Determination of tryptamine in rat brain by gas chromatography-mass spectrometry

Tryptamine (TA) occurs in trace levels in the brain, but its role in the central nervous system is not clear. However, there is evidence that TA may be a neuromodulator since it binds to specific binding sites in the brain. TA was measured as a diheptafluorobutyryl derivative in rat whole brain by capillary gas chromatography—mass spectrometry using negative chemical ionization (NCI) and single ion monitoring (SIM). d₄-TA was used as the internal standard. The ions m/z 532 and m/z 536 were monitored to identify TA and d₄-TA, respectively and to calculate the concentration of TA in rat whole brain which was found to be 0.19 ± 0.08 ng g⁻¹ (n = 8). The results confirm the earlier TA concentrations measured by GC—MS using positive electron impact ionization. However, NCI improved the signal/noise ratio of the method increasing its sensitivity for TA.     

Mass spectrometric analysis of anatoxin-a

Secondary ion mass spectrometry (SIMS), gas chromatography/mass spectrometry (GC/MS), desorption chemical ionization/mass spectrometry (DCI/MS), and thermospray/mass spectrometry (TSP/MS) were evaluated for the detection of a low-molecular weight biological toxin, anatoxin-a. The lowest detection limit was obtained using isobutane or ammonia DCI/MS. Tandem mass spectrometry (MS/MS) was used to enhance the selectivity and sensitivity of the analysis. The detection limit for the pure material is 10 pg, and 100 pg of the toxin can be analyzed directly from urine using DCI/MS/MS.     

Sensitive and selective liquid chromatography-tandem mass spectrometry method for the determination of five ganoderic acids in Ganoderma lucidum and its related species

The present paper describes a novel, sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous analysis of ganoderic acids C(2), B, A, H, D in Ganoderma lucidum and its related species. Ganoderma samples were prepared using simple ultrasonic extraction. Chromatographic separation was carried out on an Agilent Zorbax XDB C(18) column (250 mm × 4.6 mm i.d., 5μm) with an isocratic mobile phase consisting of acetonitrile, water and formic acid (42:58:0.5, v/v/v). Mass spectrometric detection was achieved by a triple-quadrupole mass spectrometer equipped with an atmospheric pressure chemical ionization (APCI) interface operating in negative and positive ionization mode via a single within-run polarity switching. Quantitation of five ganoderic acids was performed using selective reaction monitoring (SRM) mode. The intra- and inter-day precision was less than 6.2% and the accuracy ranged from 90.0% to 105.7%. The limit of quantification (LOQ) was 20.0-40.0 ng/mL and the limit of detection (LOD) was 3.0-25.0 ng/mL. With this method, low levels of ganoderic acids in the fruiting bodies of Ganoderma sinense and Ganoderma applanatum were accurately quantified for the first time. Importantly, the method allows unequivocal quantification of the five ganoderic acids in the spores and fruiting bodies of Ganoderma lucidum, whereas the previously published methods have lacked the capability. The method presented will be a powerful tool for quality control of Ganoderma lucidum and its related species.     

Application of surface ionization methods for highly sensitive and selective analysis of benzodiazepine derivatives

In this work, the results of studying the possibilities of surface ionization mass spectrometry (SI/MS) and atmosphere pressure thermodesorption surface ionization (APTDSI) spectroscopy for high-sensitivity and selective detection and identification of psychotropic preparations of benzodiazepine derivatives – medazepam, diazepam and chlordiazepoxide – are presented. It has been established that the SI mass spectra of benzodiazepines have a small number of lines and are significantly different from those obtained by electron ionization (EI) and that the molecules of benzodiazepines can be ionized by surface ionization with high efficiency (≥100 times and more than by EI) and the current density increases from diazepam to medazepam.

It has been found that the APTDSI spectra of benzodiazepine derivatives have two characteristic maxima connected with energy of sublimation and desorption.

The ionization efficiency is several C/g (Coulomb per gram), the linear range of the concentration dependence is 3–4 orders of a magnitude. The results obtained by the SI/MS and APTDSI methods have been compared with those obtained by the conventional TLC and GC/MS with electron ionization.     

