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To establish a simple and rapid ultra-performance liquid chromatography tandem mass spectrometry( UPLC-MS/MS) method for the determination of paraquat in serum, and to apply to the toxicokinetics of paraquat in rats.The samples separated on ACQUITY UPLC BEH HILIC column( 2. 1 mm × 50 mm, 1. 7 μm)with acetonitrile-50 mmol/L ammonium formate( 0. 4% formic acid) as mobile phase. The analytes were analyzed using ESI operating in the positive multiple reaction monitoring( MRM) mode. The method was used in toxicokinetic study in poisoned rat. Toxicokinetic parameters were calculated by WinNonlin 7. 0 statistical software.Paraquat was linear in the range of 0. 3-1000. 0 μg/L, the recovery rate was 89. 0%-107. 7%, and the relative standard deviation( RSD) 1. 9%-13. 8%( n = 6). Toxicokinetic parameterswere as follows: C_(max), T_(max)and T_(1/2) were( 46. 50 ± 5. 11) mg/L, 0. 167 h, ( 63. 2 ±16. 2) h, respectively.This method is highly sensitive, high accuracy and is suitable for the analysis of paraquat in the toxicokinetic study in rats.

To establish a rapid and sensitive method for the analysis of eight bisphenols in breast milk using small amount of samples.Breast milk samples were extracted by acetonitrile and the lipid substances were removed by freezing under-20 ℃ condition. Then the samples were derivatized with dansyl chloride and analyzed by ultra-performance liquid chromatography-tandem mass spectrometry( UPLCMS/MS). The seperation was performed on an ACQUITY UPLC BEH Phenyl column( 2. 1 mm × 100 mm, 1. 7 μm) with methanol and 0. 1% formic acid in water as mobile phase. The electrospray source was in the positive ion mode and monitored in the multiple reactions monitoring mode. Isotope internal standard dilution technique was used for the quantification analysis. At last, the methodology was studied.The linear range of 8 bisphenols was 0. 010-10. 00 μg/L. The recoveries of the three spiked levels were84. 6%-108. 1%, with the relative standard deviations no more than 12%( n = 6). 30 samples of breast milk were analyzed, in which BPA was detected in 11 breast milk samples, and the concentrations ranged from 0. 13 μg/L to 2. 25 μg/L. BPAF was detected in 1 breast milk sample, and the concentration was 0. 02 μg/L.The established method using a small amount of breast milk is highly sensitive, simple and fast, and can be used for the simultaneous determination of 8 bisphenols in breast milk.

To estimate the exposure characteristic of six emerging brominated flame retardant for Beijing residents by dietary intake.2,3,5,6-tetrabromo-p-xylene (pTBX), pentabromotoluene (PBT), 1, 2, 3, 4, 5-pentabromo-6- ethylbenzene (PBEB), hexahromobenzene (HBB), hexachlorocyclopentadienyl- dibromocyclooctane (DBHCTD) and 1,2-bis(2 ,4 ,6-tribromo phenoxy) ethane (BTBPE) were detected by atmospheric pressure gas chromatography tandem mass spectrometry (APGC-MS/MS) in total dietary samples from Beijing. Dietary intake assessments of human exposure were carried out according to results of determination.PBT, PBEB, HBB and BTBPE were occurred with concentration between 1.2-29.4 pg/g wet weight. The detection rates of HBB and BTBPE in animal--origin samples were higher than those in plant-origin samples, and there were significant differences (P0.05). The exposure level of Beijing residents to six emerging brominated flame retardants were 296.8 pg/(kg-d).The exposure level of emerging brominated flame retardants by dietary intake in Beijing is relatively low, and meat is the main source of BTBPE dietary intake.

