食品中胆固醇色谱／质谱／质谱的测定

确立了用色谱／质谱／质谱测定食品中胆固醇的一种新方法，试样经乙酸乙酯提取后，ＧＣ／ＭＳ／ＭＳ测定分析，以胆固醇分子离子为母离了，以其子离子为定量分析的碎片离子。线性好，回收率高，方法可靠。     

Differential Contribution of Albumin and Lipids to the Hydrophobic Extraction of Bis-(2-ethylhexyl) Phthalate from Hemodialysis Tubing by Human Serum: Analysis by Gas Chromatography - Stable Isotope Dilution Mass Spectrometry

Abstract

A method is presented which allows quantitative assignment of hydrophobic human serum components to the extraction of bis-(2-ethylhexyl) phthalate (DEHP) from medical tubing. Under optimized conditions (sample pH 5.5; fluid-fluid extraction with ethyl acetate + tert-butyl methyl ether 1 + 1 v/v; DEHP-ring-D4 as internal standard with ratios of endogenous (m/z = 149) and added deuterated DEHP (m/z = 153) adjusted to around 1.0; equilibration of added internal standard with the hydrophobic sample for 24 hours), a high precision can be achieved with an intra-assay coefficient of variation of 1.5% (n = 7) for sample DEHP quantification. Phthalate migration from hemodialysis tubing was quantified by use of a peristaltic pump and recirculation (200 minutes) of serum with different degrces of hypertriglyceridemia (range from 2.26 to 14.5 g/L) or solutions of human albumin (10 to 50 g/L). Only DEHP, but no other phthalates are detected in the extracts. There exist linear relations between DEHP extraction and triglyceride content (increase by 1.01 μg DEHP/g tubing material per g triglyceride/L serum) as well as between DEHP extraction and albumin content (0.59 μg DEHP/g tubing material per g albumin/L). Under physiological conditions, the total amount of albumin extracts 17.7-fold more DEHP than the total triglyceride amount in human serum. The suitability of the proposed method as a candidate reference method as well as consequences for dyslipidemic and hypalbuminemic patients on hemodialysis schemes are discussed.     

Application of Mass Spectrometry/Mass Spectrometry (MS/MS) to the Identification of Natural Products in Psilocybe Cyanescens

Abstract

Temperature profiling of MIKE spectra allows identification of protonated psilocin in the presence of other compounds with the same mass. The use of multiple ionizing methods to give ions (M+H)⁺, (M+ML₄)⁺, and M is shown to assist in determining the molecular weights of new natural products. Structural information is obtained from the MIKE spectra. All these determinations can be made on the intact mushroom or its simple alcoholic extracts.     

Determination of Ethion Residues in Soil by Extraction and by Mass Spectrometry Using Different Procedures

Optimized experimental procedures including time of extraction, extraction solvent in Soxhlet extraction technique were sought for detection of trace ethion residues in soil. The largest recoveries over 96% were achieved with a 1:1 mixture of methanol and acetone as extraction solvent for three hours. In comparing EI, CI, EI-CAD, and PCI-CAD modes of a four sector mass spectrometry for detection ethion, it was shown the best monitoring mode to be EI monitoring of the M⁺ of ethion, m/z 384, which fragments to give the m/z 231 product ion. The limit of detection obtained was 170 pg/g in soil.     

Electrospray Ionization Mass Spectrometry of Hexanitrohexaazaisowurtzitane (CL‐20)

Abstract

Hexanitrohexaazaisowurzitane (CL‐20) is a newly developed propellant and has been examined using negative ion electrospray mass spectrometry. The primary ions observed included adduct ions (M+Cl)^– and (M+ONO₂)^?.     

