程序升温大体积进样在HRGC-HRMS法测定食品中PCDD/F的应用

目的通过优化程序升温蒸发进样口的相关参数,建立测定食品中多氯代二苯并二噁英和多氯代二苯并呋喃(PCDD/Fs)的程序升温大体积进样高分辨气相色谱-高分辨质谱(HRGC-HRMS)方法。方法食品样品提取、净化分离和浓缩按《GB/T 5009.205-2007食品中二噁英及其类似物毒性当量的测定》规定进行,待测试样进样15μL,应用HRGC-HRMS结合同位素稀释技术测定其中PCDD/Fs。结果最佳条件为进样口初始温度115℃,蒸发相温度140℃,蒸发相吹扫流速为5 mL。大体积进样所获得的待测物峰面积及S/N存在显著增加(P0.05)。结论程序升温大体积进样方式能显著提高食品基质中PCDD/Fs的检测能力,有助于保证食品安全风险评估结果的准确可靠。     

婴幼儿配方奶粉中二噁英类物质的实验室检测质量控制影响因素分析

目的 评价常用质量控制措施在保证多实验室结果可比性中的适用性。方法 收集7家实验室在开展婴幼儿配方奶粉中二噁英及其类似物污染调查项目过程中的实验室空白、质控样品等测量数据,从空白控制、灵敏度、准确度、稳定同位素内标回收率等多方面评价实验室检测工作质量。结果 实验室空白中总多氯联苯平均含量为0.55 pg/g,多氯代二苯并-对-二噁英和多氯代二苯并呋喃的平均含量为0.08 pg/g。定量内标平均回收率为55.1%~81.5%。实验室空白水平、灵敏度、稳定同位素回收率等指标都符合GB 5009.205—2013《食品安全国家标准 食品中二噁英及其类似物毒物性当量的测定》规定要求,但不同实验室间在具体数值上存在差别。结论 各实验室都满足基于欧盟婴儿食品中限量的合规测定需要,但仍有必要进一步提升实验室食品分析的能力,以满足膳食暴露精确评估的需要。     

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。     

牛乳中二噁英类化合物标准物质的研制

研制乳粉中非添加二噁英类化合物的标准物质,加强我国二噁英类化合物实验室检测质控能力建设。方法 选择满足侯选物筛选原则和要求的牛乳样品作为候选物,经混匀、分装、冻干后,以高分辨气相色谱-高分辨质谱法同位素稀释技术测定多氯代苯并二噁英、多氯代苯并呋喃(PCDD/Fs)和二噁英样多氯联苯(dl-PCBs),经均匀性和稳定性试验后,采用多家实验室联合定值方法对样品中二噁英类化合物含量进行定值及不确定度分析。结果 经单因素方差分析和F检验,瓶间均匀性试验的检验值F均小于临界值F0.01(9,40)。室温下1年的稳定性试验结果显示,定值化合物一元线性拟合方程中斜率|b₁|均小于t(0.95,3)×s(b₁),表明特征值变化趋势无统计学意义。结论 本研究提出了二噁英类化合物定值结果,为二噁英检测提供质控参考和能力评价。     

甘肃省市售食品中二噁英类化合物污染现状研究

摘 要：目的 了解甘肃省居民市售食品中二噁英类化合物污染现状。方法 按总膳食研究方法,对我省8类市售食品样品（水产及其制品、肉类及其制品、蛋及其制品、乳及乳制品、谷类及其制品、薯类及其制品、豆类及其制品、蔬菜类及其制品）中17种多氯代苯并二噁英和多氯代苯并呋喃（polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, PCDD/Fs）同系物和12种二噁英样多氯联苯（dioxin like polychlorinated biphenyls, dl-PCBs） 同系物进行含量测定和毒性当量浓度汇总分析和评价。结果 甘肃省送检的食物样品中水产、肉类均检出二噁英类化合物,其余6类食品样品个别同系物未检出。按TEQ 计时,肉类食品样品中PCDD/Fs和dl-PCBs毒性当量浓度最高,均为0.08pgTEQ/g。结论 甘肃省8类市售食品样品中动物性食品二噁英类化合物检出率高于植物性食品,肉类食品样品中PCDD/Fs和dl-PCBs毒性当量浓度均高于全国平均水平。建议对我省二噁英类化合物暴露水平高的食品进行长期监测,提出相应的风险管理措施。     

