植物源食品中总砷和无机砷的分布浅析

砷化合物在人体内有蓄积作用,能引起急性或慢性中毒。生物体内的砷主要是有机砷,而砷的致毒性和致癌作用主要取决于无机砷的含量。在食品污染物限量标准中,将砷作为非有意添加的污染物,并规定了不同食品的总砷或无机砷限量标准。本文采用氢化物原子荧光光谱法测定植物源食品中的总砷和无机砷含量,讨论了总砷和无机砷在不同植物源食品中的分布。这有助于我们了解不同种类植物对砷的富集能力。     

深圳周边海域海产品中二十碳五烯酸、二十二碳六烯酸含量分析

分析深圳周边海域常见水产品中EPA、DHA含量。将购买的22种海产品取可食部位,用有机溶剂提取脂肪,甲酯化后的脂肪酸用气相色谱分离分析。结果表明:EPA含量从沙尖鱼的4.38 mg/100 g到秋刀鱼的574 mg/100 g,DHA含量从红三鱼的4.05 mg/100 g到秋刀鱼的881 mg/100 g,EPA+DHA总含量从沙尖鱼的4.38 mg/100 g到秋刀鱼的1455 mg/100 g。不同海产品中EPA、DHA含量存在显著性差异。结论:海产品中EPA、DHA含量因种类不同而存在差异。黄花鱼、海鲈鱼、带鱼、金鲳鱼、秋刀鱼的EPA+DHA总含量较高,每日按推荐量食用,可满足人体对EPA+DHA的需求。     

湛江海域6种经济海藻的营养成分分析

分析采自湛江海域的6种经济海藻的营养成分。除海蒿子外,碳水化合物是这些海藻的主要营养成分,平均为39.49%;粗蛋白含量4.08%~23.70%;粗脂肪含量最低,其中的4种皆不足藻体干重的0.5%;矿物质含量丰富,异枝麒麟菜的Fe,Mn,Zn的含量都较高,分别为261.20 mg/100g,62.27 mg/100g,206.10 mg/100g;氨基酸含量较高,均符合1973年联合国粮农组织/世界卫生组织（FAO/WHO）推荐的理想蛋白质模式;不少种类中镉、铅、砷等含量超出我国食品卫生标准。海藻体内的营养成分含量因海藻种类和生长海域的不同而有差异。     

原子荧光光谱法测定绵头雪莲花中的痕量砷

采用原子荧光光谱法测定绵头雪莲花中的微量砷,测量结果为0.5994 mg/kg,方法检出限为0.02μg/L,回收率为93%~105%,RSD为0.607%。测量结果表明绵头雪莲花中的砷含量没有超出国家安全标准,而且原子荧光光谱法对于测定绵头雪莲花中的砷含量具有精密度高、操作简单、快速和灵敏度高的优点。     

氢化物发生原子荧光光度法测定果蜡中的砷含量

采用微波消解法对某公司生产的吗啉脂肪酸盐果蜡进行前处理,应用氢化物发生原子荧光光度法测定果蜡中砷含量。实验优化了载流HCl和还原剂KBH4的浓度条件,并测定了标准曲线、方法检出限、精密度和加标回收率。当盐酸浓度为5.0%,硼氢化钾浓度为20.0 g/L,测定6.0μg/L的砷溶液时,荧光强度达最大值,仪器灵敏度最高。砷浓度范围在2.0~10.0μg/L,标准曲线方程为:I=125.945 C+144.86,相关系数为0.999 3,方法检出限为0.0305μg/L,精密度为1.61%。测定了果蜡样品中砷加标量为2.0、4.0、6.0μg/L时的加标回收率,回收率在92.65%~101.18%之间,平均回收率为95.78%。实验测得该批次果蜡中砷含量为0.048 mg/kg,满足国家标准砷元素限量要求。     

食用海产品中亚硝酸盐含量的分析

根据食品中亚硝酸盐测定的国家标准,针对食用海产品的特点,应用分光光度法,对海虾皮、海蜒、淡菜干、海虾米、海带、海蜇、紫菜等十多种海产品进行检测,并对检测数据进行统计分析,得出上述海产品中亚硝酸盐的含量情况。结果表明:海虾皮、凤尾鱼干、对虾干中亚硝酸盐含量相对偏高,已超过国家标准GB2762—2005中鱼肉的限量指标(3 mg/kg),但仍低于上述国标中酱腌菜的限值(20 mg/kg)和GB2760—2011中腌腊肉制品类的限量指标(30 mg/kg);正规渠道经销的大部分海产品亚硝酸盐含量低于国家标准允许的范围。     