Quantitative bioanalysis of bavachalcone in rat plasma by LC–MS/MS and its application in a pharmacokinetics study

This study aims to develop and validate a simple and sensitive liquid chromatography with tandem mass spectrometry (LC–MS/MS) method for investigating the pharmacokinetic characteristics of bavachalcone. Liquid–liquid extraction was used to prepare plasma sample. Chromatographic separation of bavachalcone and IS was achieved using a Venusil ASB C₁₈ (2.1 × 50 mm, 5 μm) column with a mobile phase of methanol (A)–water (B) (70:30, v /v). The detection and quantification of analytes was performed in selected‐reaction monitoring mode using precursor → product ion combinations of m/z 323.1 → 203.2 for bavachalcone, and m/z 373.0 → 179.0 for IS. Linear calibration plots were achieved in the range of 1–1000 ng/mL for bavachalcone (r ² > 0.99) in rat plasma. The recovery of bavachalcone ranged from 84.1 to 87.0%. The method was precise, accurate and reliable. It was fully validated and successfully applied to pharmacokinetic study of bavachalcone.     

Determination of Dydrogesterone in Human Plasma by Tandem Mass Spectrometry: Application to Therapeutic Drug Monitoring of Dydrogesterone in Gynecological Disorders

A sensitive and specific tandem mass spectrometric (MS–MS) method was developed and validated for the determination of dydrogesterone (Duphaston^®), an orally active synthetic progestogen, in human plasma. Multiple reaction monitoring (MRM) scans at m/z 313.1 > 105.5 (dydrogesterone) and m/z 393 > 147 (dexamethasone, internal standard) were selected to determine dydrogesterone by the internal standard method. Linear correlations (r: ～0.99 ± 0.05) of the calibration curves were established over the concentration range 10–60 ng mL^?1 with a lower limit of quantification (LLQ) of 10 ng mL^?1 (RSD% 14.9 and %DEVs ?10.5 to +15.6). Solid-phase extraction (SPE) technique was used for extraction of dydrogesterone and internal standard from patient plasma samples using Oasis^® Max C18 cartridges. Ion suppression studies indicated negligible effects of plasma matrix on the mass ions detection of dydrogesterone and IS, when measured in MRM mode. Validation data showed that RSD% values were <22.0%, whereas %DEV values were in the range of ?20.2 to +13.3 for intra- and inter-day precision and accuracy, respectively. Analytical recoveries of dydrogesterone from supplemented plasma samples with the drug were in the range of 100.7–112%, indicating the efficiency of the SPE for separation of dydrogesterone from human plasma. Stability studies conducted at ?20 °C, showed that dydrogesterone was stable in plasma as indicated from the measured degradation kinetic parameters. The developed method was applied for monitoring plasma levels of dydrogesterone in 25 patients treated with Duphaston^® tablets at a dose of 10 mg three times daily. Mean plasma concentration of 16.1 ± 3.5 ng mL^?1 of dydrogesterone were measured at the steady state. The data suggest the utility of tandem mass method in therapeutic drug monitoring of plasma levels of dydrogesterone in gynecological disorders treated with Duphaston^® tablets.     

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     

Application of Derivatization Gas Chromatography/Mass Spectrometry for the Identification and Quantitation of Pinitol in Plant Roots

Abstract

Pinitol (D-3-O-methyl-chiro-inositol), a cyclitol, has a variety of roles in plant biology, and is being used as a nutritional supplement. These applications increase the importance of finding new methods for determining the pinitol content in plant tissues. A reliable method for the identification and quantitation of pinitol using trimethylsilyl imidazole (TMSI) derivatization and gas chromatography/mass spectrometry (GC/MS) was developed. One major ion fragment, m/z 260, was used to quantify pinitol in three plant species. Soybeans contained approximately 1.9 mg/g wet weight pinitol while levels in sugar beets and snap beans were below detection limits.     

