A method for rapid determination of arsenic species in vegetables using microwave‐assisted extraction followed by detection with HPLC hyphenated to inductively coupled plasma‐mass spectrometry

Driven by the significant need for characterization of the chemical speciation of arsenic in food, this work developed a method for rapid determination of four common arsenic species, namely, arsenite, arsenate, monomethyl arsenic acid, and dimethyl arsenic acid, in vegetables using microwave‐assisted extraction, followed by detection with high‐performance liquid chromatography hyphenated to inductively coupled plasma‐mass spectrometry. Initial screening results showed that microwave‐assisted extraction using 1% HNO₃ exhibited the highest overall efficiencies for all arsenic species without causing significant degradation of the organic ones. With the aid of response surface methodology, the optimum conditions established for extraction of arsenic species from vegetables were: 500 mg of freeze‐dried vegetable sample, extracted by closed vessel microwave‐assisted extraction using 10 mL of 2% v/v HNO₃ at 90°C for 17 min. Application of the method in the analysis of 24 market vegetable samples indicates that the extraction efficiencies for total arsenic species were in the range of 91.4–106%. Arsenite and arsenate were found to be the predominant arsenic species in the vegetables, which suggests that vegetable consumption could be an important route of inorganic arsenic exposure for the population with a heavy vegetable diet in arsenic polluted regions.     

Elemental composition of vegetables cultivated in illegal mining towns in Ghana using neutron activation analysis

The elemental concentrations of 12 elements from five species of the most consumed vegetables in Ghana cultivated in five mining and three non-mining towns have been analyzed using neutron activation analysis. About 50% of the total concentrations recorded for cadmium and arsenic for the various towns and vegetables were found to be above the World Health Organization (WHO) permissible levels. The statistical methods employed in this work also provided more understanding on the geographical distribution of the elements, vegetables and sampling towns. The principal component analysis of our data showed two major clusters consisting of gold mining towns and non-gold mining towns in relation to the elemental concentrations of vegetables cultivated in these towns.     

Space-resolved analysis of trace elements in fresh vegetables using ultraviolet nanosecond laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy (LIBS) has been applied to analyze trace elements contained in fresh vegetables. A quadrupled Nd:YAG laser is used in the experiments for ablation. Analyzed samples come from local markets and represent frequently consumed vegetables. For a typical root vegetable, such as potato, spectral analysis of the plasma emission reveals more than 400 lines emitted by 27 elements and 2 molecules, C₂ and CN. Among these species, one can find trace as well as ultra-trace elements. A space-resolved analysis of several trace elements with strong emissions is then applied to typical root, stem and fruit vegetables. The results from this study demonstrate the potential of an interesting tool for botanical and agricultural studies as well for food quality/safety and environment pollution assessment and control.     

Effects of uranium stress on physiological and biochemical characteristics in seedlings of six common edible vegetables

The large-scale exploitation of uranium (U) not only causes radioactive pollution to the soil, but also has a great adverse effect on human health. However, the current understanding of the effects of U stress on organisms is not deep enough. As food sources of human beings, vegetables can enrich U into the human body along the food chain. Therefore, the effects of soil U on seed germination, seedling growth and physiological and biochemical characteristics of six common edible vegetables (tomato, cucumber, kohlrabi, radish, cabbage, and spinach) were investigated. The results show that the toxicity of U to the six vegetables in sandy loam is cucumber?>?radish?>?spinach?>?cabbage?>?tomato?>?kohlrabi. The lower U concentration in sandy loam has certain promoting effect on seed germination and root growth. The accumulation and tolerance capacity of cucumber and radish to U in sandy loam is stronger than that of other four vegetables, which may be used as candidate species for biological treatment of U pollution. These results provide theoretical basis for clarifying the biological effects and toxicological mechanism of U pollution, and also provide theoretical basis for scientific prevention and control of soil U pollution.     

