液相色谱-电喷雾串联质谱分析人全血中环孢素的基质效应评估及其机理探究

目的： 评估液相色谱-电喷雾串联质谱（LC-ESI-MS/MS）分析人全血中环孢素的基质效应，并探究其发生机理。方法： 全血裂解物的蛋白沉淀上清液用作全血基质。分别用乙腈水溶液和全血基质配制等浓度环孢素A（CyA）、环孢素C（CyC）的质控样品。分别在添加H⁺、NH₄⁺和Na⁺的流动相中，用LC-ESI-MS/MS的MRM模式检测质控样品中CyA，CyC的[M+H]⁺、[M+NH₄]⁺和[M+Na]⁺（M=CyA，CyC）峰面积，以其计算基质效应因子；用MS Scan模式检查质控样品中CyA、CyC色谱流出峰的质谱离子组成情况，用于判断基质效应原因。结果： 在添加H⁺、NH₄⁺和Na⁺的流动相中，全血基质中CyA、CyC基质效应因子分别为-76.6%~-54.0%、-86.0%~-55.3%和-42.8%~-34.1%。在加H⁺、加NH₄⁺流动相中，标准液加全血基质的CyA、CyC色谱峰的质谱中出现丰度很高的[M+Na]⁺和[M+K]⁺，在加Na⁺流动相中它们出现丰度很高的[M+K]⁺，而对应的定量离子[M+H]⁺、[M+NH₄]⁺或[M+Na]⁺的丰度显著降低。结论： 全血基质对环孢素的LC-ESI-MS/MS分析产生明显的基质效应，其原因与基质中Na⁺、K⁺同添加在流动相中用于辅助电离的H⁺、NH₄⁺或Na⁺竞争与环孢素加合，导致定量目标加合离子丰度显著降低有关。     

基于UPLC-Q-TOF/MS技术的三黄片化学成分解析

目的：采用超高效液相色谱-四级杆飞行时间质谱（UPLC-Q-TOF/MS）串联技术对三黄片化学成分进行解析鉴定。方法：采用Acquity UPLC^TM BEH C₁₈色谱柱（100 mm×2.1 mm，1.7 μm），以甲醇-0.1%甲酸水溶液为流动相对三黄片95%乙醇提取物中各成分进行快速分离；采用配备电喷雾离子源的Waters Q-TOF Xevo G2质谱仪，运用正负离子扫描模式对样品中各成分进行高分辨检测。对于已知成分，根据对照品色谱保留时间和质谱裂解规律进行确证；对于未知化合物，则根据其准确的相对分子量、二级特征碎片离子，并进一步结合相关文献进行推测。对三黄片各化合物来源也进行了归属。结果：共解析鉴定出28个化学成分，包括8个蒽醌类化合物，18个黄酮类化合物，1个多酚类成分和1个生物碱类成分。结论：UPLC-Q-TOF/MS能快捷、准确地鉴定三黄片化学成分，研究结果可为三黄片药动学、代谢产物推测、药效物质基础及作用机制等研究提供科学的参考依据。     

Chemical investigation on Sijunzi decoction and its two major herbs Panax ginseng and Glycyrrhiza uralensis by LC/MS/MS

Sijunzi decoction consists of Panax ginseng, Poria cocos, Atractylodes macrocephala and Glycyrrhiza uralensis. High performance liquid chromatography coupled with tandem mass spectrometry (LC/MSⁿ) was applied to identify and characterize three types of active components, ginsenoside (from P. ginseng), flavonoid and triterpenoid (from G. uralensis) in Sijunzi decoction. Spectra of MS and MS/MS from [M + Na]⁺ ions of ginsenosides were acquired and interpreted for their identification. Fragmentations with losing masses of 194 or 176 Da were the characteristic ions of triterpenoids in the MS/MS analysis. A characteristic fragment ion of the aglycon moiety at m/z 257 from source collision-induced dissociation was observed for flavonoid. LC/MS was also applied for the comparison of relative peak area of major active components between Sijunzi decoction and the single herb extracts. The concentration ratios of major active components detected in the individual herbs of P. ginseng and G. uralensis were found different from those in Sijunzi decoction. The experimental data indicated that the decocting process could result in the difference in the amount of active components.     