The determination of 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in hair using negative ion gas chromatography-mass spectrometry and high-volume injection

The determination of 11-nor-delta9-THC-9-carboxylic acid (THC-COOH) in hair specimens at the sensitivity required to detect marijuana users is a difficult analytical problem. A sensitive and specific method has been developed for the quantitative assay of THC-COOH in hair. Hair specimens were washed, incubated in sodium hydroxide, subjected to solid-phase extraction, and analyzed using high-volume injection coupled with negative chemical ionization (NCI) mass spectrometry. A common disadvantage of chemical ionization, the production of a single mass-to-charge ratio ion, was also addressed. By specific selection of the derivatizing agent, three ions were monitored, allowing the calculation of two ion ratios, as in electron impact mode. The method was applied to several hair specimens taken from known marijuana users and workplace specimens. This is the first publication describing the use of high-volume injection and NCI mass spectrometry for the determination of THC-COOH in hair.     

基于UPLC-Q-Orbitrap-HRMS技术分析半夏白术天麻汤的化学成分及入血成分

目的:采用超高效液相色谱-四极杆-静电场轨道阱高分辨质谱(UPLC-Q-Orbitrap-HRMS)技术分析半夏白术天麻汤(Banxia Baizhu Tianma Decoction,BBTD)化学成分及入血成分,阐明其可能的药效物质基础。方法:色谱柱为Waters ACQUITY UPLC HSS T3 C₁₈(2.1mm×100mm,1.8μm),流动相为0.1%甲酸乙腈(A)-0.1%甲酸水溶液(B)梯度洗脱,流速0.2mL·min^-1。采用电喷雾离子源ESI,正、负离子模式扫描。根据准分子离子与二级碎片离子,结合对照品及文献数据鉴定BBTD化学成分、入血成分。结果:BBTD表征出133个成分,含药大鼠血浆样品分析出48个化合物,包括39个原型成分和9个代谢产物。结论:通过UPLC-Q-Orbitrap-HRMS技术对BBTD化学成分及入血成分进行表征,为其药效物质基础研究和质量控制奠定基础。     

Determination of SR 49059 in human plasma and urine by LC-APCI/MS/MS

SR 49 059 ((2S 1-[(2R 3S)-5-chloro-3-(2-chlorophenyl)-1-(3,4-dimethoxybenzene-sulfonyl)-3-hydroxy-2,3-dihydro-1H-indole-2-carbonyl]-pyrrolidine-2-carboxamide) is an orally active non-peptide vasopressin V_1a antagonist. A sensitive, selective, and robust LC-MS/MS method was developed to determine the plasma and urine concentrations of SR 49 059 in support of clinical studies. Plasma samples were prepared based on a rapid extraction procedure using Chem Elut™ cartridges. The extracted samples were analyzed on a C₁₈ HPLC column interfaced with a Finnigan TSQ 700 mass spectrometer. Positive atmospheric chemical ionization (APCI) was employed as the ionization source. The analyte and its internal standard (²H₆-SR 49 059) were detected by use of multiple reaction monitoring (MRM) mode. The plasma matrix had a calibration range 0.2−20 ng ml⁻¹, with within and between run accuracy and precision both less than 10%. The chromatographic run time was approximately 3 min. Urine samples were prepared based on a simple dilution with water, followed by analysis under the same conditions as plasma. The calibration range for urine matrix was 20–5000 ng ml⁻¹, with within and between run accuracy and precision less than 11%. The method has been successfully applied to the clinical sample analysis. The plasma assay was also evaluated on a Finnigan TSQ 7000 mass spectrometer. The performance based on precision and accuracy was virtually identical to that on the TSQ 700, with the exception of linearity in calibration curve (the TSQ 700 was linear, the TSQ 7000 was quadratic).     

Isolation of an unknown metabolite of the non-steroidal anti-inflammatory drug etodolac and its identification as 5-hydroxy etodolac

The non-steroidal anti-inflammatory drug etodolac is extensively metabolized in the liver. Renal elimination of etodolac mainly as glucuronide and its other phase I and phase II metabolites is the primary route of excretion. High-performance liquid chromatography assays of human urine after application of etodolac indicated the existence of a further monohydroxylated metabolite (metabolite X) that was identified as 5-hydroxy etodolac. For the identification, electrospray ionization mass spectrometry (ESI-MS) as well as ¹H-nuclear magnetic resonance (¹H-NMR) and ¹³C-NMR spectroscopy have been used.     

