Analysis of the essential oil from radix bupleuri using capillary gas chromatography

A simple and rapid capillary gas chromatographic (CGC) method with flame ionization detection has been newly developed for analysis of the essential oil from Radix Bupleuri. Twenty components were identified with gas chromatography-mass spectrometry. E-2-heptenal, furan, 2-pentyl, and E-2-nonenal were quantified simultaneously using the internal standard method. Decane was used as an internal standard. Separation and quantification were achieved on a DB-5 capillary column (30 m x 0.25 mm i. d., 0.25-microm film thickness). The oven temperature was programmed as follows: 60 degrees C to 70 degrees C at 1 degree C/min rate, 70 degrees C for 10 min, 3 degrees C/min to 120 degrees C, 20 degrees C/min to 250 degrees C, and held at 250 degrees C for 5 min. The oven pressure was programmed as follows: 46.1 kPa for 25 min, 20.0 kPa/min to 77.6 kPa, and then held for 22 min. Split injection was conducted with a split ratio of 10:1; flow-rate, 1.00 ml/min; carrier gas, nitrogen; injector temperature, 280 degrees C; and detector temperature, 280 degrees C. The system proved effective in resolving E-2-heptenal, furan, 2-pentyl, and E-2-nonenal peaks from their interfering components. The method displayed excellent linearity in the range of 26.8-1072 microg/ml (E-2-heptenal), 6.5-1292 microg/ml (furan, 2-pentyl), and 7.8-1564 microg/ml (E-2-nonenal). The average recovery rates of E-2-heptenal, furan, 2-pentyl, and E-2-nonenal were 100.3%, 102.8%, and 97%, respectively. CGC is a quick and accurate method for analysis of the essential oil from Radix Bupleuri.     

Solid-phase microextraction for the assay of levomepromazine in human plasma

Solid-phase microextraction (SPME) was investigated as sample preparation for the assay of the neuroleptic drug levomepromazine in human plasma. A mixture of human plasma, water, chloramitriptyline as internal standard, and aqueous NaOH was extracted with a 100-microm polydimethylsiloxane (PDMS) fiber (Supelco). The desorption of the fiber was performed in the injection port of a gas chromatograph at 260 degrees C [HP 5890; BPX-5 (SGE): 30 m x 0.53 mm ID, 1-microm film capillary; nitrogen-phosphorus selective detection]. As repeatedly found for SPME analysis of drugs in plasma, the recovery was low (i.e., 7% for levomepromazine). However, the analyte and internal standard were well separated and the calibration was linear from 5 to 180 ng/mL. The within-day precision was 2%, 4%, and 19% at concentrations of 160 ng/mL, 80 ng/mL, and 5 ng/mL, respectively. The between-day precision was 3%, 7%, and 19%, respectively. The limit of determination was 5 ng/mL. The comparison with an established liquid-liquid extraction gas-liquid chromatography method revealed good agreement for spiked samples and patient samples. No interfering peaks of drugs coadministered with levomepromazine or of endogenous substances were found. It is concluded that the method can be used in the therapeutic drug monitoring and clinical toxicology of levomepromazine.     

Capillary gas chromatographic determination of phenylpropanolamine in pharmaceutical preparation

Analytical procedure has been developed for the gas chromatographic determination of phenylpropanolamine (PPA) using trifluoroacetylacetone (FAA) as derivatizing reagent. Elution is carried out from the column HP-5 (30 mx0.32 mm i.d.) with film thickness 0.25 microm at initial column temperature 70 degrees C for 5 min, followed by heating rate 10 degrees C/min up to 120 degrees C. Injection port temperature was maintained at 270 degrees C. Nitrogen flow rate was 2 ml/min and detection was by FID. The linear calibration curve was obtained with 30-150 microg/ml PPA with detection limit of 6.0 microg/ml. The method was used for the determination of PPA from Sinutab and Tavegyl-D tablets. The relative standard deviation (R.S.D.) for the analysis of pharmaceutical preparation was obtained within 0.4-0.9%.     