To quantitatively assess the concentration and the distribution of the body iron (BI) for women in the poor rural areas.Resampling based on the blood sample of Nutrition and Health Survey in China from 2010 to 2012, serum ferritin (SF) and serum soluble transferrin receptor (sTfR) were measured for the selected blood samples by immunoturbidimetric assay. BI was calculated, and the concentrations and distribution in different aged subgroup were assessed. Distribution of BI subgrouped in different aged women was compared. The correlations of BI to hemoglobin (Hb), SF and sTfR were analyzed.The average levels of BI were (7.35 ± 2.37) mg/kg for schoolgirls aged 6-11 years, (6.50 ± 3.59) mg/kg for adolescent girls aged 12-17 years, (6.07 ± 4.78) mg/kg for women of childbearing aged 18-44 years, (8.60 ± 4.45) mg/kg for women aged 45-59 years, and (10.35 ± 3.38) mg/kg for elderly female aged ≥ 60 years, respectively. The proportion of low BI in the 12-17 years and 18-44 years women was the highest. BI level was positively correlated to SF and negatively correlated to sTfR (P0.01). BI level was positively correlated to Hb in the BI0 mg/kg subgroup.The BI methodology allows the full range of iron status of populations to be evaluated. The iron status for adolesecent girls aged 12-17 years and women of childbearing aged 18-44 years should be improved.

An analytical method was developed to simultaneously detect triclosan (TCS) and triclocarban (TCC) in human breast milk using solid-phase extraction (SPE) with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).Samples were extracted by acetonitrile and purified with C -18 SPE cartridge after enzymolysis with β-glucuronidase/arylsulfatase. The chromatographic separation was performed on a Waters ACQUITY UPLC™ HSS T3 column (100 mm x 2. 1 mm, 1. 8 µm) with gradient elution using methanol and water at a flow rate of 0. 3 ml/min. The target analytes were assayed by triple quadrupole mass spectrometer operating in the negative ion mode. Quantification was performed by isotopic internal standard calibration.Satisfactory linearity (r20. 999) was obtained over the range of 0. 2 - 20. 0 µg/L and 0. 02 - 2. 0 µg/L for triclosan and triclocarban, respectively, with the limits of quantifications (LOQs) of 0. 41 and 0. 03 µg/kg. Average recoveries of two target compounds (spiked at three concentration levels) ranged from 100. 2% to 119. 3%, with the relative standard deviations (RSDs) between 5. 91% and 11. 31% (n =6). Twenty-five real samples (n = 25) were detected containing TCS and TCC at concentrations ofLOQ - 0. 77 µg/kg andLOQ - 4. 28 µg/kg, respectively.Due to its high sensitivity and good reproductivity, this method can be applied to analyze TCS and TCC in human breast milk.

To develop a method for bisphenol A (BPA) and nonylphenol (NP) analysis in drinking water by on-line solid phase extraction (SPE) column switching liquid chromatography tandem mass spectrometry.Target compounds were concentrated and purified by a Waters Direct Connect HP XBridge C18 column, with average particle size 10 microm. The mobile phase of SPE extraction column was methanol/water at a flow-rate of 2.0 ml/min. The analytical column was Waters BEH C18 column (2.1 mm x 50 mm, 1.7 microm) and the mobile phase was methanol/0.1% ammonia water at a flow-rate of 0.4 ml/min. BPA and NP were analyzed by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) in the negative ion mode with multiple reactions monitoring (MRM).The whole run time of an individual sample was about 10 min. The linear calibration curves covered the range of 5 - 1000 ng/L and 10 - 5000 ng/L for BPA and NP, respectively, while the correlation coefficients (r2) were above 0.999. The quantification limits of the method were 5 and 10 ng/L for BPA and NP, respectively. Recovery test was performed at three fortification levels, mean recoveries ranged from 86.6% to 105% with acceptable coefficients of variation (3.11% - 18.2%, n = 6). The inter-day precisions were less than 13.2%.The established On-line SPE LC-MS/MS method needs no complicated sample pretreatment step, which is significantly time-saving. The analytical procedure is rapid, simple, and high-sensitive. It can be applied to analysis BPA and NP in drinking water.