Identification of the degradation product of ezlopitant,a non-peptidic substance P antagonist receptor,by hydrogen deuterium exchange,electrospray ionization tandem mass spectrometry (ESI/MS/MS) and nuclear magnetic resonance (NMR) spectroscopy

The degradation product of ezlopitant was isolated from low specific activity material and identified by solution phase hydrogen/deuterium (H/D) exchange and electrospray ionization tandem mass spectrometry (ESI/MS/MS) to be an isopropyl peroxide analog of ezlopitant. The structure of the degradant was further confirmed by nuclear magnetic resonance (NMR) spectroscopy utilizing complete ¹H and ¹³C assignments. Studies were also performed to identify the factors responsible for the oxidative degradation of ezlopitant, which included salt form, storage conditions and salt formation solvent. Of all the variable studies over a 3 weeks period, only a change in the salt form prevented this oxidative degradation.     

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.     

Characterization of polymethoxylated flavones in Fructus aurantii by liquid chromatography with atmospheric pressure chemical ionization combined with tandem mass spectrometry

Atmospheric pressure chemical ionization mass spectrometry (APCI-MS) was operated in positive mode (PI) to characterize polymethoxylated flavonoids (PMFs) through its specific radical cations by collision-induced dissociation (CID). The fragments of [M + H − n × 15]⁺ produced by loss of one or more methyl group from the protonated molecule, as well as [M + H − 29]⁺, [M + H − 31]⁺, [M + H − 33]⁺, [M + H − 43]⁺, [M + H − 46]⁺, and [M + H − 61]⁺ fragment ions were detected, which were diagnostic for the polymethoxylated species, and could be adopted to form the multiple MS (MSⁿ) “fingerprint” of PMFs. Based on this “fingerprint”, 29 PMFs were screened out from extracts of Fructus aurantii, among which two of them were identified as sinensetin and tangeretin. It was proved that the PI was suitable for structural characterization of PMFs by APCI-MSⁿ.     

LC/MS/MS analysis of vesnarinone and its principal metabolites in plasma and urine

An LC/MS/MS assay was developed and successfully used to quantitate vesnarinone and its principal metabolites (OPC-8230, OPC-18136, and OPC-18137) in human plasma and urine. Samples were pre-treated with liquid–solid extraction followed by simultaneous monitoring of primary and daughter ions which were used for the identification and quantitation of the analytes on LC/MS/MS. This assay offers advantages of specificity, speed and greater sensitivity over the previously developed HPLC-UV assay. The lower limit of quantitation is 500 ng ml⁻¹ for vesnarinone and 20 ng ml⁻¹ for OPC-8230, OPC-18137, and OPC-18136 in plasma. Methodology is similar for the estimation of these analytes in urine with the lower limit of quantitation being 500 ng ml⁻¹ for vesnarinone and 100 ng ml⁻¹ for each metabolite. Ascorbic acid was added to stabilize the analytes from degradation. This LC/MS/MS method was developed to overcome many practical problems associated with the HPLC method. The LC/MS/MS method offers the flexibility of analyzing additional metabolites and changing the linearity range to accommodate the differences in linear range (200–10 000 ng ml⁻¹ for vesnarinone and 20–1000 for metabolites) for the analytes.     

比较高效液相色谱法和液质联用法测定化疗患者血浆中甲氨蝶呤浓度的相关性

目的 比较高效液相色谱(HPLC)法和液质联用(LC-MS/MS)法测定人血浆中甲氨蝶呤(MTX)浓度的相关性.方法 收集接受大剂量MTX化疗后的患者的血液样品,分别用HPLC、LC-MS/MS法进行MTX血药浓度测定,通过Wilcoxon检验或配对t检验来比较2种测定方法在不同浓度范围的差异,通过压轴回归分析法建立回...     

安神益脑丸中黄曲霉毒素残留量测定及LC-QQQ/MS确证

目的:建立高效液相色谱-荧光检测器测定安神益脑丸中黄曲霉毒素G2、G1、B2、B1的方法;分析安神益脑丸中黄曲霉毒素的污染情况.方法:待测样品采用80％乙腈作为提取溶剂,经免疫亲和柱净化、高效液相色谱分离、光化学柱后衍生后,通过荧光检测器测定其中黄曲霉毒素的含量;采用超高效液相色谱串联三重四极杆质谱法对以上实验测定结果...     

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).     

