液-质联用测定人血浆中罗红霉素浓度

目的:建立高效液相色谱-质谱联用法测定人血浆中罗红霉素浓度。方法:以克拉霉素为内标,血浆样品经乙腈沉淀后,经HPLC-MS/MS分离分析。采用Waters ODS C18柱(2.1mm×50mm,3.5μm),以甲醇-5mmol.L-1醋酸铵(含0.03%甲酸)(55∶45)为流动相;流速:0.2mL.min-1,采用电喷雾离子源(ESI),以多离子反应监测方式(MRM)进行正离子监测,罗红霉素和内标克拉霉素的定量分析离子对分别为m/z837.5→679.4和m/z748.5→590.3。结果:罗红霉素血浆浓度测定方法线性范围为0.02025~13.500mg.L-1,r=0.999 0。定量下限为0.02025mg.L-1,方法回收率在85%~115%之间。日内和日间RSD均小于15%。结论:本试验所建立的方法灵敏、准确、可靠,适于罗红霉素的人体内药动学研究。     

高效液相-质谱联用法测定盐酸二甲双胍血药质量浓度

目的：建立测定盐酸二甲双胍血药质量浓度的高效液相-质谱联用方法（LC／MS／MS）。方法：色谱柱：CAPCELL C18柱（150mm×2．0mm，5μm）；流动相：10mmol·L^-1醋酸铵缓冲液-乙腈（50：50）；流速：0．2mL·min^-1；血浆样品用乙腈沉淀蛋白法处理，在三级四极杆串联质谱中经ESI源离子化，以多反应离子监测方式测定盐酸二甲双胍（m／z 130．0→71．0）的质量浓度。结果：盐酸二甲双胍血药质量浓度在10～2000μg·L^-1范围线性良好（r=0．9981），回收率为86．01％～98．28％，绝对回收率为92．72%～96．08％，日内、日间精密度均不大于10％。结论：方法灵敏、准确、快速、特异性强，可用于该药临床药动学特征的研究。     

Determination of amprolium in feed by a liquid chromatography-mass spectrometry method

As a consequence of the finding of veterinarian drugs in food European Community banned several compounds like coccidiostats as amprolium (APL). This antibiotic has been used as a preventive and clinical anticoccidial drug in chicken. The 2005/187/CE, 2005/925/EC Recommendations ban the use of amprolium as additive in chicken feed. For this reason a rapid and sensitive liquid chromatography–mass spectrometry (LC–MS) method was developed to detect amprolium in chicken feed following the European community proposed technique (1999/27/EC) for sample preparation. Cause the validation is required for the analytical methods used in feed official control, this method was validated according to 2004/882/EC Regulation.     

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.     

液相色谱-质谱联用法测定人血浆中卢比替康的浓度

目的建立液相-质谱(LC-MS)联用方法,用于抗肿瘤药卢比替康在肿瘤患者血浆中的定量分析。方法血浆样品用0.2 mL盐酸(0.5 mol·L~(-1))酸化后,乙酸乙酯提取,上清液在40℃水浴条件下氮气流吹干,萃取物用流动相复溶后进LC-MS联用仪分析测定。采用反相C_(18)柱进行色谱分离,流动相为:乙腈:10 mmol·L~(-1)醋酸铵水溶液(90:10,V/V)。结果本方法在5～500μg·L~(-1)内线性良好,r=0.999 4(n=4),低、中、高3种浓度质控样品的批内及批间RSD均<5%,提取回收率分别为80.66%、88.47%、85.05%,最低定量限5μg·L~(-1)。结论本方法灵敏度高,操作简便易行,能够满足该药进行临床药动学研究的要求。     

Quantitative determination of daumone in rat plasma by liquid chromatography-mass spectrometry

Daumone, 6-(3,5-dihydroxy-6-methyl-tetrahydro-pyran-2-yloxy)-heptanoic acid is a pheromone secreted by Caenorhabditis elegans, and has been known as a pivotal regulator of chemosensory processes in development and ageing. A quantification method using mass spectrometry was developed for the determination of daumone in rat plasma. After simple protein precipitation with acetonitrile including an internal standard, the analytes were chromatographed on a reversed-phase column and detected by liquid chromatography/tandem mass spectrometry with electrospray ionization. The accuracy and precision of the assay were in accordance with FDA regulations for validation of bioanalytical methods. This method was applied to measure the plasma daumone concentrations after a single intravenous administration of daumone in rats.     