Method development and validation for the GC-FID assay of p-cymene in tea tree oil formulation

This paper describes the development and validation of an isothermal gas chromatography-flame ionisation detection (GC-FID) method for the assay of pure tea tree oil. The chromatographic conditions of the method employ a 5% carbowax packed column (20 m x 0.25 mm), isothermal elution with hydrogen at a column flow of 36 ml/min, injector and detector temperature at 220 degrees C and oven temperature at 100 degrees C, and a 1.5 microl injection volume. Samples and standard were diluted in hexane. The calibration curve for p-cymene was linear (r2=0.9995) from 20 to 120% range of the analytical concentration of 100 microg/ml. The precision of this method was calculated as the relative standard deviation (R.S.D.) was 0.66% (n=6). The R.S.D. for intermediate precision study was 0.13 and recovery of the p-cymene ranged between 93.39 and 97.86%. The limits of detection and quantitation were determined to be 2.08 and 10.39 ng/ml, respectively.     

Optimized procedure for lamotrigine analysis in serum by high-performance liquid chromatography without interferences from other frequently coadministered anticonvulsants

The authors have developed a simple isocratic high-pressure liquid chromatographic (HPLC) assay for the simultaneous determination of lamotrigine and other frequently coadministered antiepileptic drugs in serum samples. Lamotrigine extraction was performed on a reversed-phase Oasis HBL preparation column. The eluates containing butalbital as internal standard were separated with a 7-microm Chromsystems C18 250 x 4.0 mm I.D. reversed-phase column at a temperature of 40 degrees C using a mobile phase consisting of pH 3.8 phosphate-acetonitrile buffer (55:45, v/v), at a flow rate of 0.8 mL/min. Ultraviolet detection was carried out at 210 nm. Measurement of the peak:height ratio allowed quantitative determination of the samples. The method was linear over a concentration range of 0.2 to 20 microg/mL for lamotrigine. Recovery was >90%. Within-day and between-day coefficients of variation ranged from 1.8% to 6.7%. The mean lamotrigine concentration was 8.01 +/- 5.63 microg/mL. After studying sera from 130 patients treated with lamotrigine the authors confirmed that associated antiepileptic therapy affected the serum lamotrigine levels, which were significantly higher in patients under valproic acid treatment.     

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.     

Stability of meperidine in an implantable infusion pump using capillary gas chromatography-mass spectrometry and a deuterated internal standard

A capillary gas chromatographic-mass spectrometric (GC MS) method is described for the analysis of meperidine using 3,3,5,5-[2H4]-meperidine as an internal standard. Chromatography was performed on a (5% phenyl) methylpolysiloxane column (30 m x 0.32 mm I.D., 0.25 microm film thickness) operated at 195 degrees C; helium carrier gas-50 cm/s(-1), tR = 2.3 min. Ionization was by electron impact (EI) and detection by selected ion monitoring of the molecular ions. The method provided high response linearity (mean r = 0.9982) and precision (< 6.5% C.V.). Application of this method to a pilot study of aqueous meperidine x HCl (10 mg/ml(-1)) stability in a surgically implantable infusion pump at 37 degrees C for 90 days revealed no demonstrable drug degradation.     