Definition of the alpha-KTx15 subfamily

Three novel scorpion toxins, Aa1 from Androctonus australis, BmTX3 from Buthus martensi and AmmTX3 from Androctonus mauretanicus were shown able to selectively block A-type K⁺ currents in cerebellum granular cells or cultured striatum neurons from rat brain. In electrophysiology experiments, the transient A-current completely disappeared when 1 μM of the toxins was applied to the external solution whereas the sustained K⁺ current was unaffected.

The three toxins shared high sequence homologies (more than 94%) and constituted a new ‘short-chain’ scorpion toxin subfamily: -KTx₁₅. Monoiododerivative of ¹²⁵I-sBmTX3 specifically bound to rat brain synaptosomes. Under equilibrium binding conditions, maximum binding was 14 fmol/mg of protein and the dissociation constant (K_d) was 0.21 nM. This K_d value was confirmed by kinetic experiments (k_on=6.0×10⁶ M⁻¹ s⁻¹ and k_off=6.0×10⁻⁴ s⁻¹). Competitions with AmmTX3 and Aa1 with ¹²⁵I-sBmTX3 bound to its receptor on rat brain synaptosomes showed that they fully inhibited the ¹²⁵I-sBmTX3 binding (K_i values of 20 and 44 pM, respectively), demonstrating unambiguously that the three molecules shared the same target in rat brain. A panel of toxins described as specific ligands for different K⁺, Na⁺ and Ca²⁺ channels were not able to displace ¹²⁵I-sBmTX3 from its binding site. Thus, ¹²⁵I-sBmTX3 is a new ligand for a still unidentified target in rat brain. In autoradiography, the distribution of ¹²⁵I-sBmTX3 binding sites in the adult rat brain indicated a high density of ¹²⁵I-sBmTX3 receptors in the striatum, hippocampus, superior colliculus, and cerebellum.     

A study of matrix effects on an LC/MS/MS assay for olanzapine and desmethyl olanzapine

The purpose of this research project was to investigate potential matrix effects of anticoagulant and lipemia on the response of olanzapine, desmethyl olanzapine, olanzapine-D₃ and desmethyl olanzapine-D₈ in an LC/MS/MS assay. Blank human serum and sodium heparin, sodium citrate, and K₃EDTA plasma with various degrees of lipemia were fortified with olanzapine, desmethyl olanzapine, olanzapine-D₃ and desmethyl olanzapine-D₈. Six replicates of each sample were extracted using Waters Oasis^® MCX cartridges and analyzed using electrospray LC/MS/MS. The analytes were separated on a Phenomenex LUNA phenyl hexyl, 2 mm×50 mm, 5 μm, analytical column and a gradient rising from 2 to 85% mobile phase B. Mobile phase A consisted of acetonitrile–ammonium acetate (20 mM) (52:48 v/v) and mobile phase B was formic acid–acetonitrile (0.1:100 v/v). Ion suppression was investigated through post column infusion experiments. The degree of lipemia of each sample, indicated by turbidity, was ranked into categories from least to greatest and used for statistical analyses. The results from analysis of variance testing indicated that lipemia, anticoagulant and their interaction significantly influenced mass spectral matrix effects and extraction matrix effects. Differential behavior between the analytes and labeled internal standards contributed to variability. The most significant source of variability however, was ion suppression due to co-eluting matrix components.     

超高效液相色谱-串联质谱法测定大鼠血浆及组织中贝达喹啉浓度及其药动学考察

目的:建立超高效液相色谱-串联质谱(UPLC-MS/MS)法测定SD大鼠血液及组织中贝达喹啉的浓度,研究其在大鼠体内的药动学及组织分布.方法:采用UPLC-MS/MS联用技术,测定大鼠血液及组织中贝达喹啉的药物浓度,并利用DAS软件及非房室模型统计矩方法计算药动学参数.结果:贝达喹啉线性范围为0.1～500 ng·mL...     

