兔金属硫蛋白的分离与纯化

兔皮下注射ＣｄＣｌ２诱导金属硫蛋白（Ｍｅｔａｌｌｏｔｈｉｏｎｅｉｎ，简称ＭＴ），取肝脏匀浆，用乙醇─氯仿混合液萃取后经ＳｅｐｈｄｅｘＧ－５０柱分离，得到混合型ＭＴ．进一步用纤维素弱碱性阴离子交换树脂进行拆分，并在ＳｅｐｈａｄｅｘＧ－２５柱上脱盐，得到ＭＴ－１和ＭＴ－２两种亚型．经氨基酸组咸、凝胶电泳及ＨＰＬＣ柱层析等分析表明，所得的两种亚型具有高度的均一性．     

气相色谱-微波诱导等离子体原子发射光谱法测定土壤中的微量路?…

用气相色谱－微波诱导等离子体原子发射光谱（ＧＣ－ＭＩＰ－ＡＥＤ）对土壤中路晚氏剂的测定方法进行了研究，用稀盐酸萃取土壤中的路易氏剂或它的降解产物２－氯乙烯亚肿酸，再与１，３－二巯基丙烷反应生成挥发性环状化合物，用甲苯萃取衍生物，在４８０．１９２，１８１．３９７，１８９．０４２ｎｍ波长处分析检测了衍生物中的氯，硫，砷等元素的发射信号，检测了妫１０ｐｇ，路易氏剂的加标回收率在７１．２０％～８７．８８％     

气相色谱-微波诱导等离子体原子发射光谱法测定土壤中的微量路易氏剂

用气相色谱－微波诱导等离子体原子发射光谱（ＧＣＭＩＰＡＥＤ）对土壤中的路易氏剂的测定方法进行了研究。用稀盐酸萃取土壤中的路易氏剂或它的降解产物２－氯乙烯亚胂酸，再与１，３－二巯基丙烷反应生成挥发性环状化合物。用甲苯萃取衍生物，在４８０１９２、１８１３９７、１８９０４２ｎｍ波长处分析检测了衍生物中的氯、硫、砷等元素的发射信号。检测限为１０ｐｇ。路易氏剂的加标回收率在７１２０％～８７８８％之间。     

人尿中克仑特罗的测定

本文采用直接液－液萃取和ＴＭＳ衍生化方法，利用ＧＣ／ＭＳ选择离子检测技术对人尿中的克仑特罗进行了分析研究，建立了灵敏的分析方法。给出了克仑特罗的回收率、检测限及人尿中的排泄曲线。     

BIOTRANSFORMATION OF 2α，5α，10β，14β－TETRA－ACETOXY－4（20），11－TAXADIENE BY THE FUNGIJS CUNNINGHAMELLA ECHINULATA

ＢＩＯＴＲＡＮＳＦＯＲＭＡＴＩＯＮＯＦ２α，５α，１０β，１４β－ＴＥＴＲＡ－ＡＣＥＴＯＸＹ－４（２０），１１－ＴＡＸＡＤＩＥＮＥ　ＢＹ　ＴＨＥ　ＦＵＮＧＩＪＳ　ＣＵＮＮＩＮＧＨＡＭＥＬＬＡ　ＥＣＨＩＮＵＬＡＴＡＳｈａｎｇＨｕｔＨＵ；ＸｕＦａｎｇＴＩ...     

METALLIC GALLIUM-PROMOTED REFORMATSKY-TYPE REACTION

ＭＥＴＡＬＬＩＣ　ＧＡＬＬＩＵＭ－ＰＲＯＭＯＴＥＤ　ＲＥＦＯＲＭＡＴＳＫＹ－ＴＹＰＥ　ＲＥＡＣＴＩＯＮＭＥＴＡＬＬＩＣＧＡＬＬＩＵＭ－ＰＲＯＭＯＴＥＤＲＥＦＯＲＭＡＴＳＫＹ－ＴＹＰＥＲＥＡＣＴＩＯＮ￥ＹｉｎｇＨＡＮ；ＺｈｅｎｇＦａＣＨＩ；ａｎｄＹａｏ...     

