1.Preparation and Evaluation of Core-Shell Resveratrol Molecularly Imprinted Microspheres
Minglei ZHANG ; Zhaohui ZHANG ; Li LIU ; Liji ZHANG ; Lihua NIE
Chinese Journal of Analytical Chemistry 2010;38(1):129-132
Employing resveratrol as template molecule, acrylamide as functional monomer and ethyleneglycol dimethacrylate as cross-linkers, a core-shell resveratrol imprinted microspheres was prepared based on the surface of SiO_2 with a surface imprinting technique.The molecularly imprinted microsphere was characterized by infrared spectroscopy and scanning electron microscopy, and the results showed that the surface grafting of molecularly imprinted polymer-shell particle on SiO_2 was successful and the particles were evenly distributed.High performance liquid chromatography was also used to investigate the imprinted microsphere adsorption per formance, and the results showed that the imprinted microsphere exhibited good recognition performance.The maximum adsorption capacities were Q_(maxl)=9.087 mg/g and Q_(max2)= 13.80 mg/g by the model of Scatchard analysis.The imprinted micospheres was applied to separate resveratrol from the extraction of rhizoma polygoni cuspidate successfully.
2.Determination of Cyromazine and Dicyclanil Residues on Greasy Wool by High Performance Liquid Chromatography
Yuanmu FAN ; Xuejun YU ; Xiaojun GU ; Juyi YIN ; Yajun QIU ; Shubing CHEN ; Jie CHEN ; Jia ZHAN ; Xiaoyu HE ; Jun CHEN ; Shaotang HUANG
Chinese Journal of Analytical Chemistry 2010;38(1):113-116
A method for the determination of cyromazine and dicyclanil residues on greasy wool was developed with HPLC and confirmed with HPLC-MS/MS.The cyromazine and dicyclanil residues on greasy wool were extracted with 1% trichloroacetic acid solution with ultrasonic, and cleaned up by MCX SPE column.The HPLC separation was performed on a Hypersil NH_2 using water-acetonitrile (V/V) as the mobile phase with gradient elution and detected at the wavelength of 214 nm.The corroboration method of HPLC-MS/MS was used with electro-spray ionization of positive ion mode.The [ M + H ]~+ and characteristic ions of dicyclanil were m/z 191.0, 150.0 and 163.0, and cyromazine were m/z 167.0, 85.0 and 125.0.The linear ranges of cyromazine and dicyclanil were 0.05-5.0 mg/L.There were good linear relationships between the peak area and concentration in the linear range.The correlation coefficient was 0.9999.The detection limit of cyroma zine was 0.02 mg/kg, and dicyclanil was 0.01 mg/kg.The average recoveries of cyromazine and the dicycla nil were 95.0%-99.9% and 83.6%-92.2%, respectively.
3.Preparation and Application of Naringin Sensor Based on Molecularly Imprinting Technique
Xiuling MA ; Riyao CHEN ; Xi ZHENG ; Xiao CHEN ; Zhen CHEN
Chinese Journal of Analytical Chemistry 2010;38(1):100-104
The sensor of naringin(NG), a non-electroactive substance, was prepared based on the molecular imprinting technique.Using cyclic voltammetry technique (scan rate is 100 mV/s), the naringin imprinting sensitive film, poly-o-aminophenol was coated on the surface of a graphite electrode in the presence of naringin which was considered as the template, and characterized by SEM and X-ray reflective spectrophotometry (XRR).Using K_3Fe(CN)_6 as an electroactive marker, the electrochemical properties of the NG sensor were investigated by CV, electrochemical impedance spectroscopy (EIS), differential pulse voltammmetric and chronoamperometric.The results showed that the imprinted electrode was significantly different from the non imprinted electrode in morphologies and electrochemical properties, and a linear relationship between the peak current and the naringin concentration was found in the range of 6.0 × 10 ~(-5)-1.4 × 10 ~(-4) mol/L with a detec tion limit of 1.6 × 10 ~(-5) mol/L.Moreover, the imprinted electrode exhibited a good selectivity and rapid response to the naringin template molecules, as well as an excellent reproducibility(RSD = 1.8 %, n=5).
