毛细管柱气相色谱法测定煤焦油中萘

研究了毛细管柱气相色谱法测定煤焦油中萘含量的方法。正辛烷和对四甲基苯分别用作样品的溶剂和内标物,采用内标法定量。对汽化温度、检测温度、气体流速等进行了探讨。方法用于煤焦油中萘含量的分析,标准加入回收率在97.4%~100.4%之间。该法与国家标准方法相比,样品分离效果好,结果准确度高,满足了产品质量检验准确、快速的要求。     

Determination of triazolam in serum by deactivated metal capillary gas chromatography with electron-capture detection

A method for the determination of trace amounts of triazolam in serum by deactivated metal capillary gas chromatography with electron-capture detection was established. The column used exhibits excellent thermostability in high-temperature analysis and easy handling and a long lifetime of the column and well shaped peaks on the chromatograms are obtained. With the metal capillary column, it was found to be easier to maintain suitable analytical conditions for the routine assay of triazolam than with a fused-silica column. With this method, 0.5 ng/ml of triazolam in serum can be determined. The method is useful for pharmacokinetic and therapeutic purposes.     

Determination of fat in olestra-containing savory snack products by capillary gas chromatography

A quantitative method to determine fat in olestra-containing savory snack products was validated within the AOAC Peer-Verified Methods Program. The method may be used to demonstrate compliance with the guidelines of the U.S. Nutrition Labeling and Education Act for labeling products as "fat free" or "low fat." The method can measure total and saturated fat in savory snacks when present at levels of 0.2-10 g total fat and 0.1-3 g saturated fat per 30 g serving. The method is standardized to measure C6-C24 fatty acids. Extraction of olestra-containing savory snack samples with chloroform-methanol (modified AOAC Official Method 983.23) yields a lipid extract containing the total fat and olestra. The extracted lipid is hydrolyzed by lipase, yielding fatty acids and unreacted olestra. The fatty acids are precipitated as calcium soaps. Olestra is extracted from insoluble soaps with hexane and then discarded. The isolated soaps are converted back into fatty acids with hydrochloric acid and extracted with hexane. The isolated fatty acids are converted to methyl esters with boron trifluoride-methanol and quantitated by capillary gas chromatography using internal standard. Test samples were prepared by blending olestra-containing and full-fat (triglyceride) snacks to obtain 6 levels of spiking (0-10 g total fat added/30 g serving) in potato chips, potato crisps, cheese puffs, and nacho cheese-flavored corn chips. Results were linear (r2 > 0.997) between 0 and 10 g fat/30 g serving for each product matrix. Mean recovery was 101 +/- 6% standard deviation (SD) for total fat and 104 +/- 6% SD for saturated fat. Mean recovery by peer laboratory was 88 +/- 5% SD for total fat and 95 +/- 4% SD for saturated fat in potato chips (0-3 g total fat added/30 g serving). Two sets of 10 replicates of potato chips (0.5 g total fat/30 g serving and 0.16 g saturated fat/30 g serving) and potato crisps (0.5 g total fat/30 g serving and 0.16 g saturated fat/30 g serving) were analyzed by submitting and peer laboratories. Repeatability relative standard deviations ranged from 3.90 to 7.33% for total fat and from 4.01 to 11.53% for saturated fat. Reproducibility relative standard deviations were 7.33% (total fat, potato chips), 7.15% (total fat, potato crisps), 11.36% (saturated fat, potato chips), and 13.50% (saturated fat, potato crisps).     

