Residue analysis and risk assessment of tebuconazole in jujube (Ziziphus jujuba Mill)

In this study, a sensitive and reliable analytical method, based on a modified Quick, Easy, Cheap, Effective, Rugged and Safe procedure, was established for determination of tebuconazole in jujube. After extraction with acetonitrile, the samples were cleaned up by dispersive solid‐phase extraction with primary secondary amine, and determined by high‐performance liquid chromatography tandem mass spectrometry. At fortification levels of 0.01, 0.1 and 2.0 mg kg⁻¹, the average recoveries of tebuconazole in jujube were in the range 97.6–101.9%, with relative standard deviations of 1.5–3.5%. The dissipation and residual levels of tebuconazole in jujube under field conditions were investigated. Tebuconazole dissipated relatively slowly in jujube, with a half‐life of 33.0 days. The terminal residue experiments of tebuconazole in jujube were conducted in four locations in China and the risk was evaluated using risk quotients (RQ ). RQ values were found to be significantly lower than RQ = 1, indicating that the risk to human health of using the recommended doses of tebuconazole in jujube was not significant. This study could provide guidance for the safe and reasonable use of tebuconazole in jujube and serve as a reference for the establishment of limit of maximum residue in China.     

Dissipation kinetics,residues and risk assessment of propiconazole and azoxystrobin in ginseng and soil

The combinational fungicide suspension (11.7% propiconazole + 7% azoxystrobin), developed by Syngenta Co., Ltd., is very effective for the control of Alternaria black spot on ginseng. A simple and effective method was developed for determining propiconazole and azoxystrobin residues by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). The recoveries of propiconazole ranged from 81.0% to 98.0% with relative standard deviations (RSDs) of 1.23–8.46%, while the recoveries of azoxystrobin ranged from 83.2% to 98.8% with RSDs of 3.29–9.50%. For the dissipation kinetics, the combinational fungicide was sprayed with dosage of 225 g a.i.ha^?1 (1.5 times of recommended dosage) in ginseng and soil at two different locations. The dissipation kinetics followed the first-order kinetics with half-lives of 6.66–13.33 days for propiconazole and 4.92–9.12 days for azoxystrobin. Based on the terminal residues data, the preharvest interval (PHI) could be 35 days at recommended dosage in ginseng. The dietary exposure risk was estimated by risk quotient (RQ). The result showed that the RQ value was obviously lower than RQ = 1, indicating that spraying propiconazole and azoxystrobin in ginseng at recommended dosage was safe for human beings.     

Determination,residue and risk assessment of trifloxystrobin,trifloxystrobin acid and tebuconazole in Chinese rice consumption

A simple and rapid analytical method for the detection of trifloxystrobin, trifloxystrobin acid and tebuconazole in soil, brown rice, paddy plants and rice hulls was established and validated by liquid chromatography with tandem mass spectrometry. Acceptable linearity (R² > 0.99), accuracy (average recoveries of 74.3–108.5%) and precision (intra- and inter-day relative standard deviations of 0.9–8.8%) were obtained using the developed determination approach. In the field trial, the half-lives of trifloxystrobin and tebuconazole in paddy plants were 5.7–8.3 days in three locations throughout China, and the terminal residue concentrations of trifloxystrobin and tebuconazole were <100 and 500 μg/kg (maximum residue limits set by China), respectively, at harvest, which indicated that, based on the recommended application procedure, trifloxystrobin and tebuconazole are safe for use on rice. The risk assessment results demonstrated that, owing to risk quotient values of both fungicides being <100%, the potential risk of trifloxystrobin and tebuconazole on rice was acceptable for Chinese consumers. These data could provide supporting information for the proper use and safety evaluation of trifloxystrobin and tebuconazole in rice.     

气相色谱-串联质谱法测定台湾青枣中的炔螨特、戊唑醇和溴螨酯残留

建立了台湾青枣（Zizyphus mauritiana Lam）中炔螨特、戊唑醇和溴螨酯同时测定的气相色谱-串联质谱（GC-MS/MS）分析方法。样品用乙腈匀浆提取,盐析,石墨化炭黑/氨基混合型固相萃取柱净化,乙腈/甲苯（3：1,v/v）洗脱,浓缩定容后检测。目标化合物经SLB-5MS色谱柱（30 m×0.25 mm×0.25 μm）分离,采用三重串联四极杆质谱多反应监测（MRM）模式进行定性定量分析。结果表明,在0.01~0.50 mg/kg添加水平时,3种农药的回收率为75.8%~103.6%,相对标准偏差为1.7%~9.3%（n=5）。方法的线性范围为0.01~0.50 mg/kg,决定系数（R²）>0.99。该方法对炔螨特、戊唑醇和溴螨酯的定量限均为0.01 mg/kg,能满足台湾青枣中炔螨特、戊唑醇和溴螨酯残留检测的要求。     

Improved liquid chromatographic method for determination of carotenoids in Taiwanese mango (Mangifera indica L.)

