Microextraction of Tetracyclines from Milk to Deep Eutectic Solvents for the Subsequent Determination by High-Performance Liquid Chromatography–Tandem Mass Spectrometry

Journal of Analytical Chemistry - A method of liquid–liquid microextraction is proposed for the extraction and preconcentration of tetracycline antibiotics from milk. It involves the...     

In-Solution Derivatization and Headspace Gas Chromatography–Mass Spectrometry for 56 Carbonyl Compounds in Tobacco Heating Products,Traditional Tobacco Products and Flavoring Capsules

Chromatographia - Optimal derivatization conditions were established for the simultaneous determination of 12 aliphatic saturated aldehydes, 8 aliphatic saturated ketones, 4 cyclic ketones, 3...     

人体尿液中双酚A与壬基酚的同位素稀释的LC-MS/MS分析

采用固相萃取、高效液相色谱-质谱/质谱仪同位素稀释技术,建立了尿中双酚A(BPA)和壬基酚(NP)的检测方法.液相色谱分离用C18柱,流动相为甲醇和水,负离子电喷雾模式电离,多反应离子监测方式检测,BPA和NP的定量离子对分别为m/z 226.9/132.9、219.3/118.8, 13C和氘代同位素化合物分别做回收率控制和内标定量.BPA和NP的基质加标回收率分别为86% ～106%、90% ～114%,定量下限分别为0.97、2.3 μg/L.实际尿样的测定验证了该方法的可行性.     

Tert-Butyldiphenylsilyl Derivatization for Liquid Chromatography and Mass Spectrometry

Abstract

Tert?butyldiphenylsilyl (TBDPS) derivatization has been investigated for the purposes of improving the HPLC analysis of polar compounds such as fatty acids, cholesterol and bile acids with ultraviolet absorption and/or mass spectral detection. Very mild reaction conditions (room temperature, 30 min) gave quantitative conversion of carboxyls and sterically accessible hydroxyls. The sterically hindered 7α and 12α hydroxyls of bile acids were not silylated to any extent under these conditions. The TBDPS ethers and esters proved stable under HPLC conditions and could be separated on an octylsilyl (RP-8) reverse phase column using acetonitrile as the mobile phase. Detection with an ultraviolet absorption detector at 254 nm was possible but 220 nm provided maximum sensitivity. The derivatives proved to be sufficiently volatile for electron-impact mass spectrometry and the apolar nature of the mobile phase facilitated combined LC/MS with a moving belt interface. The spectra were characterized by abundant ions at [M-57]⁺ due to loss of a tert?butyl radical and m/z 199 due to Ph₂SiOH⁺.     

Rapid Liquid Chromatographic – Tandem Mass Spectrometric Method for the Quantification of Pentoxifylline in Human Plasma

A simple, rapid, sensitive and selective liquid chromatography / tandem mass spectrometry method was developed and validated for the quantification of pentoxifylline, a haemorheological agent. The analyte and internal standard, tamsulosin were extracted by liquid-liquid extraction with ethyl acetate and were separated using an isocratic mobile phase on a reverse phase C₁₈ column. The analytes were analyzed by mass spectrometry in the multiple reaction monitoring mode using the respective [M+H]⁺ ions, m/z 279/138 for pentoxifylline and m/z 409/228 for the IS. The assay exhibited a linear dynamic range of 2–1000 ng mL⁻¹ for pentoxifylline in human plasma. The lower limit of quantification was 2 ng mL⁻¹ with a relative standard deviation of less than 10%. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. A run time of 1.5 min for each sample made it possible to analyze more than 400 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability or bioequivalence studies. Revised: 4 and 20 October 2005     

Development and Validation of Multi-Residue Method for Drugs Analysis in Human Feces by Liquid Chromatography–Tandem Mass Spectrometry

The use of veterinary drugs in animal production is a common practice to secure animal and human health. However, residues of administrated drugs could be present in animal food products. Levels of drugs in food of animal origin are regulated within the European Union. In recent years, residues have been detected not only in food, but also in the environmental elements such as water or soil, meaning that humans are involuntarily exposed to these substances. This article presents a multiclass method for the analysis of various therapeutic groups of pharmaceuticals in human feces. Pharmaceuticals are extracted from feces with an acid extraction solvent, and after filtration the extract was analyzed by HPLC–MS/MS. A limit of detection of 10 ng/g was achieved for 9 pharmaceuticals, with linearity over 0.99 and repeatability and reproducibility lower than 20%. The method was satisfactorily applied in 25 feces samples of individuals that had declared not to be under medical treatment for the last two months. Results indicate the presence of six different compounds at concentration between 10 and 456 ng/g. This preliminary study showed the involuntary exposure of human gut microbiota to active substances such as pharmaceuticals     

