A method for determining the main neutral aroma components in tobacco was developed by combining solvent extraction with heart-cut multidimensional gas chromatography-mass spectrometry (MDGC-MS). Tobacco sample(0.5 g)was extracted by ethyl ether(5 mL), the extract was washed with 5% H2SO4(2 mL)subsequently, then analyzed by MDGC-MS after standing overnight. The neutral aromatic components, including solanone, β-damascenone, geranylacetone, β-ionone, megastigmatrienone and dihydroactinidiolide were determined qualitatively and quantitatively by using methyl eugenol as the internal standard. Further, this method was compared with simultaneous distillation extraction(SDE)-gas chromatography-mass spectrometry(GC/MS). The results showed that: The detection limit of the analytes ranged from 0.02 to 0.18 μg/mL, the recoveries were between 80.0% to 123.4% with the intra-day relative standard deviation (RSD)≤7.5%. The developed method is simple, fast, accurate and suitable for the analysis of neutral aroma compounds in batches of tobacco samples.

To extract, preconcentrate and determine the trace level of environmental contaminants, a novel mixed hemimicelles solid-phase extraction (MHSPE) method based on mesoporous silica-coated magnetic nanoparticles (Fe3O4/meso-SiO2 NPs) as adsorbent was developed for extraction of phthalate esters from water samples. The Fe3O4/meso-SiO2 NPs were synthesized by using a combination of hydrothermal method and sol-gel method. The obtained Fe3O4/meso-SiO2 NPs possessed a large surface area (570 m(2)/g), superparamagnetism, and uniform mesopores (2.8 nm). MHSPE parameters, such as the amount of surfactant, pH of sample, shaking and separation time, eluent and breakthrough volume that may influence the extraction of analytes greatly, were further investigated. Under the optimized conditions, the extraction was completed in 20 min and a concentration factor of 500 was achieved by extracting 250 mL water sample. Detection limits obtained of butyl-benzyl phthalate (BBP), di-n-butyl phthalate (DnBP), di-(2-ethylhexyl) phthalate (DEHP) and di-n-cotyl phthalate (DnOP) were 12, 21, 12, and 32 ng/L, respectively. The proposed method exhibited high extraction efficiency and relatively short time for extracting the target compounds.

A simple and efficient pressurized liquid extraction followed by HPLC analysis method has been investigated for the extraction of polyphenols in tobacco. After pressurized liquid extraction and C-18 disposable cartridge solid-phase extraction clean-up, to reduce the co-extraction of interference, polyphenols (chlorogenic acid, esculetin, rutin, scopoletin and quercitrin) were analyzed by HPLC with a diode array detector. When the method was validated, recoveries obtained were varied from 86.9 to 96.4 % and RSDs from 3.4 to 8.2 %.

A new effect of aging time (AT) on the shrinkage of ordered mesoporous carbon (OMC) prepared by an evaporation-induced triconstituent co-assembly method has been reported. Increasing AT from 0.5 to 2.0 h can gradually reduce framework shrinkage of the OMC during carbonization. This novel effect is effective and simple for preparing the OMC with large mesopore sizes, high pore volumes and surface area.

Method of determining semi-volatile compounds,i.e.pyridine,styrene, and quinoline in side-stream smoke was developed.Side-stream smoke was collected with a fishtail chimney,a Cambridge filter pad,and two impingers containing methanol.Collected semi-volatile compounds were analyzed by GC/MS with selected ion scan(SIM) mode.The method had achieved excellent reproducibility.The RSDs for inner-assay were below 3.42%,and the RSDs for inter-assay were 6.33%.Limit of detection for every semi-volatile compound was less than 0.15 μg/cig.The recoveries were in the range of 92.87% to 98.0%.This method was applicable for routine analysis of semi-volatiles in side-stream cigarette smoke.

A method was developed to determine eight acetanilide herbicides from cereal crops based on accelerated solvent extraction (ASE) and solid-phase extraction (SPE) followed by gas chromatography-electron capture detector (GC-ECD) analysis. During the ASE process, the effect of four parameters (temperature, static time, static cycles and solvent) on the extraction efficiency was considered and compared with shake-flask extraction method. After extraction with ASE, four SPE tubes (graphitic carbon black/primary secondary amine (GCB/PSA), GCB, Florisil and alumina-N) were assayed for comparison to obtain the best clean-up efficiency. The results show that GCB/PSA cartridge gave the best recoveries and cleanest chromatograms. The analytical process was validated by the analysis of spiked blank samples. Performance characteristics such as linearity, limit of detection (LOD), limit of quantitation (LOQ), precision and recovery were studied. At 0.05 mg/kg spiked level, recoveries and precision values for rice, wheat and maize were 82.3-115.8 and 1.1-13.6%, respectively. For all the herbicides, LOD and LOQ ranged from 0.8 to 1.7 μg/kg and from 2.4 to 5.3 μg/kg, respectively. The proposed analytical methodology was applied for the analysis of the targets in samples; only three herbicides, propyzamid, metolachlor and diflufenican, were detected in two samples.