模板分子TMEDA成CF—3及ZSM—39沸石笼中的位置及其与骨…

用ＸＲＤ、ＦＴＩＲ、ＴＧ－ＤＴＡ、＾１３Ｃ魔角固体核磁共振表征用四甲基乙基二胺（ＴＭＥＤＡ）为结构异向剂合成的高硅沸石ＣＦ－３及ＺＳＭ－３９．ＴＭＥＤＡ不同基团的＾１３Ｃ化学位移，共振峰相对强度在交叉极化（ＣＰ）及高功率去偶（ＨＰＤＥＣ）核磁共振谱中的变化，揭示出模板分子在尺寸不同的沸石笼中的位置、运动状态及其与骨架的相互作用。在ＺＳＭ－３９沸石中的ＴＭＥＤＡ分子，它的－Ｃ２Ｈ４－基团＾１３Ｃ共振     

离线超临界流体萃取和气相色谱-红外-质谱联用测定水中有机污染物

 利用吸附剂ＧＤＸ－３０１对黄河水中的有机污染物富集并以超临界ＣＯ２脱附后，通过气相色谱、色谱－红外－质谱联用技术对各目标分析物逐一定性，并比较了超临界ＣＯ２萃取和溶剂洗脱的结果。实验表明，在２０ＭＰａ，６０℃，４０ｍｉｎ条件下进行超临界ＣＯ２萃取时的萃取效率和溶剂萃取效率相当或略高。     

体液中一叶Qiu碱检测方法的研究

本文报道了用气相色谱及气相色谱－质谱联用检出人体液中一叶Ｑｉｕ碱的方法。尿样经碱化后用乙醚直接萃取，回收率为７２．１％；血浆样品用Ｓｅｐ－ｐａｋ小柱提取，回收率为４３．９％，ＧＣ／ＭＳ的检测限为２０ｎｇ。方法快速、简便、准确。     

MCM-48介孔分子筛的合成研究

利用水热法合成了ＭＣＭ－４８介孔分子筛,通过ＩＲ,ＴＧ－ＤＴＡ,ＸＲＤ,ＴＥＭ,Ｎ２吸附等方法对产物进行了表征,并系统地研究了晶化温度、晶化时间、凝胶组成等对合成ＭＣＭ－４８介孔分子筛的影响     

Development of a simple sample preparation technique for gas chromatographic–mass spectrometric determination of nicotine in edible nightshades (Solanaceae)

The purpose of this study was to develop a rapid analytical method for the reliable determination of low concentrations of nicotine in foods for large numbers of samples. Food material was extracted using a simple liquid–liquid extraction method. For processed foods, further clean-up steps had to be employed to eliminate interfering compounds. The determination of nicotine was performed by gas chromatography–mass spectrometry. Quantitative analysis was accomplished using deuterium labeled nicotine as an internal standard. Recoveries of over 95% were obtained for a single step extraction, as well as for a multiple-stage extraction procedure, respectively. The method has been applied to the determination of nicotine in edible nightshades (i.e. tomatoes, potatoes and aubergines) and their processed products.     

Optimisation of a solid-phase microextraction method for the analysis of nicotine in hair

A headspace solid-phase microextraction method (HS-SPME) followed by gas chromatography with mass spectrometric detection (GC/MS) has been developed for the determination of low concentrations of nicotine in hair. Parameters affecting the SPME procedure including type of fiber coating, extraction mode, extraction temperature and time, desorption time, stirring, and salt addition have been evaluated and optimised. The method provided good linearity (r(2)≥0.9980) over the concentration range tested (0.2-20 ng/mg) and low detection limit (0.02 ng/mg). Precision expressed as relative standard deviation was <10%. The average accuracy was 95%. The proposed method was used to determine hair nicotine levels in 100 children in order to assess exposure to environmental tobacco smoke (ETS). The described HS-SPME procedure is fast, simple, sensitive, and solvent-free and is therefore suitable for studies involving ETS exposure assessment.     