闽东沿海养殖紫菜和海带中无机砷含量的监测及其安全性评价

通过酸浸提-银盐法检测闽东沿海养殖海带和紫菜中无机砷的含量,并对其安全性进行评价。结果表明:紫菜、干海带以及盐渍海带样品的无机砷平均值分别为0.16 mg/kg、0.19 mg/kg和0.22 mg/kg,明显低于国家标准的限量值1.5 mg/kg。海带和紫菜等藻类产品总砷含量比较高,但无机砷所占比例仅为0~0.98%。安全性评价结果表明砷污染对于海藻食用风险性贡献很小。     

不同砷含量下煤中砷与硫的脱洗研究

为研究不同砷含量下煤中砷和硫的脱洗率,将砷含量分为3个等级分别讨论,即:0 mg/kg～5.50 mg/kg,5.50 mg/kg～8.00 mg/kg和8.00 mg/kg以上.研究发现,在砷含量为0 mg/kg～5.50 mg/kg之间,砷的赋存状态极为复杂,总体以有机态为主,洗选后,砷容易富集到精煤之中.全硫脱洗率和砷含量无相关性,而与有机硫占全硫的比重呈负相关;当砷含量大于5.50mg/kg时,随着砷含量的增加,砷逐渐以无机态为主,易于洗选.     

茶叶中砷、铅盐含量的测定

在有些不合格的茶叶中砷和铅的含量较高,茶叶中砷和铅主要来自于土壤和农药的施用.按我国国家标准规定[1-2]:茶叶中砷的含量不得高于0.5mg/kg;铅的含量不得高于1mg/kg.砷的化合物具有强烈的毒性,人若服用0.005g-0.05g就可引起急性中毒,服用0.1 g-0.2g即可致死[3];铅是有害金属之一,当人们长...     

新型家用除砷氟净水器研制与试验研究

针对我国部分地区饮用水砷、氟含量超标问题,设计出一种分散型的家用净水器,以预氧化—吸附—膜处理为技术路线,以曝气—改良活性炭—活性氧化铝—反渗透膜为实际组成单元,分别对单独除砷、单独除氟、砷氟共除效果进行实验测定。实验结果表明,单砷浓度1.994 mg/L,单氟浓度（以F-计）4.925 mg/L,及砷氟共存砷浓度2.128 mg/L,氟浓度（以F-计）5.293 mg/L时,出水砷氟浓度均符合《生活饮用水卫生标准》（GB 5749-2006）。砷氟共除时,浓水砷氟含量符合《污水综合排放标准》（GB 8978-1996）,可以安全排放。说明此净水器方法可行,有实用价值。     

Dietary intakes and food sources of n−6 and n−3 PUFA in french adult men and women

The intake of individual n−6 and n−3 PUFA has been estimated in 4,884 adult subjects (2,099 men and 2,785 women), volunteers from the French SU.VI.MAX intervention trial. The food intakes of each subject were recorded in at least ten 24-h record questionnaires completed over a period of 2.5 yr, allowing the estimation of the daily intake of energy; total fat; and linoleic, α-linolenic, arachidonic, eicosapentaenoic (EPA), n−3 docosapentaenoic (DPA), and docosahexaenoic (DHA) acids. The mean total fat intake corresponded to 94.1 g/d (36.3% of total energy intake) in men and 73.4 g/d (38.1% of energy) in women. The intake of linoleic acid was 10.6 g/d in men and 8.1 g/d in women, representing 4.2% of energy intake; that of α-linolenic acid was 0.94 g/d in men and 0.74 g/d in women, representing 0.37% of energy intake, with a mean linoleic/α-linolenic acid ratio of 11.3. The mean intakes of long-chain PUFA were: arachidonic acid, 204 mg/d in men and 152 mg/d in women; EPA, 150 mg/d in men and 118 mg/d in women; DPA, 75 mg/d in men and 56 mg/d in women; DHA, 273 mg/d in men and 226 mg/d in women; long-chain n−3 PUFA, 497 mg/d in men and 400 mg/d in women. Ninety-five percent of the sample consumed less than 0.5% of energy as α-linolenic acid, which is well below the current French recommendation for adults (0.8% of energy). In contrast, the mean intakes of long-chain n−6 and n−3 PUFA appear fairly high and fit the current French recommendations (total long-chain PUFA: 500 mg/d in men and 400 mg/d in women; DHA: 120 mg/d in men and 100 mg/d in women). The intakes of α-linolenic acid, and to a lesser extent of linoleic acid, were highly correlated with that of lipids. Whereas the main source of linoleic acid was vegetable oils, all food types contributed to α-linolenic acid intake, the main ones being animal products (meat, poultry, and dairy products). The main source of EPA and DHA (and of total long-chain n−3 PUFA) was fish and seafood, but the major source of DPA was meat, poultry, and eggs. Fish and seafood consumption showed very large interindividual variations, the low consumers being at risk of insufficient n−3 PUFA intake.     