Transfer factors of 31 elements in several agricultural plants collected from 150 farm fields in Aomori, Japan

Soil-to-plant transfer factors of 31 stable elements were determined by neutron activation analysis. The transfer factor is one of the important parameters used to estimate the internal radiation dose from radionuclides through food ingestion. In the present study, 12 species of agricultural plants such as root crops, fruit vegetables, green vegetables and pasture grasses, and their soils were collected from 150 farm fields in Aomori prefecture, Japan. The elements described are those that could be detected by this method, which include both essential and nonessential elements for plant growth. The concentrations of individual elements in the cultivated soil samples for each plant were similar in values and their standard deviations were within one order of magnitude, because of the relatively narrow geographic sampling area. The elements were classified into two groups, each having different transfer factor characteristics. In the first group of elements there was an inverse correlation between the transfer factors and the concentrations of elements in the soil, especially for Cl, K and Ca. In the second group, especially Sc and Co, however, the transfer factors were independent of the concentrations of elements in the soil.     

基质固相分散-液相色谱-质谱法测定蔬菜中的邻苯二甲酸酯

采用基质固相分散-液相色谱-质谱法测定保护地蔬菜中邻苯二甲酸酯(PAEs)含量,并分析了蔬菜中PAEs污染状况,研究了水和洗涤液浸泡对蔬菜中PAEs的消除效果。蔬菜样品经弗罗里硅土和石墨化碳黑研磨均匀后,用乙酸乙酯淋洗净化,再用液相色谱/电喷雾质谱法测定。PAEs的添加回收率为82.7%~105.7%;RSD为1.7%~6.1%;检出限为邻苯二甲酸二甲酯(DMP):0.99ng;邻苯二甲酸二乙酯(DEP):0.75ng;邻苯二甲酸二丁酯(DBP):0.70ng;邻苯二甲酸二异辛酯(DEHP):1.9ng。本方法前处理简单,具有较高的准确度和灵敏度。黄瓜、番茄、西葫芦中4种PAEs总量分别为2.02、1.26、0.91mg/kg;洗涤实验结果表明,水和洗涤液浸泡可显著降低蔬菜中的PAEs含量。     

Analysis on the Chlorophyll Content of Commercial Green Leafy Vegetables

The objectives of the present study were to evaluate the chlorophyll content of green leafy vegetables found commercially and carry out a comparative investigation between in vivo and in vitro data. The chlorophyll of green leafy vegetable can be used as visible parameters of the quality of vegetables during storage, since it will be degraded gradually along with post-harvest senescence. Therefore, the development of reliable in vivo chlorophyll measurement should be advantageous rather than visual observation for the purpose of quality control and product sortation. Here, the existence of chlorophylls in ten green leafy vegetables were reported as SPAD values of a handheld SPAD-502 chlorophyll meter and % N of an Agriexpert CCN-6000 nitrogen meter (in vivo data), as well as total peak area data of HPLC measurement for chlorophyll a and b after exhaustive extraction using methanol (in vitro data). Both in vivo and in vitro measurement gave comparable grouping of vegetables with high and low content of chlorophyll. Moreover, correlation plots between SPAD values and total peak area of HPLC showed adequate linear correlation (R² > 0.7), revealing the potency of in vivo observation for the prediction of actual chlorophyll content in commercial leafy vegetables. SPAD values and % N presented strong linear relationship (R² > 0.9), in which SPAD-meter performed better detection at very low values. The calibration curve for each species of vegetable should be substantial to overcome the limiting factors of in vivo observation, such as leaf size, tissue thickness, and variation of chloroplast distribution.     

Disappearance of dislodgable residues of methomyl from leaves and vegetables in Tamilnadu (India)

The dislodgable residues of methomyl from leaves and vegetables were determined by a single-step methanol extraction followed by reversed-phase HPLC. The residues on the bhendi vegetables and leaves were several times higher than on the brinjal vegetables and leaves. The pesticide, however, dissipates rapidly under the South Indian climatic conditions resulting in undetectable residues within three days of spraying.     

基于稳定同位素的5种蔬菜产地真实性判别

为保护蔬菜产地真实性,以上海市场5种常见蔬菜(生菜、茼蒿、辣椒、番茄和黄瓜)为研究对象,应用单因素方差分析上海和其他产地蔬菜的 δ13 C、δ15 N、δ2 H和 δ18 O值差异,并通过主成分分析(PCA)和偏最小二乘判别分析(PLS-DA)建立上海地产蔬菜真实性判别模型.结果表明,上海地产5种蔬菜总的δ15 N、δ...     