An Examination of the Coordination Chemistry of L2Pt(1,2-DITHIOLENES) Using Atmospheric Pressure Chemical Ionization Mass Spectrometry

Abstract

Atmospheric pressure chemical ionization mass spectrometry (APCI–MS) has been utilized in the characterization of two series of platinum dithiolene complexes, (COD)Pt(dt) 1, (COD)–Pt(edt) 2, (COD)Pt(dmid) 3, (COD)Pt(mnt) 4, (COD)Pt(eddo) 5, (COD)Pt(dddt) 6 and (Ph₃P)₂Pt(dt) 7, (Ph₃P)₂Pt(edt) 8, (Ph₃P)₂Pt(dmid) 9, (Ph₃P)₂Pt(dmit) 10, (Ph₃P)₂Pt(mnt) 11 (where COD = 1,5–cyclooctadiene, dt = ethane–1,2–dithiolate, edt = ethylene–1,2–dithiolate, dmid = 1,3–dithiole–2–oxo–4,5–dithiolate, dmit = 1,3–dithiole–2–thione–4,5–dithiolate, mnt = maleonitrile–1,2–dithiolate, eddo = 4–(ethylene–1′,2′–dithiolate)–1,3-dithiole–2–one, and dddt = 5,6–dihydro–1,4–dithiin–2,3–dithiolate). The series that contains triphenylphosphine is labile toward the loss of HPPh₃ ⁺. In addition, an orthometallated species involving the platinum and triphenylphosphine is identified. A dimer is identified for 2, which is shown to be a product of the experiment and not present in the parent material. In addition, a 1:1 adduct with NH₄ ⁺ is identified for 4 and 11 where the NH₄ ⁺ originates from the acid hydrolysis of acetonitrile. Finally, a highly unique ion, Pt⁺, a bare platinum ion, is observed in all COD complexes indicating that a radical mechanism must accompany the decomposition of the COD complexes during the fragmentation process.     

Paper spray tandem mass spectrometry: A rapid approach for the assay of parabens in cosmetics and drugs

A fast methodology for the assay of parabens in drug and cosmetic preparations has been presented. The procedure developed is based on paper spray tandem mass spectrometry and isotope dilution approach. For each investigated paraben, the corresponding labeled standard has been used in order to improve the accuracy and reproducibility of the analyses. The MS experiments have been performed under MRM conditions, monitoring the transitions [M‐H]^? → m/z 92 and [M‐H]^? → m/z 98, respectively, for each analyte and the corresponding labeled internal standard. The quantitative assay has been performed using a calibration curve built from 2 to 15 mg/L. The method accuracy, in all case near 100%, was evaluated using fortified samples at two concentration levels, which are representative of the lower and the higher portion of calibration curve. The good values of LOQ, LOD, and reproducibility confirm the consistency of the developed approach.     

串联质谱法快速分析皮革中五氯酚残留

建立了皮革样品中五氯酚的串联质谱分析方法,以ｍ／ｚ２６６为母离子,碰撞电压为０．８Ｖ,以子离子ｎ／ｚ２３０为定量离子,外标法定量。线性范围为０．１￣１０．０ｍｇ／Ｌ,检出限为０．００５ｍｇ／ｋｇ,回收率为８５．４％￣１０２．５％,相对标准偏差为２．５５％￣３．５５％。方法具有快速、准确的特点。     

苦参生物碱电喷雾质谱分析

用电喷雾离子阱质谱(ESI-ITMS)研究了苦参碱和氧化苦参碱一级质谱电离规律和二级质谱裂解规律。实验结果显示,苦参碱和氧化苦参碱电喷雾一级质谱中均易产生聚合及加合离子,二级质谱中易产生环逐步裂解碎片离子,即结构相似的苦参碱和氧化苦参碱具有相似的电喷雾质谱行为。苦参碱的特征碎片为m/z148和150,氧化苦参碱的特征碎片为m/z248([M H-17] )、m/z247([M H-18] )以及m/z148、m/z150。对苦参对照药材的甲醇提取物进行了电喷雾质谱分析,由一级质谱的准分子离子及其二级质谱碎裂信息对各已知组分进行了结构认证。     