HPLC法同时测定青天葵药材中7种黄酮的含量

建立同时测定青天葵中鼠李秦素(1)、鼠李柠檬素(2)、鼠李素(3)、鼠李秦素-3-O-β-D-葡萄糖苷(4)、鼠李秦素-3-O-β-D-木糖-(1→4)-β-D-葡萄糖苷(5)、鼠李秦素-3-O-β-D-葡萄糖-(1→4)-β-D-葡萄糖苷(6)和鼠李柠檬素-3-O-β-D-葡萄糖-(1→4)-β-D-葡萄糖苷(7)含量的高效液相色谱法。采用Kromasil C18色谱柱(250 mm×4.6mm,5μm),以0.4%磷酸乙腈为流动相进行梯度洗脱,流速为1.0 mL.min 1,检测波长为256 nm,柱温为40℃。7种黄酮类化合物(1～7)的线性范围分别为0.55～70.00μg.mL 1(r=0.999 7)、0.86～110.00μg.mL 1(r=0.999 7)、0.39～50.00μg.mL 1(r=0.999 7)、0.55～70.00μg.mL 1(r=0.999 5)、1.33～170.00μg.mL 1(r=0.999 8)、1.33～170.00μg.mL 1(r=0.999 8)、0.16～20.00μg.mL 1(r=0.999 5),平均回收率在97.19%～99.45%之间,RS...     

Simultaneous quantitation of opioids in blood by GC-EI-MS analysis following deproteination,detautomerization of keto analytes,solid-phase extraction,and trimethylsilyl derivatization

Seven opioid analytes including codeine, morphine, 6-acetylmorphine, hydrocodone, hydromorphone, oxycodone, and oxymorphone were detected in postmortem blood (n > 1000). Two milliliters of specimen was deproteinated with approximately 2.5 mL of methanol and derivatized with hydroxylamine before solid-phase extraction and derivatization with BSTFA + 1% TMCS. Extracts were assayed by gas chromatography-electron impact-mass spectrometry utilizing selected ion mode. One-microliter aliquots were injected onto an HP-1MS capillary column (30 m x 0.25-mm i.d., 0.25 microm) with a helium linear velocity of 62 cm/s. Temperature programming began at 160 degrees C (hold 0 min), then increased at rates of 35 degrees C/min to 195 degrees C, 5 degrees C/min to 240 degrees C, and 30 degrees C/min to 300 degrees C (hold 2 min) resulting in a total run time of 14-min. Quantitative determinations were based on the ratios of the analyte peak areas to the corresponding deuterated analogues. Calibration curves were linear for the following concentrations: 10-500 ng/mL (6-AM), 100-2000 ng/mL (oxycodone), and 50-1000 ng/mL (all other opioids). LOQs ranged from 5 ng/mL (6-AM) to 20 ng/mL (oxycodone). Between-run precision yielded CVs ranging from 2.79% to 5.34% (n = 12). These data suggest that methanolic deproteination and dual derivatization improve separation and simultaneous quantitation of seven opioid analytes in difficult matrices.     

红毛七超临界提取物化学成分的GC-MS分析

对红毛七超临界提取物进行分析。采用超临界二氧化碳流体萃取法(SFE-CO₂)对秦巴山区特有药用植物红毛七进行提取。利用气相色谱/质谱联用技术(GC-MS)对提取物中的化学成分进行了分离分析，并采用峰面积归一化法计算各成分相对百分含量。对其中的49种化学成分进行了鉴定，所鉴定的成分占总流出峰面积的97.44%。其中脂肪酸类15种，占检出化合物总量的40.12%；酯类6种，占28.84%；烯类4种，占总11.30%；醇类12种，占5.92%；酮类化合物6种，占4.74%；生物碱类3种，占2.61%。实验结果为了解红毛七的化学物质基础和进一步开研究提供了依据。     

Capillary gas chromatography determination of benzaldehyde arising from benzyl alcohol used as preservative in injectable formulations

A simple, precise and accurate capillary gas-liquid chromatographic procedure has been developed to determine benzaldehyde, the toxic oxidation product of the widely used preservative and co-solvent benzyl alcohol, in injectable formulations of the non-steroidal anti-inflammatory drugs, diclofenac and piroxicam, as well as in Vitamin B-complex injection solutions. Following liquid-liquid extraction with chloroform, separation and quantification are achieved on a fused silica capillary column (25 m x 0.53 mm i.d.) coated with 0.5 microm film of OV-101. 3-Chlorobenzaldehyde was used as internal standard with flame-ionization as the detection mode. The ability of the system to resolve benzaldehyde peak from interfering components is good. The method displays excellent linearity over the concentration range 0.5-100 microg/ml of benzaldehyde and a precision of better than 2.5% from intra- and inter-day analyses. The quantification limit for benzaldehyde is 0.4 microg/ml. Levels of benzaldehyde in generic diclofenac and piroxicam injection formulations were found to be seven to 15 times higher than in reference formulations, and double in generic Vitamin B-complex injection formulations.     

