连续光源火焰原子吸收法同时测定薏苡中金属元素

建立一种新的高分辨率连续光源火焰原子吸收光谱法以同时测定薏苡中Cu、Fe、Mn和Ca。样品采用湿法消解处理样品,用连续光源原子吸收光谱仪对薏苡中Cu、Fe、Mn和Ca的含量进行检测,并对精密度,检出限和回收率进行分析。结果表明:测定薏苡中Cu、Fe、Mn、Ca含量分别为4.457、42.63、15.84、66.63 mg/kg,方法检出限分别为0.005 4、0.015、0.004 1、0.15 mg/L,精密度为0.96%~3.4%,回收率为93.4%~106.8%。本方法可实现一次进样连续测定Cu、Fe、Mn、Ca,适用于食品中多种金属元素的快速测定。     

微波消解-原子吸收法测定鸡精中金属元素

建立了微波消解-连续光源原子吸收光谱法测定鸡精中Ca、Fe、Mg、Zn的方法。实验选择微波消解作为样品的前处理方式,分析研究了乙炔流量和燃烧器高度对测定结果的影响,通过实验分别确定了测定Ca、Fe、Mg、Zn的最佳参数。在此条件下,利用高分辨连续光源原子吸收光谱仪测定鸡精中Ca、Fe、Mg、Zn的含量分别为:206.2、3.6、144.7、4.0μg/g,加标回收率为98.4%~106.7%,本法的精密度(RSD)为1.0%~2.2%。该方法快速、准确、稳定、污染少,具有较高的实用价值,为食品中多元素检测提供了科学依据。     

连续光源火焰原子吸收光谱法同时测定蓝莓中Ca、Mg、Fe、Zn含量

建立高分辨率连续光源火焰原子吸收光谱法同时测定蓝莓中Ca、Mg、Fe、Zn方法。样品采用湿法消解处理样品,用连续光源原子吸收光谱仪对蓝莓中Ca、Mg、Fe、Zn的含量进行检测,并对方法的精密度、检出限和回收率进行分析。结果表明：方法测定出蓝莓中Ca、Mg、Fe、Zn含量分别为100.3、55.80、2.330、1.413 mg/kg,方法检出限分别为0.030、0.830、0.088、0.049 mg/L,相对标准偏差为1.9%～4.7%,回收率为94.6%～107.0%。本方法可对同时检测蓝莓等果蔬食品中多种金属元素的工作提供帮助,具有灵敏度高、效率高,稳定性好、操作简单的特点。     

江西名茶中10种金属元素含量的测定

对K、Ca、Na、Mg、Fe、Cu、Mn、Zn 8种必需元素火焰原子吸收光谱法的最佳工作条件(乙炔流量、空心阴极灯灯流量和燃烧器高度)进行优化,对铅、镉两种有毒元素石墨炉原子吸收光谱法的最佳工作条件(灰化温度、灰化时间、原子化温度及原子化时间)进行优化,绘制各元素的标准曲线,考察方法的检出限和精密度,优化样品前处理条件及测定样品加标回收率,并对江西名茶中对应的10种金属元素的含量进行测定比较。结果表明,建立的各元素原子吸收光谱法在相应浓度区间内线性关系良好,相关系数为0.991 8～0.999 2,精密度为0.77%～3.32%,检出限为0.004～0.050μg/mL,回收率为99.25%～102.25%,均符合要求。10种金属元素在8种茶叶中的含量差异性显著,其排序基本为KMgMnCaFeNaZnCuPbCd;遂川狗牯脑中K、Ca、Fe含量最高,庐山云雾中Na含量最高,靖安白茶中Mg、Zn含量最高,井冈山翠绿中Mn含量最高,武夷红茶中Cu含量最高,8种茶叶中Pb、Cd含量均较低。试验建立的原子吸收光谱法操作简便、干扰较少、灵敏度高,适用于各种茶叶中相应元素含量的测定;8种江西名茶中K、Ca、Na、Mg 4种常量元素和Fe、Cu、Mn、Zn 4种微量元素含量都比较丰富,Pb、Cd两种有毒元素含量均低于国家标准。     