The thermal decomposition behavior and the pyrolysis products of benzyl-2,3,4,6-tetra-O-acetyl-beta D-glucopyranoside (BGLU) were studied with synchrotron vacuum ultraviolet (VUV) photoionization mass spectrometry at temperatures of 300, 500 and 700 degrees C at 0.062 Pa. Several pyrolysis products and intermediates were identified by the measurement of photoionization mass spectra at different photon energies. The results indicated that the primary decomposition reaction was the cleavage of O-glycosidic bond of the glycoside at low temperature, proven by the discoveries of benzyloxy radical (m/z = 107) and glycon radical (m/z = 331) in mass spectra. As pyrolysis temperature increased from 300 to 700 degrees C, two possible pyrolytic modes were observed. This work reported an application of synchrotron VUV photoionization mass spectrometry in the study of the thermal decomposition of glycoside flavor precursor, which was expected to help understand the thermal decomposition mechanism of this type of compound. The possibility of this glycoside to be used as a flavor precursor in high temperature process was evaluated.

A method has been developed for analysis of 14 organochlorine pesticide residues in cereals. After accelerated solvent extraction and solid-phase extraction clean-up on graphitized carbon black/primary–secondary amine (GCB/PSA), to reduce co-extraction of interferences, pesticide residues were analyzed by gas chromatography with electron-capture detection. When the method was validated, recoveries were in the range 78–116%, relative standard deviations were in the range 1.1–16.3%, and limits of detection and quantification were from 1.5 to 4.2 μg kg−1 and from 4.6 to 12.5 μg kg−1, respectively.

An analytical methodology for the analysis of methamidophos in water and soil samples incoporating a molecularly imprinted solid-phase extraction process using methamidophos-imprinted polymer was developed. Binding study demonstrated that the polymer exhibited excellent affinity and high selectivity to the methamidophos. Evidence was also found by FT-IR analysis that hydrogen bonding between the CO2H in the polymer cavities and the NH2 and P=O of the template was the origin of methamidophos recognition. The use of molecularly imprinted solid-phase extraction improved the accuracy and precision of the GC method and lowered the limit of detection. The recovery of methamidophos extracted from a 10.0 g soil sample at the 100 ng/g spike level was 95.4%. The limit of detection was 3.8 ng/g. The recovery of methamidophos extracted from 100 mL tap and river water at 1 ng/mL spike level was 96.1% and 95.8%, and the limits of detection were 10 and 13 ng/L respectively. These molecularly imprinted solid-phase extraction procedures enabled selective extraction of polar methamidophos successfully from water and soil samples, demonstrating the potential of molecularly imprinted solid-phase extraction for rapid, selective, and cost-effective sample pretreatment.

An ultra-high-pressure liquid chromatography/MS3 (UPLC-MS3) method has been developed and validated for the quantitative determination of four major TSNAs in mainstream cigarette smoke using MS3 scan mode on a hybrid triple quadrupole-linear ion trap mass spectrometer. The new method combining the UPLC with MS3 scan mode offers decreased sample analysis time and good selectivity. After mainstream cigarette smoke was collected on a Cambridge filter pad, the particulate matter was extracted with ammonium acetate solution and analyzed by UPLC-MS3 using isotopically labeled analogues as internal standards. Four TSNAs were completely separated on an Agilent XDB-C18 UPLC column using isocratic elution during a 6 min LC run time. Excellent linearity was obtained over the concentration range of 1.0-150.0 ng/mL for all TSNAs with values for correlation coefficient (r) between 0.9985-0.9994. Limits of detection (LOD) of each TSNA varied from 0.023 to 0.067 ng/mL, and lower limits of quantification (LLOQ) varied from 0.077 to 0.223 ng/mL, respctively. The recovery of each TSNA was from 89.2 to 106.8%. The method achieved excellent reproducibility with RSD 2.1-6.8% for intra-assay and 3.4-9.1% for inter-assay. This method can be used as an effective approach to significantly improve the detection capability for TSNAs in complex matrices.