Determination of caderofloxacin lactate in rat plasma by high-performance liquid chromatography-mass spectrometry and its application in rat pharmacokinetic studies

A sensitive liquid chromatography–electrospray ionization mass spectrometric (LC–ESI-MS) method for the quantification of a newly active quinolone carboxylic acid caderofloxacin lactate in rat plasma was developed and validated after precipitation method with methanol. Chromatographic separation was achieved on a reversed-phase Shimadzu 2.0 μm C18 column (150 mm × 2.00 mm) with the mobile phase of methanol–0.02% formic acid and step gradient elution resulted in a total run time of about 10.0 min. The analytes were detected by using an electrospray positive ionization mass spectrometry in the selected ion monitoring (SIM) mode. A good linear relationship was obtained in the concentration range studied (5–2000 ng/mL) (r = 0.9998). The lowest limit of quantification (LLOQ) was 5 ng/mL and the lowest limit of detection (LLOD) was 2 ng/mL. Average recoveries ranged from 88.80 to 93.05% in plasma at the concentrations of 10, 100 and 1000 ng/mL. Intra- and inter-day relative standard deviations were 4.01–7.30 and 4.15–7.51%, respectively. This method was successfully applied in the pharmacokinetic studies in rats.     

Determination of indeloxazine in plasma by liquid chromatography and gas chromatography-mass spectrometry

Two methods have been developed for the quantitative determination of indeloxazine, a cerebral activator, in plasma by HPLC or GC-MS. After addition of viloxazine as the internal standard, indeloxazine was extracted from alkalinized plasma. In the HPLC method, the plasma extract was treated with 5-dimethylamino-1-naphthalenesulfonyl chloride and analyzed by HPLC with fluorescence detection. In the GC-MS method, the two plasma compounds were converted to their pentafluoropropionyl derivatives for selected-ion monitoring. The limits of detection were 5 and 2 ng/mL for the HPLC and GC-MS methods, respectively. When plasma samples obtained by giving indeloxazine hydrochloride to volunteers were analyzed by the two methods, good correlation between the data was obtained (r = 0.9901).     

Determination of lamotrigine and its metabolites in human plasma by liquid chromatography-mass spectrometry

A method based on electrospray ionization liquid chromatography-mass spectrometry was developed for the quantitative determination of lamotrigine and three of its reported metabolites, lamotrigine-2-N-glucuronide, lamotrigine-2-N-methyl, and lamotrigine-2-N-oxide in human blood plasma. The method utilized sample preparation by precipitation of proteins with acetonitrile, chromatographic separation on a reversed-phase system by gradient elution, and monitoring of the protonated molecular ions. Two internal standards, 3,5-diamino-6-(2-methoxyphenyl)-1,2,4-triazine and morphine-3-glucuronide-D3, were utilized to achieve precise quantification. The method validation comprised a demonstration of an agreement in the quantification of lamotrigine with that of a routine HPLC-UV method. The limits of detection were between 0.05 and 0.16 micromol/L. The method was employed for the measurement of clinical samples collected from 55 patients in steady-state prior to the dose intake (trough level). Lamotrigine and the 2-N-glucuronide were typically detected, while the N-methyl and N-oxide metabolites were detected only rarely. The median lamotrigine plasma level was 24.0 micromol/L (range, 4.3 to 64 micromol/L), the median 2-N-glucuronide level was 2.4 micromol/L (range, <0.05 to 24 micromol/L), and the median lamotrigine 2-N-glucuronide/lamotrigine ratio was 0.11 (range, <0.01 to 0.64). In conclusion, this liquid chromatographic-mass spectrometric method is suitable for simultaneous determination of lamotrigine and its metabolites in human plasma.     