原子吸收光谱法测定琐琐葡萄中的无机元素

目的用原子吸收光谱法测定琐琐葡萄中12种无机元素的含量.方法 称取5份经粉碎、干燥恒重后的琐琐葡萄样品1.0000 g置于150 ml三角烧瓶中,加入硝酸+高氯酸(4+1)混合溶液20 ml,电热板消化后,用超纯水稀释至刘度,在仪器工作条件下用3％稀硝酸做空白测定吸光度.用火焰原子吸收光谱法测定了琐琐葡萄中K、Ca、Na、Mg、Fe、Mn、Zn、Cu、Cr元素的含量,Cd、Pb、Se元素含量用石墨炉原子吸收光谱法测定.结果 原子吸收光谱法测定的线性相关系数为0.997 9 ～0.999 9,相对标准偏差在0.19％～4.55％之间.样品中的K、Ca、Na、Fe、Mn、Cu、Cd、Cr、Se含量分别为11 906.50、1 409.01、479.03、208.80、8.97、5.21、0.06、0.25、1.98 μg/g,Mg、Zn和Pb未检出.结论原子吸收光谱法检测琐琐葡萄中的无机元素具有良好的准确度和精密度;琐琐葡萄中K、Ca、Na、Fe、Se含量较高;琐琐葡萄抗炎作用可能与其中无机元素含量较高有关.     

氢化物发生-高分辨连续光源原子吸收光谱法测定食品中的汞和砷

使用氢化物发生-高分辨连续光源原子吸收光谱法对谷类、蔬菜、饮品、水产品和乳制品5 类共22 种常见食品中汞和砷的含量进行检测。建立样品预处理和连续光源原子吸收光谱法定量分析的方法,汞和砷的检出限分别为0.067、0.088 μg/L,加标回收率为97.0%～104.2%和96.4%～105.1%,相对标准偏差为0.8%～4.7%和3.5%～4.9%（n=6）。结果表明：全麦面、咖啡和4 种海鲜类样品中的汞含量较高;韭菜、带鱼、贝类和虾中的砷含量较高。     

微波消解-电感耦合等离子体质谱法测定奶粉中的铬

本方法采用微波高压消化仪消解奶粉样品,以电感耦合等离子体质谱法(ICP-MS)测定奶粉中的铬元素含量,同时采用干灰化-原子吸收石墨炉法(国标法)测定样品,与本方法进行比较。实验表明样品浓度、积分时间与响应值呈正相关,当样品中铬的浓度大于10μg/L时,应采用0.1s的积分时间;当铬的浓度小于10μg/L时,应采用高于2.0s的积分时间。实验结果显示该方法与国标法的测定结果相吻合,测得相对标准偏差为0.92%~4.21%,回收率为95.6%~102.2%,在1.0~500μg/L范围内呈良好的线性关系(r=0.9999)。本方法具有操作简单、快速、灵敏度高、抗离子干扰能力强的优点,完全适用于快速准确测定奶粉中的铬元素含量。     

胶体钯基体改进剂石墨炉原子吸收光谱法测定食盐中铅、镉

建立了胶体钯基体改进剂用于石墨炉原子吸收光谱法测定食盐中铅、镉的方法。方法采用食盐直接溶解后,以胶体钯作为基体改进剂,石墨炉原子吸收光谱法直接测定。在铅浓度为0~40μg/L、镉浓度为0~4μg/L的相关系数均0.999,铅的检出限为0.3μg/L,样品加标回收率为95.2~101.8%;镉的检出限为0.1μg/L,样品加标回收率为91.0~103.3%,相对标准偏差均5%。该方法准确、灵敏、简便,满足食盐中铅、镉的测定。     

茶叶中七种金属元素的测定及成分分析

用原子吸收光谱法测定了云南省红河州5个县的茶叶中金属元素Ca、Mg、Na、Fe、Zn、Cu、Mn的含量,回收率在96.09%-102.7%之间,分析结果满意,方法简单、结果准确,同一样品处理液可以连续测定多种金属元素的含量.结果表明:不同茶叶中金属元素含量顺序为Ca>Mg>Mn>Fe(Na)>Zn>Cu.红河州茶叶中Ca、Mg、Mn、Fe、Na、Zn、Cu等人体必须的生命元素含量较高,为品质优良茶叶.     