毛细管气相色谱法测定人血清中二十二碳六烯酸的浓度

毛细管气相色谱法测定人血清中二十二碳六烯酸的浓度李青翠张驰彭会明夏桂珠（北京医科大学药学院，北京１０００８３；山西省药品检验所，太原０３０００１）二十二碳六烯酸（ｃｉｓ４，７，１０，１３，１６，１９ｄｏｃｏｓａｈｅｘｅｎｏｉｃａｃｉｄ，Ｄ...     

Simultaneous determination of diastereomers (+)-licarin A and isolicarin A from Myristica fragrans in rat plasma by HPLC and its application to their pharmacokinetics

A rapid and simple high-performance liquid chromatographic (HPLC) method was developed and validated to simultaneously analyze the diastereomers of (+)-licarin A and isolicarin A in rat plasma after intravenous administration. The analytes were extracted from the plasma by solid-phase extraction (SPE). Diastereomeric separation and determination were successfully achieved using a Diamonsil ODS C (18) reversed-phase column (250 mm x 4.6 mm i. d., 5 microm) with an RP18 guard column (8 mm x 4.6 mm i. d., 5 microm) and a mobile phase of MeOH-H (2)O (4 : 1, v/v). UV detection was at 270 nm. The linear ranges of the standard curves were 0.25 - 150.00 microg/mL for (+)-licarin A and 0.10 - 75.00 microg/mL for isolicarin A. The lower limits of detection and quantification were 0.05 and 0.25 microg/mL for (+)-licarin A, and 0.05 and 0.10 microg/mL for isolicarin A, respectively. This assay method was successfully applied to study the pharmacokinetics of diastereomers (+)-licarin A and isolicarin A in rat plasma.     

固相萃取-GC-MS联用法测定何首乌中有机氯农药残留量

目的:测定何首乌中9种有机氯农药残留量。方法:样品用乙酸乙酯超声提取并经Florisil固相萃取柱净化后,采用毛细管气-质联用仪测定有机氯农药残留量:色谱柱为DB-5MS弹性石英毛细管柱(30m×0.25mm,0.25μm),进样口温度为230℃,程序升温(初始温度100℃,以8℃·min-1升温至220℃,再以5℃·min-1升温至250℃,保持10min),载气流速为1mL·min-1,进样量为1μL。结果:9种有机氯农药能在30min内完全分离;平均回收率为80.4%～97.2%,RSD为3.5%～7.4%(n=6)。结论:本方法灵敏、准确,符合多种有机氯农药残留的检测要求。     

Determination of picogram nitroglycerin plasma concentrations using capillary gas chromatography with on-column injection

A specific, sensitive, and precise capillary gas chromatographic (GC) assay capable of analyzing picogram concentrations of nitroglycerin in human plasma was developed. The analytical procedure involves a double extraction of 1 mL of plasma with pentane, after the addition of internal standard (1 ng of 2,6-dinitrotoluene), followed by evaporation and reconstitution in 50 microL of heptane. The extract (1 microL) was injected onto a capillary column using the on-column injection technique. The GC oven temperature was programmed from 120 degrees C to 180 degrees C at a rate of 5 degrees C/min. The oven temperature was then programmed to 250 degrees C and was maintained for 10 min. The nitroglycerin and internal standard retention times were 8.6 and 11.4 min, respectively. The position of the end of the capillary column inside the detector is a critical determinant of sensitivity: the column exit must be positioned such that nitroglycerin adsorption to the detector is minimized (i.e., sensitivity maximized). The assay limit of quantitation was 25 pg/mL (CV = 7.6%) using 1 mL of plasma. This GC assay, specific for nitroglycerin in the presence of its metabolites, isosorbide dinitrate, and several other drugs, may be used to quantitate plasma levels obtained after therapeutic nitroglycerin doses.     