液相色谱-电喷雾电离质谱法检测地高辛人血浆药物浓度方法学的建立与考证

目的:建立适用于地高辛临床血药浓度监测的液相色谱-电喷雾电离质谱方法(LC-ESI-MS)。方法:地高辛人血浆样本采用乙酸乙酯液液萃取后以LC-ESI-MS方法进行分析。采用Kro-masilC18柱(150mm×2.00mm,3.5μm)分析柱;在乙腈和氯化铵的混合流动相的流动相系统中,进行梯度洗脱,选择性负离子检测,地高辛m/z为815.40,内标Rg2m/z为819.00。结果:地高辛在0.05～10.0ng/mL浓度范围内线性关系良好(r=0.9989),血浆内杂质不影响药物的检测,方法回收率大于75%,批内、批间变异均小于15%,冻融稳定性良好。结论:本研究所建立的LC-ESI-MS测定方法操作简便、快速、灵敏,准确,重现性好,所需血浆量少,可用于地高辛临床血药浓度监测及临床药动学研究。     

高效液相色谱-电喷雾离子阱串联质谱分析水苏碱及其大鼠体内代谢物

目的鉴定水苏碱在大鼠体内的代谢物。方法应用高效液相色谱-电喷雾离子阱串联质谱(HPLC-ESI/MSⁿ)技术研究水苏碱的一级质谱电离规律、二级质谱裂解规律及其色谱保留，以此作为水苏碱大鼠体内代谢物分析鉴定的依据；再将健康大鼠空腹灌胃25 mg·kg^-1水苏碱，收集0～24 h的尿样，经C₁₈小柱固相萃取分离纯化后，应用HPLC-ESI/MS分析尿样中水苏碱代谢物。结果在大鼠尿样中发现了母药及其N-去甲基、氧化脱氢、环氧化等6种I相代谢产物及两种环氧化物的甘氨酸轭合II相代谢产物。结论HPLC-ESI/MS法灵敏度高，快速，定性能力强，适合于水苏碱大鼠体内代谢物的分析。     

基于UPLC-Q-TOF-MS技术的通滞苏润江片化学成分分析

目的: 采用超高效液相色谱串联四极杆飞行时间质谱联用技术(UPLC-Q-TOF-MS)对复方通滞苏润江片中的化学成分进行定性研究,阐明其所含部分化合物可能的裂解途径。方法: 色谱柱为YMC-Triart C₁₈(2.1 mm×100 mm,1.9 μm),以乙腈-0.1%甲酸水溶液为流动相,梯度洗脱,体积流量0.4 mL·min^-1,柱温35℃。采用电喷雾离子源,正、负离子模式扫描,扫描范围m/z 50~1 200,对通滞苏润江片复方及其单味药材进行扫描。根据精确质荷比和二级碎片离子信息,结合对照品和文献数据鉴定通滞苏润江片中的化学成分。结果: 共指认出通滞苏润江片中60个化学成分,包括生物碱类、黄酮类、鞣质类、酚酸类、蒽酮类等。结论: 该化学成分研究为通滞苏润江片的有效物质基础研究及质量控制提供了理论和实践依据。     

Production of identical retention times and mass spectra for {delta}9-tetrahydrocannabinol and cannabidiol following derivatization with trifluoracetic anhydride with 1,1,1,3,3,3-hexafluoroisopropanol*

The use of perfluorinated anhydrides coupled with perfluoroalcohols for the derivatization of cannabinoids has been well documented. Derivatization is used in the detection of cannabinoids using gas chromatography-mass spectrometry (GC-MS) with both electron impact ionization (EI) and negative chemical ionization (NCI). During method development for the analysis of cannabinoids in biological samples using GC-MS in EI and NCI mode, it was observed that when Δ(9)-tetrahydrocannabinol (THC) and cannabidiol (CBD) were derivatized with trifluoroacetic anhydride (TFAA), the resultant derivatives produced the same retention times and mass spectra. This was not observed with the trimethylsilyl (TMS) derivatives of THC and CBD. This complication is due to the conversion of CBD to THC under acidic conditions. The work here highlights the unsuitability of the derivatizing reagent TFAA for the detection of THC and CBD. For the analysis of case samples, even if only THC is of interest, the presence of CBD cannot be excluded, and other derivatization techniques should be used.     

