[Determination of inorganic arsenic in rice by liquid chromatography-atomic fluorescence spectrometry].

Objective: To develop a method for the determination of inorganic arsenic (As(i)) in rice and to provide the basis for revising the national standard method GB/T 5009.11 "Determination of Inorganic Arsenic in Food". To compare the extracting ability of trifluoroacetic acid (TFA) under different concentrations and the different time for extracting samples.

Determination of enantiomeric fractions of cypermethrin and cis-bifenthrin in Chinese teas by GC/ECD.

Background: The pyrethroids cypermethrin and cis-bifenthrin are the major pesticides used in tea plantations in China. Potential neurotoxic, genotoxic and immunotoxic effects of chronic exposure to pyrethroids have been reported. All synthetic pyrethroids are chiral compounds.

[Establishment of database for food classification and coding in Chinese dietary exposure assessment].

Objective: To establish the basis for Chinese dietary exposure assessment database by classifying and coding the data from the national dietary survey and pollutant surveillance.

Methods: The method, which combined CODEX food classifying and coding of Codex Alimentarius Commission (CAC) with Chinese food classification of food composition table, was applied to classify and code the data of 1 810 703 Chinese dietary consumption and 487 819 pollutant surveillance. The coding system was according to the first two letters of the respective food group that represent the type or source of foods, the last four digits represent the serial number of the food in the CAC food classification.

The occurrence of perfluorinated alkyl compounds in human milk from different regions of China.

Perfluorinated compounds (PFCs), especially perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA), are known to occur throughout the environment and in the human population (Houde et al., 2006). The occurrence of PFCs in human umbilical cord blood and human milk, coupled with the potential developmental toxicity of PFCs, suggests the need for determining the exposure sources and magnitudes of PFCs in infants.

Analysis of hormone antagonists in clinical and municipal wastewater by isotopic dilution liquid chromatography tandem mass spectrometry.

A comprehensive method was developed for the simultaneous trace analysis of ten hormone antagonist pharmaceuticals (raloxifene, exemestane, letrozole, anastrozole, mifepristone, finastride, tamoxifen, N-desmethyltamoxifen, clomiphene, and toremifene) in municipal sewage and hospital wastewater samples. The target compounds were firstly extracted using an Oasis HLB cartridge, followed by purification by an aminopropyl cartridge, and were then analyzed by liquid chromatography electrospray ionization tandem mass spectrometry in positive ion mode. The recoveries for the analytes based on internal standard calibration in different test matrices ranged from 67.

[An improved BALB/c 3T3 cell transformation assay and its application in the cocarcinogenesis study].

Objective: To improve the protocol of BALB/c 3T3 cell transformation assay, and apply it to the cocarcinogenesis study.

Method: Appropriate serum concentration, culture media and method of administration were selected by testing their effects on the growth and transformation of BALB/c 3T3 cells. The co-carcinogenic activity between diethylnitrosamine (DEN) and microcystin-LR (MC-LR) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were examined using the improved cell transformation assay.

[Smoking status or age impact on urinary 8-hydroxy-2'-deoxyguanosine in electrical and electronic equipment waste dismantling workers].

Objective: To investigate the smoking or age impact on occupational workers in electrical and electronic equipment waste (e-waste) dismantling procedure, using 8-Hydroxy-2'-deoxyguanosine (8-OHdG) in the urine as a biomarker for oxidative damage to DNA.

Methods: The pre-workshift and post-workshift urinary samples of 64 male workers in e-waste dismantling procedure were detected by solid-phase extraction-high performance liquid chromatography-electrochemical detector (SPE-HPLC-ECD). The data were statistically analyzed by two factors, age or smoking status.

Hydrophobic solvent induced phase transition extraction to extract drugs from plasma for high performance liquid chromatography-mass spectrometric analysis.

Novel sample preparation approaches for HPLC bioanalysis based on the phenomenon that acetonitrile can be separated from water by adding salts or cooling at subzero temperatures have been reported. These two methods are superior to conventional liquid-liquid extraction since the separated acetonitrile phase can be directly injected to the RP-LC system. However, the salting-out method suffers from a potential problem that the remained salt in the acetonitrile phase may harm the MS detector, while the subzero-temperature method is troublesome to operate.