4.Identification of Mequindox and Its Metabolites by High Performance Liquid Chromatography Combined with Ion Trap-Time of Flight-Mass Spectrometry
Yingchun LIU ; Hongbin SI ; Limin HE ; Huanzhong DING ; Xianhui HUANG ; Jianxin CHEN ; Zhangliu CHEN ; Zhenling ZENG
Chinese Journal of Analytical Chemistry 2010;38(1):82-86
The chemical structures of mequindox related metabolites in chicken plasma had been investigated using high performance liquid chromatography combined with linear ion trap quadrupole(LC-ESI/LTQ) and high performance liquid chromatography combined with ion trap-time of flight-mass spectrometry (LC-ESI/IT-TOF).Samples were separated by Hypersil BDS C_(18) and symmetry Shield columns, respectively, and 0.01% formic acid aqueous(A) and methanol(B) were used as mobile phase with gradient elution.Electros pray ionization mass spectrometric(ESI) source was used and operated in positive ion mode.When chickens were orally administered with mequindox at dosage of 20 mg/kg, blood samples were collected from the brachi al vein.Mequindox and its metabolites were extracted by the mixture of acetonitrile and acetoacetate (3:2, V/V).After solvent evaporated, the residue was dissolved in 30% methanol aqueous and the solution was detected by LC/IT-TOF MS and LC-ESI/LTQ.The molecule weight from LC-ESI/IT-TOF was analyzed by software Shimadzu's Composition and the mass chromatogram from LC-ESI/LTQ was analyzed by software Xcalibur 2.0.7.According to the molecular weight and MS~n data, referring the metabolic reaction rules, five chemical structures of mequindox related metabolites in chicken plasma were identified.Metabolites (M1-M4) were synthesized to verify the structure of metabolites.The metabolites are 3-methyl-2-(1-hydroxy) ethyl-qui-noxaline-N~1,N~4-dioxide(Ml), 3-methyl-2-(1-hydroxy) ethyl-quinoxaline-N~4-oxide(M2), 3-methyl-2-acetyl-quinoxaline-N~4-oxide, 3-methyl-2-acetyl-quinoxaline (M4), 3-hydroxymethyl-2-(1-hydroxy) ethyl-quinoxa-line-N~1,N~4-dioxide (M5).
5.Determination of Alkylphenol in Water Samples by Stir Bar Sorptive Extraction Based on Poly (vinylimidazole-divinylbenzene) Monolithic Material and Liquid Chromatographic Analysis
Fuhua LIN ; Ningning QIU ; Xiaojia HUANG ; Dongxing YUAN
Chinese Journal of Analytical Chemistry 2010;38(1):67-71
A method for the determination of bisphenol A, octyphenol, nonylphenol in water samples was developed using stir bar sorptive extraction (SBSE) based on poly (vinylimidazole-divinylbenzene) monolithic material (SBSEM) combined with high performance liquid chromatography with diode array detection.To achieve the optimum extraction performance, several main extraction parameters, including extraction and desorption time, pH value and contents of inorganic salt in the sample matrix, were investigated.Under the optimized experimental conditions, the method showed good linearity and repeatability, low detection limits (S/N = 3) and quantification limits (S/N = 10) of the proposed method for the target compounds were achieved within the range of 0.13-0.66 and 0.44-2.19 μg/L, respectively.The extraction performance of SBSEM to the target compounds was also compared with commercial SBSE which used polydimethylsiloxane as coating.The proposed method was successfully applied to the determination of the target compounds in water samples.The recoveries of spiked target compounds in real samples ranged from 37.8%-101.1%.The results indicated that the developed method possessed advantages such as sensitivity, simplicity, low cost and high feasibility.
