Xu D.,Inspection and Quarantine Technology Center |
Deng X.,Animal Plants and Foods Inspection and Quarantine Technical Center |
Fang E.,Inspection and Quarantine Technology Center |
Zheng X.,Inspection and Quarantine Technology Center |
And 5 more authors.
Journal of Chromatography A | Year: 2014
A rapid and sensitive method was developed for the determination of 23 phthalates in food samples including milk-based products, distilled liquor, wine, beverage, grain, meat, oil, biscuit (cookie), and canned food by liquid chromatography tandem mass spectrometry (LC-MS/MS). Liquid samples were exacted by acetonitrile, while solid samples were prepared by QuEChERS or glass-based SPE methods. The 23 phthalates were separated on Poroshell 120 EC-C18 column and followed by positive electrospray ionization as well as multi-reaction monitoring provided by a triple-quadrupole tandem mass spectrometer. To reduce contamination, the plastic materials were avoided in sample handling and preparation The LODs were between 0.8 and 15μgkg-1 and LOQs were between 10 and 100μgkg-1. By using different concentrations: 100, 500, and 1000μgkg-1) for DINP and DIDP; 50, 100, and 1000μgkg-1 for other 21 phthalate compounds, the spiked recoveries were within 75.5-115.2% and the relative standard deviations (RSDs) were in the range of 3.2-18.9%. The proposed protocol was then applied to the analysis of 623 real samples collected from the two sides of the Taiwan Straits, and the DEHP was found in almost all samples tested in this study, with levels ranging from 0.02 to 2685mgkg-1. The present study demonstrated a rapid, sensitive, and accurate method for determining 23 phthalates in foodstuffs. © 2013 Elsevier B.V.
Wei S.,Jinan University |
Zhao H.,Inspection and Quarantine Technology Center |
Xian Y.,Jinan University |
Hussain M.A.,Lincoln University at Christchurch |
Wu X.,Jinan University
Diagnostic Microbiology and Infectious Disease | Year: 2014
A multiplex polymerase chain reaction (PCR) assay that can simultaneously detect 4 major Vibrio spp., Vibrio alginolyticus, Vibrio parahaemolyticus, Vibrio vulnificus, and Vibrio cholerae, in the presence of an internal amplification control (IAC) was developed. Species-specific PCR primers were designed based on the gyrB gene for V. alginolyticus, the collagenase gene for V. parahaemolyticus, the vvhA gene for V. vulnificus, and the ompW gene for V. cholerae. Additionally, an IAC primer pair was designed in conserved regions of the bacterial 16S rRNA gene that is used to indicate false-negative results. A multiplex PCR method was developed after optimization of the reaction conditions. The specificity of the PCR was validated by using 83 Vibrio strains and 10 other non-Vibrio bacterial species. The detection limit of the PCR was 10 CFU per tube for V. alginolyticus, V. parahaemolyticus, V. vulnificus, and 105 CFU per tube for V. cholerae in mixed conditions. This method was used to identify 69 suspicious Vibrio isolates, and the results were consistent with physiological and biochemical tests. This multiplex PCR method proved to be rapid, sensitive, and specific. The existence of IAC could successfully eliminate false-negative results for the detection of V. alginolyticus, V. parahaemolyticus, V. vulnificus, and V. cholerae. © 2014 Elsevier Inc.
Liu T.,Shandong Agricultural University |
Cao P.,Inspection and Quarantine Technology Center |
Geng J.,Inspection and Quarantine Technology Center |
Li J.,Inspection and Quarantine Technology Center |
And 3 more authors.
Food Chemistry | Year: 2014
High-performance liquid chromatography with UV detection was used to detect four triazines in milk. An efficient pretreatment method known as cloud point extraction (CPE) was proposed for extracting and preconcentrating analytes. The parameters of CPE including surfactant type and concentration, electrolyte, sample pH, incubation temperature and duration were investigated. Under optimal conditions, satisfying recoveries in the range of 70.5-96.9% were achieved for four triazines. The limits of detection ranged from 6.79 to 11.19 μg L -1. The linear range of quantitation for the four triazines was 50- 2000 μg L-1, and the correlation coefficients of the calibration curves were all 0.9999. The results demonstrated that the proposed method was efficient and reliable for the determination of triazine herbicides in milk samples. © 2013 Elsevier Ltd.