牡丹皮化学成分的液相色谱-飞行时间串联质谱分析

目的分析牡丹皮中的化学成分。方法应用优化的高效液相色谱-质谱联用方法对牡丹皮供试品进行分析。结果较好地分离了单萜苷、鞣质和酚酮类等38种化学成分。在负离子检测模式下，由电喷雾质谱得到各成分的准分子离子峰，再根据串联飞行时间质谱获得进一步的结构信息，推测出其中38种主要成分的可能结构。并对牡丹皮中主要化学成分的质谱裂解规律进行了分析。结论本方法能快速检测牡丹皮的化学成分。     

A highly sensitive and selective method for the determination of Leukotriene B4 in human plasma by negative ion chemical ionization/gas chromatography/tandem mass spectrometry

We have developed a highly sensitive and highly selective method for the determination of Leukotriene B₄ (LTB₄) in human plasma using negative ion chemical ionization/gas chromatography/tandem mass spectrometry (NICI/GS/MS/MS) analysis. The developed method was summarized as follows. Deuterated LTB₄ (d₄-LTB₄) was added to human plasma samples as an internal standard, and samples were extracted by a Sep-pak C18 column. Extracted LTB₄ was derivatized into the pentafluorobenzyl ester of bis-trimethylsilyl ether (PFB-TMS-LTB₄) and quantified on the basis of selected reaction monitoring (SRM) at m/z 299 of [M-PFB-2TMSOH]⁻ by NICI/GC/MS/MS analysis, which was the product ion of [M-PFB]⁻. The detection limit for the quantification of LTB₄ in human plasma was 10 pg ml⁻¹, sufficiently sensitive to determine the concentrations of endogenous LTB₄ in human plasma. The plasma level of LTB₄ measured in healthy male volunteers was 33.85 ± 33.91 pg ml⁻¹ (mean ± S.D. in six volunteers). The technique of MS/MS used in this method offers much greater sensitivity and selectivity than single-stage mass spectrometry. The developed method showed good reproducibility with a simple and rapid extraction procedure, and would be useful for examining the relationship between various disease states and the levels of LTB₄ in biological fluids.     

A rapid and sensitive technique for assessing exposure to VX via GC-MS-MS analysis

A rapid and sensitive method for the determination of the chemical warfare agent VX in plasma taken from G?ttingen minipigs has been developed using isotope-dilution gas chromatography-tandem mass spectrometry (GC-MS-MS). Chromatographic separation was achieved on a 5% diphenyl/95% dimethyl polysiloxane capillary column with a total run time of about 11 min. The analyte was detected using ammonia chemical ionization in the multiple reaction monitoring mode, following a simple extraction with 10% 2-propanol in hexane. A good linear relationship was obtained in the quantitative concentration range of 10 ng/mL to 1000 ng/mL (r(2) = 0.9998) with an average slope of 1.275 +/- 0.037 (n = 7), and an absolute detection limit of 0.4 pg on column. The average recovery for VX was 95% in saline in the concentration range of 50-100 ng/mL. The method was successfully applied to the analysis of VX in minipig plasma in a preliminary toxicokinetic study.     

Gas chromatographic/mass spectrometric determination of clonidine in body fluids. Application to pharmacokinetics

Depending on the very low therapeutic doses of clonidine and the resulting low blood levels (in the pg/ml range), for quantitative determinations in body fluids only methods of necessary selectivity as well as corresponding sensitivity can be employed successfully. Furthermore, the method should also be suited for the rapid processing of large sample numbers generated e.g. during clinical studies evaluating pharmacokinetics and/or the bioavailability/bioequivalence. Thus a gas chromatographic/mass spectrometric assay was developed employing fused-silica, bonded-phase capillary columns, chemical ionization with ammonia as a selective reagent gas in combination with the registration of preselected, characteristic negative ions (SIR, NICI) and a deuterated internal standard. Therefore, the method proves to be exceptionally selective and sensitive: a lower limit of detection of 10 pg/ml plasma is reached, the calibration curve is linear in the 25-1500 pg/ml range and the recovery from blood exceeds 90%. The assay has been successfully approved in several clinical studies, whereby especially the simple sample preparation led to very short times for analysis.     

