Isotope chemometrics determines farming methods and geographical origin of vegetables from Yangtze River Delta Region, China.

Shanghai city has encountered possible food fraud regarding the geographical mislabeling of vegetables for economic gain. A combination of δC, δN, δH and δO values and partial least squares discrimination analysis and support vector machine (SVM) methods were used for the first time to assess farming methods and determine the origin of vegetables from Shanghai city, Anhui and Zhejiang provinces. The results showed that 65.

Estimating inorganic arsenic exposure from rice intake in Chinese Urban Population.

Background: Rice intake is a major route of oral exposure to inorganic arsenic (iAs), a known human carcinogen. The recent risk assessment on iAs in rice conducted by the US Food & Drug Administration (FDA) didn't propose an action level for iAs in rice mainly because of the relatively low consumption rate in the general US population. However, this decision may not be applicable to high rice-intake populations, such as the Chinese population.

Hollow fiber-solid phase microextraction of phthalate esters from bottled water followed by flash evaporation gas chromatography-flame ionization detection.

A solid phase microextraction coupled with flash evaporation gas chromatography method was applied to the determination of phthalate esters (PAEs). Polysulfone (PSF) hollow fiber at 1 cm length was employed as extraction element to adsorb PAEs directly. Predominant parameters including stirring velocity, salt concentration, extraction time and extraction temperature were optimized.

Combined anti-androgenic effects of mixtures of agricultural pesticides using in vitro and in silico methods.

Humans and wildlife are continuously and simultaneously exposed to various pesticides that have been identified as endocrine disruptors which interfere with regulations of sexual differentiation and fertility. Low-dose effects of combined exposure from mixtures of pesticides have been extensively reported and need to be addressed in the context of human health risk assessment. The objective of the study is to assess the individual and combined anti-androgenic effects of twelve widely used pesticides in MDA-kb2 cells.

Pyrimethanil Ionic Liquids Paired with Various Natural Organic Acid Anions for Reducing Its Adverse Impacts on the Environment.

In this study, nine pyrimethanil ionic liquids (PILs) were synthesized through an acid-base reaction with nine naturally derived organic acid anions to improve the physicochemical properties and reduce the environmental adverse impacts. The PILs presented lower volatilization, higher photostability, better soil adsorption capacity, and improved fungicidal activity relative to pyrimethanil. When the length of the carbon chains in the anions was increased, the PILs showed better properties in terms of melting point, water solubility, volatility, and surface tension.

Sugaring-out assisted liquid-liquid extraction coupled with high performance liquid chromatography-electrochemical detection for the determination of 17 phenolic compounds in honey.

In this work, a simple sugaring-out assisted liquid-liquid extraction (SULLE) method coupled with high performance liquid chromatography-electrochemical detection (HPLC-ECD) has been developed for rapid and sensitive determination of 17 phenolic compounds in honey. To achieve the maximum extraction efficiency of target analytes, several parameters, such as pH, ionic strength, extraction times and the volume of extracting solvent were optimized. Chromatographic separation was performed on a C18 column with a gradient methanol/aqueous formic acid elution, and the ECD was set at 1.

Effects of 2,4-Dichlorophenoxyacetic Acid on Cucumber Fruit Development and Metabolism.

The auxin-like compound 2,4-dichlorophenoxyacetic acid (2,4-D) has been widely used as a plant growth regulator in cucumber fruit production; however, its influence on fruit development and metabolism has not been evaluated. In this study, the phenotype of cucumber fruits in both 2,4-D treatment and non-treatment control groups were recorded, and the metabolome of different segments of cucumber fruit at various sampling time points were profiled by a standardized non-targeted metabolomics method based on UPLC-qTOF-MS. The application of 2,4-D increased the early growth rate of the fruit length but had no significant effect on the final fruit length, and produced cucumber fruits with fresh flowers at the top.

[Determination of anserine, homocarnosine and carnosine in meat products by ion chromatography with integrated pulsed amperometric detection].

A method was developed for the simultaneous determination of anserine, homocarnosine and carnosine in meat samples using ion chromatography (IC) with integrated pulsed amperometric detection (IPAD). The samples were separated on a high performance anion exchange AminoPac PA10 column (250 mm×2 mm) using 100 mmol/L NaOH as the eluent. The flow rate was kept at 0.

Reduction of the fitness cost of antibiotic resistance caused by chromosomal mutations under poor nutrient conditions.

The prevalence of antibiotic resistance in drinking water system is pressing public health risk. Antibiotic resistance conferred by chromosomal mutations often produces fitness cost, which may affect its spread and persistence. In this study, the rifampin-resistant strains were competed with their wild-type counterparts at different nutrient levels.

Quantitative ecotoxicity analysis for pesticide mixtures using benchmark dose methodology.

Pesticide mixtures can often be found on crops and in the natural environment due to the usage of multiple pesticides in crop production. However, the toxicity of pesticides is mostly evaluated individually but not jointly. Many studies have pointed out that pesticide mixture may have elevated toxicity compared with its individual counterpart, therefore, it is important to quantify the change in toxicity.

Identification of Conserved and Diverse Metabolic Shift of the Stylar, Intermediate and Peduncular Segments of Cucumber Fruit during Development.

Cucumber ( L.) is one of the most important vegetables and contains a high content of nutritionally beneficial metabolites. However, little is known about the metabolic variations among different parts of cucumber fruit and their kinetics during growth.