Various ordered mesoporous carbons (OMCs) have been prepared by evaporation-induced triconstituent co-assembly method. Their mesostructural stability under different carbon content, aging time and acidity were conveniently monitored by X-ray diffraction, transmission electron microscopy, and N2 sorption isotherms techniques. The results show mesostructural stability of OMCs is enhanced as the carbon content increases from 36% to 46%, further increasing carbon content deteriorates the mesostructural stability. Increasing aging time from 0.5 h to 5.0 h make the mesostructural stability go through an optimum (2.0 h) and gradually reduce framework shrinkage of the OMCs. Highly OMCs can only be obtained in the acidity range of 0.2–1.2 mol/L HCl, when the acidity is near the isoelectric point of silica, the resulting OMCs have the best mesostructure stability. Under the optimum condition, the carbon content of 46%, aging time of 2.0 h, and 0.2 mol/L HCl, the resulting OMCs have the best mesostructure stability and the highest BET surface areas of 2281 m2/g.

A rapid, sensitive and accurate matrix solid phase dispersion-accelerated solvent extraction (MSPD-ASE) method for selective determination of sixteen organochlorine pesticide (OCP) residues in fish samples has been developed and validated. 2 g fresh fish muscle was dispersed with 10 g anhydrous sodium sulfate and 2 g acid alumina thoroughly, and loaded into the stainless-steel extraction cell containing 6 g of acid alumina and 10 g anhydrous sodium sulfate. The temperature 60 degrees C and two extraction cycles of 5 min gave adequate extraction efficiency using DCM-hexane (3:7, v/v) mixture as solvent. Not only the lipids, but also other co-extracts, which peaks mostly located in the forepart of chromatograms and maybe interfere the identification or quantitation of analytes, were eliminated exhaustively, while analytes were extracted selectively. Sixteen OCPs were identified by retention time of standards and quantified using mirex as internal standards. These detected OCPs were confirmed by GC-MS in real samples. The performance of proposed method was evaluated and validated: the detection limits were 0.008-0.05 ng g(-1), relative standard deviations were 1.9-5.0%, and recoveries were 91.0-104.1% spiked at 10 ng g(-1) level. The accuracy and precision of proposed method were equal to or better than that of traditional Soxhlet extraction method.

分别以聚乙烯亚胺（PEI）、十六烷基三甲基溴化铵（CTMAB）对硅胶（SiO2）表面进行修饰,并以苯酚为模板,合成硅胶表面修饰分子印迹聚合物（MIP-SiO2）,制备获得功能添加剂PEI-SiO2、CTMAB-SiO2、MIP-SiO2。按不同剂量分别将功能添加剂加入到卷烟滤嘴中,考察对卷烟主流烟气中苯酚的截留效率。结果表明,各添加剂均可有效降低卷烟烟气中的苯酚释放量。当添加量达到20mg/支时,各功能材料对苯酚的截留效率均超过39%。且添加剂对烟气中苯酚的截留能力大于对烟气中焦油的吸附能力,表明功能添加剂具有选择性降低卷烟烟气中苯酚的作用。

Ordered mesoporous carbons with high specific surface areas were prepared by evaporation induced triconstituent co-assembly method,with phenolic resin oligomers as organic precursor,tetraethyl orthosilicate(TEOS) as inorganic precursor and segmented copolymer F127 as template.The composition,structure and morphology of the prepared samples were characterized by XRD,TEM,FTIR,Raman and N2 sorption techniques.The prepared ordered mesoporous carbons had highly ordered two dimension-hexagonal mesostructured with the average aperture of 6.5nm,and the specific surface area and pore volume reached up to 2281m2/g and 1.92cm3/g,respectively.

Hollow core, mesoporous shell carbon nanospheres (HCMSs) with large bimodal mesopores (6.4 and 3.1 nm) and high surface area (1704 m(2) g(-1)) have been synthesized by a triconstituent surface co-assembly of monodisperse silica nanospheres method. The resulted HCMS show a high specific capacity of 251 F g(-1) at 50 mV s(-1) in 2 M H(2)SO(4) and long cyclic life.