母乳和不同婴儿配方乳粉中蛋白质消化性研究

以母乳为对照,模拟婴儿胃肠消化环境对两种普通婴儿配方乳粉和一种适度水解蛋白婴儿配方乳粉中的蛋白质进行体外模拟消化研究,测定其体外胃、肠以及胃肠总消化率和消化液中的氨基酸含量。结果表明体外胃消化率、肠消化率及胃肠总消化率从高到低依次均为:母乳适度水解蛋白婴儿配方乳粉婴儿配方乳粉B婴儿配方乳粉A,且母乳中蛋白质的体外消化率均显著高于适度水解蛋白婴儿配方乳粉和两种普通婴儿配方乳粉(p0.05)。此外,在体外胃肠总消化液中,适度水解蛋白婴儿配方乳粉中的必需氨基酸总量显著高于母乳和婴儿配方乳粉A、B(p0.05),母乳和适度水解蛋白婴儿配方乳粉中的氨基酸总量显著高于婴儿配方乳粉A、B(p0.05)。与两种普通婴儿配方乳粉相比,适度水解蛋白婴儿配方乳粉中蛋白质能更好的被机体消化利用,营养价值更高。     

优良母乳代乳品—婴儿配方乳粉

随着我国食品工业和乳品工业的发展,优良的母乳代乳品——婴儿配方乳粉Ⅰ和婴儿配方乳粉Ⅱ于七十年代末和八十年代初相继在我国问世,这两种产品的原名分别称为婴儿奶粉和母乳化奶粉。牛乳(包括羊乳)及乳粉虽为极好的营养食品,但因其蛋白质、脂肪和碳水化合物的组成及质量与人乳不同,因而在作为母乳代乳品喂养婴儿时出现了这样或那样的缺陷。过量的酪蛋白和不足的乳糖引起了严重的消化问题,维生素、微量元素和亚油酸的不足对婴儿身体及智力发育的影响难以估量,免疫性物质的匮乏引起婴儿的患病率上升,等等弊端,驱使人们去考虑制造与母乳成分     

2,4一二硝基苯肼比色法测定婴幼儿配方食品和乳粉及其制品中总抗坏血酸(Vc)的含量

随着婴儿配方食品和乳粉及其制品的发展,其中的营养成分及强化元素的含量已经普遍受到社会的关注.本文主要阐述了利用2,4二硝基苯肼比色法测定婴儿配方食品和乳粉及其制品中总抗坏血酸(Vc)含量的测定方法.本方法具有操作简便、快速、准确度高、不需要特殊仪器的特点.     

酸水解法测定婴幼儿配方食品、乳和乳制品中二噁英类持久性有机污染物

建立适合婴幼儿配方食品、乳及乳制品中二噁英类持久性有机污染物(POPs)分析的前处理技术。方法 利用索氏抽提法和酸水解法分别提取婴幼儿配方食品、乳及乳制品中的脂肪,比较两种方法的差异。结果对于婴幼儿配方食品,两种萃取方法测得的结果差异不大;对于乳粉和液态鲜乳,索氏抽提法的结果与实际值偏差较大。结论 不同类型乳粉的组分(酪蛋白与乳清蛋白比例等)和加工工艺差异很大,酸水解法能有效地使乳及乳制品中的脂肪转变为游离态,提高了脂肪的提取率,为准确测定POPs奠定基础。     