Fang E.,Inspection and Quarantine Technology Center |
Zhang Z.,Inspection and Quarantine Technology Center |
Chen X.,Xiamen University
Analytical Chemistry | Year: 2015
By coupling thin-film microextraction (TFME) with surface-enhanced Raman scattering (SERS), a facile method was developed for the determination of sulfur dioxide (SO2), the most effective food additive in winemaking technology. The TFME substrate was made by free settling of sea urchin-like ZnO nanomaterials on a glass sheet. The headspace sampling (HS) procedure for SO2 was performed in a simple homemade device, and then the SO2 was determined using SERS after uniformly dropping or spraying a SERS-active substrate (gold nanoparticles, AuNPs) onto the surface of the TFME substrate. A reproducible and strong SERS response of the SO2 absorbed onto the ZnO substrate was obtained. After condition optimization, the SERS signal intensity at a shift of 600 cm-1 and the SO2 concentration showed a good linearity in the range of 1-200 μg/mL, and the linear correlation coefficient was 0.992. The detection limit for SO2 was found to be 0.1 μg/mL. The HS-TFME-SERS method was applied for the determination of SO2 in wine, and the results obtained agreed very well with those obtained using the traditional distillation and titration method. Analysis of variance and Student t test show that there is no significant difference between the two methods, indicating that the newly developed method is fast, convenient, sensitive and has selective characteristics in the determination of SO2 in wine. © 2014 American Chemical Society.
Gao F.,Fujian Agriculture and forestry University |
Chang F.,Fujian Agriculture and forestry University |
Shen J.,Inspection and Quarantine Technology Center |
Shi F.,Fujian Agriculture and forestry University |
And 2 more authors.
Archives of Virology | Year: 2014
The complete sequence of GF_YL20, a potato virus Y (PVY) isolate from China, encodes a polyprotein of 3,061 amino acids. Sequence analysis indicates that GF_YL20 has a genomic structure different from previously reported PVY strains. It shares 99 % nucleotide sequence identity with PB209 (PVYN:O) except in VPg, but more than 97 % nucleotide sequence identity with the VPg of Mont (PVYN), PB312 (PVYNTN) and HN2 (SYR-I). Phylogenetic analysis indicates that GF_YL20 is a novel N:O recombinant with three recombination breakpoints. © 2014, Springer-Verlag Wien.
Huang Y.-J.,Hangzhou Normal University |
Zhang X.-H.,Zhejiang University |
Hua Z.-J.,Inspection and Quarantine Technology Center |
Chen S.-L.,Hangzhou Normal University |
Qi G.-R.,Zhejiang University
Macromolecular Chemistry and Physics | Year: 2010
Highly active CaCl2-modified Zn-Co(III) DMCs were prepared. XRD results showed that the modified catalyst Ca-DMC containing 0.14 wt.-% CaCl 2 was amorphous. A higher polymer yield (>61 kg polymer/g catalyst) and a shorter induction period for ROP of PO were observed for Ca- DMC than for unmodified DMC catalysts. An initiator had an inhibitory effect on the initiation and polymerization rate of PO ROP. As the molar ratio of the initiator functionality to the catalyst was increased, the reaction rate and polymer yield decreased, whereas the induction period increased. An increase in reaction temperature tended to reduce the polymer yield and broaden the MWD. The 13C NMR spectrum for an oligomer from a model polymerization without an initiator revealed that the main terminal unit of the polymer was -CH 2CH(CH3)OH because H2O in the system participated in reaction initiation. Cl- and t-BuOH may also initiate the reaction according to the small amounts of terminal -CH2Cl and -OC(CH3)3 units observed by 13C NMR spectroscopy. On the basis of common characteristics and some new evidence for DMC catalysis, a mechanism similar to a classical coordination insertion process is proposed. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Zhan J.,Zhejiang University |
Zhan J.,Inspection and Quarantine Technology Center |
Zhong Y.-Y.,Inspection and Quarantine Technology Center |
Yu X.-J.,Inspection and Quarantine Technology Center |
And 5 more authors.