Determination of 76 pharmaceutical drugs by liquid chromatography-tandem mass spectrometry in slaughterhouse wastewater.

A multi-residue method for the analysis of 76 pharmaceutical agents of nine classes of drugs (tetracyclines, macrolides, fluoroquinolones, beta-agonists, beta-blockers, diuretics, sedatives, sulfonamides and chloramphenicol) in slaughterhouse wastewater and a receiving river is presented. After simultaneous extraction with an Oasis HLB solid-phase extraction (SPE) cartridge and further purification using an amino SPE cartridge, analytes were detected by liquid chromatography-electrospray ionization-tandem mass spectrometry in positive or negative ion mode. Standard addition was used for quantification to overcome unavoidable matrix effects during ESI-MS analysis.

Levels and congener profiles of PCDD/Fs, PCBs and PBDEs in seafood from China.

A nationwide investigation into polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) in market seafood was conducted for the first time in this study. Total PCDD/F concentrations in fatty fish ranged from 0.13 to 8.

Selection of anti-sulfadimidine specific ScFvs from a hybridoma cell by eukaryotic ribosome display.

Background: Ribosome display technology has provided an alternative platform technology for the development of novel low-cost antibody based on evaluating antibiotics derived residues in food matrixes.

Methodology/principal Findings: In our current studies, the single chain variable fragments (scFvs) were selected from hybridoma cell lines against sulfadimidine (SM(2)) by using a ribosome library technology. A DNA library of scFv antibody fragments was constructed for ribosome display, and then mRNA-ribosome-antibody (MRA) complexes were produced by a rabbit reticulocyte lysate system.

Assessment on dietary melamine exposure from tainted infant formula.

Objective: To estimate the dietary melamine exposure in Chinese infants and young children from the consumption of melamine adulterated Sanlu infant formula.

Methods: Four age groups of infants and young children (3, 6, 12, and 24 months) were chosen as the assessed subjects and the maximum amount of infant formula consumption was estimated based on the recommended usage level in the package insert of Sanlu infant formula and other brands. Melamine was analyzed in 111 Sanlu infant formula samples collected from the markets in Beijing and Gansu province using the LC-MS-MS with a limit of quantification of 0.

A survey on occurrence of melamine and its analogues in tainted infant formula in China.

Objective: To investigate the occurrence and concentrations of melamine and its analogues in tainted infant formula and to identify the etiologic factors for the urinary stones epidemic in infants and young children in China in 2008.

Methods: Sanlu infant formula samples were collected from families of the affected children in Gansu province, and markets in Gansu and Hebei provinces and Beijing city. Melamine and its analogues, including cyanuric acid, ammeline, and ammelide were measured by gas chromatography/tandem mass spectrometry.

Simultaneous determination of melamine, ammelide, ammeline, and cyanuric acid in milk and milk products by gas chromatography-tandem mass spectrometry.

Objective: To develop an analytical method for simultaneously qualitative and quantitative determination of melamine and triazine-related by-products including ammelide, ammeline, and cyanuric acid in milk and milk products by gas chromatography-tandem mass spectrometry (GC-MS/MS).

Methods: Melamine and triazine-related by-products namely ammelide, ammeline and cyanuric acid in the samples were extracted in a solvent mixture of diethylamine, water, and acetonitrile (10:40:50, V/V/V). After centrifugation, an aliquot of the supernatant was evaporated to dryness under a gentle stream of nitrogen gas, and then melamine and triazine-related by-products were derivatized using BSTFA with 1% TMCS.

Dietary exposure assessment of Chinese adults and nursing infants to tetrabromobisphenol-A and hexabromocyclododecanes: occurrence measurements in foods and human milk.

Tetrabromobisphenol A(TBBPA) and hexabromocyclododecane diastereoisomers (alpha, beta, and gamma-HBCD) were determined in 24 pooled human milk samples and 48 Chinese total diet study (TDS) samples collected in 2007. On the basis of ultra performance liquid chromatography-mass spectrometry (UPLC-MS/MS) analysis, levels of TBBPA ranged from < LOD to 5124 pg/g lipid weight (lw) in human milk and from < LOD to 2044 pg/g lw in TDS samples. The alpha-HBCD diastereoisomer, which ranged from < LOD to 2776 pg/g lw in human milk and from < LOD to 2224 pg/g lw in TDS samples, was generally the most abundant isomer comparing with beta- and gamma-HBCD.