液相色谱–同位素稀释质谱法测定人体生长激素

建立了准确、快速测定痕量人体生长激素的同位素稀释质谱法。选取同位素标记脯氨酸、缬氨酸和苯丙氨酸为内标物,将内标物以重量法与待测样品准确混合,利用Kinetex C18色谱柱分离,以电喷雾三重串联四级杆质谱多反应监测模式测定,建立了人体生长激素的液相色谱–同位素稀释质谱联用定量方法。人体生长激素溶液标准物质的含量测定结果为(1.82±0.04)mg/g,相对标准偏差为0.43%(n=6)。该方法简易、实用、准确、可靠,可作为人体生长激素溶液标准物质的定值方法,并为人体生长激素的日常检测提供参考。     

Rapid Quantification of Efavirenz in Human Plasma by Electrospray Ionization Tandem Mass Spectrometry

We report a rapid and sensitive method for detecting efavirenz in human plasma by electrospray ionization tandem mass spectrometry (ESI‐MS/MS). Detection of efavirenz in human plasma samples was confirmed by acquiring MS/MS of protonated efavirenz at m/z 316.5 to yield the characteristic fragment ions at m/z 298, 274, 272, 251, 246, 237, 232, 203 and 168, respectively. This approach provided good linearity for the quantification of efavirenz (R² = ～0.9989), with good precision (RSD >10%) and limit of detection (0.20 nM). This method can be widely applied for precise quantitative analysis of a variety of drugs in clinical samples.     

高效液相色谱串联质谱法测定血清中内美通

研究了高效液相色谱串联质谱联用测定人血清中内美通的方法。用乙醚提取血清中的内美通,米非斯酮做内标,电喷雾离子化,选择内美勇母、子离子对m/z309-m/z241;内标的母、子离对对m/z430-m/z372;串联质谱采用多反应扫描监测方法,定量测定人血清的内美通。该方法测定速度快,灵敏度高,选择性好。方法的标准曲线线性范围3.5-177μg/L（r^2=-0.999);检出限0.8μg/L;进行6次平行测定,日间RSD=2.3%-13.7%,RD=4.8%-3.0%;日内RSD=5.5%-14.8%,RE=3.1%-6.7%;回收率内美通是91.0%,内标米非斯酮是90.6%。4min完成一个样品测定。     

Determination of Tropisetron in Human Plasma by Liquid Chromatography Tandem Mass Spectrometry

A fast and sensitive liquid chromatography tandem mass spectrometric method has been developed and validated for the determination of tropisetron in human plasma. The HPLC separation was performed on a Phenomenex Synergi Fusion RP80 column using acetonitrile ?13 mM ammonium acetate – acetic acid (30:70:0.035, v/v) as the isocratic mobile phase. The assay was linear over the concentration range 0.5–128 ng/mL. The intra- and inter-assay precision was less than 11.6% for tropisetron. The method was successfully used to characterize the pharmacokinetic profiles of tropisetron in 20 healthy volunteers after an intravenous infusion of 5 mg tropisetron.     

Development and Validation of a Method of Liquid Chromatography Coupled with Tandem Mass Spectrometry for Quantification of ST-246 (Tecovirimat) in Human Plasma

The aim of this work was to develop and validate a sensitive and robust method of liquid chromatography coupled with tandem mass spectrometry to quantitate ST-246 (tecovirimat) in plasma using an internal standard (2-hydroxy-N-{3,5-dioxo-4-azatetracyclo [5.3.2.02.6.08.10]dodec-11-en-4-yl}-5-methylbenzamide). The method was validated in negative multiple reaction monitoring mode following recommendations of the European Medicines Agency for the validation of bioanalytical methods. The calibration curve for the analyte was linear in the 10–2500 ng/mL range with determination coefficient R² > 0.99. Intra- and inter-day accuracy and precision for three concentrations of quality control were <15%. Testing of long-term stability of ST-246 (tecovirimat) in plasma showed no degradation at −20 °C for at least 3 months. The method was applied to a clinical assay of a new antipoxvirus compound, NIOCH-14. Thus, the proposed method is suitable for therapeutic drug monitoring of ST-246 (tecovirimat) itself and of NIOCH-14 as its metabolic precursor.     

Quantification of Erdosteine in the Low-volume of Dog Plasma by Liquid Chromatography Tandem Mass Spectrometry

Introduction Erdosteine[N-(carboxymethylthioacetyl)-homocysteine thiolactone](Fig.1)is a synthetic derivative of natural amino acid methionine[1].It has been commonly used in clinical practice as a mucolytic drug and as an enhancer of respiratory ventilation in the treatment of patients with chronic obstructive respiratory disease.     

A New Approach to Sampling Petroleum Product Films from Water Surfaces and Their Subsequent Analysis by Gas Chromatography–Mass Spectrometry

Journal of Analytical Chemistry - The capabilities of a new approach to sampling oil product films from water surfaces in order to accurately control the surface area from which the films are taken...     

