Quantitative determination of tramadol in human serum by gas chromatography-mass spectrometry

A gas chromatographic-mass spectrometric method for the quantitative determination of tramadol in human serum, plasma or whole blood samples is described. The method involves the use of [2H2, 15N]tramadol hydrochloride as an internal standard and chemical ionization with isobutane, employing single-ion monitoring for quantification. It is specific, sensitive and precise, and has high accuracy. The within-run coefficient of variation is about 1% between 25 and 200 ng/ml and 1.8-2.9% at the lowest concentrations tested (6.25 and 12.5 ng/ml). The between-run coefficient of variation increases from 1.6% to 5.2% with decreasing concentration from 200 to 12.5 ng/ml. The calibration graphs were linear in the tested concentration range, and the accuracy of the assay was not dependent on the sample volume used. The detection limit was about 4 ng/ml for serum samples of 1 ml. The method proved suitable for pharmacokinetic studies. Its high sensitivity allows measurements of serum concentrations for at least 30 h after the single administration of therapeutic doses of tramadol hydrochloride.     

Quantitative determination of tertatolol in biological fluids by gas chromatography-mass spectrometry

Quantitative determination of tertatolol concentrations in plasma and urine was performed by gas chromatography-mass spectrometry in the chemical-ionization mode with ammonia after successive extractions of the beta-blocking drug in alkaline, acid and final alkaline medium. [2H9]Tertatolol, isotopically stable under the operating conditions employed, was used as an internal standard, thus allowing quantities of 1 ng/ml to be specifically determined. Overall analytical error was less than 10%. Prior to isothermal chromatography at 240 degrees C on a column packed with 3% SE-30, both compounds were silylated with bis(trimethylsilyl)trifluoroacetamide. Detection was performed by monitoring the quasimolecular ions of tertatolol, m/z 368 and m/z 377, for the [2H9]tertatolol in the chemical-ionization mode with ammonia. The calibration curves obtained had linear characteristics for the concentration range 1-1125 ng/ml.     

气相色谱-质谱法同时快速测定血清中5种剧毒灭鼠剂

建立了同时快速测定血清样品中毒鼠强、氟乙酰胺、氟乙酸钠、甘氟Ⅰ与甘氟Ⅱ 5种灭鼠剂的气相色谱-质谱联用法。在pH 2.0条件下,以N,N-二乙基对苯二胺为衍生剂,N,N'-二环己基碳二亚胺为催化剂,氟乙酸钠在室温下振荡衍生5 min,衍生物与毒鼠强、氟乙酰胺、甘氟Ⅰ、甘氟Ⅱ一并被乙酸乙酯萃取,经50 ℃下氮吹浓缩后用气相色谱-质谱同时测定,采用选择离子监测(SIM)模式,基质标准外标法定量。方法选用SLB-IL59离子液体毛细管柱(30 m×0.25 mm×0.20 μm,最高温度:300 ℃),流速1.0 mL/min,经程序升温在15 min内成功地分离了5种灭鼠剂。结果显示,血清中氟乙酰胺的线性范围为0.02~2.0 mg/L,毒鼠强的线性范围为0.02~10 mg/L,其他目标物的线性范围为0.01~1.0 mg/L;检出限为0.001~0.002 mg/L (S/N=3),相关系数R²>0.995。在3个加标水平下,方法加标回收率介于84.0%和110.0%之间,相对标准偏差(n=6)介于2.9%和7.5%之间。方法操作简便、准确,灵敏度高,适于中毒病人的快速诊断检测。     

Specific and sensitive determination of medroxyprogesterone acetate in human serum by gas chromatography-mass spectrometry

The mass fragmentographic determination of medroxyprogesterone acetate (MPA) in serum, using as internal standard medroxyprogesterone propionate (MPP) synthesized from MPA, is described. After addition of MPP, the sera are extracted on Sep-Pak C18 cartridges and MPA and MPP are detected as their respective 3-enol trifluoroacyl esters. Serum samples from 84 patients with breast cancer, daily receiving MPA orally, were determined showing a large variation in MPA concentrations (4-349 ng/ml). Our proposed gas chromatographic-mass spectrometric (GC-MS) method, which can be considered as a reference, was compared with a radioimmunoassay (RIA) method showing a correlation coefficient of 0.73 (n = 69; p much less than 0.001). The assay was also used to determine sequential serum levels of patients receiving a single oral dose of MPA. With only minor adjustments, the GC-MS method allows the determination of serum concentrations of related steroids such as megestrol acetate and cyproterone acetate.     