Investigation and Analysis of Pesticide Residues in Four Common Vegetables and Risk Assessment of Dietary Exposure in Ceramic Capital,China

In order to understand the basic situation of pesticide residues in vegetables in China’s porcelain capital, four kinds of common vegetables on the market were selected in this study for detection and analysis of pesticide residues. The pesticide residues in vegetables were analyzed through sample selection, optimization of instrument and equipment conditions, and comparison of detection pass rates. The sampling locations were common vegetables purchasing places such as large and medium-sized supermarkets. QuEChERS method was used as the sample pretreatment, and gas chromatography (GC-MS/MS) was used for quantitative analysis. Finally, the exposure risk of pesticides was assessed according to the test results. The results showed that all the pesticides were detected in four kinds of vegetables, but the detected pesticides did not exceed the national standard (GB 2763-2014, China). Moreover, the target risk coefficient (THQ) and risk index (HI) values of four vegetables were less than one, indicating that the combined and toxic effect of pesticide residual mixed contamination was smaller in four vegetables. Therefore, there was no significant harm from people using these vegetables.     

Visualization of anthocyanin species in rabbiteye blueberry Vaccinium ashei by matrix-assisted laser desorption/ionization imaging mass spectrometry

Anthocyanins are naturally occurring compounds that impart color to fruits, vegetables, and plants, and are believed to have a number of beneficial health effects in both humans and animals. Because of these properties, pharmacokinetic analysis of anthocyanins in tissue has been performed to quantify and identify anthocyanin species although, currently, no methods exist for investigating tissue localization of anthocyanin species or for elucidating the mechanisms of anthocyanin activity. Imaging mass spectrometry (IMS) is powerful tool for determining and visualizing the distribution of a wide range of biomolecules. To investigate whether anthocyanin species could be identified and visualized by IMS, we performed matrix-assisted laser desorption/ionization (MALDI)-IMS analysis, by tandem mass spectrometry (MALDI-IMS-MS), of ten anthocyanin molecular species in rabbiteye blueberry (Vaccinium ashei). The distribution patterns of each anthocyanin species were different in the exocarp and endocarp of blueberry sections. Anthocyanin species composed of delphinidin and petunidin were localized mainly in the exocarp. In contrast, those species composed of cyanidin, peonidin, and malvidin were localized in both the exocarp and the endocarp. Moreover, MALDI-IMS analysis of anthocyanidins in a blueberry section indicated that the distribution patterns of each anthocyanidin species were nearly identical with those of the corresponding anthocyanins. These results suggested that the different distribution patterns of anthocyanin species in the exocarp and endocarp depended on the aglycone rather than on the sugar moieties. This study is the first to visualize anthocyanin molecular species in fruits.     

Antioxidant and antibacterial activity of six edible wild plants (Sonchus spp.) in China

The total phenolic and flavonoid, antioxidant and antibacterial activities of six Sonchus wild vegetables (Sonchus oleraceus L., Sonchus arvensis L., Sonchus asper (L.) Hill., Sonchus uliginosus M.B., Sonchus brachyotus DC. and Sonchus lingianus Shih) in China were investigated. The results revealed that S. arvensis extract and S. oleraceus extract contained the highest amount of phenolic and flavonoid, respectively. Among the methanol extracts of six Sonchus species, S. arvensis extract exhibited the highest radical (DPPH and ABTS+ scavenging power and lipid peroxidation inhibitory power. It also exhibited the highest reducing power at 500?μg?mL?1 by A (700)?=?0.80. The results of antibacterial test indicated that the S. oleraceus extract showed higher activity than the other five Sonchus wild vegetables extracts, both in Gram-negative bacteria (Escherichia coli, Salmonella enterica and Vibrio parahaemolyticus) and in a Gram-positive bacterium (Staphylococcus aureus). These results indicate that Sonchus wild food plants might be applicable in natural medicine and healthy food.     