To develop a method based on on-line solid phase extraction followed liquid chromatography mass spectrometry for determination of 9 pesticides and microcystin-LR in drinking water.Drinking water samples were concentrated by a HRP-SPE cartridge and separated on a HSS T3 column with a gradient mobile phase of acetonitrile and aqueous 0.1% formic acid, then analyzed by triple quadrupole mass spectrometry (TQ-MS) and time of flight mass spectrometry (TOF-MS), respectively. Mass acquisition was conducted under positive electrospray ionization mode. Quantification was performed by external standard calibration.The quantification limits (LOQs) of 10 target compounds were far below the limits set by the National Standards for Drinking Water Quality. The LOQs of TOF-MS was 0.01-0.40 microg/L and the LOQs of TQ-MS was 0.01-0.19 microg/L. Recoveries of 10 target compounds were 66.5%-130.3% with relative standard deviation between 0.8% and 14.5%.Due to its rapidness, simpleness, and high sensitivity, the method is suitable for the determination of pesticides and microcystin-LR in drinking water.

To develop a method for simultaneous determination of bromate and perchiorate in vegetable using ion chromatography tandem mass spectrometry.Target ions in vegetable matrix were extracted by water and purified using a GCB cartridge. With the hydrophilic Ion Pac AS19 column and linear gradient potassium hydroxide used as eluent, bromate and perchlorate were analyzed by a triple quadrupole mass spectrometer under negative electronspray ionization mode and multiple reaction monitoring (MRM). Internal standard calibration was used for quantification.Good linearity was achieved for bromate and perchlorate over the range of 0.1- 50 microg/L and 0.05-50 microg/L, respectively, with correlation coefficients R20.998. The quantification limits of the method were 2.5 microg/kg and 0.7 microg/kg for bromate and perchlorate, respectively. Mean recoveries of two target analytes (spiked at three concentration levels in 5 kinds of vegetables) ranged from 80.3% to 124%, with within-day precisions no more than 21.4% and intraday precisions no more than 12.2%.This method could be applied in the simultaneous detection of bromate and perchlorate in vegetable.

To develop a comprehensive method for simultaneous analysis of 20 sulfonamides in sewage sludge by liquid chromatography tandem mass spectrometry (LC-MS/MS).Ultrasonic extraction and accelerated solvent extraction was compared with respect to the recovery of target drugs from sludge. Cleanup procedure was optimized during the test. The sludge samples were ultrasonicly extracted and purified by a mix mode anion-ion exchange solid-phase extraction, following determination using LC-MS/MS. 20 sulfonamides were separated by a C18 column and analyzed under positive ion mode with multi-reaction monitoring. Isotopic internal standards calibration was used for quantification.The method quantification limits for 20 analytes were 0.25-10.0 microg/kg with overall recoveries of 50.1%-120.0%, and the relative standard deviations less than 30%. The method was finally used to analyze sulfonamides in sludge from sewage treatment plants in Beijing, and 3 target compounds (sulfadiazine, sulfapyridine and sulfamethoxazole) were detected at a concentration range of 2.1-153.1 microg/kg.This method could be applied in simultaneous analysis of 20 sulfonamides in municipal sludge samples.

To develop and validate in vitro digestion model for assessing the bioaccessibility of deoxynivalenol (DON) derived from foods, and optimize the major parameters affecting the model.To study the effect of digestion time, the fasting and feeding status, the volume and the pH of digestive juice, as well as other food components ingested with DON derived from mixed foodstuff on the bioaccessiblity of DON in a model simulating the process manner on gastrointestinal physiological digestion. To optimize some technical parameters of the model and validate it with both mycotoxin adsorbents and foods naturally contaminated by DON.The optimized conditions of which DON released from the ingested foods at the highest concentration in gastrointestinal tract are as follows: digestion of 6 min, 1.5h and 1.5h in mouth, stomach and duodenum, respectively. At pH value of 6.5, 0.9, 7.5 and 8.0 as well as digestive juice volume of 6 ml, 13 ml, 11 ml and 6 ml for saliva, gastric juice, intestinal juice and bile, respectively. The bioaccessibility of DON at fasting and different feeding status was in the range from 81.28% to 99.58%, and the bioaccessibility of DON was reduced with the increase of contents in stomach. No significant effect of food matrix type (corn or wheat) on the bioaccessibility of DON was observed. However, other food components consumed along with DON can reduce the bioaccessibility of DON in cereals.The in vitro digestion model developed for assessing the bioaccessibility of DON is stable and reproducible, which can meet the requirement of studies on the bioaccessibility of DON derived from foods.