毛细管柱气相色谱法测定粗蒽中蒽和菲

选用N,N-二甲基乙酰胺为溶剂溶解样品,采用外标法进行定量,建立了毛细管柱气相色谱法测定粗蒽中蒽和菲的方法。实验确定了色谱柱的程序升温条件为:柱温起始温度120 ℃,保留4 min;再以40 ℃/min升温至180 ℃,保留5 min;再以40 ℃/min升温至200 ℃,保留5 min。采用实验方法测定蒽和菲的含量,蒽和菲在10～100 mg/L范围内呈良好的线性关系,蒽和菲的检出限分别为2.12×10^-2 mg/L和1.76×10^-2 mg/L。将方法应用于3个粗蒽样品中蒽和菲的测定,结果的相对标准偏差(RSD, n=8)为0.59%～1.3%。对6个粗蒽样品按照实验方法进行分析,测定结果与紫外分光光度法测定菲含量及化学滴定法测定蒽含量的结果基本一致。     

Determination of amino acids in biological fluids by capillary gas chromatography with nitrogen-phosphorus selective detection

A selective and sensitive method for the determination of protein and non-protein amino acids in biological fluids by capillary gas chromatography (GC) has been developed. The amino acids in the samples were directly converted into their N(O,S)-isobutoxycarbonyl methyl ester derivatives and measured by GC with nitrogen-phosphorus selective detection (NPD) using a DB-17ht capillary column. Using this method, the derivatives of the 21 protein amino acids and the 25 non-protein amino acids provided excellent NPD responses and were quantitatively and reproducibly resolved within 28 min. The lower detection limits of these amino acids, at a signal-to-noise ratio of 3, were ca. 6-150 pg injected. The calibration curves for each amino acid in the range of 0.02-2 micrograms were linear and sufficiently reproducible for quantitative analysis. This method was successfully applied to small urine and serum samples without prior clean-up; there was no evidence of interference from coexisting substances. Overall recoveries of amino acids added to urine and serum samples were 83-112%. The intra-assay and inter-assay R.S.D. of amino acids in these samples were 0.3-8.9% (n = 3) and 1.9-15.8% (n = 3), respectively.     

毛细管柱气相色谱法测定循环洗油中萘

采用DB-1毛细管柱和FID检测器,以毛细管柱气相色谱法测定循环洗油中的萘含量。研究发现:以正己烷为溶剂,在汽化温度为270℃,检测温度为250℃的条件下,洗油中的萘与其他组分完全分开。萘含量在0~10%范围内与峰面积呈良好的线性关系,相关系数为0.9992。方法的检出限为0.015%。考察了方法的准确度和精密度,其相对标准偏差≤3.6%,标准加入回收率在98%~105%之间。外标法定量分析洗油中的萘含量,测定结果允许误差满足国家标准要求。     

Determination of propofol in rat whole blood and plasma by high-performance liquid chromatography

A simple, accurate and sensitive high-performance liquid chromatographic method was developed for the determination of propofol, an intravenous anaesthetic agent, in rat whole blood or plasma samples. The method is based on precipitation of the protein in the biological fluid sample and direct injection of the supernatant into an HPLC system involving a C18 reversed-phase column using a methanol-water (70:30) mobile phase delivered at 1 ml/min. Propofol and the internal standard (4-tert.-octylphenol) were quantified using a fluorescence detector set at 276 nm (excitation) and 310 nm (emission). The analyte and internal standard had retention times of 6.3 and 10.5 min, respectively. The limit of quantification for propofol was 50 ng/ml using 100 microl of whole blood or plasma sample. Calibration curves were linear (r2=0.99) over a 1-10 microg/ml concentration range and intra- and inter-day precision were between 4-11%. The assay was applied to the determination of propofol whole blood pharmacokinetics and propofol whole blood to plasma distribution ratios in rats.     