High-throughput dynamic microwave-assisted extraction on-line coupled with solid-phase extraction for analysis of nicotine in mushroom

A simple and low-cost high-throughput dynamic microwave-assisted extraction (HTDMAE) device was firstly assembled and validated by the extraction of nicotine in mushroom samples. In this device, a household microwave oven was applied to provide the microwave energy; a vacuum pump was used to deliver the solvent. Compared with traditional dynamic microwave-assisted extraction method, the sample throughput and microwave energy utilization were improved by the HTDMAE, up to 20 samples could be treated simultaneously in 9 min. Taking extraction of nicotine in mushroom sample as an example, a method was established with extraction, separation and enrichment of nicotine in a single step by the device on-line coupled with solid-phase extraction (SPE). Nicotine was first extracted from the mushroom samples with water under the action of microwave energy, and then directly introduced into the SPE column which was packed with cation-exchange resins. Subsequently, the nicotine trapped on the resins was eluted with methanol-ammonia (95:5, v/v) and determined by high-performance liquid chromatography. The limit of detection of nicotine obtained is 5.6 μg kg(-1) in fresh mushroom sample. The recovery of nicotine in mushroom samples is in the range of 87.4-104.0%. The proposed method which significantly reduced the overall analysis time and increased sample throughput should be favored for routine analyse of complex solid sample.     

Determination of nicotine and its metabolites accumulated in fish tissue using hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry

The determination of nicotine and its major metabolites (cotinine and anabasine) in fish tissue was performed using liquid chromatography and tandem mass spectrometry. Marine and freshwater fish were purchased from local grocery stores and were prepared based on a quick, easy, cheap, effective, rugged, and safe sample preparation protocol. To determine the highly polar compounds, hydrophilic interaction liquid chromatography was also used. There were modest suppressions on measured nicotine signals (10%) due to the matrix effects from marine fish but no obvious effects on freshwater fish signals. Method validation was incorporated with internal standards and carried out with matrix‐matched calibration. The detection limits for nicotine, cotinine, and anabasine were 9.4, 3.0, and 1.5 ng/g in fish, respectively. Precision was quite acceptable returning less than 8% RSD at low, medium, and high concentrations. Acceptable and reproducible extraction recoveries (70–120%) of all three compounds were achieved, except for anabasine at low concentration (61%). The method was then applied to define nicotine bioaccumulation in a fathead minnow model, which resulted in rapid uptake with steady state internal tissue levels, reached within 12 h. This developed method offers a fast, easy, and sensitive way to evaluate nicotine and its metabolite residues in fish tissues.     

加速溶剂萃取快速洗脱印迹聚合物中的模板分子

通过优化实验条件,选择洗脱温度80℃、加热时间5min、萃取压力10.4MPa、洗脱溶剂为300mL的甲醇/乙酸(90∶10,V/V),静态萃取时间8min、吹扫时间100s,对1.000g尼古丁印迹聚合物中的模板分子进行连续6次的萃取洗脱,洗脱效率达94.2%,模板渗漏量仅为9.8μg/L,萃取时间<70min。将2000mg洗脱后的印迹聚合物颗粒装填于3mL的聚丙烯固相萃取小柱中,用10mL甲醇/乙酸(90∶1,V/V)淋洗小柱,用高效液相色谱检测淋洗液中的尼古丁,获得模板的渗漏量为9.8μg/L。     

Flow injection Fourier transform infrared determination of nicotine in tobacco

A fully automated procedure is proposed for the Fourier transform infrared (FTIR) determination of nicotine in tobacco. The method is based on the on-line extraction of nicotine with CHCl3. Samples, weighed inside empty extraction cartridges, were humidified with NH3 and the cartridges were installed in a flow manifold in which they were extracted with 2 ml CHCl3 for 2 min, then 400 microliters of the extract were introduced into a micro-flow cell using a carrier of CHCl3 and the IR spectrum was registered continuously. The absorbance, in the wavenumber range 1334-1300 cm-1, was measured, obtaining a peak as a function of time. The area of this peak was interpolated on a calibration line established from standard solutions of nicotine in chloroform treated in the same way as samples. The method provided a limit of detection of 0.1 mg ml-1 nicotine, an RSD lower than 2% and a sampling frequency of the whole procedure of 6 h-1. Results obtained for natural samples of cut tobacco and cigar compared well with those obtained by a batch FTIR procedure, involving an off-line extraction with a total time of 16 min. However, for yellow tobacco cigarette, an on-line extraction time of 10 min was required to obtain a good recovery of nicotine.     