Food Chemistry | Year: 2013
A rapid, simple and generic analytical method which was able to simultaneously determine 220 undesirable chemical residues in infant formula had been developed. The method comprised of extraction with acetonitrile, clean-up by low temperature and water precipitation, and analysis by ultra performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (UPLC-ESI-MS-MS) using multiple reaction monitoring (MRM) mode. Most fat materials in acetonitrile extract were eliminated by low temperature clean-up. The water precipitation, providing a necessary and supplementary cleanup, could avoid losses of hydrophobic analytes (avermectins, ionophores). Average recoveries for spiked infant formula were in the range from 57% to 147% with associated RSD values between 1% and 28%. For over 80% of the analytes, the recoveries were between 70% and 120% with RSD values in the range of 1-15%. The limits of quantification (LOQs) were from 0.01 to 5 μg/kg, which were usually sufficient to verify the compliance of products with legal tolerances. Application of this method in routine monitoring programs would imply a drastic reduction of both effort and time. © 2012 Elsevier Ltd. All rights reserved.
He Q.,Inspection and Quarantine Technology Center
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui | Year: 2010
An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/ MS) method was developed for the determination of altenuene (ALT), alternariol (AOH), tentoxin and alternariol monomethyl ether (AME) in apple juice concentrate (AJC). The sample was diluted with water, and then cleaned up with a PS DVB column. The quantification was carried out using an external standard method. The UPLC was performed on a BEH C18 column (50 mm x 2.1 mm, 1.7 microm) using a gradient elution of acetonitrile and water. The MS/MS was performed with multiple reaction monitoring (MRM) mode. The limits of quantification of the four Alternaria toxins were between 1.0 and 5.0 microg/L. The recoveries were 77.8%-117.2% with the relative standard deviations less than 9.7%. The method is sensitive, stable and reliable. It's suitable for the quantitative and qualitative analyses of the four Alternaria toxins in AJC.
Zhang J.,Inspection and Quarantine Technology Center
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui | Year: 2011
A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/ MS) method was established for the determination of spinosyns A and D residues in foodstuffs. The food samples were extracted with acetonitrile-water (50:50, v/v), and then purified by an HLB solid phase extraction (SPE) column. The analytes were determined by HPLC-MS/MS and quantified by external standard method. The mass spectrometric detection was operated with electrospray in positive ionization mode and the spinosyns A and D were identified in multiple reaction monitoring (MRM) mode. The linear range of the method was 1-20 microg/L, with the correlation coefficient (r2) of 0.999 9. No significant matrix effect was found for spiked samples. The recoveries of spinosyns A and D spiked in food were 76.2%-114.0% at the spiked levels of 1-10 microg/kg. The relative standard deviations (RSDs) were less than 10%. The limits of detection (LODs) and quantification (LOQs) were 0.2 microg/kg and 0.5 microg/kg for spinosyn A, 0.5 microg/kg and 1.0 microg/kg for spinosyn D, respectively. The proposed procedure was applied to the analysis of 969 real samples from Xiamen, Fujian Province (China), of which 15 positive samples were found. The results showed that the proposed method is sensitive and accurate for the determination of spinosyns A and D in foodstuffs.
Yin Y.-g.,CAS Research Center for Eco Environmental Sciences |
Chen M.,CAS Research Center for Eco Environmental Sciences |
Peng J.-f.,Inspection and Quarantine Technology Center |
Liu J.-f.,CAS Research Center for Eco Environmental Sciences |
Jiang G.-b.,CAS Research Center for Eco Environmental Sciences
Talanta | Year: 2010
A novel and simple solid phase extraction (SPE)-high performance liquid chromatography (HPLC)-inductively coupled plasma mass spectrometry (ICP-MS) method was developed for determination of inorganic mercury (IHg), methylmercury MeHg and ethylmercury (EtHg) in water samples in the present work. The procedure involves pre-functionalization of the commercially available C18 SPE column with dithizone, loading water sample, displacement elution of mercury species by Na2S2O3 solution, followed by HPLC-ICP-MS determination. Characterization and optimization of operation parameters of this new SPE procedure were discussed, including eluting reagent selection, concentration of eluting reagent, volume of eluting reagent, effect of NaCl and humic acid in sample matrix. At optimized conditions, the detection limits of mercury species for 100 mL water sample were about 3 ng L-1 and the average recoveries were 93.7, 83.4, and 71.7% for MeHg, IHg and EtHg, respectively, by spiking 0.2 μg L-1 mercury species into de-ion water. Stability experiment reveals that both the dithizone-functionalized SPE cartridge and the mercury species incorporated were stable in the storage procedure. These results obtained demonstrate that SPE-HPLC-ICP-MS is a simple and sensitive technique for the determination of mercury species at trace level in water samples with high reproducibility and accuracy. © 2010 Elsevier B.V. All rights reserved.