微波消解-原子吸收光谱法测定羧基麦芽糖铁中铅和砷

目的建立羧基麦芽糖铁中铅和砷含量测定的方法。方法采用微波消解法处理样品,石墨炉原子吸收光谱法(GTA-AAS)标准加入法测定铅含量,氢化物发生-原子吸收光谱法(HG-AAS)测定砷含量。结果铅浓度在5.0～50.0μg/L,砷浓度在1.0～10.0μg/L范围内线性关系良好,相关系数分别为0.9999,0.9998;铅检出限为0.68μg/L,砷检出限为0.1μg/L;铅测定精密度RSD为3.91%,砷测定精密度RSD为4.31%;铅回收率96.8%～101.3%,砷回收率95.8%～98.9%。结论该测定方法准确、灵敏度高,适用于含铁量高的营养品中重金属元素的检测。     

Mineral contents of some southern Italian wines. II. Determination of Li, Na, Mg, K, Ca, Co, As, Rb, Sr, Ag, Sb, Ba

Following our study of the mineral contents of some Southern Italian wines, this work reports on the detection of 12 elemental components. The elements were determined using ICP-AES, flame atomic emission or absorption spectroscopy. The values determined for Li, Na, Mg, K, Ca, Rb, Sr and Ba were within the usual ranges for wines (average values for these elements were: 0.010, 26.2; 94.4; 888; 94.0; 3.30, 0.82 and 0.11 mg/l respectively). All the wines contained low levels of As, the concentrations of which were always under 0.20 mg/l, the maximum level permitted by E.E.C. standards. The measuring of Co, Ag, and Sb led us to ascertain, in all the wines, concentrations lower than 0.01 mg/l for Co and Ag and below the instrumental detection level for Sb (0.06 mg/l). In a previous study wines from D.O.C. areas of Southern Italy were analysed by the technique of inductively coupled plasma atomic emission spectroscopy (ICP-AES), for 14 minerals. This paper deals with further investigation of the mineral composition of the same wines for different metal constituents, analysed by ICP-AES, flame atomic emission, or atomic-absorption spectroscopy (two techniques). The first technique was applied to the detection of Co, As, Sr, Ag, Sb, and Ba. The alkaline metals Li, Na, K, and Rb were determined by flame atomic emission, a technique which possesses better detection limits for these elements. For Mg and Ca the atomic absorption methods were applied.     

Isolation,Composition, Structure,Properties, Modifications,and Uses of Yam Starch

Starch is the major carbohydrate in yam tubers and can amount up to 80% of the dry matter. The starch quality determines the quality of food and industrial products made from yam tubers. This review summarizes the present knowledge of the isolation, composition, structure, property, modifications, and uses of starches from diverse yam species. Compared with other tuber and root starches, there is a lack of systematic information on the yam starches. This hinders the further development of yams as sustainable crops as well as the value‐added processing of the starches. Therefore, suggestions on how to better understand and utilize these starches are provided.     

