ABSTRACT
Objective@#To analyze liquid milk exposure of thiocyanate among Chinese population and preliminarily assess its health risk.@*Methods@#A total of 2 059 raw milk samples were collected during 2013 and 2014 from 12 Chinese provinces, New Zealand and Netherlands. Farms were chosed according to the main sources of dairy companies, the distribution of farms and the yield of milk. Content of thiocyanate were detected by ion chromatography. Liquid milk consumption data were taken from Chinese beverage and alcoholic beverage consumption survey in 18 cities or counties in 9 provinces, including 16 775 subjects older than 3. A simple distribution model was used to estimate the exposure of thiocyanate from liquid milk. The tolerable daily intake (TDI) of thiocyanate was made 0.08 mg·kg-1·d-1. Then the exposures of different age groups were compared with TDI.@*Results@#Finally, 1 331 samples out of 2 059 were detected to contain thiocyanate. The detection rate was 65%. The average concentration of thiocyanate was 2.11 mg/kg, with a range of 0.10-16.20 mg/kg. The general population's consumption of thiocyanate by drinking liquid milk was 0.001 mg · kg-1 · d-1, which was lower than TDI. The P95 of general population and consumers were 0.009 mg · kg-1 · d-1 and 0.020 mg·kg -1·d-1 respectively, which were also lower than TDI. Mean exposures of population aged 3-6, 7-12, 13-17, 18-59 as well as elderly aged 60 and above were 0.007, 0.003, 0.002, 0.001 and 0.001 mg · kg-1·d-1 respectively, which were all lower than TDI.@*Conclusion@#The results suggested that the health risk of thiocyanate exposure by drinking liquid milk among Chinese population was at a low level. However, milk products for children deserve more concern.
ABSTRACT
A method was developed for simultaneous determination of pyrrolizidine alkaloids and isoquinoline alkaloids in honey by dispersive solid phase extraction and high performance liquid chromatography-tandem mass spectrometry ( QuEChERS-HPLC-MS/MS) . The honey samples were extracted with acetonitrile solution and cleaned up with PSA absorbent. Agilent Poroshell 120 SB-C18 chromatographic column was used to separate alkaloids with high sensitivity and satisfactory resolution. The identification and quantification were achieved by using electrospray ionization in positive ion mode ( ESI+) with multiple reaction monitoring (MRM). Matrix-matched calibration curves with good correlation coefficients (R2>0. 99) were obtained in the concentration range of 0. 1-100 μg/L. The recoveries of the spiked samples at 1-100 μg/kg were in the range of 70% to 110% with the RSD of intra-day and inter-day lower than 15% and 20%, respectively. The limits of detection ( LOD) and limits of quantification ( LOQ) for all alkaloids were 0. 3 and 1. 0 μg/kg, respectively. This method was successfully applied to the simultaneous determination of pyrrolizidine alkaloids and isoquinoline alkaloids for quantification and confirmation in honey samples.