广藿香醇及广藿香油中广藿香醇在大鼠体内药代动力学比较

目的建立毛细管气相色谱法测定大鼠血浆中广藿香醇的方法；比较广藿香醇和广藿香油单次静脉注射给药后，广藿香醇在大鼠体内的药代动力学差异。方法以丁香酚为内标；用毛细管气相色谱法，色谱柱为HP-5MS 毛细管气相色谱柱 (30 m×0.32 mm×0.25 μm)；氢火焰离子化检测器；用程序升温法，初始温度80 ℃，保持1 min；15 ℃·min^-1升温至200 ℃，保持1 min；60 ℃·min^-1升温至290 ℃，保持1 min。结果广藿香醇在25～5 000 μg·L^-1线性关系良好（r=0.999 0），定量限为25 μg·L^-1，检测限为10 μg·L^-1，方法精密度（RSD％）小于10％，方法准确度为90%～110％。结论该法可用于广藿香醇的药代动力学研究；广藿香醇单体与广藿香油中广藿香醇在大鼠体内的主要药代动力学参数（AUC，t_1/2β，MRT等）有显著性差异。     

Determination of cocaine and benzoylecgonine by direct injection of human urine into a column-switching liquid chromatography system with diode-array detection

A method for the determination of cocaine (COC) and benzoylecgonine (BZE) in human urine using a column-switching liquid chromatography system is reported. A homemade precolumn (20 mm x 4.6 mm i.d.) dry-packed with Alltech ODS-C18 (35-750 microm) was employed as an extraction precolumn in order to extract and concentrate the COC and BZE from the human urine sample. The analytes were continuously transferred to the analytical column (Spherisorb-C8, 250 mm x 4.6 mm i.d.; dp = 5 microm) by means of the switching arrangement in the backflush mode. Detection was carried out at 235 nm in a UV-diode array detector. The validation of the method revealed analytes quantitative recoveries (96-102%) at three concentrations in the range from 0.25 to 4.00 and from 0.5 to 12.0 microg/mL for COC and BZE, respectively. These values demonstrate the excellent extraction efficiency of the precolumn. The detection limits for COC and BZE at a signal-to-noise ratio of 3 were 0.08 and 0.15 microg/mL when a sample volume of 50 microL was injected. The overlap of sample preparation, analysis and recondition of the precolumn increases the sample throughput to four samples per hour. The proposed method has been applied to the determination of COC and BZE in human urine samples from 73 suspecting drug addicts. Urine concentrations of 1.0-118.10 microg of BZE/mL and 0.1-41.0 microg of COC/mL were found.     

An automated method for the bioanalysis of vincristine suitable for therapeutic drug monitoring and pharmacokinetic studies in young children

Pharmacokinetic studies in young children require very sensitive methods using low plasma volumes. Although vincristine has been used as an antineoplastic drug for almost 40 years, data on vincristine pharmacokinetics and pharmacodynamics are scarce, especially in young children. One of the reasons for this is the lack of a specific and sensitive assay suitable for small plasma volumes. Therefore the authors aimed to improve an existing high-performance liquid chromatography (HPLC) assay by changing the solid-phase extraction material and by using a more sensitive and controlled electrochemical detector. An on-line solid-phase extraction was used with a preconcentration column of 10 * 3 mm ID containing octadecyl silane (ODS) reversed-phase material and an analytical microsphere C18 column. The mobile phase was unchanged and consisted of 35% phosphate buffer 0.02 mol (pH 7.00 +/- 0.10), 50% methanol, and 15% acetonitrile. Detection was performed with a new electrochemical detector. This detector comprised a highly stable Faraday-shielded oven compartment that accommodated a column and flowcell. The flowcell had a spacer thickness of 0.25 microm set at 830 mV. It also had an excellent signal-to-noise ratio, which resulted in very sensitive electrochemical analysis. These improvements resulted in a lower required sample volume of only 0.3 mL instead of 1.2 mL plasma with a very low limit of quantitation of 0.483 microg/L according to good laboratory practice (GLP) rules. The intraday coefficients of variation were 6.2% (0.483 microg/L) and 4.2% (18.4 microg/L). The interday coefficients of variation were 10.3% (0.483 microg/L) and 8.5% (18.4 microg/L).     