Determination and pharmacokinetics of ascaridole in rat plasma by gas chromatography-mass spectrometry

A rapid and sensitive method for determination of ascaridole in rat plasma was developed based on gas chromatography-mass spectrometry (GC/MS). The analyte and internal standard (IS), naphthalene, were extracted from plasma with ethyl acetate and then separated by GC on a HP-5MS capillary analytical column (30 m x 0.25 mm, 0.25 microm) and determined by a quadrupole mass spectrometer detector operated under selected ion monitoring mode (SIM). Excellent linearity was found to be from 10 to 1,000 ng/mL with a lower limit of quantitation (LLOQ) of 10 ng/mL. The accuracy was between 85.3% and 114.0%, and the precision was less than 14.5% (intra- and inter-day). The method was successfully applied to investigate the pharmacokinetic study of ascaridole in rats after a single oral dose of 30, 60 and 120 mg/kg, respectively.     

高效液相色谱-质谱联用法检测患者血浆中替考拉宁的浓度

目的：建立高效液相色谱-质谱联用法（HPLC-MS）定量测定人血浆中替考拉宁的浓度。方法：采用乙腈蛋白沉淀法处理50 μL血浆,以达托霉素为内标,色谱柱：Welch Ultimate XB C₁₈（2.1 mm×50 mm,3 μm）;柱温：40℃;流动相：乙腈-水（0.5%甲酸）,梯度洗脱5.5 min。采用ESI离子源,正离子模式多反应监测方式（MRM）检测血浆中替考拉宁浓度,替考拉宁定量离子对分别为m/z 940.5→316.2,内标达托霉素离子对为m/z 811.0→313.0,碰撞电压分别为20 eV和42 eV。考察方法的选择性、残留、基质效应、线性范围、准确度与精密度和样本稳定性等。结果：血浆替考拉宁在1.0~100.0 mg·L^-1线性关系良好,定量下限为1.0 mg·L^-1。批内、批间精密度的标准偏差（RSD）均≤10.9%,替考拉宁的内标归一化基质效应在92.7%~109.3%且RSD≤12.0%。血浆样本可在-20℃条件下长期冻存至少41 d。临床实际样本检测中未发现干扰,方法稳定性良好。结论：该方法简便灵敏、准确可靠,适用于人体血浆中替考拉宁浓度的测定。     

Determination of a novel low-voltage-activated calcium channel blocker (HYP-10) in rat plasma by liquid chromatography-mass spectrometry

A novel T-type calcium channel blocker, 4-amino-1-{4-[(4-chloro-phenyl)-phenyl-methyl]-piperazin-1-yl}-butan-1-one (HYP-10) has been synthesized, and the compound has shown promise as both a nociceptive and inflammatory pain reliever as well as an analgesic in a rat neuropathic pain model. A quantification method was developed for the determination of HYP-10 in rat plasma. After simple protein precipitation with methanol, HYP-10 and the internal standard, methaqualone were chromatographed on a reversed-phase column and detected by liquid chromatography/tandem mass spectrometry with electrospray ionization. The accuracy and precision of the assay were in accordance with FDA regulations for validation of bioanalytical methods. This method was applied to measure the plasma HYP-10 concentration after a single intravenous administration of the compound in rats.     

用液相色谱-串联质谱法测定血浆总同型半胱氨酸

目的：建立血浆中总同型半胱氨酸(tHcy)的液相色谱-串联质谱(LC-MS／MS)测定法。方法：血浆tHcy及内标氘代高胱氨酸经巯基乙醇还原后，用10％三氯乙酸沉淀血浆蛋白，经液相色谱分离后，采用电喷雾离子化-串联质谱进行多反应监测(MRM)检测，离子选择通道分别为m／z：136．2／46．9(Hcy)，140．2／48．9(Hcy-d4，氘化Hcy)。Hcy、Hcy-d4的保留时间均为6.3min。结果：Hcy在2．5～640μmol／L范围内线性关系良好。本法的最低检测浓度为O．3μmol／L(S／N≥5)。批内、批间精密度分别为1.97％～8.79％、2．55％～4．14％。方法回收率为100．3％～109．1％。结论：该方法的预处理快速、简便，检测专一灵敏，试剂成本低廉，可适应开展大规模临床Hcy研究的需要。     