液相色谱-串联质谱法测定尿液中的泛酸

该文建立了检测尿液中泛酸含量的液相色谱-串联质谱(HPLC-MS/MS)方法,尿液经过离心、稀释后,采用ACPUITY UPLC SS T3(2.1 mm×100 mm,1.8μm)色谱柱进行分离,电喷雾正离子模式电离,多反应监测模式进行检测,方法的线性关系良好(r=0.999 3),方法检出限为0.46 ng/m L,回收率为87.9%~95.3%,相对标准偏差(RSD)为2.5%~13.0%。该方法具有灵敏度高、分析时间短等特点,可用于尿液中泛酸含量的分析。     

Determination of Captopril in Human Plasma by Liquid Chromatography/Tandem Mass Spectrometry

Abstract

In this study, a fast and sensitive liquid chromatography/tandem mass spectrometry method for the determination of captopril in human plasma was developed and validated. The analyte and enalaprilat, used as the internal standard, were extracted from plasma using methanol directly precipitate protein. Analysis was performed on a Lichrospher CN column with water (containing 0.1% formic acid) and methanol (60∶40, v/v) as the mobile phase. Linearity was assessed from 6.25 to 800 ng/ml in plasma. The analytical method proved to be applicable in a pharmacokinetic study of captopril after oral administration of 20 mg captopril tablet to 20 healthy volunteers.     

Determination of Perfluorochemicals in Human Milk Using Isotope‐dilution Liquid Chromatography Tandem Mass Spectrometry

A highly precise and accurate analytical method utilizing an isotope‐dilution liquid chromatography tandem mass spectrometry was developed and validated to determine two perfluorochemicals (PFCs): perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS) in human milk samples. Identification of the analytes was confirmed under negative electrospray with multiple reaction monitoring (MRM) mode by the monitoring of one precursor ion and two product ions, and matching of relative ion intensities of the ions concerned in samples and calibration standards. Quantitation was based on the measurement of concentration ratios of the natural and labeled‐analogues in the samples and calibration mixtures. The isotope‐labeled internal standards were also used to correct the matrix effect and variations associated with the analysis. Intra‐ and inter‐day repeatabilities of replicate analyses of the PFOA and PFOS in milk samples were below 8%. The limit of quantitation was 2 pg/mL in a 5 mL milk sample. The PFOA and PFOS were detected in all 20 human milk samples at concentrations from 27.0 to 207 pg/mL. This is the first study to measure the occurrence of PFOA and PFOS in human milk from Taiwan.     

Quantification of Clenbuterol in Human Plasma and Urine by Liquid Chromatography-Tandem Mass Spectrometry

The quantitative determination of clenbuterol in human plasma and urine is of particular interest for various fields such as clinical and forensic research and doping controls. A simple and rapid sample preparation procedure based on liquid-liquid extraction with subsequent re-extraction followed by liquid chromatography and electrospray ionization tandem mass spectrometry allowed the determination of clenbuterol in urine and plasma at detection and quantification limits of 0.1 ng mL⁻¹ and 0.2 ng mL⁻¹, respectively, with recoveries ranging from 85–96%. The fast and robust nature of the assay provides a rapid and cost-effective alternative to established procedures utilizing solid-phase extraction strategies.     

Rapid and Sensitive Liquid Chromatography-Tandem Mass Spectrometry for Quantification of Glycyrrhetic Acid in Human Plasma

A simple, rapid and sensitive liquid chromatography-tandem mass spectrometry(LC-MS/MS) for the determination of glycyrrhetic acid in human plasma with ginsenoside Rh2 as internal standard was developed and validated. The plasma samples were prepared via liquid-liquid extraction with ethyl acetate. Chromatographic separation was accomplished on a Venusil MP-C18(50 mm×2.1 mm, 5 μm i.d.) column at 25 °C. The mobile phase consisted of acetonitrile/5 mmol?L-1 ammonium acetate(10:90, volume ratio) at a flow rate ...     

超高效液相色谱-串联质谱法测定人血浆中氯苯那敏

研究并建立了测定人血浆中氯苯那敏的超高效液相色谱-串联质谱(UPLCMS/MS)分析方法。血浆样品中加入内标,经2.5倍体积甲醇沉淀蛋白,涡旋离心后,取上清液进样测定。采用Waters ACQUITY UPLC HSS C18色谱柱(150×2.1mm,1.8μm)分离,以5mmol/L乙酸铵水溶液(含0.1%甲酸)-甲醇为流动相,梯度洗脱,流速为0.2 mL/min。氯苯那敏的线性范围为0.10~50.0μg/L,相关系数(r2)为0.9995,检出限和定量限分别为0.05、0.10μg/L。该方法操作简便、专属性强、灵敏度高,适用于人体血浆中氯苯那敏的测定。