RESUMO
Objective@#To observe the migration of 4,4＇-diaminostilbene-2,2＇-disulfonc acid-based fluorescent whitening agents ( DSD-FWAs ) in food packaging paper, so as to provide evidence for quality and safety supervision for paper packaging materials.@*Methods@#Forty-one paper samples with DSD-FWAs positive were made into 6 cm2 pieces and were soaked in four food simulants ( distilled water, 3% acetic acid, 10% ethanol and 95% ethanol, 10 mL each ). The experiment was carried out at the specified soaking temperature and time. The migration amounts of eleven DSD-FWAs were detected by high performance liquid chromatography-fluorescence detection. @*Results@#C.I.220, C.I.24, C.I.210, C.I.85, C.I.113, C.I.264, C.I.353 and C.I.357 were found in all the four food simulants. At the same time and temperature, the migration amount was highest in 10% ethanol, followed by distilled water, 3% acetic acid and 95% ethanol. C.I.220 was dissolved in all four food simulants, in the range of 20-90 ℃, the migration amount increased with soaking temperature; at 20 ℃, 40 ℃ and 60 ℃, the migration amount increased first and then stabilized over time.@*Conclusion@#The higher the storage temperature and the longer the storage time of paper packaging, the easier the DSD-FWAs in packaging paper migrate to food.
RESUMO
Objective@#To establish analytical method for the determination of vanadium ( V ), chromium ( Cr ), nickel ( Ni ), selenium ( Se ) and arsenic ( As ) in calcium based toothpastes by microwave digestion-inductively coupled plasma tandem mass spectrometry ( ICP-MS/MS ).@*Methods@#The 21 calcium based toothpaste samples from supermarkets and shops in the urban areas of Hangzhou were digested by 6 mL HNO3 and 1 mL H2O2 in microwave digestion system. Then He-SQ mode and O2-MS/MS mode of ICP-MS/MS were respectively used for the determination of Ni and V, Cr, Se, As. Indium ( In ) was used as internal standard for calibration. @*Results@# Good linear relationships were obtained for these five elements from 1.0 to 32.0 μg/L, with the correlation coefficients ranged from 0.999 3 to 1.000 0. The detection limits of the method ranged from 0.000 25 to 0.006 08 mg/kg. The recovery rates of standard spiking were 80.7%-105.7% when set at 0.4, 0.8 and 1.6 mg/kg, the recovery of standard reference material was 102.2%, and the relative standard deviations were 2.6%-4.8%. The concentrations of V, Cr, Ni, Se and As in 21 calcium based toothpaste samples were 0.024-1.935 mg/kg, 0.085-5.759 mg/kg, 0.090-3.673 mg/kg, <0.002 72-0.016 mg/kg and <0.006 08-0.321 mg/kg.@*Conclusion@#Microwave digestion-ICP-MS/MS can effectively reduce the interferences of polyatomic ions and doubly charged ions from the matrix, which is suitable for the determination of V, Cr, Ni, Se and As in calcium based toothpaste.