Determination of γ-hydroxybutyrate in human urine samples by ion exclusion and ion exchange two-dimensional chromatography system.

A two-dimensional ion chromatography system was developed for the determination of γ-hydroxybutyrate (GHB) in human urine samples. Ion exclusion chromatography was used in the first dimensional separation for elimination of urine matrices and detection of GHB above 10mgL, ion exchange chromatography was used in the second dimensional separation via column-switching technique for detection of GHB above 0.08mgL.

Transfer and Metabolism of Triadimefon Residues from Rape Flowers to Apicultural Products.

This paper presents a study on the transfer and metabolism of triadimefon residues from rape flowers to apicultural products. In the field trials, honeybee colonies were placed in four rape greenhouses treated with triadimefon on standard dosage. Apicultural products (pollen, honey, and royal jelly) were collected on a regular basis.

Transfer Assessment of Carbendazim Residues from Rape Flowers to Apicultural Products.

Carbendazim is usually used to control the of rapes during the flowering period. This paper presents a study on transfer assessment of carbendazim residues from rape flowers to apicultural products. In the field trials, the rapes were sprayed with carbendazim on standard dosage.

Etoxazole is Metabolized Enantioselectively in Liver Microsomes of Rat and Human in Vitro.

Acaricide etoxazole belongs to the ovicides/miticides diphenyloxazole class, affecting adults to lay sterile eggs by inhibiting chitin biosynthesis possibly. The reverse-phase HPLC-MS/MS method was used to determine the etoxazole enantiomers. The enantioselective degradation behavior of rac-etoxazole in liver microsomes of rat and human in vitro with NADPH was dramatically different.

Determination of methacrylic acid in food simulants by pyrolytic butylation-gas chromatography.

An on-line pyrolytic butylation approach was proposed to determine methacrylic acid (MA) in food simulants by gas chromatography (GC) without an expensive pyrolyzer. MA in food simulants was converted into butyl methacrylate in the presence of tetrabutylammonium hydroxide (TBAH) without any pretreatment at 330°C in the injection-port, contributing to high GC signal response. The derivatizing conditions for the proposed method were optimized, namely the injection-port temperature, type and amount of the organic alkaline used for derivatization.

Enantioselective Metabolism of Flufiprole in Rat and Human Liver Microsomes.

The enantioselective metabolism of flufiprole in rat and human liver microsomes in vitro was investigated in this study. The separation and determination were performed using a liquid chromatography system equipped with a triple-quadrupole mass spectrometer and a Lux Cellulose-2 chiral column. The enantioselective metabolism of rac-flufiprole was dramatically different in rat and human liver microsomes in the presence of the β-nicotinamide adenine dinucleotide phosphate regenerating system.

Slow Release of Plant Volatiles Using Sol-Gel Dispensers.

The black citrus aphid, also known as the tea aphid, (Toxoptera aurantii Boyer) attacks economically important crops, including tea (Camellia sinensis (L.) O. Kuntze).

Joint toxicity of chlorpyrifos, atrazine, and cadmium at lethal concentrations to the earthworm Eisenia fetida.

Contaminants in the environment often occur as complex mixtures, and their combined effect may exhibit toxicity to organisms. Risk assessments based on individual components tend to underestimate the effects associated with toxic action of mixtures. Toxicity studies on chemical mixtures are urgently required to assess their potential combined toxicities.

Enantioselective determination of acaricide etoxazole in orange pulp, peel, and whole orange by chiral liquid chromatography with tandem mass spectrometry.

An efficient enantioselective method for the determination of etoxazole in orange pulp, peel, and whole orange was developed using liquid chromatography with tandem mass spectrometry. The enantioseparation was performed on a Chiralpak AD-3R column at 30ºC using acetonitrile with 0.1% formic acid solution (80:20, v/v) as the mobile phase in less than 5 min.

Simultaneous determination of zearalenone and its derivatives in edible vegetable oil by gel permeation chromatography and gas chromatography-triple quadrupole mass spectrometry.

A sensitive gas chromatographic-triple quadrupole mass spectrometric (GC-QqQ MS) analytical method, for the determination of zearalenone and its five derivatives in edible vegetable oil, was developed. After the vegetable oil samples were prepared using gel permeation chromatography, the eluent was collected, evaporated and dried with nitrogen gas. The residue was silylated with N,O-bis-trimethylsilyltrifluoroacetamide, containing 1% trimethylchlorosilane.

Multiplex event-specific qualitative polymerase chain reaction for detecting three transgenic rice lines and application of a standard plasmid as a quantitative reference molecule.

The three most well-known genetically modified (GM) rice lines in China are TT51-1, KMD1, and KF6. The purposes of this study were to establish a multiplex event-specific qualitative polymerase chain reaction (meqPCR) system for simultaneous detection of the three transgenic rice events and to construct a plasmid as the reference molecule for quantitative analysis. Event-specific primers for each event were selected or designed by focusing on the transgene borders between the inserted DNA and the flanking rice DNA.

Enantioselective determination of carboxyl acid amide fungicide mandipropamid in vegetables and fruits by chiral LC coupled with MS/MS.

An efficient enantioselective method for the determination of mandipropamid in vegetables and fruits was presented by LC coupled with MS/MS. The mandipropamid residues in samples (potato, pepper, grape, and watermelon) were extracted with acetonitrile containing 1% acetic acid. An aliquot was cleaned up with primary and secondary amine and C18 sorbent.