超高效液相色谱-质谱法测定药包材中的双酚A

目的 建立超高效液相色谱-串联三重四级杆质谱联用测定药品包装材料中双酚A的检测方法。方法 采用BEH C18液相柱分离,流动相为乙腈和水,采用梯度洗脱方式,电喷雾离子源,负离子扫描,多反应监测模式进行质谱分析。结果 BPA在0.5~106.3 ng·mL^-1范围内,线性关系良好（r=0.9 999）。结论 该方法操作简便,灵敏度高,能满足药品包装材料中双酚A含量的测定。     

Determination of chlorophylls and their derivatives in Gynostemma pentaphyllum Makino by liquid chromatography-mass spectrometry

The objectives of this study were to develop a high performance liquid chromatography-mass spectrometry (HPLC-MS) method for determination of chlorophylls and their derivatives in Gynostemma pentaphyllum Makino, a traditional Chinese herb possessing vital biological activities. Chlorophylls were extracted with a quaternary solvent system of hexane-acetone-ethanol-toluene (10:7:6:7, v/v/v/v), followed by separation of a total of 15 chlorophylls and their derivatives within 32min using a gradient mobile phase of acetone, acetonitrile and methanol and a HyPURITY C18 column, with detection at 660nm and flow rate at 1mL/min. Identification was carried out on the basis of retention behavior, absorption spectra and mass spectra using atmospheric pressure chemical ionization (APCI) in positive ion mode for detection. Of the 15 analytes, chlorophyll a, chlorophyll b, pheophytin a and pheophytin b were quantified by using standard calibration curves, with the other 11 being quantified with an internal standard Fast Green FCF. Chlorophyll extracts in G. pentaphyllum were found to contain pheophytin a (2508.3mug/g), pheophytin a' (111.2mug/g), chlorophyll a (113.8mug/g), chlorophyll a' (11.0mug/g), hydroxypheophytin a (88.6mug/g), hydroxypheophytin a' (66.5mug/g), pyropheophytin a (76.0mug/g), hydroxychlorophyll a (23.8mug/g), pheophytin b (319.6mug/g), pheophytin b' (13.2mug/g), chlorophyll b (287.9mug/g), chlorophyll b' (11.1mug/g), hydroxychlorophyll b (15.0mug/g), hydroxypheophytin b (11.2mug/g) and hydroxypheophytin b' (8.5mug/g).     

Determination of methamphetamine and its metabolites incorporated in hair by column-switching liquid chromatography-mass spectrometry

An automated column-switching liquid chromatographic-electrospray ionization-mass spectrometric (LC-ESI-MS) method has been established for the determination of methamphetamine (MA) and its metabolites, amphetamine (AP), and p-hydroxymethamphetamine (p-OH-MA) in hair. The combination of an N-vinylacetamide-containing hydrophilic polymer online extraction column, an SCX semi-micro LC column, and an electrospray ionization interface provided the successful concentration, separations, and highly sensitive MS determinations of these analytes in a hair extract without tedious sample pretreatments. The limits of detection of these analytes were 0.02 ng/mg and 0.1-0.2 ng/mg in the selected-ion monitoring (SIM) and full-scan modes, respectively, when using a 100-microL hair extract sample that corresponds to a 2.5-mg sample of hair. The calibration curves using dibenzylamine as an internal standard were linear up to 30 ng/mg hair equivalents for all these analytes in the SIM mode. p-OH-MA, the detection of which in MA users' hair had not been previously reported, was detectable in all 22 hair specimens/sections from which 1 ng or more of MA was detected per milligram hair. The amount of p-OH-MA detected per milligram of hair is presented with those of MA and AP among the MA users population. The detection of AP and p-OH-MA, in addition to the parent drug MA with reasonable ratios, was found to be a useful indicator for distinguishing internal MA incorporation from external contamination.     