卷烟中锂、铬、镍、铜、砷、硒、钼、镉、铊和铅含量分析

采用微波消解-电感耦合等离子体质谱法测定了41个牌号烤烟型卷烟和雪茄烟样品烟丝中的锂、铬、镍、铜、砷、硒、钼、镉、铊和铅含量,并按照类型和价位对卷烟中这10种有害元素含量进行了统计分析。结果发现:①卷烟中锂和铜的含量较高,铊的含量很低,铬、镍、镉、铅、砷、硒和钼7种元素的平均含量为0.55～4.42μg/g;②雪茄烟中铬、镍、砷、钼、镉、铊和铅的含量一般高于烤烟型卷烟,而硒元素的含量则相反,但差别较小;烤烟型卷烟中锂和铜的含量与雪茄烟没有显著差异;③高档卷烟中的锂、镍、镉、铊和铬含量较低,而砷、铅的含量较高;不同价位卷烟的铜、硒和钼含量差异不显著。     

Survey of trace elements (Al,As, Cd,Cr, Co,Hg, Mn,Ni, Pb,Se, and Si) in retail samples of flavoured and bottled waters

Concentrations of eleven trace elements (Al, As, Cd, Cr, Co, Hg, Mn, Ni, Pb, Se, and Si) were measured in 39 (natural and flavoured) water samples. Determinations were performed using graphite furnace electrothermetry for almost all elements (Al, As, Cd, Cr, Co, Mn, Ni, Pb, and Si). For Se determination hydride generation was used, and cold vapour generation for Hg. These techniques were coupled to atomic absorption spectrophotometry. The trace element content of still or sparkling natural waters changed from brand to brand. Significant differences between natural still and natural sparkling waters (p < 0.001) were only apparent for Mn. The Mann–Whitney U-test was used to search for significant differences between flavoured and natural waters. The concentration of each element was compared with the presence of flavours, preservatives, acidifying agents, fruit juice and/or sweeteners, according to the labelled composition. It was shown that flavoured waters generally increase the trace element content. The addition of preservatives and acidifying regulators had a significant influence on Mn, Co, As and Si contents (p < 0.05). Fruit juice can also be correlated to the increase of Co and As. Sweeteners did not provide any significant difference in Mn, Co, Se and Si content.     

Varied Composition of Tocochromanols in Different Types of Bran: Rye,Wheat, Oat,Spelt, Buckwheat,Corn, and Rice

The profiles of tocopherol (T) and tocotrienol (T3) homologues in 37 samples of seven different types of bran (rye, wheat, oat, spelt, buckwheat, rice, and corn), available on the Polish market, were studied. Tocochromanols were identified and quantified by reverse phase-high-performance liquid chromatograph/fluorescence detector and reverse phase-ultra performance liquid chromatography-electrospray ionization/mass spectrometry. Only rice bran contained all eight tocochromanol types. Corn bran lacked β-T3; rye, wheat, oat, and spelt bran lacked γ-T3 and δ-T3; and buckwheat bran lacked β-T3, γ-T3, and δ-T3. In buckwheat and corn bran tocopherols predominated (98 and 78%, respectively); whereas rye, wheat, oat, spelt, and rice bran were rich in tocotrienols (78, 76, 66, 87, and 66%, respectively). The average total tocochromanol contents in the oat, corn, spelt, buckwheat, wheat, rye, and rice bran were 5.5, 16.2, 15.8, 14.7, 12.8, 10.7, and 9.1 mg/100 g of dry weight, respectively. Tocochromanol concentrations in samples of the same type bran from different sources varied considerably. Better labeling of bran products to reflect this variation would assist with control of vitamin E daily dietary requirements.     

Optimization of extraction conditions of total phenolics, antioxidant activities, and anthocyanin of oregano, thyme, terebinth, and pomegranate

The purpose of this study was to evaluate the total phenolic extracts and antioxidant activity and anthocyanins of varieties of the investigated plants. These plants include oregano, thyme, terebinth, and pomegranate. The optimum extraction conditions including temperature and solvent of the extraction process itself were investigated. Total phenolic and anthocyanin extracts were examined according to Folin-Ciocalteu assay and Rabino and Mancinelli method, respectively. The effect of different extracting solvents and temperatures on extracts of phenolic compounds and anthocyanins were studied. Plant samples were evaluated for their antioxidant chemical activity by 2, 2-diphenyl-1-picrylhydrazl assay, to determine their potential as a source of natural antioxidant. Results showed that all tested plants exhibited appreciable amounts of phenolic compounds. The methanolic extract (60 °C) of sour pomegranate peel contained the highest phenolic extract (4952.4 mg/100 g of dry weight). Terebinth green seed had the lowest phenolic extract (599.4 mg/100 g of dry weight). Anthocyanins ranged between 3.5 (terebinth red seed) and 0.2 mg/100 g of dry material (thyme). Significant effect of different extracting solvents and temperatures on total phenolics and anthocyanin extracts were found. The methanol and 60 °C of extraction conditions found to be the best for extracting phenolic compounds. The distilled water and 60 °C extraction conditions found to be the best for extracting anthocyanin.     