6.Simultaneous Determination of 16 Carcinogenic and Allergenous Dyestuffs in Toys by Ultra Performance Liquid Chromatography Tandem Mass Spectrometry
Qiang MA ; Hua BAI ; Chao WANG ; Qing ZHANG ; Wei MA ; Xin ZHOU ; Yiyang DONG ; Baolin WANG
Chinese Journal of Analytical Chemistry 2010;38(1):51-56
A comprehensive analytical method based on ultra performance liquid chromatography tandem mass spectrometry has been developed for the simultaneous determination of 16 carcinogenic and allergenous dye stuffs (acid red 26, basic red 9, disperse blue 1, acid violet 49, disperse blue 3, solvent yellow 1, dispersed blue 106, disperse orange 3, disperse yellow 3, basic violet 1, basic violet 3, disperse red 1, solvent yellow 3, disperse blue 124, solvent yellow 2 and disperse orange 37).Various toy samples, including textile, leath er, paper, wood, balloon, modeling clay, limitation tattoo and aqueous liquid, were extracted under ultrason ication.Qualitative and quantitative analysis was carried out for the analyte under the MRM mode after the chromatographic separation on Waters ACQUITY UPLC BEH C_(18)(50 mm x 2.1 mm, 1.7 μm) column.The limits of quantitation(LOQ) for the 16 dyestuffs were in the range of 1.0-8.0 μg/kg.The mean recoveries at the three spiked levels of 5-100 μg/kg were 81.3%-98.6%, with the intra-day precision less than 11% and the inter-day precision less than 14%.The method is accurate, rapid, sensitive, and adapt to the inspec tion of the 16 dyestuffs in toys.
7.Molecular Recognition Properties of p-Phenylenediamine-Imprinted Polymers
Tieli ZHANG ; Xiangjun MENG ; Junfang JIA ; Liling HAN
Chinese Journal of Analytical Chemistry 2010;38(1):33-38
Two p-phenylenediamine (p-PD)-imprinted polymers, P (MAA) and P (AA), were synthesized using methacrylic acid (MAA) and acrylamide(AA) as functional monomer, respectively, in order to prepare molecular recognition material with high selectivity for p-PD and explore the feasibility of methods such as molecular spectrometry and computational approach of quantum chemistry for the selection of functional mono mer with high imprinting efficiency.The molecular recognition properties of the imprinted polymers were evaluated by high performance liquid chromatography.The results indicated that P(AA) exhibited no imprint ing effect for p-PD, while P(MAA) can bind p-PD selectively(k' =3.57), which showed remarkable imprint ing effect (IF=2.95), and p-PD and its analogues o-phenylenediamine and p-aminobenzoic acid can almost realize baseline separation on P (MAA) column in the mobile phase of methanol.Furthermore, we made a comparative study on the interaction of p-PD with MAA and AA by spectroscopic techniques such as UV and fluorometry as well as HF/6-31G~* computational approach.The results demonstrated that the complex of p-PD-MAA was more stable than that of p-PD-AA, which can give a good explanation for the molecular recog nition properties of P (MAA) and P (AA).The study indicated that both molecular spectrometry (UV and fluorometry)and computational approach of quantum chemistry can be employed as efficient means for the selection of efficient functional monomer.The results showed that fluorometry is sensitive and convenient for the choice of functional monomer if the template molecule is fluorescent.