Quantitative determination of octadecenedioic acid in human skin and transdermal perfusates by gas chromatography-mass spectrometry

A gas chromatographic (GC) method with mass spectrometric (MS) detection is developed and validated for the accurate and precise determination of octadecenedioic acid (C18:1 DIOIC) in human skin samples and transdermal perfusates. C18:1 DIOIC is extracted using methanol. The saturated analogue 1,18-octadecanedioic acid (C18:0 DIOIC) is added as internal standard. Prior to analysis, both compounds are converted to their trimethylsilylated derivatives using N,O-bis(trimethylsilyl)trifluoroacetamide with 15% trimethylchlorosilane. Quantitation is performed in selected ion monitoring mode with a limit of quantitation of 250 ng/mL. Linearity with a correlation coefficient of 0.998 is obtained over a concentration range of 250-2000 ng/mL. Values for within-day accuracy range from 94.5% to 102.4%, and from 97.5% to 105.8% for between-day accuracy. Within- and between-day precision values are better than 5% and 7%, respectively. The recovery values from the various matrices vary from 92.6% to 104.0%. The GC-MS method is employed for the determination of C18:1 DIOIC after application of an emulsion containing the active ingredient onto human skin in vitro. The results demonstrate that the method is suitable for the determination of C18:1 DIOIC in human skin samples and transdermal perfusates.     

Quantitative determination of lipase activity by liquid chromatography-mass spectrometry

We developed a novel in vitro lipase assay based on the quantitation of fatty acids by liquid chromatography-mass spectrometry. Oleic acids enzymatically released from triolein substrates were isolated from the reaction mixture by reverse-phase chromatography, ionized in negative mode electrospray mass spectrometry and quantitated with the aid of [(13)C]-oleic acid internal standard. The enzymatic activity was measured by monitoring oleic acid productions at multiple time points. This method overcomes the substrate and pH limitations of conventional techniques and thus serves as a generic lipase activity assay.     

Determination of telenzepine in human serum by gas chromatography-mass spectrometry

A method for determining telenzepine in human serum is described. Analytes are obtained from alkalinized serum by extraction of the drug using reversed-phase octadecylsilane-bonded silica cartridges. Telenzepine and a desmethyl analogue added to serum as internal standard are retained on the C18 cartridge and recovered by elution with methanol. The gas chromatographic properties of telenzepine and the internal standard are improved by a two-step derivatization involving a benzodiazepinone-benzimidazole rearrangement and simultaneous formation of a methyl ester function. The processed extract is analysed by gas chromatography-mass spectrometry with selected-ion monitoring. Quantification is linear over the range 2-40 ng/ml. Inter-day precision is within 7%, except at the detection limit of 2 ng/ml (16%). Application of this assay to routine analysis is limited by the extensive sample pretreatment essential for derivatization of telenzepine.     

气相色谱-质谱法测定人血清中多溴联苯

建立了血清中8种多溴联苯(PBBs,包括BB-15、18、52、101、153、180、194和206)的气相色谱-质谱检测方法。采用Oasis HLB固相萃取柱对血清样品中的多溴联苯进行萃取和初步净化,再使用自制的硅胶/酸化硅胶固相萃取柱(Sep-Pak silica/acidified silica)进行进一步的净化,并以正己烷为洗脱溶剂洗脱,氮吹洗脱液浓缩至100 μL后上样分析。以DB-5ms色谱柱(15 m×0.25 mm×0.1 μm)分离样品,在选择离子监测(SIM)模式下进行质谱检测,使用同位素内标法对8种目标物进行准确定量。结果显示,8种多溴联苯单体的方法检出限(LOD,以3.14倍标准偏差计)为0.002～0.029 ng/mL,方法定量限(LOQ,以10倍标准偏差计)为0.008～0.092 ng/mL;低、中、高3个加标水平的平均回收率为74.24%～119.49%,相对标准偏差(RSD)为1.23%～12.02%。采用本方法测定标准参考物质SRM1957和SRM1958中的BB-153含量,结果在参考值范围内。本方法准确、灵敏、操作简便,适用于血清中多溴联苯的测定。     

Quantitative analysis of unlabelled and polydeuterated compounds by gas chromatography-mass spectrometry

Summary A system for computer evaluation of gas chromatographic-mass spectrometric analyses of unlabelled and polydeuterated compounds is described. The system has been in routine use for two years and has been found to fulfil most of the needs of the laboratory in connection with studies of steroid and bile acid metabolism. Complete or partial spectra are taken by repetitive magnetic scanning and are recorded on magnetic tape. Methods for qualitative evaluation have been described previously [6, 9]. Quantitative determinations of unlabelled compounds are based on areas of gas chromatographic peaks in selected specific fragment ion current chromatograms generated by the computer. Percentage distribution of molecular or fragment ion species containing 0–19 deuterium atoms is calculated from averaged spectra by comparison with spectra of the unlabelled reference compound analyzed on the same day. When small amounts of material are available and when ions occur in low abundance, repetitive accelerating voltage scanning over a short mass range is used. A slow scan rate, 1–5 s, and a high data sampling rate, 10 kHz, permit a 100–300 fold increase of amplification. After bunching of intensity readings, partial mass spectra are constructed which are treated in the same way as complete spectra.     