羧甲基壳聚糖在果蔬保鲜中的应用研究进展

综述了羧甲基壳聚糖的特性及其在果蔬的涂膜保鲜中的应用研究进展,讨论了羧甲基壳聚糖的浓度、分子量、pH值、取代度对其特性的影响,介绍了羧甲基壳聚糖对果蔬的涂膜保鲜效果。本文对开发羧甲基壳聚糖在果蔬防腐保鲜方面的应用具有理论指导意义。     

Time-resolved characterization of laser-induced plasma from fresh potatoes

Optical emission of laser-induced plasma on the surface of fresh vegetables provides sensitive analysis of trace elements for in situ or online detection of these materials. This emergent technique promises applications with expected outcomes in food security or nutrition quality, as well as environment pollution detection. Characterization of the plasma induced on such soft and humid materials represents the first step towards quantitative measurement using this technique. In this paper, we present the experimental setup and protocol that optimize the plasma generation on fresh vegetables, potatoes for instance. The temporal evolution of the plasma properties are investigated using time-resolved laser-induced breakdown spectroscopy (LIBS). In particular, the electron density and the temperatures of the plasma are reported as functions of its decay time. The temperatures are evaluated from the well known Boltzmann and Saha-Boltzmann plot methods. These temperatures are further compared to that of the typical molecular species, CN, for laser-induced plasma from plant materials. This comparison validates the local thermodynamic equilibrium (LTE) in the specific case of fresh vegetables ablated in the typical LIBS conditions. A study of the temporal evolution of the signal to noise ratio also provides practical indications for an optimized detection of trace elements. We demonstrate finally that, under certain conditions, the calibration-free LIBS procedure can be applied to determine the concentrations of trace elements in fresh vegetables.     

基于QuEChERS提取方法优化的液相色谱-串联质谱法测定蔬菜中51种氨基甲酸酯类农药残留

采用气相色谱-质谱（GC-MS）全扫描结合NIST谱库检索方法分析6种蔬菜（番茄、青刀豆、大葱、青花菜、姜、胡萝卜）提取液中的基质干扰物,以蒸发残渣重量法探讨乙二胺N-丙基硅烷（PSA）、十八烷基硅烷（C18）及两者组合对6种蔬菜提取液基质干扰物的净化效果及吸附机理,考察了原创QuEChERS方法及AOAC 2007.01方法对蔬菜中51种氨基甲酸酯类农药提取的适用性,并建立了液相色谱-串联质谱法测定蔬菜中51种氨基甲酸酯类农药残留的方法。结果表明,C18与PSA组合进行分散固相萃取的净化效果最好;AOAC 2007.01方法适用于二氧威以外的50种农药残留的提取,而原创QuEChERS方法对二氧威残留的提取可获得满意结果。经电喷雾正离子电离及多反应监测模式来测定目标化合物,采用基质匹配标准溶液曲线法进行定量。结果表明：51种农药在6种基质中3个添加水平（10、20、100 μg/kg）的回收率为58.4%~126%,相对标准偏差为3.3%~26%;以信噪比（S/N）≥10计,久效威及杀螟丹的定量限（LOQ）为50 μg/kg,其他49种农药的LOQ为0.2~10 μg/kg。本文方法有效、灵敏,适用于不同蔬菜基质中51种氨基甲酸酯类农药残留的测定。     

Representative commodity for five brassica vegetables based on the determination and dissipation of six pesticide residues

A Quick, Easy, Cheap, Effective, Rugged and Safe method for determination of thiophanate-methyl, carbendazim, metalaxyl, fluazifop-P-butyl, chlorpyrifos and lambda-cyhalothrin in five brassica vegetables by high performance liquid chromatography-mass spectrometry/mass spectrometry and gas chromatography-electron capture detector has been developed. The average recoveries of six pesticides in five brassica vegetables were in the range of 77.4%–117.4% with relative standard deviation of 3.7–10.8%. Residues of thiophanate-methyl, carbendazim, metalaxyl, fluazifop-P-butyl, chlorpyrifos and lambda-cyhalothrin in five brassica vegetables were studied with the developed method for the classification of crop group and selection of representative commodity of five brassica vegetables. Totally 48 open field trials on five brassica vegetables were conducted at two locations in two different seasons. The residue dynamics and final residues of the six pesticides at three preharvest intervals in different vegetables were compared. All six pesticides had the longest half-lives in cabbage (2.1–3.5 days). Residues of carbendazim (sum of thiophanate-methyl and carbendazim), metalaxyl, chlorpyrifos and lambda-cyhalothrin had similar trend in different brassica vegetables. The maximal concentrations of these pesticide residues were found in kale (0.28–10.9 mg kg^?1). Fluazifop-P-butyl residues were at low levels in all five brassica vegetables (<0.01–0.03 mg kg^?1). Cabbage, red cabbage, Brussels sprouts and kohlrabi had no significant difference in all six pesticide residues and could be classified in a subgroup of Head Brassicas. Cabbage should be selected as the representative commodity. Considering the highest residues in kale and its different morphology, kale should not be classified into the subgroup of Head Brassicas.     