鱼肉粉中二噁英及二噁英类多氯联苯成分分析标准物质的研制

目的 研制鱼肉粉基体中二噁英及二噁英类多氯联苯成分分析标准物质。方法 以草鱼为原料,采用污染物含量较高的飞灰样品配合饲料喂养,经去骨去皮,匀浆干燥、研磨筛分等过程后制得候选标准物质,经均匀性和稳定性评价,由8家实验室定值,分析评估其不确定度。结果 经检验基体标准物质均匀性良好,能长期稳定保存至少12个月,PCDD/Fs的特性值为0.017～1.4 pg/g,扩展不确定度为0.02～0.6 pg/g;DL-PCBs的特性值为0.54～16 pg/g,扩展不确定度为0.28～6 pg/g。此标准物质已通过标准物质评审,编号为GBW(E)100741。结论 该标准物质均匀性及稳定性良好,定值准确,可用于食品、环境等领域二噁英及二噁英类多氯联苯的量值溯源、分析检测、质量控制、实验室能力验证、分析仪器校准、分析方法的准确性评估和验证等。     

Open dumping site in Asian developing countries: a potential source of polychlorinated dibenz-p-dioxins and polychlorinated dibenzofurans

Open landfill dumping areas for municipal wastes in Asian developing countries have recently received particular attention with regard to environmental pollution problems. Because of the uncontrolled burning of solid wastes, elevated contamination by various toxic chemicals including dioxins and related compounds in these dumping sites has been anticipated. In this study, concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (PCBs) were determined in soils from dumping sites in the Philippines, Cambodia, India, and Vietnam. Residue concentrations of PCDD/Fs and coplanar PCBs in dumping site soils were apparently greater than those in soils collected in agricultural or urban areas far from dumping sites, suggesting that dumping sites are potential sources of PCDD/Fs and related compounds. Observed PCDD/F concentrations in soils from dumping sites in the Philippines and Cambodia were comparable or higher than those reported for dioxin-contaminated locations in the world (e.g., near the municipal waste incinerators and open landfill dumping sites). Homologue profiles of PCDD/Fs in dumping site soils from the Philippines and, to a lesser extent, from Cambodia and India reflected patterns of samples representing typical emissions, while profiles of agricultural or urban soils were similar to those of typical environmental sinks. This result suggests recent formation of PCDD/Fs in dumping site areas and that open dumping sites are a potential source of dioxins in Asian developing countries. Uncontrolled combustions of solid wastes by waste pickers, generation of methane gas, and low-temperature burning can be major factors for the formation of dioxins in dumping sites. Elevated fluxes of PCDD/Fs to soils in dumping sites were encountered in the Philippines, Cambodia, India, and Vietnam-Hanoi, and these levels were higher than those reported for other countries. Considerable loading rates of PCDD/Fs in the dumping sites of these countries were observed, ranging from 20 to 3900 mg/yr (0.12-35 mg TEQ/yr). PCDD/F concentrations in some soil samples from the Philippines, Cambodia, India, and Vietnam-Hanoi exceeded environmental guideline values, suggesting potential health effects on humans and wildlife living near these dumping sites. The estimated intakes of dioxins via soil ingestion and dermal exposure for children were higher than those for adults, suggesting greater risk of dioxin exposure for children in dumping sites. To our knowledge, this is the first comprehensive study on PCDD/Fs contamination in open dumping sites of Asian developing countries. On the basis of the result of this study, we have addressed a new environmental issue that open dumping sites are potential sources of PCDD/Fs and related compounds, and dioxin contamination in dumping sites may become a key environmental problem in developing countries.     

Effects of cooking on concentrations of polychlorinated dibenzo-p-dioxins and related compounds in green leafy vegetable 'Komatsuna'.

The effects of ordinary household cooking processes on concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs) (dioxins) were investigated in 'komatsuna', a green leafy vegetable popular in Japan. The concentrations of dioxins were compared using isomer-specific analyses of both uncooked and cooked edible parts of the plant. The mean total 2,3,7,8-chlorine substituted PCDD and PCDF concentrations were reduced from 46.53 pg/g and 0.714 pg/g to 8.301 pg/g and 0.210 pg/g by washing with tap water, and further reduced to 6.054 pg/g and 0.148 pg/g by subsequent boiling, respectively. The cooking processes markedly decreased the concentrations of PCDD/Fs, while having little effect on those of dioxin-like PCBs. The mean total concentration as 2,3,7,8-tetraCDD equivalents (TEQ) was reduced from 0.058 pgTEQ/g to 0.026 pgTEQ/g by washing with tap water and further reduced to 0.019 pgTEQ/g by subsequent boiling. These results suggest that ordinary cooking processes provide a means of reducing the level of dioxins in green leafy vegetables.     

