我国大闸蟹中二噁英类持久性有机污染物的暴露水平研究

目的研究我国大闸蟹中二噁英类持久性有机污染物(persistent organic pollutants,POPs)的暴露水平,评估大闸蟹中二噁英类POPs的主要污染来源。方法样品经正己烷和二氯甲烷(1:1,V:V)提取,浓硫酸沉淀脂类杂质后,过复合硅胶柱和碱性氧化铝柱净化分离目标物。采用同位素稀释高分辨气相色谱-高分辨质谱法(isotope dilution high resolution gas chromatograph-high resolution mass spectrometer,isotope dilution HRGC-HRMS)分析大闸蟹及其食物源中二噁英和多氯联苯的含量。结果蟹肉中二噁英类POPs的总毒性当量(toxic equivalent,TEQ)为0.0092～1.65 pg TEQ/g,平均浓度为0.27 pg TEQ/g。蟹黄(蟹膏)中二噁英类POPs的TEQ浓度水平为1.3～15 pg TEQ/g,平均浓度是蟹肉中平均TEQ值的21倍。估算一亩蟹塘中的物料平衡,发现饲料中二噁英类POPs的TEQ值是大闸蟹的0.85倍,玉米、水草和水仅贡献蟹塘中TEQ输入的4.7%,不考虑生物过程,沉积物中TEQ输入是饲料输入的77倍。结论蟹塘中二噁英类POPs的TEQ输入量高于其输出量,其中沉积物是大闸蟹中二噁英类POPs的主要贡献者,定期清理和更换养殖蟹塘中的沉积物可有效减少大闸蟹对二噁英类POPs的暴露。     

同位素稀释高分辨气相色谱-高分辨磁质谱法测定大闸蟹中二噁英及其类似物

建立了同位素稀释高分辨气相色谱-高分辨磁质谱法测定大闸蟹中二噁英类化合物及二噁英类多氯联苯。对大闸蟹的白肉及棕肉分别进行测定,样品经加速溶剂萃取(丙酮-正己烷-二氯甲烷：20:40:40,体积比)、酸化硅胶初步净化、全自动二噁英净化系统净化后,分别收集PCDD/ Fs、DL-PCBs的净化液,浓缩后上机分析。采用选择离子监测模式进行测定,白肉PCDD/ Fs的检出限在0.016ng/kg~0.106 ng/kg范围内,DL-PCBs的检出限在0.105 ng/kg~0.252 ng/kg范围内;棕肉PCDD/ Fs的检出限在0.053 ng/kg ~0.353 ng/kg范围内,DL-PCBs的检出限在0.120 ng/kg~0.840 ng/kg范围内。大闸蟹白肉PCDD/ Fs、DL-PCBs的同位素定量内标溶液的平均回收率分别为73.4%~103.5%、74.8%~93.0%;RSD分别为6.4%~21.5%、10.5%~24.7%;大闸蟹棕肉PCDD/ Fs、DL-PCBs的同位素定量内标溶液的平均回收率分别为59.8%~90.1%、65.7%~92.1%;RSD分别为7.5%~23.5%、7.5%~24.8%。本文建立的方法灵敏度高,干扰小,能完全满足国内外的检测需要。     

血清中二噁英类物质的同位素稀释-全二维气 相色谱-串联质谱法研究

目的建立高灵敏度和高选择性的全二维气相色谱-串联质谱法(GC×GC-MS/MS)测定17种多氯代二苯并二噁英和多氯代二苯并呋喃(PCDD/Fs)同系物的痕量分析方法。方法将牛血清样品经过加速溶剂萃取,全自动净化仪净化后,通过配备DB-5MS和BPX-50柱全二维气相色谱-串联质谱进行样品分析。结果 17种PCDD/Fs同系物的标准曲线在范围内显示良好线性(R20.99)。方法的检出限为0.1~0.8 pg/g。结论本方法满足血清样品中PCDD/Fs的痕量分析需求。     