舟山群岛新区海产品中甲醛含量分析

应用高效液相色谱一紫外检测法分析了购至舟山国际水产城和沈家门东河市场的海产品中的甲醛。结果显示：不同市场购买的同种海产品中甲醛含量相差不明显,而不同种类的海产品中甲醛的含量差别巨大,其中龙头鱼甲醛含量最高达96．7mg／kg,大部分样品中甲醛含量小于5．0mg／kg,海鳗甲醛则未检出。     

超声对铁锰氧化物吸附废水中无机砷的强化效应

快速吸附去除废水中无机砷的技术,由于其高效性成为污水处理领域亟需的一种技术。采用草酸沉淀法制备了不同铁锰比（物质的量比）的铁锰复合草酸盐,以铁锰复合草酸盐为前驱体通过热分解得到铁锰元素均匀分布的复合氧化物,以铁锰复合氧化物为吸附剂吸附去除废水中的无机砷。在超声波辅助下,铁锰复合氧化物对废水中无机砷的去除效果显著。实验结果表明,铁锰物质的量比为6:4的铁锰复合氧化物,因具有较高的比表面积（396.6 m²/g）和独特的形貌,超声辅助1 min对废水中无机砷的吸附率可达95%以上。吸附动力学研究表明,该吸附过程符合准二级动力学模型,吸附速率常数为1.11 g/（mg·s）。吸附剂再生实验表明,将吸附砷的吸附剂采用碳酸氢钠溶液洗脱重复用于吸附实验,吸附剂重复使用3次对砷的吸附率仍可达到83.6%。     

Quality of groundwater in eastern Croatia. The problem of arsenic pollution

Groundwater in the area of eastern Croatia contains high concentrations of iron, manganese, ammonia, organic substances and arsenic. The appearance of inorganic arsenic in groundwater is mainly caused by arsenic from natural geological sources. Since the groundwater is the main source of drinking water for the population in this area, almost 200,000 people are daily drinking water with arsenic concentration ranging from 10 to 610 μg/L. The Croatian legislation recently revised the maximum concentration limit (MCL) for arsenic in drinking water to 10 μg/L. The population in the two towns (Osijek and Vinkovci) of this region is supplied with groundwater processed by coagulation-filtration method, but in the other towns and villages water treatment implies only rapid sand filtration. Both methods for water treatment have resulted with higher arsenic concentration than MCL, so the main goal of this study was determination of population exposure to arsenic via drinking water and possible improvement of drinking water quality. Population exposure to arsenic via drinking water is determined with hair analysis, since the hair arsenic concentration is one of three most commonly employed biomarkers used to identify or quantify overall arsenic exposure. During this study the preliminary analyses of hair arsenic concentrations in several towns and villages in eastern Croatia were provided. The positive correlation between heightened arsenic concentration in drinking water and hair arsenic concentration was determined. In order to improve drinking water quality e.g. arsenic removal from contaminated drinking water, different modified adsorbents were used and compared (zeolite–clinoptilolite, manganese greensand and cationic exchange resin). Adsorbents were chemically modified and saturated with Fe(III) ions, while the arsenic solutions were prepared by processed groundwater.     

Food colorants: their past,present and future

Whether we are purchasing fresh vegetables from a market stall, ready meals from the supermarket, eating at home or in a five‐star restaurant, we use colour to tell us what to expect in terms of taste, nutrition and safety. This review considers the techniques that have, over the years, been employed to modify the colour of our food, and the interactions of these techniques with issues of safety and nutrition. The demand for brightly coloured food resulted in the incorporation of some questionable inorganic and organic chemistry being used in food products. A limited number of synthetic dyes are still used in food today, but health concerns and the consumer‐driven demand for natural colorants has brought about a change in the way food is coloured. The proliferation of products with labels that state they contain “No artificial colours” on supermarket shelves suggests that the future of azo dyes and their various derivatives is strictly limited. Nature produces an abundance of colours and many of these are extracted and used as natural food colorants; however, they are subject to application limitations and stability problems. Significant research by academia and industry into methods to stabilise and expand the application possibilities for the various approved natural food colorants is ongoing, but most developments that food colour manufacturers proclaim are enhanced vehicles for delivering established natural pigments into food products.     