Determination of mitoxantrone in mouse whole blood and different tissues by high-performance liquid chromatography

A high-performance liquid chromatographic (HPLC) method was developed for the specific determination of mitoxantrone (MTO) in whole blood and different tissues of mice (liver, heart, spleen, kidneys). MTO was extracted into dichloromethane with ametantrone (AMT) as internal standard. The different tissues were homogenised in citrate buffer (pH 3.0) containing 20% ascorbic acid. Separation of MTO and AMT was carried out using a Nucleosil C18 column. The mobile phase consisted of acetonitrile (33%) and 0.16 M ammonium formate buffer, pH 2.7. UV detection was used at 658 nm. Baseline separation of AMT and MTO was achieved in all matrices. The calibration curves were linear in all matrices (r > 0.999) in the concentration range of 2-200 micrograms/l for whole blood and 2-700 micrograms/l for tissue homogenates, respectively. The within-day and between-day precision studies showed good reproducibility with coefficients of variation below 4.5% for whole blood and below 10% for tissue homogenates, respectively. The extraction efficiencies of MTO are 60% in whole blood and 38% in tissue homogenates. The method described is suitable for pharmacokinetic studies on the distribution of MTO in different tissues of mice.     

Quantitative analysis of acetaldehyde in whole blood from human and various animals by gas chromatography

Acetaldehyde present in the blood of bull, chicken, hamster, horse, human, monkey, pig, rabbit, rat and sheep, was quantitatively analyzed by a newly developed gas chromatographic method. Acetaldehyde in a blood sample was reacted with cysteamine to give 2-methylthiazolidine, which was extracted with dichloromethane and subsequently analyzed by gas chromatography with a fused-silica capillary column and a nitrogen-phosphorus detector. The quantities of acetaldehyde found in blood ranged from 2.04 micromol/ml (hamster) to 14.8 micromol/ml (pig). The quantity of acetaldehyde recovered from human blood was 6.17 micromol/ml.     

固相微萃取-气相色谱法测定煤气中萘

采用特制采样瓶收集煤气后,应用固相微萃取(SPME)对样品进行前处理,采用气相色谱(GC)对煤气中的萘进行测定。通过试验确定了SPME的最佳萃取条件为:采用100 μm聚二甲基硅氧烷(PDMS)萃取涂层,于转速为800 r/min时室温下萃取5 min,气相色谱解吸时间为3 min。在丙酮溶剂峰存在的情况下,基线平稳,丙酮峰对萘的测定并无影响。实验结果表明,萘在5～200 mg/m³范围内有良好的线性关系,相关系数为0.999 9。方法检出限为0.08 mg/m³。实验方法用于煤气中萘的测定,相对标准偏差(RSD,n=7)为2.6%～4.9%,加标回收率为85%～108%。     

Determination of embutramide in biological matrices by gas chromatography with nitrogen-phosphorus detection

Embutramide is a general anesthetic having a strong narcotic effect on the central nervous system where it paralyzes the brain center that controls respiration. It is a constituent of T61, a veterinary euthanasia drug. This paper describes a gas chromatographic procedure using nitrogen-phosphorus detection for the determination of embutramide in biological matrices. The drug and the internal standard (ambucetamide) are extracted with dichloromethane under alkaline conditions. The method is linear from 100 to 3000 ng/ml. The within-day and day-to-day coefficients of variation range from 5.1 to 5.7% and from 9.1 to 10.0%, respectively. The recovery is above 80% while the minimum detectable level under the conditions described is 40 ng/ml analyzing a 1-ml or a 1-g aliquot of a sample (blood or tissue). The method is also applied to different samples from dogs euthanized with T61.     

Headspace gas chromatography with capillary column for urine alcohol determination

A headspace gas chromatographic method using a fused-silica capillary column Poraplot Q has been developed and validated for the detection and quantification of ethanol in urine. Under optimized conditions, ethanol was properly separated from acetaldehyde, acetone, isopropanol, methanol and n-propanol. Limits of detection (LODs) and quantification (LOQs) were 0.008 and 0.010 g/l, respectively. The precision studies within-run and between-run, using spiked urine samples (0.08, 0.8 and 2.0 g/l) showed maximum coefficients of variation 5.9 and 6.5%, respectively. Results of ethanol recovery varied from 91.6+/-0.8 to 103.3+/-1.8% over the concentration range from 0.01 to 3.20 g/l. The method was appropriate for the detection of ethanol in urine samples. This matrix can be used for monitoring alcohol abuse in the workplace and used in alcohol rehabilitation programs.     