The determination of nicotine and cotinine in plasma

A method to determine plasma nicotine and cotinine simultaneously is described. After a simple extraction procedure, the amounts of nicotine and cotinine present in a sample are determined by gas chromatography using nitrogen-sensitive detection and a fused silica capillary column. The method has been demonstrated to detect nicotine and cotinine plasma concentrations within 1 and 9 ng/ml, respectively. The accuracy and precision of the method was demonstrated using spiked calf and human sera. Data are presented for the direct comparison of the present method with other methods of determination for plasma nicotine and cotinine.     

Quantitation of nicotine in tobacco products by capillary electrophoresis

A simple and rapid capillary electrophoresis (CE) method was developed for the quantitation of nicotine in commercial tobacco products. The method involves a 6 min run at 30 kV, using a 50 mM phosphate buffer (pH 2.5), paraquat as internal standard, and UV detection at 260 nm. Nicotine was extracted from tobacco products in <15 min. Recoveries from spiked extracts were >95%, and the extraction efficiencies of water, 1 M HCI, 1 M acetic acid, 5 mM phosphate buffer (pH 2.5), and 1% triethanol amine were similar. Nicotine concentrations in 67 samples of cigarettes, cigars, and bidis varied between 0.37 and 2.96% (w/w). An established gas chromatography/mass spectrometry method using toluene extraction consistently yielded lower nicotine values than the CE method. Experimental evidence suggests that this is due to insufficient extraction of nicotine by toluene.     

Comparison of methods for extraction of tobacco alkaloids

Ultrasound and microwave techniques were used to extract tobacco alkaloids, and response surface methodology was used to optimize extraction conditions. Ultrasonic technique factors were temperature, 30-85 degrees C; time, 3-45 min; solvent volume, 8-80 mL. Microwave extraction factors were pressure, 15-75 psi; time, 3-40 min; power, 30-90% of the maximum magnetron power of 650 W. Soxhlet and solvent AOAC-modified extraction methods were also applied after some improvements. Nicotine, nornicotine, anabasine, and anatabine were quantified by gas chromatography. A steam distillation International Standards Organization method for total alkaloid evaluation was used as reference. The results obtained by the different methods were compared using a least squares deviation test. The ultrasonic and the proposed modified-AOAC extraction method were the more convenient with regard to practicability and precision. The relative deviations (n = 5) were as follows: For the ultrasonic method in low-level alkaloid tobaccos, 0.7% nicotine and 1.4-14% minor alkaloids; in high-level alkaloid tobaccos, 2.4% nicotine and 4.5-5.1% minor alkaloids. For the modified AOAC method in low-level alkaloid tobaccos, 0.9% nicotine and 2.4-11.6% minor alkaloids; and in high-level alkaloid tobaccos, 1.7% nicotine and 2.0-2.4% minor alkaloids.     

A simple, sensitive, and rapid method for the determination of cotinine in urine by high-performance liquid chromatography with UV detection

Cotinine levels in biological fluids are a reliable indicator of the presence of nicotine. In this paper, a simple and sensitive high-performance liquid chromatography (HPLC) procedure for the determination of cotinine in urine following liquid-liquid extraction with dichloromethane in an alkaline medium is described. Calibration curves show linearity over the 50 to 3000 ng/mL range with low intra- and interday variability as well as good selectivity and specificity. No solid-phase extraction is performed because the liquid dichloromethane extraction step yields excellent results. This method is a good alternative for routine analysis of urinary cotinine in laboratories where gas chromatography or HPLC-mass spectrometry is not available.