An HPLC method was developed to determine the various carotenoids in Taiwanese mango (Mangifera indica L.). Initially, the peel and seed of mangoes were removed, the pulps were cut into pieces, freeze-dried, ground into powder, extracted and subjected to HPLC analysis. A mobile phase of methanol-isopropanol (99:1, v/v) (A) and methylene chloride (100%) (B) with the following gradient elution was developed: 100% A and 0% B in the beginning, maintained for 15 min, decreased to 70% A in 45 min, maintained for 15 min and returned to 100% A in 65 min. A total of 25 carotenoids were resolved within 53 min by using a C-30 column with flow rate at 1 mL/min and detection at 450 nm. alpha-Carotene was used as an internal standard to quantify all the carotenoids. All-trans-beta-carotene was present in largest amount (29.34 microg/g), followed by cis isomers of beta-carotene (9.86 microg/g), violaxanthin and its cis isomers (6.40 microg/g), neochrome (5.03 microg/g), luteoxanthin (3.6 microg/g), neoxanthin and its cis isomers (1.88 microg/g), zeaxanthin (1.16 microg/g) and 9- or 9'-cis-lutein (0.78 microg/g).     

气相色谱法分离检定血中八种氨基甲酸酯

采用国产Ｃ＿１８往固相提取血中八种氨基甲酸酯,用乙酸乙酯洗脱,用气相色谱分离检定,用气相色谱／质谱进行确证。此法灵敏度为１～２μｇ／ｍＬ血,最低检出限为２０～４０ｎｇ,回收率在６２～９２％之间。     

Dissipation behavior,residue distribution and dietary risk assessment of chlorfenapyr and clothianidin in leek using RRLC-QqQ-MS/MS technique

Commercial suspension emulsion (SE) of (8% chlorfenapyr + 20% clothianidin), as a pre-registered product in China, was firstly investigated under Chinese open-field conditions. A MWCNTs-based QuEChERS method for simultaneous determination of chlorfenapyr and clothianidin in leek was established and validated through RRLC-QqQ-MS/MS.     

气相色谱（电子捕获检测器）和气相色谱－质谱联用测定血中十种单端孢霉烯族毒素

本文建立了人血中十种单端孢霉烯族毒素的气相色谱（电子捕获检测器）和气相色谱－质谱（气质）联用分析法。该法采用乙酸乙酯萃取血中毒素后，将萃取液浓缩至干，用七氟丁酰咪唑衍生化，用气相色谱和色／质联用分析测定。方法的最低检出限为１～１０ｎｇ／ｍＬ血，回收率为６０．８～１０１．１％。     

Mango (Mangifera indica L.) Polyphenols: Anti-Inflammatory Intestinal Microbial Health Benefits,and Associated Mechanisms of Actions

Mango is rich in polyphenols including gallotannins and gallic acid, among others. The bioavailability of mango polyphenols, especially polymeric gallotannins, is largely dependent on the intestinal microbiota, where the generation of absorbable metabolites depends on microbial enzymes. Mango polyphenols can favorably modulate bacteria associated with the production of bioactive gallotannin metabolites including Lactobacillus plantarum, resulting in intestinal health benefits. In several studies, the prebiotic effects of mango polyphenols and dietary fiber, their potential contribution to lower intestinal inflammation and promotion of intestinal integrity have been demonstrated. Additionally, polyphenols occurring in mango have some potential to interact with intestinal and less likely with hepatic enzymes or transporter systems. This review provides an overview of interactions of mango polyphenols with the intestinal microbiome, associated health benefits and underlying mechanisms.     

Comparison of microwave-assisted and conventional hydrodistillation in the extraction of essential oils from mango (Mangifera indica L.) flowers

Microwave-assisted hydrodistillation (MAHD) is an advanced hydrodistillation (HD) technique, in which a microwave oven is used in the extraction process. MAHD and HD methods have been compared and evaluated for their effectiveness in the isolation of essential oils from fresh mango (Mangifera indica L.) flowers. MAHD offers important advantages over HD in terms of energy savings and extraction time (75 min against 4 h). The composition of the extracted essential oils was investigated by GC-FID and GC-MS. Results indicate that the use of microwave irradiation did not adversely influence the composition of the essential oils. MAHD was also found to be a green technology.     