Determination of N,N',N"-triethylenthiophosphoramide in biological samples using capillary gas chromatography

A sensitive assay for the determination of N,N',N"-triethylenthiophosphoramide (thioTEPA) in microvolumes of human plasma and urine has been developed. ThioTEPA was analysed using gas chromatography with selective nitrogen-phosphorus detection, after extraction with ethyl acetate from the biological matrix. Diphenylamine is the internal standard. The limit of quantitation was 0.1 ng/ml, using only 100 microl of sample; recoveries ranged between 85 and 100% and both accuracy and precision were less than 10%. Using a flame ionisation nitrogen-phosphorus detector, the assay was not linear over the concentration range of 2-1000 ng/ml for plasma and 10-1000 ng/ml for urine. Linearity was accomplished in the range of 1-1000 ng/ml for plasma and urine when a thermionic nitrogen/phosphorous detector was used. The stability of thioTEPA in plasma proved to be satisfactory over a period of 3 months, when kept at -20 degrees C, whereas it was stable in urine for at least 1 month at -80 degrees C. ThioTEPA plasma concentrations of two patients treated with thioTEPA are presented demonstrating the applicability of the assay.     

离子色谱法测定废气中甲酸

采用离子色谱法分离电导检测废气中甲酸的含量。考察Dionex IonPac AS18和Ion-PacAS11-HC色谱分离柱在不同淋洗液浓度条件下对甲酸的分离效果,淋洗液流速对分离的影响。讨论绘制校准曲线时标准溶液介质的选择。结果表明:当用Dionex IonPac AS18柱,5mmol/L氢氧化钾为淋洗液,以1.0 mL/min的淋洗速度进行梯度洗脱并用吸收液配制校准曲线的标准溶液时可达到预期废气中甲酸分析的目的。该法线性范围为0.1~10 mg/L和10~100 mg/L,检出限为0.007 mg/m3。用本法测定甲酸生产装置30 m高度排气筒废气中的甲酸回收率为88%~104%。     

气相色谱法测定韭菜中有机磷农药残留量

建立了毛细管气相色谱法、火焰光度检测器分析韭菜中的8种有机磷农药残留量的方法．实验结果表明:采用程序升温所测定的8种有机磷农药,在色谱柱DB-608上分离良好,回收率在70%-119%之间;最低检测质量浓度分别为敌敌畏0．02μg·mL^-1,甲胺磷0．01 μg·mL^-1,乙酰甲胺磷0．02μg·mL^-1,甲拌磷0．01 μg·mL^-1,氧化乐果0．05μg·mL^-1,乐果0．01μg·mL^-1,甲基对硫磷0．01μg·mL^-1,毒死蜱0．02μg·mL^-1．该方法快速灵敏,符合实际应用的需要．     

Determination of cysteamine and cystamine by gas chromatography with flame photometric detection

A gas chromatographic method for the determination of cysteamine and its disulphide cystamine is described. Cysteamine and cystamine are converted into N,S-diisobutoxycarbonyl and N,N-diisobutoxycarbonyl derivatives, respectively. The derivatives are analysed by gas chromatography with flame photometric detection, using a DB-210 capillary column. The calibration curves for cysteamine and cystamine in the range of 0.2-5.0 nmol are linear and sufficiently reproducible for quantitative analysis, and the detection limit is about 0.5 pmol injected. Cysteamine in mouse tissues is found in the free reduced, free oxidized and protein-bound forms. Free oxidized and protein-bound forms are reduced to free cysteamine by the use of sodium borohydride, and then derivatized. Cysteamine and cystamine in mouse tissues can be measured without any interference from coexisting substances by this method. The recoveries of cysteamine and cystamine added to the tissue samples are 91-106%, and their reproducibilities are found to be satisfactory. Analytical results for the determination of various forms of cysteamine in mouse tissues are presented.