Survey on some contaminants in white sugar from Serbian sugar beet refineries

Refined white sugar is a very pure food product, even though it contains very small amounts of soluble and insoluble impurities. The content of these impurities has nutritional significance and determines the usefulness of sugar for various industrial applications. The main quality criteria used to indicate the content of these impurities are ash and colour. The aim of this paper was to evaluate the quality according to the EU sugar market regime and the content of iron, copper and zinc in white sugar samples from Serbian sugar beet refineries during the 2003 campaign. A total of 166 samples representative of the production of four Serbian sugar refineries were investigated. After wet digestion the concentrations of iron, copper and zinc were determined by flame atomic absorption spectrometry. The mean content of iron, copper and zinc in sugar samples was 0.37 mg/kg, 0.06 mg/kg and 0.02 mg/kg and was significantly different from the average content 0.28 mg/kg, 0.09 mg/kg and 0.07 mg/kg respectively in the analysed European sugar factories. The data were also compared with literature values for commercial white sugar samples from European sugar beet refineries and European legislation set for copper and zinc. Furthermore, the quality of produced sugar was evaluated according to the standards of the European Union indicating that 76% of all investigated Serbian samples belonged to the second sugar quality category.     

火焰原子吸收分光光度法测定四氧化三锰中的钙

在弱酸性介质中,经六次甲基四胺分离锰、铁、铝及重金属离子,采用火焰原子吸收分光光度法测定四氧化三锰中的钙,考察了HCl、SrCl2对测定的影响。在选定条件下,方法线性相关系数为0.9998,检测限为0.0072mg/L,标准偏差为0.0008,变异系数为2.0%,回收率为96.8%~104.8%。     

Essential elements and contaminants in edible tissues of European and American lobsters

In several European countries clawed lobsters, such as the European (Homarus gammarus) and American (H. americanus) ones are widely consumed. Yet, information about essential elements and contaminants in both species is still scarce. Therefore, the aim of this work was to characterise the elemental content in the edible part (muscle, hepatopancreas, gonads and roe) of both homarids and to compare them with the daily intake recommendations and maximum allowed levels. Two techniques were employed: energy-dispersive X-ray fluorescence (EDXRF) to quantify Cl, S, K, Ca, