they were fed to volunteers as part of a biomarker study to estimate total exposure to phthalates. The targeted substances were 13C-monobutylphthalate (MBP), 2H4-monobutylphthalate (MBP), 2H4-monobenzylphthalate (MBeP), 13C-monocyclohexylphthalate (MCHP), 13C-monoethylhexylphthalate (MEHP), and 13C-monoisodecylphthalate (MIDP). The monoesters in urine were deconjugated enzymatically, extracted into solvent, and then determined by high performance liquid chromatography-mass spectrometry (LC-MS) using atmospheric pressure chemical ionisation in the negative ion mode. The limits of determination were 10 ng ml(-1) for MBP, MCHP, MBeP and MEHP, and 40 ng ml(-1) for MIDP. The recovery from urine spiked at 100 ng ml(-1) was in the range from 70 to 85% except for MIDP which was lower at 55%. The between-batch reproducibility of the analysis was in the range 8 to 17% (n = 6 batches on separate days).     

Determination of polyunsaturated fatty acid monoepoxides by high performance liquid chromatography-mass spectrometry

Despite the implication of polyunsaturated fatty acid monoepoxides in a large panel of biological effects, few methods allowing their separation in a single run are available. We describe here a simple method based on reversed-phase ion-pair high-performance liquid chromatography (RP-HPLC) and developed to successfully separate the various monoepoxides of eicosatrienoic, arachidonic, eicosapentaenoic and docosahexaenoic acids. These compounds were easily identified by liquid chromatography-mass spectrometry (LC-MS) with atmospheric pressure chemical ionisation owing to the volatility of counter-ion species. Compared to established methods, this new protocol proved its ability to totally resolve, in a single run, all of the different regioisomeric epoxides. In the long run, this method will demonstrate its efficacy to give insights into the cytochrome P450-dependent metabolism of polyunsaturated fatty acids (PUFAs) and the generation of physiologically active epoxy-derivatives.