我国部分地区猪肉、猪肝二噁英污染状况与风险评估

目的 分析来自A、B、C、D、E五省猪肉、猪肝二噁英污染状况,并针对人群膳食暴露量进行评价,为未来制定国家食品安全二噁英限量标准提供基础数据。方法 于2013年至2019年共采集146份猪肉和猪肝样品,参照国家标准方法《食品中二噁英及其类似物毒性当量的测定》（GB 5009.205—2013）,采用同位素稀释的高分辨气相色谱/高分辨双聚焦磁式质谱联用（HRGC/HRMS）技术,对样品中的17种二噁英单体进行准确定量分析检测。根据食物消费量数据,采用点评估方法进行人群膳食暴露量评估。结果 猪肉和猪肝样品中二噁英毒性当量浓度中位数分别是0.106、2.32 pg/g·fat;各地区猪肉二噁英浓度水平以A(0.859 pg/g·fat)>D(0.145 pg/g·fat)>C(0.097 4 pg/g·fat)>B(0.039 9 pg/g·fat)>E(0.023 pg/g·fat)依次降低,猪肝二噁英的浓度水平以A(3.616 pg/g·fat)>B(1.84 pg/g·fat)>D(1.313 pg/g·fat)>E(0.85 pg/g·fat...     

QuEChERS-酶联免疫快速检测法测定茶叶中 黄曲霉毒素B1

目的建立QuEChERS-酶联免疫快速检测茶叶中黄曲霉毒素B1的方法,并对样品前处理条件进行优化。方法茶叶样品用70%乙腈水提取溶液进行提取目标物,离心后取上清液并用PSA+MgSO4进行净化处理后,采用酶联免疫快速检测方法进行分析测定。结果本方法的检出限为0.078μg/kg,线性范围为0.125~0.854μg/kg,IC50值为0.327 ng/m L。在三个不同添加水平下,样品的平均回收率为87.66%~97.17%,相对标准偏差为4.89%~7.16%。检测结果与高效液相色谱法(high performance liquid chromatography,HPLC)方法的相关系r2=0.9854,线性相关性良好。结论该方法更加简便、快速、高效,能够用于茶叶中黄曲霉毒素B1的检测。     

基于QuEChERS前处理技术的水产品中喹诺酮类药物多残留ELISA检测方法的建立

建立了水产品中3种喹诺酮类(恩诺沙星、环丙沙星、氧氟沙星)兽药多残留的新型Qu ECh ERS前处理技术结合酶联免疫快速检测的分析方法。基本流程为样品经90%乙腈(1%乙酸)均质提取离心后,上清液依次用C18净化、静置沉淀蛋白后用于测定,该前处理方法灵敏、快速、经济、实用性强。测试曲线线性范围为0.107~177.896ng/m L,检出限为0.0087μg/kg,IC50值为4.34ng/m L。样品批内和批间平均回收率分别为94.10%、93.70%,批内变异系数为4.09%~8.41%,批间变异系数2.78%~7.99%。检测结果与HPLC的相关系数R2=0.9897,表明酶联免疫检测方法及样品前处理方法适合喹诺酮类药物多残留检测。     

基于QuEChERS前处理技术的水产品中喹诺酮类药物多残留ELISA检测方法的建立

建立了水产品中3种喹诺酮类(恩诺沙星、环丙沙星、氧氟沙星)兽药多残留的新型Qu ECh ERS前处理技术结合酶联免疫快速检测的分析方法。基本流程为样品经90%乙腈(1%乙酸)均质提取离心后,上清液依次用C18净化、静置沉淀蛋白后用于测定,该前处理方法灵敏、快速、经济、实用性强。测试曲线线性范围为0.107~177.896ng/m L,检出限为0.0087μg/kg,IC50值为4.34ng/m L。样品批内和批间平均回收率分别为94.10%、93.70%,批内变异系数为4.09%~8.41%,批间变异系数2.78%~7.99%。检测结果与HPLC的相关系数R2=0.9897,表明酶联免疫检测方法及样品前处理方法适合喹诺酮类药物多残留检测。      

直接竞争酶联免疫分析方法检测猪肉中的沙丁胺醇

建立了一种用于检测沙丁胺醇的直接竞争酶联免疫分析(ELISA)方法,方法灵敏度(IC50)为0.80μg/L,检测限(IC15)为0.06μg/L,检测的线性范围0.06～20.00μg/L。与克伦特罗的交叉反应率为100%,与特布他林的交叉反应率为10.5%,与其他结构类似物并无明显的交叉反应,因此可以采用本实验建立的直接竞争酶联免疫方法同时测定食品中的沙丁胺醇和克伦特罗。本实验的样品处理方法简便,猪肉样品中的检测限为0.6μg/kg,添加三个浓度的样品,其添加回收率均在85%～100%之间,RSD值小于5.51%。      

