The Food In The Six Hbcd And Tetrabromobisphenol A Detection Technology And Exposure Assessment

Hexabromocyclododecane(HBCD) and Tetrabromobisphenol A(TBBPA) are two brominated flame retardants(BFRs) currently in use all over the world.They are now ubiquitous contaminants in wildlife,as well as in humans.Studies indicated that BFRs are bioaccumulative and persistent compounds,thus they should be regarded as persistent organic pollutants(POPs).However,we are still lacking information on the contaminant level of BFR in food and,especially,in human being.It is generally accepted that human exposure to BFRs is mainly through diet.However,there were relatively few studies reporting the presence of HBCD and TBBPA in the foodstuffs or human milk from China. In order to assess dietary exposure of Chinese adults and nursing Infants to TBBPA and HBCD,a UPLC-MS/MS method was developed for simultaneous determination of TBPPA and HBCD in foods of animal origins.On the basis of the analytical method,the levels of HBCD diastereomers(α,β,andγ-HBCD) and TBBPA in two categories of samples: pooled human milk samples collected in 2007 from 12 provinces of China and TDS samples from the fourth Chinese total diet study in 2007,were examined.Based on the obtained data,the human daily intake of TBBPA and HBCD via human milk or food consumption in China was estimated and compared.In order to explore the acute toxicity effect of TBBPA or HBCD to human being or mammal,metabonomics methodology was used to investigate the TBBPA/HBCD induced injure in rats.1.Method for the determination of TBBPA and HBCD in foodAn ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for simultaneous determination ofα,β,γ-HBCD and TBBPA in foods of animal origin,include meat and meat products,egg and egg products,milk and milk products and aquatic foods.The methodology was based on solid-liquid extraction,GPC cleanup or SPE cleanup,and isotope dilution.Samples were extracted by Soxhlet extraction or accelerated solvent extraction(ASE).The extract was purified by gel permeation chromatography(GPC) pretreatment or concentrated sulfuric acid treatment follow by SPE cleanup.The separation was carried out on a UPLC BEH C18 reversed-phase column,using methanol-acetonitrile and water as the gradient elution solvent,the four BFRs were eluted within 5min.A triple quadrupole mass spectrometer equipped with electrospray ionization source was operated in negative ion mode.Multiple reaction monitoring(MRM) was employed for quantitative measurement.The MRM transitions monitored were as 640.7→80.7 for HBCD,542.6→447.6 for TBBPA.Good linearities were found within the ranges of 5-250ng/mL with the LOD of 10-100pg/g.The mean recovery of different spiking level varied from 86.8%to 110.5%in different foodstuffs,with the relative standard deviations(RSDs) between 1.07%and 14.4%.The results demonstrated that the UPLC-MS/MS method developed is highly effective for analyzing trace amounts of TBBPA and HBCDs in animal original foods.2.Contamination level in foods and dietary exposure assessment by the Chinese Total Diet StudyOn the basis of UPLC-MS/MS analysis,TBBPA andα,β,γ-HBCD were determined in 48 Chinese total diet study(TDS) samples collected from 12 provinces in 2007.In the four food groups include meat,egg,milk and aquatic foods,levels of TBBPA ranged from＜LOD to 2044 pg/g lw.Theα-HBCD diastereoisomer was generally the most abundant isomer comparing withβ-andγ-HBCD.Levels of HBCD ranged from＜LOD to 9208pg/g lw.The highest contamination level of TBBPA and HBCD were both found in the aquatic food group.The lowest concentrations occurred in the egg group and milk group.Daily dietary intakes of TBBPA andΣHBCD for the Chinese were estimated by multiplying the measured concentrations of TBBPA andΣHBCD with the daily consumption data.The medium bound(＜LOD=1/2LOD) EDI_TBBPA for a "reference" man (male adult,63kg bodyweight) via animal origin foods was 256 pg/kg bw/day and EDI_ΣHBCD was 432 pg/kg bw/day.Meat and meat products were the main source in the total dietary intake of TBBPA andΣHBCD.3.Contamination level of HBCD and TBBPA in humanTBBPA andα,β,andγ-HBCD were determined in 24 pooled human milk samples collected from 12 provinces in 2007.Levels of TBBPA ranged from＜LOD to 5124 pg/g lw with mean concentration of 941pg/g lw.Theα-HBCD diastereoisomer,which ranged from＜LOD to 2776 pg/g lw with mean concentration of 1050pg/g lw,was the most abundant isomer as same as in animal original foods.However,levels of TBBPA and HBCD in human milk were higher than that in foods.It was indicated that levels of HBCDs or TBBPA are elevated in species at the top of the food chain,which clearly points toward biomagnification.It also suggests that human exposure to TBBPA/HBCDs may occur from multiple routes,besides from food,intakes from indoor air or dust is probably another major route.The average estimated daily intake(EDI) of TBBPA via human milk for nursing infants was 5094 pg/kg bw/day with a range 320-37240 pg/kg bodyweight (bw)/day,while that ofΣHBCD was 5837 pg/kg bw/day with a range 670-17320 pg/kg bw/day.Which were much higher than that for a male adult.It is indicated that the body BFRs burden of a nursing infant in China is much higher than that of adult.The possible toxicological impact of such a high daily intake should certainly be investigated.4.Within the past few years,metabonomics,as a new part of system biology,has gained great prominence besides genomics,transcriptomics and proteomics.In this paper, metabolism disorders induced by TBBPA or HBCD in a rat model with different dosage of intoxication were studied by metabonomics.Ultra performance liquid chromatography (UPLC) coupled with quatropde-time of flight(Q-TOF) mass spectrometer were used to analyze serum and urine obtained from rats treated with a range of doses of TBBPA or HBCD,with the objective to reveal the characteristics of the damage caused by these BFRs and identify the latent biomarkers.SD rats were randomly assigned into dosed groups and control group,rats were given daily TBBPA(30,300mg/kg) or HBCD(30,300mg/kg) for 7 days and sacrificed on Day 8 for serum collecting.24h urine samples were collected every day before dosing.All serum and some urine samples were performed UPLC-Q-TOF-MS analysis.A normalization method was performed to match the peaks between the chromatograms.A supervised learning algorithm i.e.partial least squares discriminant analysis(PLS-DA) was used for the pattern recognition and visualization.The PLS-DA score plot presented distinct separation between control group and dosed groups of TBBPA or HBCD.It was demonstrated that the metabolic patterns of the rats have been disturbed after oral dosed.According to score plot of TBBPA dosed group and control group,a positive correlation of dose dependent effect and time dependent effect was found. However,the score plot of HBCD indicating that the metabolic patterns might not be further deteriorated by increasing HBCD dosage or duration of administration.When comparing the control and dosed groups,the difference in the concentrations of some kinds of compounds include amino acid,glucoside and phospholipid etc was significant.It is indicated that these compounds should be the latent biomarkers.