Pesticide residue analysis of vegetables by gas chromatography with electron-capture detection

A new and original analytical method was developed for the routine analysis of 28 multiclass pesticide residues in vegetables (green pepper, red pepper, and tomato). The extraction was performed with acetone, and the pesticides were partitioned into ethyl acetate-cyclohexane (1 + 1, v/v). Residue levels in vegetables were determined by gas chromatography (GC) with electron-capture detection. Residue identities were confirmed by GC coupled with mass spectrometry in the selected ion monitoring mode. The average recoveries in pepper and tomato obtained for all analytes studied were 67.3 and 123.1%, respectively, with relative standard deviation between 1.8 and 7.0%. The detection limit for the pesticides studied varied from 0.1 to 2.6 microg/kg. The proposed method was applied to the analysis of these compounds in vegetables grown in experimental greenhouses.     

Determination of multiple antibiotics in leafy vegetables using QuEChERS–UHPLC–MS/MS

A modified quick, easy, cheap, effective, rugged, and safe method was established for simultaneous extraction and cleanup of multiple antibiotics in leafy vegetables, and ultra‐high performance liquid chromatography with tandem mass spectrometry was used for analysis. Antibiotics in leafy vegetables were extracted with citric acid/sodium citrate in mixed solvents consisting of acetonitrile/methanol (85:15, v/v) from 10 g of vegetables. Octadecylsilyl and graphitized carbon black were used as dispersant adsorbents. This method was able to effectively extract all of the target antibiotics from leafy vegetables. The average recoveries of 20 antibiotics ranged from 57 to 91%. The limits of detection were 0.33–2.92 μg/kg. The developed method subsequently demonstrated its selectivity, sensitivity, and reliability for detecting multiple antibiotics in 15 samples. Antibiotic residues in vegetables have attracted great concern with respect to human health. It is recommended that standards should be established for antibiotic residues in vegetables to ensure food safety.     

Plant-mediated asymmetric reduction of 1-(3,4-dimethylphenyl)ethanone

Bioreduction mediated by plants is a highly selective and environmentally friendly approach to synthesise optically active alcohols. Herein the bioreduction of 1-(3,4)-dimethylphenyl)ethanone to the corresponding chiral alcohol 1-(3,4-dimethylphenyl)ethanol has been evaluated using nine different vegetables roots as biocatalysts. The chiral alcohol was prepared in yields ranging from 44.1% to 88.2%, and with enantiomeric excess up to 97.2% for the (S)-enantiomer. Sugar beet was the most promising among the tested vegetables roots. Therefore, sugar beet cell cultures (normal and transformed) were obtained and tested for the reduction as well, yielding the corresponding alcohol in the range from 62.1% to 88.2% yield and with enantiomeric excesses of >99%. Based on these results reported, there are no profound differences in the reductive capacity of undifferentiated cells and organs of the same plant species (sugar beet). Due to overall advantages of using cell cultures, we have highlighted this approach as a promising method for preparation of enantiomerically pure 1-(3,4-dimethylphenyl)ethanol.     

液相色谱串联质谱测定蔬菜中残留的唑菌胺酯

唑菌胺酯(pyraclostrobin)俗称百泰,德国巴斯夫公司于1993年开发的兼具吡唑结构的甲氧基丙烯酯酯类菌剂~([1]),主要用于防治小麦、水稻、花生、葡萄、蔬菜、香蕉、 柠檬、咖啡、果树、核桃、蔬菜、茶树、烟草和观赏植物、草坪及其他大田作物上由子囊菌纲、担子菌纲、半知菌类和卵菌纲真菌引起的作物病害~([2]).