Chromium content in foods and dietary intake estimation in the Northwest of Mexico

Chromium is an indispensable nutrient for the carbohydrates and lipids metabolism. In this study the chromium content in the twenty main foods of the diet from Northwestern Mexico was determined, as well as the daily mean intake which was estimated based on the food intake basket of this region. Chromium content was analyzed by atomic absorption spectrophotometry using the graphite furnace technique and previous digestion of foods in microwave oven. The chromium mean intake was estimated considering the chromium daily mean intake for person per day and the chromium content of the foods analyzed in this study. The range chromium content in the foods analyzed was between 0.0004 and 0.1641 microgram/g dry weight. White cheese showed the highest chromium content followed by pasta soup, wheat tortilla, bread and meat. The main foods chromium contributors in the diet were: wheat tortilla (20%), white cheese (11%), corn tortilla (11%), pasta soup (10%), milk (10%), meat (9%) and white bread (8%). The daily chromium intake was 30.43 +/- 1.6 micrograms/d. Chromium values obtained in the food analyzed are considered low. Moreover, chromium intake obtained from the diet is not enough to meet the safety and adequate daily chromium intake. Therefore, the population from the Northwestern Mexico has a suboptimal dietary chromium intake.     

The intake of carotenoids in Denmark

To estimate the intake of carotenoids in the Danish population Danish fruits and vegetables were screened with an HPLC method consisting of extraction with ethanol:tetrahydrofuran, separation by reversed phase HPLC with the mobile phase acetonitril:methanol:dichlormethan, triethylamin, BHT and detection at 450 nm. Food intakes were estimated by the national dietary surveys (1995) from 7 days' food registration (n = 1837 adults), which allows the whole diet to be described by the mean intake and intake distribution of 207 raw or semiprepared foods. By multiplication with the mean content in the foods the mean intake and intake distribution of the carotenoids were calculated. Carrots and tomatoes have both high contents of carotenoids (8,450 μg/100 g α‐ + β‐carotene and 4,790 μg/100 g lycopene, respectively) and high intakes (19 and 15 g/day, respectively) and were responsible for 47% and 32%, respectively, of the mean intake of carotenoids of 4.8 mg/day. A median value of 4.1 mg/day was found indicating skewed intake distributions. The difference between men and women was 0.4 mg/day (p < 0.0065). Only four carotenoids, α‐carotene, β‐carotene, lutein and lycopene, contributed significantly to the intake. Women had a 6 g/day higher intake of carrots than men (p < 0.0001), which explains the 0.4 mg/day difference in the intake between men and women, and the 25th percentile was well over zero (5.0 g/day for men and 5.9 g/day for women) indicating that almost everybody consumed at least some carrots.     

Equilibrium and dynamic studies of the removal of As(III) and As(V) from contaminated aqueous systems using a functionalized biopolymer

BACKGROUND: A study of the removal of arsenic from a sample of actual groundwater using crosslinked xanthated chitosan is described. RESULTS: Removal of As(III) and As(V) was studied at pH 7.5 under equilibrium and dynamic conditions. The equilibrium data were fitted to Langmuir and Freundlich adsorption models and the various model parameters evaluated. The monolayer adsorption capacity from the Langmuir model for xanthated chitosan flakes (XCF) (As(V) 20.0 ± 0.56 mg g^?1; As(III) 33.0 ± 0.32 mg g^?1) were lower than obtained for xanthated chitosan granules (XCB) (As(V) 36.0 ± 0.52 mg g^?1; As(III) 48.0 ± 0.45 mg g^?1). Adsorption of As (V) was unaffected by the presence of other anions while in the case of As(III) the presence of sulfate and silicate caused a 26.5–50.9% decrease in adsorption. A sample (940 bed volumes) of a groundwater spiked with 200 µg L^?1 As(V) treated with XCF in column experiments reduced the arsenic concentration to < 10 µg L^?1. The adsorbent was also successfully applied for the removal of total inorganic arsenic down to < 10 µg L^?1 from real samples of arsenic‐contaminated groundwater. CONCLUSION: Xanthated chitosan was an efficient adsorbent for the removal of both forms of arsenic from groundwater under near neutral conditions. The presence of sulfur and the amino groups resulted in increased adsorption capacity of the sorbent. Copyright © 2012 Society of Chemical Industry     

盐酸脱除聚磷酸中砷的工艺方法研究

聚磷酸是一种重要的磷化工产品,可用于医药、食品、纺织、石油化工等领域。聚磷酸中常含有杂质砷,限制了其在医药、食品、饲料、电子材料等对聚磷酸纯度要求较高领域中的应用,因此亟需一种低成本、高效的脱砷方法。开发了一种使用盐酸脱除聚磷酸中砷的工艺方法,介绍了该方法的脱砷效果、反应控制情况、产品质量变化情况以及过程产生的尾气的处理情况。实验结果表明,该方法是一种有效的聚磷酸脱砷工艺方法。