Comparison of microwave‐assisted and conventional extraction of mangiferin from mango (Mangifera indica L.) leaves

Mangiferin is the main bioactive component in mango leaves, which possesses anti‐inflammatory, antioxidative, antidiabetic, immunomodulatory, and antitumor activities. In the present study, a microwave‐assisted extraction method was developed for the extraction of mangiferin from mango leaves. Some parameters such as ethanol concentration, liquid‐to‐solid ratio, microwave power, and extraction time were optimized by single‐factor experiments and response surface methodology. The optimal extraction conditions were 45% ethanol, liquid‐to‐solid ratio of 30:1 (mL/g), and extraction time of 123 s under microwave irradiation of 474 W. Under optimal conditions, the yield of mangiferin was 36.10 ± 0.72 mg/g, significantly higher than that of conventional extraction. The results obtained are beneficial for the full utilization of mango leaves and also indicate that microwave‐assisted extraction is a very useful method for extracting mangiferin from plant materials.     

Determination of tebuconazole, trifloxystrobin and its metabolite in fruit and vegetables by a Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method using gas chromatography with a nitrogen-phosphorus detector and ion trap mass spectrometry

A new analytical method using QuEChERS procedure by gas chromatography with a nitrogen-phosphorus detector (GC-NPD) and ion trap mass spectrometry (GC-IT-MS) for the quantitative determination of tebuconazole, trifloxystrobin and its metabolite trifloxystrobin acid has been developed and validated. The analytes were extracted from five fruit and vegetable matrices using acetonitrile and subsequently cleaned up using primary secondary amine (PSA) or octadecylsilane (C18) as sorbent prior to GC analysis. The present methods provided sufficient sensitivity as reflected by the values of limit of detection (LOD) and limit of quantification (LOQ) of 0.4-7 and 1.2-20 μg/kg for GC-IT-MS/MS and GC-NPD. The recoveries were, on average, 68-117 and 68-121%, respectively, for three compounds by GC-NPD and GC-IT-MS/MS with intra-day precision achieved with an RSD of 2.7-19.1%. The inter-day precision was better than 15.1% as determined by GC-NPD. The QuEChERS procedure, by using two sorbents (PSA and C18) and the matrix-matched standards, gave satisfactory recoveries and RSD values in different matrices. IT-MS acquisition provided higher specificity and selectivity for pesticides and better limit of detection and quantification. However, the repeatability and precision of NPD method were better compared with IT-MS.     

色谱法分析检测苦荞籽粒中的可溶性糖(醇)

通过气相色谱-质谱联用、气相色谱、高效液相色谱等手段,在苦荞籽粒中检测出了手性肌醇(DCI)、木糖醇、果糖、葡萄糖、山梨醇、肌醇、蔗糖、乙基-β-芸香糖苷等可溶性糖(醇)和两种未知化合物,苦荞籽粒各部分(壳、麸皮、外层粉、心粉)所含糖(醇)种类基本相同。活性成分DCI主要以游离状态存在,在籽粒中的质量分数分别为0.004%(壳),0.334%(麸皮),0.230%(外层粉),0.050%(心粉)和0.158%(全粉)。苦荞籽粒提取液流过强碱、强酸离子交换树脂柱后,其中的还原性糖、蔗糖及未知化合物1滞留于柱     

快速溶剂萃取–气相色谱质谱法测定土壤中戊唑醇残留量

建立快速溶剂萃取–气相色谱质谱法测定土壤中戊唑醇残留量的分析方法。土壤样品经ASE–350快速溶剂萃取仪萃取,萃取液用硅酸镁(弗罗里硅土)柱净化浓缩,然后用选择离子监测/全扫描(SIM/SCAN)模式,气相色谱–质谱法测定土壤中的戊唑醇含量。该方法检出限为0.008 mg/kg,加标回收率为84.0%~97.5%,测定结果的相对标准偏差为2.2%~11.6%(n=6)。该方法具有分离效果好,灵敏度高,重现性好,前处理操作简便等优点,可用于测定土壤中戊唑醇的残留量。     