QuEChERS-超高效液相色谱串联质谱法同时测定土壤中5种常用除草剂

建立了超高效液相色谱串联质谱法(UPLC-MS/MS)简单、快速、灵敏、准确地同时测定土壤中5种常用除草剂多残留量的方法。样品经改进的QuEChERS(快速、简单、廉价、高效、灵活和安全)方法一步完成萃取净化,未使用缓冲盐溶液,经乙腈萃取,N-丙基乙二胺(PSA)和C18吸附剂填料净化,离心后直接过膜上机检测,萃取和净化的效果满足检测要求。UPLC-MS/MS方法采用Waters ACQUITY UPLCTMBEH C18(50 mm×2.1 mm i.d.,1.7 mm)色谱柱,柱温30℃,流动相为甲醇和水,梯度洗脱,流速0.25 mL/min,电喷雾电离源正离子(ESI+)多反应监测(MRM)模式检测,外标法定量。5种常用除草剂在0.5~200 mg/L范围内线性关系良好,相关系数为0.9947~0.9984。在4和40 mg/kg水平下的平均加标回收率为75.4%~98.5%;相对标准偏差为3.2%~11.8%;方法的检出限(S/N=3)为0.005~0.020 mg/kg,定量限(S/N=10)为0.017~0.067 mg/kg。     

Development of an LC–MS/MS method for quantification of two pairs of isomeric flavonoid glycosides and other ones in rat plasma: Application to pharmacokinetic studies

A liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed and validated for simultaneous determination of six flavonoid glycosides – isoorientin ( 1 ), orientin ( 2 ), 2″‐O‐β ‐d ‐xylopyranosyl isoorientin ( 3 ), 2″‐O‐β ‐d ‐xylopyranosyl isovitexin ( 4 ), 6‐C‐l ‐α ‐arabipyranosyl vitexin ( 5 ) and vitexin ( 6 ) – in rat plasma using isoquercitrin as the internal standard (IS). Plasma samples were prepared by a one‐step protein precipitation with acetonitrile. Chromatographic analysis was carried out on a 25 cm C₁₈ column with a gradient mobile phase consisting of acetonitrile and 0.1% aqueous formic acid. Six analytes and IS were detected through electrospray ionization in negative‐ion selection reaction monitoring mode. The mass transitions were as follows: m/z 447.2 → 327.0 for 1 , m/z 447.2 → 327.0 for 2 , m/z 579.3 → 458.9 for 3 , m/z 563.0 → 293.1 for 4 , m/z 563.0 → 353.0 for 5 , m/z 431.1 → 311.1 for 6 , and m/z 463.1 → 300.2 for IS. Calibration curves exhibited good linearity (r ² > 0.9908) over a wide concentration range for all compounds. Intra‐ and inter‐day precision (RSD, %) at four different levels were both <14.2% and the accuracy (RE, %) ranged from −11.9 to 12.0%. The extraction recoveries of the six components ranged from 88.2 to 103.6%. The validated assay was successfully applied to the pharmacokinetic studies of the six components in male rat plasma after intravenous administration of total flavonoids of Scorzonera austriaca Wild.     

Pharmacokinetic study of amoxicillin in human plasma by solid‐phase microextraction followed by high‐performance liquid chromatography–triple quadrupole mass spectrometry

Sensitive and selective analytical procedures based on high‐performance liquid chromatography with mass spectrometric detection were developed for the determination of amoxicillin in human plasma samples. Samples were prepared by applying in‐house manufactured molecularly imprinted solid‐phase microextraction probes. The detection of target compounds was performed in multiple reaction monitoring mode. The multiple reaction monitoring detection was operated in the positive electrospray ionization mode using the transitions of m/z 366 ([M + H]⁺) → 349 for amoxicillin and m/z 390 ([M + H]⁺) → 372 for gemifloxacin. The method was validated with precision within 15% relative standard deviation and accuracy within 15% relative error. The method was successfully applied to study of the pharmacokinetics of amoxicillin in human plasma after oral administration of amoxicillin. Copyright © 2013 John Wiley & Sons, Ltd.     