Severe PCDD/F and PBDD/F pollution in air around an electronic waste dismantling area in China

The presence of chlorinated and brominated compounds in electronic waste (EW) results in the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) during the EW dismantling process. In this study, we investigated the dioxins present in ambient air around the EW dismantling area Guiyu in Guangdong, China. Atmospheric PCDD/F (tetra to octa) abundances and toxic equivalent (TEQ) values were 64.9-2365 pg/m3 and 0.909-48.9 pg of W-TEQ/m3, respectively; these are the highest documented values of these compounds found in ambient air in the world. PBDD/Fs (eight 2,3,7,8-substituted congeners) were also found at high pollution levels (concentrations of 8.124-61 pg/m3 and 1.6-2104 pg of I-TEQ/m3). Profiles of the 2,3,7,8-PCDD/F homologues in the air of Guiyu differed from typical urban air patterns reported in the literature, and the concentration of homologues increased with the chlorination degree of 2,3,7,8-PCDD/Fs except for OCDF. The severe dioxin pollution present in Guiyu substantially influences the adjacent area of Chendian, where atmospheric PCDD/F and 2,3,7,8-PBDD/F levels are higher than those of common urban areas in the world. Our tentative inhalation risk assessment showed that residents in Guiyu are at a high risk of exposure to dioxins. The total PCDD/F intake doses far exceed the WHO 1998 tolerable daily intake limit of 1-4 pg of W-TEQ kg(-1) day(-1).     

Dietary uptake of dioxins (PCDD/PCDFs) and dioxin-like PCBs in Spanish aquacultured turbot (Psetta maxima)

The human population is exposed to dioxins (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) mainly through diet; bioaccumulation and biomagnification in aquatic environment results in fishery products and by-products being an important vector to humans. The determination of PCDD/Fs and dl-PCBs in fillets of young turbots (Psetta maxima) (0-2 years) from aquaculture plant (Galicia, Spain) (N = 21) and in feeding stuffs were carried out, and dietary accumulation values and lipid-normalized biomagnification factors (BMF) relating concentration in fish and in feed were calculated. Levels found in feeding stuffs (0.5 pg TEQ-PCDD/F/g and 1.6 pg TEQ-dl-PCB/g), and turbots (0.13-0.27 pg TEQ-PCDD/F/g fresh weight and 0.35-1.2 pg TEQ-dl-PCB/g fresh weight) were below maximum permitted levels set by EC. Levels of toxic compounds in feeding stuff are reflected in fish fillets; predominant isomers are 2,3,7,8-TCDF, OCDD, 1,2,3,7,8-PeCDF, 2,3,4,7,8-PeCDF and 1,2,3,4,6,7,8-HpCDD, and PCBs 118, 105, 156 and 167. Relevant compounds accounting for total toxicity are the same congeners in feeding stuff and turbots: 2,3,4,7,8- PeCDF; 2,3,7,8-TCDF; 2,3,7,8-TCDD and 1,2,3,7,8-PeCDD, and PCB 126. Higher accumulation efficiency values were obtained for dl-PCBs (30-46%); tetra- and penta-chloro substituted PCDD/Fs showed the highest values (27-34%) of the PCDD/F group. Biomagnification was shown for these compounds (BMF around 1.5).     

