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Lin Q.-B.,Shanxi University | Li B.,Shanxi Border Inspection and Quarantine Bureau | Song H.,Shanxi Border Inspection and Quarantine Bureau | Wu H.-J.,Shanxi Border Inspection and Quarantine Bureau
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2011

The detection of silver in nano-plastic food packaging by microwave digestion coupled with either inductively coupled plasma atomic emission spectrometry (ICP-AES) or inductively coupled plasma mass spectrometry (ICP-MS) was investigated. Microwave digestion was optimised by trialling different acid mixtures. Both ICP-AES and ICP-MS showed good reproducibility, repeatability and recovery. For ICP-AES the limit of detection of the method (LODm) was 25.0 μg g -1, the limit of detection of the instrument (LODi) was 30.0 ng ml -1, the linear range was 0.10-10.0 μgml -1. The average recoveries for blank samples spiked with silver at 100, 250 and 500 μg g -1 ranged from 82.53% to 87.60%, and the relative standard deviations (RSDs) were from 1.79% to 8.30%. For ICP-MS analysis the LODm was 0.75 mg g -1, the LODi was 0.04 ng ml -1, the linear range was 0.20-500.0 ng ml -1, the RSDs were 2.26-4.79%, and the recoveries were 78.09-92.72% (spiked concentrations of 2.5, 5.0 and 10.0 μg g -1). These results indicate that the proposed method could be employed to analyse silver in nano-plastic food packaging. © 2011 Taylor & Francis.


Lin Q.-B.,Shanxi University | Wang T.-J.,Shanxi University | Song H.,Shanxi Border Inspection and Quarantine Bureau | Wang R.-Z.,Shanxi Analysis Center
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2011

Migration investigations were carried out on paper packaging materials in contact with solid food simulants. The aim was to investigate the migration behaviour of a series of isothiazolinone biocides (2-methyl-3-isothiazolinone (MI), 1,2-benzisothiazolinone (BIT) and 2-octyl-3-isothiazolinone (OIT)) as potential contaminants in paper materials, at varying temperatures and migration times, for the food simulants Tenax and Porapak. Based on the migration results, Tenax was found to be a good food simulant, and was more suitable than Porapak at high temperature. Petri dishes were found to be suitable for use as migration cells when the compounds to be evaluated were non-volatile. The amount of migration gradually increased with time and increasing temperature, finally reaching a steady value. When the temperature was higher than the boiling point of OIT, the migration rate decreased because of volatilization. The maximum migration rates were 3.4% for MI, 2.2% for BIT and 10.6% for OIT at high temperature (≥100 C). Two kinds of paper packaging for food were tested with the method that was developed. OIT in the papers migrated into the food simulants but the amount that migrated was less than 0.14 μg kg -1. © 2011 Taylor & Francis.


Lin Q.-B.,Shanxi University | Wang T.-J.,Shanxi University | Song H.,Shanxi Border Inspection and Quarantine Bureau | Li B.,Shanxi University
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2010

A novel and simple method to detect isothiazolinone-type biocides (2-methyl-3-isothiazolinone (MI), 5-chloro-2-methyl-3-isothiazolinone (CMI), 1,2-benzisothiazolinone (BIT) and 2-octyl-3-isothiazolinone (OIT)) in paper used for food packaging by ultrasonic extraction coupled with UPLC-MS/MS was developed. Parameters affecting process efficiency such as extraction solvents, UPLC mobile phase, gradient elution procedure and MS/MS conditions were studied to optimise the operating conditions. Using the optimised gradient elution procedure, the retention time was less than 6 min. The limits of detection (LODs) were found to be between 0.001 and 0.010 mgkg-1, which was validated using actual concentrations. After diluting the standard solution with a blank matrix, the linear calibration curve ranges were 0.002-1.000 mgkg-1for BIT and OIT, 0.005-1.000 mg kg-1 for MI, and 0.020-1.000mg kg-1for CMI, with correlation coefficients higher than 0.9985 (n=6). A good level of precision with a mean recovery greater than 81.3% and a relative standard deviation (RSD) less than 6.2% were also obtained. A methodology has been proposed for the analysis of isothiazolinones in paper. © 2010 Taylor & Francis.


Guo Z.,Shanxi University | Yao C.,Yuncheng University | Pan Y.,Shanxi Border Inspection and Quarantine Bureau | Tong H.,Shanxi University | Wei X.,Shanxi University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2011

[Ni(CH 3COO) 2·(NH 2CH 2Ph) 4] complex was synthesized using benzylamine and nickel acetate. The molecular structure of this complex was obtained by single crystal X-ray diffraction and characterized by elemental analysis, IR spectrometry and thermal analysis. The complex crystallized in the monoclinic space group P2(1)/n with cell parameters a = 11.234(4) , b = 6.459(2) , c = 22.647(8) , α = 90.00, β = 91.149(4)°, γ = 90.00, V = 1642.8(10) 3, Z = 2. The structure has been solved by direct methods and refined to R 1 = 0.0876 for 6377 observed reflections I > 2σ(I). Magnetic studies for complex show the data over the whole temperature range 5-300 K are well fitted to the Curie-Weiss law with C = 1.03 cm 3 K mol -1 and θ = -1.38 K. This fitting indicates antiferromagnetic interaction between the Ni ions and the metal center exhibits distorted octahedral coordination geometries. The thermal analysis was carried out to understand the thermal stability of the title complex. © 2011 Elsevier B.V.


Lin Q.-B.,Shanxi University | Xue Y.-Y.,Shanxi University | Song H.,Shanxi Border Inspection and Quarantine Bureau
Journal of Chromatographic Science | Year: 2010

A new method using gel permeation chromatography (GPC) cleanup followed by ultra-performance liquid chromatography combined with tandem mass spectrometry (UPLC-MS-MS) has been established for simultaneous determination of 18 carbamate pesticides in nuts (chestnut and pine nut). Recoveries obtained by fortifying nut (spiking at 0.02 mg/kg) range from 70.21% to 89.56%. The proposed method features good sensitivity. Its limits of quantification are low enough to allow pesticide residues to be determined at concentrations below the maximum residue levels legally accepted. The precision, expressed as relative standard deviation, ranges from 2.26% to 4.07%.

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