To investigate the occurrence of 13 kinds of synthetic musk and triclosan in breast milk samples collected from Beijing, and to estimate the exposure of breastfed infants.Target compounds in 65 milk samples collected from 4 districts of Beijing in 2004 were analyzed by means of gas chromatography - tandem mass spectrometry (GC - MS/MS) and quantified by internal standards. The exposure of infants was analyzed statistically by SPSS software.HHCB, AHTN, OTNE, MT and Triclosan were detected in milk samples in the range of 0.6 - 174.1 ng/g lipid, with some difference in 4 districts. It is estimated that the intake of synthetic musks and triclosan for each infant from breast milk would be 13.5 - 3917 ng/d.Commonly used synthetic musks and tricloson were generally detected in breast milk. Further study should be focused on monitoring and tracing the possible source of pollution.

To explore the distribution and elimination of thiabendazole and its metabolite 5-hydrothiabendazole residues in the hens tissues including liver, muscle, heart, fat, as well as in eggs.Laying hens were orally administred thiabendazole for 5 consecutive days (100mg per hen daily) and then the hens were sacrificed at the times of 1 day, 3 days, 5 days and 7 days after the end of treatment. Eggs, liver,muscle,fat and heart tissues were collected and homogenized. The samples were extracted by acetonitrile, further concentrated and purified by an Oasis MCX cartridge, and then the contents of thiabendazole and 5-hydrothiabendazole in tissue homogenates determinated by liquid chromatography electrospray ionisation tandem mass spectrometry (UPLC-ESI-MS/MS).The major residues in the tissue homogenates was 5-hydroxythiabendazole, with more higher concentrations than thiabendazole. Egg samples presented the large majority of both drug residues. For the tissue homogenates,the total concentrations of thiabendazole and 5-hydrothiabendazole residues followed the order of liverheartmusclefat at 1 day after the treatment. The withdrawal period of thiabendazole for eggs was about 7 days.Distribution and elimination of thiabendazole and its metabolite residues in laying hens were primarily studied in this study.

To elucidate the dietary exposure of Chinese populations to deoxynivalenol (DON), nivalenol (NIV) and zearalenone (ZEN).Ten Fusarium toxins including DON, NIV, ZEN in domestic wheat flour and corn-based products harvested and collected in 2009 were analyzed by UPLC-MS/MS. Dietary intake assessments of human exposure to DON, NIV and ZEN were carried out in combination of national food consumption data with toxin concentration data by deterministic estimate method.(1) There are 2.5% adults and 10% children with the dietary exposure to DON exceeding the tolerable daily intake (TDI) on the basis of the average food consumption. At the 75th percentile food consumption level, the dietary exposure of populations to DON was higher than its TDI, 1.72 and 2.02 times (adults) as well as 1.19 and 1.09 times higher than TDI (children), respectively, based on the higher DON exposure (adults : P90 for wheat flour and P97. 5 for corn-based products, children: P50 for wheat flour and P75 for corn-based products). At the average toxin concentration, children with the high consumption level (90th, 97. 5th and 99th percentile) of either wheat flour or corn-based products, the dietary exposure to DON exceed the TDI, 1.81 to 3.17 times (wheat flour) and 1.47 - 3.97 times (corn-based products) higher than TDI, respectively. The dietary exposure of adults to ZEN exceed the TDI, based on the average food consumption data and higher ZEN level (P99), the 75th consumption data combined with P97. 5th toxin concentration, as well as 90th percentile of both food consumption data and ZEN concentration, respectively. There are 1%, 2.5%, 25%, 25% and 50% populations of children exposed ZEN higher than TDI, respectively at the 50th, 75th, 90th, 97. 5th and 99th percentile of food consumption data. (2) The level of concern (LOC) of DON in wheat flour calculated with high consumption data (90th, 97. 5th and 99th percentile) for all populations as well as DON and ZEN in corn-based products calculated with high consumption data (adults: 99th percentile, children: 97. 5th and 99th percentile) were lower than their average concentrations in above cereals. (3) No matter adults or children, the maximum daily safe intake of both wheat flour and corn-based products with high concentration of DON (97. 5th and 99th percentile, and 90th else for children) were lower than their own average food consumption data. For adults, the maximum daily safe intake of corn-based products with high ZEN contamination level (99th percentile) was lower than the average amount of corn-based products consumption. While, the maximum daily safe intake of both wheat flour and corn-based products derived from high ZEN concentration (97.5th and 99th percentile) for children were lower than their own average food consumption.Children dietary exposure to DON, NIV and ZEN was higher than adults. Children are the populations at the high risk of dietary exposure to these three mycotoxins. The risk to health caused by long-term consumption of wheat flour and corn-based products heavily contaminated with such high concentration of DON and ZEN was relatively high. The present tolerance limit for DON and ZEN in foods implemented in China should be revised on the basis of assessment results.