Determination of tubuloside B by LC‐MS/MS and its application to a pharmacokinetic study in rats

Tubuloside B, a novel neuroprotective phenylethanoid, is a major active constituent of Cistanche tubulosa and Cistanche deserticola. A specific and sensitive liquid chromatography tandem mass spectrometry (LC‐MS/MS) method has been developed and validated for the quantification of tubuloside B in rat plasma. Sample preparation was conducted through a protein‐precipitation extraction with methanol using tubuloside A as internal standard (IS). Chromatographic separation was achieved using a Capcell Pak C₁₈ column (2.0 × 50 mm, 5 μm) with a mobile phase of methanol–10 mm ammonium acetate buffer (70:30, v/v) in an isocratic elution. Mass spectrometry analysis was performed in negative ionization mode with selected reaction monitoring transitions at m/z 665.1 → 160.9 for tubuloside B, and m/z 827.1 → 160.9 for IS. Calibration curves were linear over the range of 1.64–1640 ng/mL for plasma samples samples (R² > 0.990). The lower limit of quantification (LLOQ) was 1.64 ng/mL. The intra‐ and inter‐day accuracy was between 92.3 and 113.0% with the RSD <9.23% at all LLOQ and quality control levels. Finally, this method was successfully applied in the pharmacokinetics study of tubuloside B after intravenous administration.     

气相色谱-质谱联用法测定动物组织中氯霉素、氟甲砜霉素和甲砜霉素的残留量

建立了气相色谱-负离子化学电离源质谱同时测定动物组织中氯霉素(CAP)、甲砜霉素(TAP)和氟甲砜霉素(FF)残留量的方法。样品用乙酸乙酯提取,正己烷分配去脂肪,再用Florisil柱进一步净化,甲苯作为反应介质,用N,O-双(三甲基硅基)三氟乙酰胺(BSTFA)-三甲基氯硅烷(TMCS)(体积比为99∶1)进行硅烷化处理,用间硝基氯霉素(m-CAP)作为内标进行测定。CAP的检测限可达到0.03 μg/kg,TAP和FF的检测限可达到0.2 μg/kg;上述3种药物的标准曲线的线性相关系数均大于0.99。CAP,FF和TAP的批内测定的精密度(以相对标准偏差表示)依次为5.5%,10.4%和8.8%;批间测定的精密度依次为7.4%,20.7%和19.1%。回收率为80.0%~111.5%,相对标准偏差为1.2%~15.4%。该方法前处理步骤简单,处理后杂质干扰少,灵敏度高,适用性强,可用于猪肉及禽类、水产品等多种动物组织中氯霉素类药物残留的检测。     

Determination of rabeprazole enantiomers in dog plasma by supercritical fluid chromatography tandem mass spectrometry and its application to a pharmacokinetic study

Rabeprazole is a novel benzimidazole proton pump inhibitor used for the treatment of gastrointestinal disorders. It is a chiral molecule that gives rise to the possibility of stereoselective pharmacokinetics. To investigate this phenomenon, a rapid and sensitive chiral assay based on supercritical fluid chromatography tandem mass spectrometry was developed and applied to the determination of (R )‐rabeprazole and (S )‐rabeprazole in dog plasma. Sample preparation involved protein precipitation with acetonitrile after the addition of (R )‐lansoprazole as internal standard. Baseline separation of enantiomers in 4.5 min was achieved on an Acquity UPC² system using an ACQUITY UPC² Trefoil CEL2 column maintained at 60°C and a mobile phase consisting of methanol/CO₂ (30:70, v/v) delivered at 2.5 mL/min. Detection was achieved by multiple reaction monitoring of the transitions at m/z 360.0→242.2 (rabeprazole) and 370.3→252.0 (internal standard) in the positive ion mode. The assay was linear in the range of 1–1000 ng/mL and free of matrix effects. Intra‐ and interday precisions were less than 10.0% with accuracy in the range of –2.6 to 3.1%. The method was successfully applied to a pharmacokinetic study of rabeprazole enantiomers after administration of a single oral dose of 10 mg racemate to beagle dogs.