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

A rapid, sensitive and specific method using liquid chromatography with tandem mass spectrometric detection (LC‐MS) was developed for the analysis of sauchinone in rat plasma. Di‐O‐methyltetrahydrofuriguaiacin B was used as internal standard (IS). Analytes were extracted from rat plasma by liquid–liquid extraction using ethyl acetate. A 2.1 mm i.d. × 150 mm, 5 µm, Agilent Zorbax SB‐C₁₈ column was used to perform the chromatographic analysis. The mobile phase was methanol–deionized water (80:20, v/v). The chromatographic run time was 7 min per injection and the flow‐rate was 0.2 mL/min. The tandem mass spectrometric detection mode was achieved with electrospray ionization interface in positive‐ion mode (ESI⁺). The m/z ratios [M + Na]⁺, m/z 379.4 for sauchinone and m/z 395.4 for IS were recorded simultaneously. Calibration curve were linear over the range of 0.01–5 µg/mL. The lowest limit of quantification was 0.01 µg/mL. The intra‐day and inter‐day precision and accuracy of the quality control samples were 2.94–9.42% and 95.79–108.05%, respectively. The matrix effect was 64.20–67.34% and the extraction recovery was 93.28–95.98%. This method was simple and sensitive enough to be used in pharmacokinetic research for determination of sauchinone in rat plasma. Copyright © 2011 John Wiley & Sons, Ltd.     

Multiresidue determination of 77 pesticides in textiles by gas chromatography-mass spectrometry

A simple and efficient method for multiple determination of 77 pesticides, including one organonitrogen, eight carbamate, 12 pyrethroid, 26 organochloride, 30 organophosphorous compounds, in textiles is developed. Six representative textiles are chosen as test samples. Extraction using hexane-ethyl acetate (1:1) assisted by ultrasonic processor is carried out twice, followed by clean-up using solid-phase extraction on a florisil column. The final solution is analyzed using gas chromatography-mass spectrometry, and 77 pesticides are determined. This method is highly sensitive, selective, and reproducible, with a broad linear range and reliable accuracy. Six blank samples are spiked with 0.50 and 2.00 mg/kg of the 77 pesticides, and the corresponding recoveries are between 64.5% and 99.1%; the precisions range from 4.04% to 14.78%; and the minimum detection limits of this method are 0.02-0.20 mg/kg.     

气相色谱-质谱法快速测定牙膏中的二甘醇

建立了气相色谱-质谱法（GC-MS）快速测定牙膏中的二甘醇的方法。牙膏样品经三氯甲烷提取后,应用气相色谱-质谱联用仪,以选择离子监测（SIM）模式对其中的二甘醇进行分析。二甘醇的线性范围为21.24-1062 mg/L,线性相关系数（r）为0.9995;检出限和定量限分别为2.0、5.0 mg/L;高、中、低3种浓度下的回收率在88.51%-101.6%之间,相对标准偏差（RSD）在1.6%-8.11%之间;仪器对二甘醇的响应在24 h内保持稳定。     

The determination of impurities in caprolactam by capillary gas chromatography-mass spectrometry

A capillary gas chromatography-mass spectrometry (GC-MS) technique has been developed for the determination of impurities in caprolactam. The residual solution of the crude product extracted by benzene was analyzed. A total of 28 compounds in the residual solution were separated. In comparison with the mass spectra obtained with those published in data tables, 24 compounds of the 28 were identified. The possible origination of these impurities was discussed and could be significant in the industrial control of caprolactam.     

气相色谱-质谱法分析蜂蜜中多种有机氯农药残留

建立了气相色谱-电子轰击离子化-质谱法（GC-EI-MS）同时分析蜂蜜试样中12种有机氯农药残留的分析方法.蜂蜜试样用V（正己烷）：V（乙酸乙酯）=5：1混合提取剂超声提取和Florisil硅藻土层析柱净化后,以PCB 103为内标物,采用GC-EI-MS的选择离子监测方式（SIM）分析,同时探讨了一些有机氯农药EI-MS特征离子的结构与断裂机理.当空白试样的加标浓度为10、50、200μg/kg时,加标回收率为80%～112%,相对标准偏差为0.4%～9.8%,方法检出限为0.2～4.0μg/kg,其中8种农药的MDL＜1.0μg/kg,线性范围为10～500μg/kg,相关系数皆大于0.996,此方法已用于蜂蜜试样中多种痕量有机氯农药残留的分析.     

Quantitative measurements via co-elution and dual-isotope detection by gas chromatography-mass spectrometry.

Dual-isotope measurements by gas chromatography-mass spectrometry (GC-MS) which mimic isotope dilution may suffer from irreproducibilities or unduly large uncertainties because of variations in ionization efficacies for the respective forms in the MS source. Such variations are sometimes avoided via extensive pretreatments and high-resolution GC separations. However, in some circumstances, an alternative approach is feasible which instead exploits the advantages of decreasing GC resolution. By forcing both forms of each analyte to co-elute, their ionization efficacies in the MS source will be virtually identical, thereby allowing for highly reproducible relative response ratios to be attained despite dramatically lowered GC resolution. The co-elution results described here are nearly as precise as results from moderate-resolution separations in the absence of interferents. Thus, dual-isotope GC-MS measurements with co-elution of the target analytes and their respective isotopically labeled internal standards offer a powerful alternative to the conventional approach of requiring expensive and labor-intensive additional pretreatments and separations; however, the effects of interferences may be exacerbated by the forced co-elution and must also be considered.