Based on the historical data of bacterial foodborne illness, the scoring system applied on the pre-warning model system was established in this study according to the rated harm factors. It could build up effectively the predictive model in the analysis of foodborne illness accidents.Extracting the useful information, the principal component analysis was performed on the normalized raw data to reduce the dimension. The result was split into 70% data randomly for training set into the regression model of support vector machine that was used to predict the remaining 30% .Through reducing the dimensions for selecting the optional PCs, it could optimize the calibration and improve the efficiency. The combining method of principal component analysis (PCA) and support vector machine (SVM) could provide the reliable results in the pre-warning model, especially for the high-dimensional data with the limited sample populations. Furthermore, it could achieve 80% accuracy with the optimized parameters.The pre-warning model of bacterial foodborne illness could give the assessment of the poisoning accidents and provided the scientific theory for reducing the incidence of bacterial of food poisoning.

To study the determination method of nine beta2-agonists residues in urine.Urine samples were duconjugated with beta-glucuronidase/arylsulfatase enzyme in acetate buffer and deproteinized by perchloric acid, and then adjusted pH4.0. Sample concentration and purification were performed by Oasis HLB, Oasis MCX. The separation was performed on a Waters ACQUITY UPLCTM BEH C18 column (100mm x 2.1mm i.d., 1.7microm) with gradient elution using methanol and water (containing 0.1% formic acid) at a flow rate of 0.3ml/min.The limits of detection (LOD) of the method were from 0.002 to 0.025ng/ml and the limits of quantification (LOQ) ranged from 0.007 to 0.08ng/ml. Average recoveries for nine beta2-agonists at the spiking levels of 0.1, 0.5 and 2ng/ml ranged from 77.4% to 101.7% with relative standard deviations between 3.4% and 18% .The method can be used to determine the residues of nine beta2-agonists in urines.

In order to survey water eutrophication and microcystin levels in Beijing Miyun Reservoir.Mivrocystin-LR (MC-LR), and MC-RR were determinated by LC/MS/MS at 5 sample sites in Miyun Reservoir. Eutrophication parameters, which were determinated by conventional analytical methods, included algae number, chlorophyll-a (Chl-a), total phosphor (TP), total nitrogen (TN), COD,TOC, Fe, turbidity and water temperature.Water in Miyun Reservoir was polluted very little by organic matter. According to Chl-a, TP appraise criterion and grading method, Miyun Reservoir was eutrophicated very little. MC-LR and MC-RR could be detected out in water of Miyun Reservoir. Maximum concentration was discovered in September, MC-LR 41 ng/L and MC-RR 18 ng/L respectively.Beijing Miyun Reservoir was poor-eutrophic. Microcystins concentration in water of Miyun Reservoir was far lower than our country health standard.