Anticoagulation factor II (ACF II) isolated from the venom of Agkistrodon acutus is an activated coagulation factor X (FXa)-binding protein with both anticoagulant and hypotensive activities. The thermodynamics of the binding of alkaline earth metal ions to ACF II and their effects on the stability of ACF II and the binding of ACF II to FXa were investigated by isothermal titration calorimetry, fluorescence, differential scanning calorimetry, and surface plasmon resonance. The binding of ACF II to FXa does not have an absolute requirement for Ca 2+ . Mg 2+ , Sr 2+ , and Ba 2+ can induce the binding of ACF II to FXa. The radii of the cations bound in ACF II crucially affect the binding affinity of ACF II for cations and the structural stability of ACF II against guanidine hydrochloride and thermal denaturation, whereas the radii of cations bound in FXa markedly affect the binding affinity between ACF II and FXa. The binding affinities of ACF II for cations and the capacities of metal-induced stabilization of ACF II follow the same trend: Ca 2+ > Sr 2+ > Ba 2+ . The metal-induced binding affinities of ACF II for FXa follow the trend Mg 2+ > Ca 2+ > Sr 2+ > Ba 2+ . Although Mg 2+ shows significantly low binding affinity with ACF II, Mg 2+ is the most effective to induce the binding of ACF II with FXa. Our observations suggest that in blood the bindings of Ca 2+ in two sites of ACF II increase the structural stability of ACF II, but these bindings are not essential for the binding of ACF II with FXa, and that the binding of Mg 2+ and Ca 2+ to FXa may be essential for the recognition between FXa and ACF II. Like Ca 2+ , the abundant Mg 2+ in blood also plays an important role in the anticoagulation of ACF II.

A new chromatographic fingerprinting method has been established for quality control of tobacco flavor.Three different extraction techniques,simultaneous distillation extraction(SDE),liquid-liquid extraction and solid-phase micro-extraction were evaluated for isolation of the components of interest.After comparison of their performance,a combination of SDE and GC-MS was used for simple,reliable,and reproducible development of a chromatographic fingerprint of tobacco flavor.Twelve samples of the flavor from different batches were used to establish the fingerprint.Thirty-nine volatile components of the tobacco flavor samples,accounting for 86.54% of the total content,were identified and quantified.The 12 samples had 28 peaks in common.The method of fingerprint analysis was then validated on the basis of the relative retention times and relative peak areas of the common peaks,sample stability,and similarity analysis.The similarities of the 12 samples of tobacco flavor were>0.80,showing that samples from different batches were,to some extent,consistent.The chromatographic fingerprint developed was successfully used to differentiate tobacco flavor samples from tobacco extract prepared from tobacco leaf,both by similarity comparison and by principal-components projection analysis.The method can be used for quality control of tobacco flavor.

A new 1-naphthalenamine(NNA) specific molecularly imprinted polymer(MIP) was synthesized based on non-covalent interaction.The molecular recognition characteristics of the template polymer were evaluated by UV,IR,XPS and 1H NMR.The NNA-MAA complexes of 1∶1 mole ratio were obtained by nitrogen bonding and the complexes possessed better stabilization(K=5.537×104L/mol).Furthermore,hydrogen atom of the amino group in 1-naphthalenamine is hydrogen-bond acceptors.Hydrogen atom of the lactam group in methacrylic acid is hydrogen-bond donor,being the predominant binding sites interacting with 1-naphthalenamine.The adsorption characteristics of MIP was evaluated by equilibrium adsorption experiment.The results indicate that MIP performs highly selectivity to 1-naphthalenamine.

Two glycosides of benzyl alcohol and phenethyl alcohol as flavour precursors have been synthesized and their structures were characterized by IR,(1)H NMR spectra and ESI-MS. Their pyolysis products are investigated by the on-line pyrolysis gas chromatography-mass spectroscopy. Their transfer efficiency from tobacco to cigarette smoke was determined for evaluation of its possibility of application.

The present paper aims at the difficulty in separation and pre-concentration of rare-earth elements.Erbium(Ⅲ)-ion imprinted silica gel(Er-IISG)sorbent was synthesized by surface imprinting technique and was employed as a selective solid-phase extraction material for determination of Er(Ⅲ) from other lanthanide ions.The higher selectivity coefficient of Er-IISG for Er(Ⅲ) in the presence of competive ions such as Tb(Ⅲ),Dy(Ⅲ) and Tm(Ⅲ) was above 390,which was 42 times over non-ion imprinted silica gel(NISG).The static adsorption capacity was 58.01mg/g.The Er-IISG offered a fast kinetics for the adsorption and desorption of Er(Ⅲ).The developed method was rapid,selective,sensitive and applicable to the determination of trace Er(Ⅲ) in environmental samples with complicated matrix.