酶联免疫法与LC-MS/MS法测定水产品中呋喃唑酮代谢物

运用酶联免疫法和LC-MS/MS法对水产品中呋喃唑酮代谢物残留进行测定.样品经2-硝基苯甲醛衍生化并用乙酸乙酯提取.向样品中分别添加0.60、2.00、6.00μ g/kg三个浓度水平的呋喃唑酮代谢物时,酶联免疫法平均回收率分别为99.2%、96.0%和100.0%,变异系数(RSD)为1.8%～12.6%,最低检测限为0.3μg/kg.LC-MS/MS法平均回收率分别为90.8%、94.3%和86.3%,RSD为6.2%～14.3%,最低检测限为0.1μg/kg.用酶联免疫法对150个样品进行检测,筛选出3个阳性样品,经LC-MS/MS确证为阳性,未发现假阳性样品,且测定结果基本一致.研究表明酶联免疫法重复性较好、准确度较高,是一种水产品中呋喃唑酮代谢物残留的快速筛选方法;液- 质/质联用法灵敏度高,适用于阳性样品的确证和精确定量.     

直接竞争酶联免疫分析方法检测猪肉中的沙丁胺醇

建立了一种用于检测沙丁胺醇的直接竞争酶联免疫分析(ELISA)方法,方法灵敏度(IC50)为0.80μg/L,检测限(IC15)为0.06μg/L,检测的线性范围0.06～20.00μg/L。与克伦特罗的交叉反应率为100%,与特布他林的交叉反应率为10.5%,与其他结构类似物并无明显的交叉反应,因此可以采用本实验建立的直接竞争酶联免疫方法同时测定食品中的沙丁胺醇和克伦特罗。本实验的样品处理方法简便,猪肉样品中的检测限为0.6μg/kg,添加三个浓度的样品,其添加回收率均在85%～100%之间,RSD值小于5.51%。     

Dioxin and polychlorinated biphenyl analysis: automation and improvement of clean-up established by example of spices

To analyze polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDDs/PCDFs) and polychlorinated biphenyls (PCBs) in spices by gas chromatography-mass spectrometry, a new clean-up method had to be developed owing to the high content of essential oils in the samples. A solid-phase extraction (SPE) column with activated silica endowed with sulfuric acid and sodium hydroxide was used. Under these conditions, clean-up was achieved using at least 5-7 g of pepper and even higher amounts of other spices. The automatized clean-up comprised three additional chromatographic steps after accelerated solvent extraction (ASE) followed by gel permeation: chromatography on a florisil SPE column, extract cleaning with the above-mentioned silica SPE column and chromatography with an activated charcoal column. On the basis of this automatized clean-up, a method that is more effective, rapid, simplified and economical than the available methods for PCDD/PCDF and PCB analysis is proposed. In model studies, the average recoveries for PCDDs/PCDFs ranged between 82.6% and 105.6% and for the PCBs between 71.3% and 113.3%.     

Application of accelerated solvent extraction followed by gel performance chromatography and high-performance liquid chromatography for the determination of polycyclic aromatic hydrocarbons in mussel tissue

Accelerated solvent extraction (ASE) has been evaluated as a fast alternative to methanolic saponification for the extraction of 12 polycyclic aromatic hydrocarbons (PAHs) from mussel tissue. Several solvent systems and different operating conditions were investigated. The mixture dichloromethane-acetone (1:1, v/v) gave the best recoveries at 125°C and 1500 psi, in a total time of 10 min. No yield difference was found between freeze-drying (Fd) or drying the wet mussel with diatomaceous earth (Ded) prior to extraction. The ASE method was validated using the standard reference material SRM 2977, a freeze-dried mussel tissue with naturally present organic contaminants. The performance characteristics of the ASE method (trueness: 70-110%; precision: 4-14% and limit of quantification (LOQ): 0.1-0.25 µg/kg) meet the criteria established by the European Union for quantitative methods of analysis for official control of organic residues and contaminants. ASE provides a 24 times faster extraction than MSE and reduces 12 times the volume of solvent required.     