Geographical distribution of perfluorinated compounds in human blood from Liaoning province, China.

Perfluorinated compounds (PFCs), such as perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA), have been identified widely in human. Monitoring of geographical distribution of PFCs in human blood can provide the information to better characterize the exposure source and pathway of these compounds. In this study, 13 PFCs were detected in 138 whole blood samples collected in 2008 from seven cities (Liaoning province, China) including Fuxin, Jinzhou, Shenyang, Anshan, Yingkou, Huludao, and Dalian.

[Growth characteristics and metabolomic sampling strategy of Lactobacillus sp. 30a(ATCC33222)].

Objective: Sampling strategy for metabolomic studies of ATCC33222 was discussed according to its grown patterns under six different media.

Methods: Six media with different ingredients or pH value were prepared and ATCC33222 strain cultures were harvested from each medium. Culture samples were collected every 1-4 hours and OD600 and pH values were determined thereafter.

[Dietary intakes of mercury by children and adults from Jinhu area measured by the duplicate portion study].

Objective: To understand the dietary mercuric intakes of children and adults from Jinhu area and assess its safety.

Methods: The duplicate food portions of 62 subjects were collected over 3 consecutive days. Mercuric levels in duplicate samples were determined by the atomic fluorescence spectrometry.

Simultaneous detection of residues of beta-adrenergic receptor blockers and sedatives in animal tissues by high-performance liquid chromatography/tandem mass spectrometry.

A method using high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) was developed to screen and confirm residues of multi-class veterinary drugs in animal tissues (porcine kidney, liver, muscle; bovine muscle). Thirty target drugs (19 beta-blockers, 11 sedatives) were determined simultaneously in a single run. Homogenized tissue samples were extracted with acetonitrile and purified using a NH2 solid-phase extraction cartridge.

[Fast determination of polybrominated diphenyl ethers in human milk using gas chromatography-negative chemical ionization/mass spectrometry].

A method for the quantitative determination of 8 polybrominated diphenyl ethers (PBDEs) in human milk was established using gas chromatography-negative chemical ionization/mass spectrometry (GC-NCI/MS). After extraction by Soxhlet extractor, the lipid in the extract was removed by acidic silica, and the analyte was further purified by the multilayer silica-alumina column. The concentrations of BDE28, BDE47, BDE99, BDE100, BDE153, BDE154, BDE183 and BDE209 in human milk were fast determined by GC-NCI/MS in selected ion monitoring (SIM) mode on a 7 m column.

A national survey of polychlorinated dioxins, furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in human milk in China.

The study examined the levels of dioxin-like compounds in 24 pooled samples that were comprised of 1237 individual human milk samples from 12 provinces of China. The samples were taken in different regions to evaluate the body burden of these contaminants and assess their health risk to breast-feeding infants of China. The pooled samples were analyzed for 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and 12 dioxin-like polychlorinated biphenyls (dl-PCBs) congeners.

[Study on the construction of bridge table of Chinese dietary exposure estimation model].

Objective: To explore the construction of bridge table of Chinese dietary exposure estimation model.

Methods: Bridge table can be structured by SAS procedure based on the matching relationship of foodcode in the structural of dietary survey data and the CAC (Codex Alimentarius Commission) code in the structure of pollutant monitoring data.

Results: According to the relationship of foodcode and CAC code, bridge table comprising the information of processing methods, processing factor and variability factor could be established.

Metabolic profiling of transgenic rice with cryIAc and sck genes: an evaluation of unintended effects at metabolic level by using GC-FID and GC-MS.

The cryIAc and sck genes were introduced to the rice for the purpose of improving the insect resistance. Metabolic profiles of wild and transgenic rice were compared to assess the unintended effects related to gene modification. Wild samples with different sowing dates or sites were also examined to determine the environmental effects on metabolites.