8.Dual-Sensitive Probe of 2-( Benzoacridin) ethyl-imidazole-1-carboxylate for Determination of Aliphatic Amine with Fluorescence and Online Atmospheric Pressure Chemical Ionization Mass Spectrometry Identification
Yanyan FU ; Xiaoyan LI ; Zhiwei SUN ; Xueqin QIN ; Lian XIA ; Yourui SUO ; Yulin LI ; Jinmao YOU
Chinese Journal of Analytical Chemistry 2010;38(1):8-14
With comparison of three different methods for the marking of amines compound, an optimal deri vatization method was selected.5-(2-Hydroxyethyl) benzoacridine (HBA) reacts with coupling agent N,N'-carbonyldiimidazole(CDI) to form an activated amide intermediate 2-(benzoacridin) ethyl-imidazole-1-carbox-ylate(BAEIC).BAEIC, which is dual-sensitive probe, reacts preferably with amino compounds at 80 ℃ in the presence of 4-dimethylaminopyridine(DMAP) catalyst in N,N-dimethylformamide(DMF) solvent to give the corresponding sensitively fluorescent derivatives with an excitation maximum at λ_(ex) of 280 nm and an emis sion maximum at λ_(em) of 510 nm.BAEIC-amine derivatives simultaneously exhibited high ionization potential with percent ionization (changing from 5.62% to 58.08% in aqueous acetonitrile and from 2.14% to 56.58% in aqueous methanol.Derivatives were not only sensitive to fluorescence but also to MS ionizable potential.The fluorescence detection limits(5/iV = 3) were 0.12-0.59 μg/L.The online APCI-MS detection limits were 1.9-14 μg/L(S/N=5).
9.A New Fluorescence Immunosensing Method Based on Aptamer-plasmid Complex Amplification
Jing ZHU ; Yong HUANG ; Xiaoping JIANG ; Zhongyang TAN ; Jianhui JIANG ; Guoli SHEN ; Ruqin YU
Chinese Journal of Analytical Chemistry 2009;37(11):1596-1600
A novel simple,sensitive fluorescence immunosensing method based on aptamer-plasmid complex amplification was developed. This method utilized the specific recognition between antibody and antigen as well as aptamer-plasmid complex and the intercalation of fluorescence dye SYBR Green Ⅰ in the groove of duplex plasmid DNA in detection of Platelet-Derived Growth Factor BB (PDGF-BB). The immunoassay was performed in the microtiter wells in which rabbit anti PDGF-BB antibody was immobilized. The PDGF BB analyte was captured by the primary antibody and then sandwiched by the aptamer-plasmid DNA complex. The introduction of fluorescence dye SYBR Green Ⅰ allows for the detection of the sandwiched immunocomplex of antibody/anigen/aptamer-plasmid complex. Under the optimized conditions of salt concentration,ratio of aptamer to PUC19,and SYBR Green Ⅰ concentration,the proposed method offers a linear detection range from 0.2 μg/L to 200 μg/L with a detection limit of 0.1μg/L.
10.Analysis of Oligo-κ-carrageenan by Reversed Phase Ion-pair Ultra-Performance Liquid Chromatography Coupled with Electrospray Ionization-Time of Flight-Mass Spectrometry
Yang GAO ; Haimin CHEN ; Lilin XU ; Deying CHEN ; Xiaojun YAN
Chinese Journal of Analytical Chemistry 2009;37(11):1590-1595
A method was developed to elucidate the structures of sulfated oligosaccharides through establishment of an effective reversed phase ion pair ultra-performance liquid chromatography coupled with electrospray ionization time of flight mass spectrometry( RPIP-UPLC-ESI-TOF-MS). Heptylamine (20 mmol/L,pH4) has been selected as the ion-pairing agent.κ-Carrageenan oligosaccharides have been separated on BEH C_(18) column using MeOH/H_2O with 25% heptylammonium formate as eluent in linear gradient mode. Mass spectra were obtained by ESI-Q-TOF-MS in both positive and negative modes. κ-Carrageenan oligosaccharides were well separated up to pentatetrasaccharide,and ESIMS analysis for κ-carrageenan oligosaccharides up to hepta-cosasccharide. The results showed that all acid hydrolyzed κ-carrageenan oligosaccharides were odd sugars,which was further confirmed by polyacrylamide gel electrophoresis ( PAGE). The characteristic fragmentation pattern of ion-pair oligosaccharides in mass spectra can be applied for rapid structure identification.