高效液相色谱-串联质谱法测定人血浆中吲哒帕胺及其生物等效性研究

目的:研究用高效液相色谱-串联质谱(HPLC-MS)法进行试验制剂吲哒帕胺片剂与参比制剂市售吲哒帕胺片剂生物等效性研究。方法:男性健康志愿者20名,随机分为2组,分别交叉单剂服用受试制剂或参比制剂吲哒帕胺片剂2．5 mg,采用HPLC-MS法,选择正离子检测的大气压化学电离源(APCI源),以甲醇-1％甲酸水溶液(75:25,V／V)为流动相,测定吲哒帕胺血药浓度,计算药动学参数,评价2制剂的生物等效性。结果:受试制剂和参比制剂主要药动学参数tmax为(1．4±s 0．4)和(1．4±0．4)h, Cmax为(30±6)和(30±5)μg·L-1,t1／2为(14．7±2．1)和(14．3±2．5)h,AUC0-72为(539±103)和(534±95)μg·h·L-1,AUC0-∞为(570±105)和(565±98)μg·h·L-1。受试制剂吲哒帕胺片剂相对生物利用度(F)为(102±13)％。结论:该方法选择性强、灵敏度高、操作简便,适用于吲哒帕胺制剂的生物等效性评价及临床药动学研究。     

Analysis of acetaminophen glucuronide conjugate accompanied by adduct ion production by liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry

Liquid chromatography-mass spectrometry (LC-MS) is an effective method for the analysis of polar compounds. A coupling of LC-MS, which is used under conventional conditions, and atmospheric-pressure chemical ionization (APCI), which applies mild ionization for the analysis of water-soluble drug conjugates, would offer a very convenient method. The APCI method is effective for ionizing low- and medium-polarized compounds, but not for highly polarized compounds. In this study, we have tried derivatization of carboxyl group of glucuronic acid, to which direct ionization is difficult to apply under the APCI method, was conducted using glucuronides. Methyl ester derivatives were found to be effectively ionized. Furthermore, acetaminophen glucuronide conjugate was investigated in detail. Methyl ester derivatives of acetaminophen glucuronide conjugate (ACEG) were detected at m/z 373 as O(2) adduct ion [M+O(2)](-) in the negative mode, and p-nitrophenyl beta-D-glucuronide (PNPG) demonstrated ionization behaviors very similar to ACEG. Quantitation of ACEG was examined using PNPG as an internal standard, and satisfactory results were obtained for the recovery test and quantification.     

Improvements of the fluoride reactivation method for the verification of nerve agent exposure

One of the most appropriate biomarkers for the verification of organophosphorus nerve agent exposure is the conjugate of the nerve agent to butyrylcholinesterase (BuChE). The phosphyl moiety of the nerve agent can be released from the BuChE enzyme by incubation with fluoride ions, after which the resulting organophosphonofluoridate can be analyzed with gas chromatography-mass spectrometry (GC-MS). This paper describes recent improvements of the fluoride-induced reactivation in human plasma or serum samples by enhancing the sample preparation with new solid-phase extraction cartridges and the MS analysis with large volume injections. Analysis is performed with thermal desorption GC with either mass selective detection with ammonia chemical ionization or high-resolution MS with electron impact ionization. The organophosphorus chemical warfare agents analyzed in this study are O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate, ethyl methylphosphonofluoridate, isopropyl methylphosphonofluoridate (sarin, GB), O-ethyl N,N-dimethylphosphoramidocyanidate, ethyl N,N-dimethylphosphoramidofluoridate, and cyclohexyl methylphosphonfluoridate. Detection limits of approximately 10 pg/mL plasma were achieved for all analytes, which corresponds to 0.09% inhibition with GB on a sample with normal BuChE levels.     

Simultaneous determination of phytoestrogens and key metabolites in breast cancer patients’ urine by liquid chromatography–tandem mass spectrometry

A novel, selective and sensitive liquid chromatography–tandem mass spectrometry method has been developed and validated for the simultaneous determination of phytoestrogens and their key metabolites in human urine in this study. This method includes internal standard (IS) screening, analytical sample preparation procedure establishment, and linear range investigation. The analytical sample was extracted by liquid–liquid extraction from urine sample. The phytoestrogens and related key metabolites were separated with Agilent Zorbax Eclipse XDB-C18 chromatographic column using methanol and water as mobile phase. The Quattro premier MICROMASS mass spectrometer in negative ion selected reaction monitoring (SRM) mode using electrospray ionization was applied to detect the phytoestrogens and key metabolites. To validate the developed liquid chromatography–tandem mass spectrometry method, the intra- and inter-day precisions, specificity, sensitivity, reproducibility, and sample detective concentration range were evaluated. This is the first reported phytoestrogens analysis and validation study that demonstrates the feasibility of using liquid chromatography–electrospray ionization mass spectrometry to simultaneously analyze ten analytes including both phytoestrogens and their key metabolites in urine samples collected for epidemiological studies in human.