Dietary exposure and risk assessment of polychlorinated dibenzo-p-dioxins,polychlorinated dibenzofurans and dioxin-like polychlorinated biphenyls of the population in the Region of Valencia (Spain)

Dietary exposure of the Valencia Region population to polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and PCBs was assessed in the Region of Valencia in 2010–2011. A total of 7700 food samples were collected. Occurrence data were combined with consumption data to estimate dietary exposure in adults (>15 years of age) and young people (6–15 years of age). The estimated intake was calculated by a probabilistic approach. Average intake levels (upper-bound scenario) were 1.58 and 2.76 pg toxic equivalent (TEQ) kg^?1 body weight (bw) day^?1 for adults and young people, respectively. These average intakes are within range of the tolerable daily intake of 1–4 pg WHO-TEQ kg^?1 bw day^?1 recommended by WHO, and slightly above the tolerable weekly intake (TWI) of 14 pg TEQ kg^?1 bw week^?1 and the Provisional tolerable monthly intake of 70 pg TEQ kg^?1 bw month^?1 set by the Scientific Committee on Food and the Joint FAO/WHO Expert Committee on Food, respectively. These results show that the contamination levels in food and therefore the exposure of the general population to PCDD/Fs and PCBs have declined in this region and therefore show the efficiency of the European risk-management measures. In terms of risk characterisation, the results showed that, under the upper-bound scenario, 22% of the adult and 58% of the young people population could exceed the TWI.     

Dioxin-like polychlorinated biphenyls in marine fish from Shandong,China, and human dietary exposure

The occurrence and human dietary exposure of 12 dioxin-like polychlorinated biphenyls (DL-PCBs) in 41 marine fish samples from Shandong Province of China were investigated. The DL-PCB congeners were extracted using automated Soxhlet extraction, purified via a composite column clean-up procedure and analysed by gas chromatography-triple quadrupole mass spectrometry. DL-PCB congeners were found in all analysed samples, with a mean concentration of 0.887 ng/g ww (wet weight). The TEQ concentrations of DL-PCBs in individual fish samples ranged from 0.011 to 9.214 pg WHO TEQ/g ww. The mean dietary intake for all fish species was 36.5 pg TEQ/kg bw/month, which was lower than the provisional tolerable monthly intake of 70 pg TEQ/kg bw/month set by the Joint FAO/WHO Expert Committee on Food Additives. To monitor the trend of DL-PCBs in fish for food safety control, it is necessary to maintain a surveillance programme.     

Butter as an indicator of regional persistent organic pollutant contamination: further development of the approach using polychlorinated dioxins and furans (PCDD/Fs), and dioxin-like polychlorinated biphenyls (PCBs)

The potential for use of butter as a widely available, relatively uniform lipid-rich matrix for the determination of spatial distributions of persistent organic pollutants has already been demonstrated. The present study determines the contributions to toxicity equivalence (TEQ) from polychlorinated dioxins and furans (PCDD/Fs) and polychlorinated biphenyls (PCBs) using butter samples from 24 countries world wide. Concentrations of PCDD/Fs and dioxin-like PCBs ranged from 0.07 to 5.69 pg ΣWHO-TEQ g -1 lipid. For most samples, PCDD/F TEQ fell within ranges reported for European dairy products over the last decade (0.3-2 pg g -1 lipid I-TEQ), though a single sample from Spain was a notable exception. Other than this sample, the highest values were recorded for samples from the Netherlands and Italy, with those from India, China and Tunisia also being relatively high. The contribution from non- ortho -PCBs was particularly significant in samples from Germany, Austria, Italy, the Czech Republic, Tunisia, India and Argentina. Although overall TEQs were generally highest in European and Mediterranean butters, elevated levels were also apparent in industrializing regions of Asia (India, China) and Latin America (Argentina). More detailed regional studies would be necessary to identify likely dioxin and PCB sources in each case. Nevertheless, this study supports the utility of butter as a monitoring matrix that may be especially applicable in regions for which monitoring programmes are currently lacking.     