Dioxins and polychlorinated biphenyls (PCBs) in fish oil dietary supplements: Occurrence and human exposure in the UK

Commercially available fish oil supplements sourced from retail outlets in the UK, as well as by mail order, were surveyed in 2000-02 for dioxin (PCDD/Fs) and polychlorinated biphenyl (PCB) content. Sampled products were representative of market share. The WHO-TEQ values for these products ranged from 0.18 to 8.4 ng kg^-1 for ΣPCDD/F and from 1.1 to 41 ng kg^-1 for Σ dioxin-like PCBs. The results suggest a downward trend in the levels of dioxins in fish oil supplements over the last decade, since levels for similar products ranged from 0.3 to 10 ng kg^-1 for ΣPCDD/F WHO-TEQ in 1996. Levels of ICES (International Council for the Exploration of the Seas) 7 PCBs in the current study ranged from 8.3 to 267 µg kg^-1. Subsequent to this survey, European Union legislation has been introduced that includes a maximum limit of 2 ng kg^-1 WHO-TEQ for dioxins in fish oil products for human consumption. Twelve of the 33 products reported here would have exceeded this limit. Negotiations are in progress to incorporate dioxin-like PCBs into the European Union regulations. When manufacturer-recommended doses were applied to the observed levels, the estimated upper bound human exposure to dioxins and dioxin-like PCBs from dietary intake of these products ranged from 0.02 to 7.1 pg WHO-TEQ kg^-1 body weight day^-1 for adults and from 0.02 to 10 pg WHO-TEQ kg^-1 body weight day^-1 for schoolchildren. This level rises to 1.8-8.9 pg WHO-TEQ kg^-1 body weight day^-1 for adults and 1.4-14 pg WHO-TEQ kg^-1 body weight day^-1 for schoolchildren when combined with the average exposure from the whole diet in 1997. Again, subsequent to this survey, the Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT) revised the UK tolerable daily intake (TDI) for mixtures of dioxins and dioxin-like PCBs from 10 to 2 pg WHO-TEQ kg^-1 body weight day^-1. This is in line with the tolerable weekly intake (TWI) of 14 pg WHO-TEQ kg^-1 body weight set by the Scientific Committee on Food (SCF).     

GCMS/MS 同时测定鱼样中39 种多溴联苯醚

目的 采用快速溶剂萃取(ASE)、系列固相萃取(SPE, 包括分散性固相萃取(DSPE)和串联SPE柱)和GCMS/MS, 建立一个便捷、高效测定鱼样中39种多溴联苯醚(PBDEs)的检测方法。方法 代表性鲈鱼样品(脂肪含量11%)经冷冻干燥后ASE提取, 然后采用DSPE去除脂肪和串联SPE柱净化, 最后采用GCMS/MS检测, 同位素内标法定量。结果 本方法的检测限(MDLs)为0.16~3.29 pg/g; 具有良好的线性范围(R2>0.998)、准确度(除BDE30为53%以外, 其他组分回收率为62%~1139%)和精密度(RSD<20%); 测定参考物质的结果均在标准值范围内, 与气相色谱磁场电场双聚焦高分辨质谱(GC/HRMS)测定结果一致。结论 本方法为鱼样中PBDEs检测提供了一个快速、简便和可靠的方法, 适用于对痕量PBDEs残留水平的食用鱼进行人体健康风险评价研究。     

Accelerated,Microwave‐Assisted,and Conventional Solvent Extraction Methods Affect Anthocyanin Composition from Colored Grains

Anthocyanins are important dietary components with diverse positive functions in human health. This study investigates effects of accelerated solvent extraction (ASE) and microwave‐assisted extraction (MAE) on anthocyanin composition and extraction efficiency from blue wheat, purple corn, and black rice in comparison with the commonly used solvent extraction (CSE). Factorial experimental design was employed to study effects of ASE and MAE variables, and anthocyanin extracts were analyzed by spectrophotometry, high‐performance liquid chromatography‐diode array detector (DAD), and liquid chromatography–mass spectrometry chromatography. The extraction efficiency of ASE and MAE was comparable with CSE at the optimal conditions. The greatest extraction by ASE was achieved at 50 °C, 2500 psi, 10 min using 5 cycles, and 100% flush. For MAE, a combination of 70 °C, 300 W, and 10 min in MAE was the most effective in extracting anthocyanins from blue wheat and purple corn compared with 50 °C, 1200 W, and 20 min for black rice. The anthocyanin composition of grain extracts was influenced by the extraction method. The ASE extraction method seems to be more appropriate in extracting anthocyanins from the colored grains as being comparable with the CSE method based on changes in anthocyanin composition. The method caused lower structural changes in anthocaynins compared with the MAE method. Changes in blue wheat anthocyanins were lower in comparison with purple corn or black rice perhaps due to the absence of acylated anthocyanin compounds in blue wheat. The results show significant differences in anthocyanins among the 3 extraction methods, which indicate a need to standardize a method for valid comparisons among studies and for quality assurance purposes.     