ICP-MS测定饼干中的铅、砷、铬、镉、铜、锌、铁和锰

探讨了应用电感耦合等离子体质谱仪测定饼干中铅、砷、铬、镉、铜、锌、铁和锰8种重金属元素的方法。运用微波消解系统对样品进行消解,以铋、锗、钪和铟作为内标物,用ICP-MS对消解液进行检测,并采用国标方法对其结果进行验证。利用加标回收率试验和国家标准物质小麦(GBW 10052)检测试验考察了方法的准确性和可靠性。结果表明,该方法所测元素在标准溶液浓度范围内呈线性关系,相关系数均大于0.999,方法检出限在0.002~0.500 mg/kg之间,相对标准偏差均小于6.55%,本法与国标方法测量结果的相对偏差在3.73%~8.40%之间,加标回收率在88.0%~106%之间,标准物质的测定值与标准参考值符合要求。     

Analysis of cheese for histamine, tyramine, tryptamine, histidine, tyrosine, and tryptophane

A method is described for determining the content of selected biologically active amines (histamine, tyramine, tryptamine) and amino acids (histidine, tyrosine, tryptophane) in cheeses by high performance liquid chromatography. The amines and amino acids were quantified by employing a counter ion-containing mobile phase and by comparing peak areas of high performance liquid chromatography charts for sample cheeses versus standard cheeses containing known amounts of added amines based on dual injections of samples and standards. Recovery of amines and amino acids varied from 87.5 to 111%. Histamine, which has been associated with food poisoning in concentrations of 185 mg/100 g in Swiss cheese and 180 to 500 mg/100 g in fish, was found in concentrations above 500 mg/100 g in Swiss cheese. The high performance liquid chromatography analytical method should be useful for screening to detect cheese samples containing toxic amounts of histamine and for research studies designed to determine the cause and effect relationships for histamine production in cheese.     

接装纸中汞、砷、铅等8种元素的分析研究

本文利用电感耦合等离子体发射光谱仪(ICP-AES法)同时测定接装纸样品中铅、铜、镉、铬、锡、锑元素含量,汞、砷元素含量采用冷原子吸收光谱法和银盐法测定.结果表明接装纸样品中锡元素含量最高,铜次之,汞、砷、铅相比,砷元素含量较高,部分样品中砷、铅元素含量超出食品包装用纸的最高限量标准.采用ICP-AES法同时测定接装纸6种元素,操作简便,重复性好,回收率高.此外,本文还对接装纸荧光物质和脱色程度进行了测定分析,从随机抽检的47份国产、进口接装纸样品看,进口白色接装纸无荧光,国产白色接装纸有荧光,珠光色接装纸个别有荧光,纸边为白色的接装纸荧光程度不一.脱色试验表明,进口接装纸,国产印刷型接装纸、珠光纸不脱色,涂布型接装纸均有不同程度的脱色.     

The effect of storage of canned juices on content of the metals Fe, Cu, Zn, Pb, Sn, Al, Cd, Sb and Ni

The increase in concentration of iron, copper, zinc, lead, antimony, aluminium, cadmium, tin and nickel over a 2 year's time of juices of peach (prunus persica), pear (pyrus communis), apricot (prunus vulgaris) and apple (malus pumila) was determined. The results show a considerable increase in Fe, Cu, Pb, Zn and Sn with time, while the change in Al, Cd, Ni and Sb is negligible.