Determination of corticosteroids in tissue samples by liquid chromatography-tandem mass spectrometry

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for determination of corticosterone and 11-dehydrocorticosterone (11-DHC) levels in KKA(y) mouse liver and adipose tissue, and hydrocortisone and cortisone levels in human adipose tissue has been developed. The corticosteroids were extracted from liver tissue with methanol/water and ethyl acetate for adipose tissue samples. Corticosterone and 11-DHC were separated with a methanol gradient and hydrocortisone and cortisone with an acetonitrile gradient containing trifluoroacetic acid on a reversed-phase column within 15 min. The corticosteroids were detected after electrospray ionization in positive mode with multiple reaction monitoring (MRM). The limits of quantification (LOQ) were estimated to be 15 nmol/kg liver and 1.6 nmol/kg adipose tissue for corticosterone and 5.4 nmol/kg liver and 0.92 nmol/kg adipose tissue for 11-DHC. The LOQ was estimated to be 0.2 nmol/kg adipose tissue for hydrocortisone and 0.4 nmol/kg adipose tissue for cortisone. The limits of detection (LOD) at 3 times S/N were estimated to be 0.07 nmol/kg adipose tissue for hydrocortisone 0.1 nmol/kg adipose tissue for cortisone. The variation of endogenous levels in KKA(y) mouse from different animals (CV%) was high with mean liver tissue levels of 117+/-25 (S.D.)nmol/kg for corticosterone and 62+/-19 (S.D.)nmol/kg for 11-DHC (n=5) and adipose tissue levels of 39+/-20 (S.D.)nmol/kg for corticosterone and 2.4+/-0.9 (S.D.)nmol/kg for 11-DHC (n=9). Endogenous levels in human biopsy samples from adipose tissue were 12+/-7.0 (S.D.)nmol/kg for hydrocortisone and 3.0+/-1.6 (S.D.)nmol/kg for cortisone (n=16). The new LC-MS/MS methods showed sufficient sensitivity and selectivity for determination of endogenous levels of corticosteroids in both KKA(y) mouse liver and adipose tissue samples and human adipose tissue samples. The selectivity of the methods was verified by analysis of two different productions from each analyte.     

RP-HPLC法测定罗红霉素片中罗红霉素的含量

目的建立罗红霉素片含量测定的高效液相色谱法,并与微生物检定法、紫外分光光度法的测定结果进行比较。方法采用Agilent-C18色谱柱（4.6 mm×250 mm,5μm）;0.067 mol·L^-1磷酸二氢铵（三乙胺调节pH6.5）-乙腈（3∶2）,加入1%的三乙胺,用磷酸调节pH7.2为流动相;流速1.0 ml·min^-1;检测波长211 nm;柱温30℃。结果罗红霉素在2.14～42.80 mg·L^-1的浓度范围内有良好的线性关系（r=0.999 9）,平均回收率为97.8%,RSD为0.78%（n=5）。结论三种含量测定方法的结果相近,均可用于罗红霉素片的含量测定。     

Determination of limonin in rat plasma by liquid chromatography-electrospray mass spectrometry

A simple, sensitive and selective liquid chromatography coupled with electrospray ionization mass spectrometry (LC/ESI/MS) method for determination of limonin (LM) in rat plasma has been developed and validated. The method had advantages of a single liquid–liquid extraction with ether and high sensitivity. Analyses were conducted at a flow rate of 0.2 ml/min by a gradient elution. The detection utilized selected ion monitoring in the negative ion mode at m/z 460.00 and 423.15 for the deprotonated molecular ions of LM and the internal standard, respectively. The quantitation limit for LM in rat plasma was 1.0 ng/ml. The linearity was also excellent over the concentration range of 1.9–500 ng/ml of LM. The intra- and inter-day precision (relative standard deviation (R.S.D.%)) was lower than 10% and accuracy ranged from 90 to 110%, showing a good reproducibility. This developed method was successfully applied to analysis of LM in biological fluids.