ASE/HPLC测定纸塑包装中荧光增白剂VBL

建立加速溶剂萃取/高效液相色谱检测食品纸塑包装材料中荧光增白剂VBL的方法。以食品纸塑包装材料为研究对象,采用单因素试验和正交试验优化加速溶剂萃取法提取荧光增白剂VBL的条件:提取溶剂N,N-二甲基乙酰胺(DMF),静态萃取时间7 min,冲洗体积75%,循环次数3次,静态萃取温度110℃;选择了合适的色谱条件:采用月旭AQ-C18色谱柱,以甲醇∶水=90∶10为流动相,流速为1.0mL/min,荧光检测器激发波长362 nm、发射波长430nm,柱温为35℃,进样量10μL。采用该方法检测纸塑包装材料中VBL,当浓度0.1～10.0μg/mL时,浓度与峰面积之间存在良好的线性关系,线性方程为Y=313.13x-6.537 5(R2=0.999 9)。该方法的回收率为89.86%～91.40%,相对标准偏差RSD为2.07%～2.18%,检测限为0.20mg/kg,定量限0.40mg/kg。结果表明,该方法准确可靠,可用于纸塑包装材料中荧光增白剂VBL的检测。     

快速溶剂萃取仪提取葡萄籽中多酚物质的工艺优化

以新品种媚丽葡萄籽为研究对象,采用单因素实验研究了快速溶剂萃取仪提取多酚物质的工艺并进行了正交实验优化。结果表明:最佳提取条件为提取时间20 min、提取温度50℃、提取压强8.97 MPa、乙醇体积分数80%。在此条件下多酚提取量为28.89 mg/g。利用快速溶剂萃取仪提取葡萄籽多酚物质能极大地缩短提取时间。      

Validation and use of the CALUX-bioassay for the determination of dioxins and PCBs in bovine milk.

There is a strong need for the development of relatively cheap and rapid bioassays for the determination of dioxins and related compounds in food. A newly developed CALUX (Chemical-Activated LUciferase gene eXpression) bioassay was tested for its possible use to determine low levels of dioxins in bovine milk. Data show that this mammalian cell-based test is very sensitive for 2,3,7,8-substituted dioxins and related PCBs, thereby reflecting the relative potencies of these compounds in comparison to TCDD (TEF-values). The limit of detection was about 50 fg of TCDD. Furthermore, the response obtained with a mixture of dioxins was additive, in accordance with the TEF-principle. Milk fat was isolated by centrifugation followed by clean-up of the fat with n-pentane, removal of the fat on a 33% H2SO4 silica column, and determination of Ah receptor agonist activity with the CALUX-bioassay. An equivalent of 67 mg fat was tested per experimental unit, resulting in a limit of quantification around 1 pg i-TEQ/g fat. To investigate the performance of the method, butter fat was cleaned and spiked with a mixture of 17 different 2,3,7,8-substituted PCDD and PCDF congeners at 1, 3, 6, 9, 12 and 15 pg TEQ/g fat, as confirmed by GC/MS. In this concentration range, the method showed a recovery of TEQs around 67% (58-87%). The reproducibility, determined in three independent series showed a CV varying between 4% and 54%, with the exception of the sample spiked at 1 pg i-TEQ (CV 97%). The repeatability determined with the sample spiked at 6 pg i-TEQ/g showed a CV of 10%. Testing of 22 bovine milk samples, taken at different sites in The Netherlands, in the CALUX-assay showed combined dioxin and dioxin-like PCB levels equivalent to 1.6 pg TCDD/g fat (range 0.2-4.6). GC/MS analysis of these samples revealed an average level of 1.7 pg i-TEQ/g fat, varying between 0.5 and 4.7 pg i-TEQ/g fat. All five samples showing a GC/MS determined dioxin content of more than 2 pg i-TEQ/g fat gave a response in the CALUX-assay corresponding to more than 2 pg TCDD/g fat. These data clearly show that the CALUX-bioassay is a promising method for the rapid and low cost screening of dioxins in bovine milk.