气相色谱－质谱法测定赤鳞鱼肉中的脂肪酸

利用气相色谱质谱（ＧＣ／ＭＳ）电子轰击方法，对６种不同年龄和不同性别的赤鳞鱼肉中的饱和、不饱和脂肪酸（经甲酯化后）进行了测定，用色谱法作了定量，共鉴定出１８种脂肪酸。     

Supercritical Fluid Extraction of Phenolic Compounds from Mango (Mangifera indica L.) Seed Kernels and Their Application as an Antioxidant in an Edible Oil

Phenolic compounds from mango (M. indica) seed kernels (MSK) var. Sugar were obtained using supercritical CO₂ and EtOH as an extraction solvent. For this purpose, a central composite design was carried out to evaluate the effect of extraction pressure (11–21 MPa), temperature (40–60 °C), and co-solvent contribution (5–15% w/w EtOH) on (i) extraction yield, (ii) oxidative stability (OS) of sunflower edible oil (SEO) with added extract using the Rancimat method, (iii) total phenolics content, (iv) total flavonoids content, and (v) DPPH radical assay. The most influential variable of the supercritical fluid extraction (SFE) process was the concentration of the co-solvent. The best OS of SEO was reached with the extract obtained at 21.0 MPa, 60 °C and 15% EtOH. Under these conditions, the extract increased the OS of SEO by up to 6.1 ± 0.2 h (OS of SEO without antioxidant, Control, was 3.5 h). The composition of the extract influenced the oxidative stability of the sunflower edible oil. By SFE it was possible to obtain extracts from mango seed kernels (MSK) var. Sugar that transfer OS to the SEO. These promissory extracts could be applied to foods and other products.     

松油醇的分析及其生产工艺改进的研究

 应用气相 红外光谱(GC FTIR)和气相 质谱(GC MS)对合成松油醇及其杂质成分、原料松节油、合成过程中间体粗油(红油和黄油)和天然松油醇进行了分析研究,为判断松油醇产品中杂质产生的原因及改进生产工艺提供了依据。研究结果表明,松油醇中的杂质主要为长叶烯和石竹烯,是由原料松节油带入的。天然松油醇粗油中主要成分是1,8 桉叶素、反式 4 艹守醇、p 异丙烯基甲苯、顺式 4 艹守醇、芳樟醇、樟脑、龙脑、4 松油醇、α 松油醇和黄樟素。天然松油醇中β 松油醇和γ 松油醇含量不如合成松油醇中的含量高,以此可判断松油醇是天然的还是合成的。     

超声提取/气相色谱-质谱法测定海洋生物中的多环芳烃

建立了海洋生物体中16种优先控制多环芳烃的超声提取/气相色谱-质谱测定方法,对海洋鱼类、虾类、贝类和蟹类等生物样品的提取、净化和色谱质谱条件进行了优化。以正己烷-二氯甲烷(2∶1)作为溶剂进行超声提取,提取液经60%硫酸溶液和中性氧化铝-弗罗里硅土混合层析柱净化,采用气相色谱-质谱法定性和定量分析。在优化条件下,16种多环芳烃的线性范围为0.005～0.500 mg/L,相关系数(r)不低于0.998 4,检出限为0.03～0.28μg/kg。加标水平为2、20、100μg/kg时,平均加标回收率分别为55%～118%、80%～114%和79%～113%,相对标准偏差(RSDs,n=6)均小于10%。该方法快速、准确、灵敏度高、重复性好,能满足海洋生物体中持久性有机污染物分析的要求。     

体液中-叶萩碱检测方法的研究

本文报道了用气相色谱(GC)及气相色谱-质谱联用(GC/MS)检出人体液中一叶萩碱的方法.尿样经碱化后用乙醚直接萃取,回收率为72.1％;血浆样品用Sep-pak小柱提取,回收率为 43.9％,GC/MS的检测限为 20ng.方法快速、简便、准确.     

气相-质谱选择离子法测定化妆品中抗氧化剂丁基羟基茴香醚、二丁基羟基甲苯

 采用气相 质谱 (选择离子方式 )测定化妆品中抗氧化剂丁基羟基茴香醚 (BHA)和二丁基羟基甲苯(BHT) ,样品用甲醇振荡萃取 ,以SupelcoWAXTM 10 (30m× 0 2 5mmi.d .× 0 2 5 μm)为分析柱。该方法对样品中BHA和BHT的检测限分别为 2 5 μg/g和 0 5 μg/g。方法简便、快速、灵敏 ,可用于多种化妆品的检验。