Method development and validation for the GC-FID assay of tributyl phosphate in a phospholipid emulsion

This paper describes the development and validation of an isothermal GC-FID method for the assay of tributyl phosphate in a phospholipid emulsion. The emulsion is used as a topical ointment to deliver Triton X-100, a spermicide. The tributyl phosphate is added to the emulsion as a plasticizer or softening agent. The chromatographic conditions of the method employ a J&W DB-Wax capillary column (30 m x 0.53 mm, film thickness 1 microm), isothermal elution with He at a column flow of 2.0 ml/min, injector, detector, and oven temperatures at 210 degrees C, a split ratio of 18.0/2.0, and a 3-microl injection volume. Sample calibration was performed with tributyl phosphate purchased from Aldrich (USP Reference Standard is not available). The linearity of the tributyl phosphate peak area responses was demonstrated from approximately 50 to 150% of the analytical concentration of 100 microg/ml. System precision was determined from five replicate injections of a standard and sample solution. Reproducibility of the tributyl phosphate peak area responses showed R.S.D. of 1.2 and 0.4%, respectively. Method precision was performed by assaying five samples by two different analysts on different days. The mean %LC was 95.5% (R.S.D.=1.0%) for the first analyst, and 95.6% (R.S.D.=1.0%) for the second analyst. The mean %LC value for all ten sample preparations was 95.5% (R.S.D.=0.9%). The limits of detection and quantitation were determined to be 0.2 and 0.7 microg/ml, respectively.     

Rapid gas chromatographic procedure for the determination of topiramate in serum

A rapid gas chromatographic method for the routine determination in serum of the new anticonvulsant drug topiramate (Topamax) (TOP) is described. The method involves extracting 0.50 mL of sample, previously adjusted to pH 9.5 with saturated borate buffer with ethyl acetate. One-microliter aliquots of the extract were injected into a 10-m x 0.53-mm i.d. x 0.5-microm 100% methyl silicone megabore capillary column connected to a nitrogen-phosphorus detector. The column temperature was initially at 170 degrees C for 0.1 min, then programmed at 10 degrees C/min to 240 degrees C, then 20 degrees C/min to 280 degrees C for 0.5 min. Under these conditions of the assay, the retention times of TOP and mepivicaine, internal standard, were 4.0 and 3.4 min, respectively. Quantitative determinations were performed with peak-height ratios of TOP to the internal standard. Calibration curves were linear from 2.5 to 150 mg/L TOP. The assay had a limit of quantitation of 2.5 mg/L. The overall within-run precision of the method yielded coefficients of variation (CV) of 3.9% at 10 mg/L (n = 10) and 3.1% at 100 mg/L (n = 10). The overall between-run precision calculated by three determinations on a single day for a week yielded CVs of 7.3% at 23 mg/L (n = 12) and 7.8% at 85 mg/L (n = 12). Common anticonvulsant and basic/neutral extractable drugs were found not to interfere with the assay. At present, no correlation has been demonstrated between trough plasma TOP concentrations and clinical efficacy. However, TOP values observed in our laboratory in serums from patients receiving adjunctive treatment for seizure disorders ranged from 2.5 to 35 mg/L.