柱前衍生化法UPLC-MS/MS检测肿瘤患者不同化疗周期顺铂血药浓度

目的：建立定量检测肿瘤患者血浆中顺铂浓度的柱前衍生化超高效液相色谱-串联质谱（UPLC-MS/MS）法,比较顺铂（75 mg·m^-2·d^-1） QD*1 d和（25 mg·m^-2·d^-1） QD*3 d在不同化疗周期顺铂血药浓度的变化。方法：血浆样品的顺铂与二乙基二硫代氨基甲酸钠（DDTC）络合生成Pt （DDTC）衍生化产物,经蛋白沉淀后,采用UPLC-MS/MS测定,色谱柱为BEH C₁₈（2.1 mm×50.0 mm,1.7 μm）,流动相为乙腈-0.1%甲酸水,梯度洗脱,流速为0.35 mL·min^-1,采用电喷雾正离子模式,以多反应监测（MRM）定量分析。结果：顺铂在20~3 000 ng·mL^-1（r²=0.995 4）具有良好的线性范围;批内RSD在7.21%~12.06%,批间RSD在4.64%~11.17%;提取回收率为78.48%~99.2%,基质效应在90.7%~94.8%,稳定性良好。顺铂（75 mg·m^-2·d^-1） QD*1 d在整个化疗周期中血药浓度呈上升趋势,顺铂（25 mg·m^-2·d^-1） QD*3 d血药浓度呈下降趋势。结论：本研究建立的方法专属性高、稳定性好,适用于肿瘤患者血浆中顺铂浓度的检测。     

Composition analysis of two batches of polysorbate 60 using MS and NMR techniques

Batch variation in Tween 60 has shown to influence the rheological properties of semisolid emulsions. MS (LC–MS, GC–MS, MSⁿ) and NMR (¹³C, ¹H, ¹H COSY and HMBC) techniques were used to analyze and compare the composition of two batches of Tween 60 with particular emphasis on the number of POE groups and their distribution within the molecule. Acid and saponification values were also determined. The batches contained different proportions of components (sorbitan polyethoxylates, sorbitan monoester–diester-polyethoxylates and isosorbide monoester–diester-polyethoxylates). The number of POE groups were averaged over the four sites in sorbitan and the two sites in isosorbide molecules. The batches differed from each other in terms of (i) the POE sorbitan stearate/POE sorbitan palmitate ratios (batch 1, 3:2 and batch 2, 4:5), (ii) the ratio of sorbitans to isosorbides (batch 1, 2:3; batch 2, 7:13); and (iii) the acid values (batch 1, 3.1; batch 2, 0). It is concluded that liquid chromatography combined with electrospray mass spectrometry and ion trap separation is a useful tool for establishing the compositional profile of different batches of Tweens. ¹H NMR could provide a simple and rapid pharmacopoeial test for the ratio of sorbitan to isosorbide in Tweens.     

高效液相色谱-串联质谱法测定健康女性使用塞克硝唑栓后体内塞克硝唑的浓度及其药动学研究

目的：建立快速灵敏高效液相色谱-串联质谱（HPLC-MS/MS）法测定健康女性使用塞克硝唑栓后体内塞克硝唑栓的浓度,并研究其在体内的药代动力学特征。方法：色谱柱Welch Ultimate C₁₈（2.1 mm×50 mm,5 μm）;流动相：乙腈-0.1%乙酸+5 mmol·L^-1乙酸铵水溶液（12：88,V/V）;流速：0.5 mL·min^-1,进样量5 μL。采用ESI+源,多重反应监测（MRM）模式,对离子反应m/z 186.3→128.3（塞克硝唑）和m/z 192.4→128.3（Secnidazole-d₆）进行监测。20名健康女性受试者,单次与多次给药试验各10名,分别给予塞克硝唑栓。根据检测的血浆中塞克硝唑浓度,用DAS 3.2.7进行数据处理以及SPSS 19.0对结果进行统计分析。结果：塞克硝唑在0.05~8.0 mg·L^-1范围内线性良好（r>0.99）,定量下限0.05 mg·L^-1,批间、批内RSD皆小于15%。健康女性血浆中塞克硝唑栓单剂量C_max （3.00±0.96）mg·L^-1,t_max（8.90±2.68）h,t_1/2（18.07±2.96）h,AUC_0-96（97.78±35.81）mg·L^-1·h^-1,AUC_0-∞（101.11±36.96）mg·L^-1·h^-1;多剂量C_max,ss（6.01±2.01）mg·L^-1,t_max（7.20±2.86）h,t_1/2（21.87±7.60）h,AUC_ss（107.15±33.62）mg·L^-1·h^-1,AUC_0-96 （202.11±82.07）mg·L^-1·h^-1,AUC_0-∞（217.47±103.50）mg·L^-1·h^-1。结论：该方法灵敏、准确、可靠,专属性强,适用于塞克硝唑栓在人体内的药代动力学研究。     

Identification of oxidative degradates of the TRIS salt of a 5,6,7,8-tetrahydro-1,8-naphthyridine derivative by LC/MS/MS and NMR spectroscopy--interactions between the active pharmaceutical ingredient and its counterion