The use of the DR CALUX bioassay and indicator polychlorinated biphenyls for screening of elevated levels of dioxins and dioxin-like polychlorinated biphenyls in eel

The DR CALUX bioassay is a very suitable screening method for dioxins and dioxin-like-PCBs in feed and food. This was, e. g. demonstrated in a survey in the Netherlands to control the dioxin levels in eel. The DR CALUX assay, but also indicator polychlorinated biphenyls (PCB) were evaluated as a screening method. Based on the limit for polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/F) [at that time 8 pg toxic equivalents (TEQ)/g eel], and the relation between PCDD/F and dioxin-like-PCB, a decision limit of 30 pg TEQ/g eel was used for screening of 153 field samples. Suspected samples (21) and part of the higher contaminated negative samples (35) were analyzed by GC/MS for dioxins, non-ortho, mono-ortho and indicator PCB, revealing 13 samples exceeding the action limit of 30 pg TEQ/g eel. Only one sample slightly exceeded the dioxin level of 8 pg TEQ/g eel. The relatively low sensitivity for mono-ortho PCB was overcome by the use of reference samples, as shown by the correlation of 0.93 between GC/MS and CALUX determined total TEQ levels. The present data show that the DR CALUX assay can be used for screening of total TEQ levels in eel. The use for dioxins only requires a safe, and therefore relatively low, decision limit. The indicator PCB also showed a good correlation with total TEQ levels, mainly due to the large contribution of the mono-ortho PCB at higher concentrations. The relation with dioxins was very poor and as such indicator PCB seem less suitable than the DR CALUX assay for screening for dioxins only. The present study clearly shows that part of the wild eel samples contains high total TEQ levels and will exceed the future European Union limit of 12 pg TEQ/g eel for dioxins and dioxin-like PCB. Especially at high TEQ levels, dioxin-like PCB contribute most to the total TEQ. In practice, wild eel presents only a minor part of the eel consumed.     

Dietary intakes of polychlorinated dibenzo- p -dioxins, dibenzofurans and polychlorinated biphenyls in Finland

Samples of cow milk, pork, beef, eggs, rainbow trout, flours and vegetables were analysed for 17 polychlorinated dibenzo- p -dioxins and dibenzofurans (PCDD/F) and 36 polychlorinated biphenyls (PCB). Daily dietary intake of PCDD/Fs as toxic equivalent (I-TEq) and PCBs (PCB-TEq) was assessed using food consumption data from a 24-h dietary recall study for 2862 Finnish adults. The calculated intake of PCDD/F was 46pg I-TEq day -1 . The current level was about half of the earlier estimation of intake in Finland made in 1992. The assessed PCB intake was 53pg PCBTEqday -1 . Thus, the total intake of PCDD/Fs and PCBs was 100pg TEqday -1 (1.3pg TEqkg -1 b.w.day -1 ), which is within the range of tolerable daily intake (TDI) proposed by the WHO (1-4pg TEqkg -1 b.w.day -1 ).     

Persistent Organic Pollutants in Fish Oil Supplements on the Canadian Market: Polychlorinated Dibenzo-p-Dioxins, Dibenzofurans, and Polybrominated Diphenyl Ethers

ABSTRACT:  Canadians are interested in improving their diet through the consumption of fish oil food supplements, which are marketed to be rich in omega-3 fatty acids. Convenience samples of omega-3 enriched dietary supplements ( n  = 30) were collected in Vancouver, Canada, between 2005 and 2007. All of the omega-3 supplements were analyzed for polychlorinated dibenzo- p -dioxins/furans (PCDD/Fs) and polybrominated diphenyl ethers (PBDEs) and, although every sample was found to contain detectable residues of PBDEs, only 24 samples were found to have PCDD/F concentrations above the level of detection. PCDD/F concentrations ranged from 0.05 pg TEQ/g lipid to 45.7 pg TEQ/g lipid in salmon and shark oils, respectively. Maximum PBDE concentrations similarly were observed in shark oil (113 μg/kg lipid), however, most supplements had concentrations below 5 μg/kg lipid. Average PCDD/F and PBDE intake estimates, based on consumption of maximum supplement dose following product label recommendations, were 4.32 pg TEQ/d and 25.1 ng/d lipid, respectively.