The Tris(hydroxymethyl)aminomethane (TRIS) salt of a substituted 5,6,7,8-tetrahydro-1,8-naphthyridine compound (I) in a mannitol-based formulation was stressed at various conditions. Liquid chromatography/mass spectrometry (LC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) analyses of the stressed samples revealed that oxidation and dimerization were the primary degradation pathways for this compound. ¹H- and ¹³C-nuclear magnetic resonance (NMR) spectroscopy were used to characterize the isolated dimers. The aromatized degradate, N-oxide, amide, and three dimeric products were all confirmed by either LC/MS using authentic standards or NMR spectroscopy. In general, the aromatized product was always the primary degradate produced under all stress conditions. When stressed at 80 °C, the TRIS counterion also underwent thermal degradation to yield formaldehyde in situ which reacted with the parent compound to form a unique methylene-bridged dimeric product and an N-formyl degradate. A minor condensation product between the compound I and the TRIS counterion was also detected in the 80 °C stressed samples. Under 40 °C/75% RH stress conditions, TRIS derived degradates were insignificant, while dimers formed by compound I became predominant. In addition, two hydroxylated products (7-OH and 5-OH) were also detected. Mechanisms for the formation of the oxidative and dimeric degradates were proposed.     

LC-MS/MS法测定人血清中奥氮平的不确定度评价

目的：评价高效液相色谱串联质谱法（LC-MS/MS）测定人血清中奥氮平的不确定度。方法：通过分析LC-MS/MS法测定人血清奥氮平浓度过程中的影响因素,包括测量重复性、天平称量、溶液配制、基质效应、血清样本预处理和标准曲线拟合等,评价测定过程中各因素引起的不确定度,计算合成不确定度和扩展不确定度。结果：人血清中低（6 ng·mL^-1）,中（60 ng·mL^-1）和高（150 ng·mL^-1）浓度奥氮平的扩展不确定度分别为0.418,3.851,10.108 ng·mL^-1（P=95%,k=2）。结论：LC-MS/MS法测定人血清中奥氮平的不确定度主要由基质效应和标准曲线拟合引入。     

液-质联用法测定大鼠血浆中ZTW-41浓度

目的： 建立快速、灵敏、准确的LC-MS/MS法测定大鼠血浆中ZTW-41的浓度，并将该方法应用于ZTW-41的药动学研究。方法： 以卡马西平为内标，血浆样品用甲醇沉淀蛋白后，通过ZORBAX Esplise XDB-C₁₈色谱柱（4.6 mm×100 mm，3.5-Micron）进行分离，选择75%甲醇溶液（含5 mmol·L^-1甲酸铵和0.1%甲酸）-甲醇溶液（含5 mmol·L^-1甲酸铵和0.1%甲酸）作为流动相进行等度洗脱，流速为0.5 mL·min^-1。通过ESI，以多反应监测模式（MRM）进行正离子检测，ZTW-41和卡马西平的MRM离子对分别为m/z 540.0→168.2和m/z 237.0→194.2；大鼠尾静脉给予ZTW-41前和给药后不同时间点采集血浆，血浆样品前处理后进行LC-MS/MS检测分析。结果： 大鼠血浆中ZTW-41在10~3 000 ng·mL^-1浓度范围内具有良好的线性关系，R² ≥ 0.99；定量下限和各浓度质控样品批间、批内精密度（RSD%）在5.82%以内，准确度（RE%）在-0.81%~4.87%之间。大鼠尾静脉给予20 mg·kg^-1的ZTW-41后，C_max为（244.78±46.67）ng·mL^-1，t_1/2为（21.17±2.08）h。结论： 本研究建立的LC-MS/MS定量分析方法可快速、灵敏、准确地测定大鼠血浆中ZTW-41的浓度，并成功应用于ZTW-41的药动学研究。     

CESI-MS/MS和NanoLC-MS/MS技术对促红细胞生成素中糖肽的分析

目的:使用无鞘液毛细管电泳-质谱联用(CESI-MS/MS )和纳升液相色谱-质谱联用(NanoLC-MS/MS )2种方法,对高糖基化蛋白促红细胞生成素(EPO)的糖肽进行分析,并对2种方法的分析结果进行对比.方法:以EPO为研究对象,还原烷基化后用胰蛋白酶进行酶切,酶切得到的肽段利用CESI-MS/MS 和Nano...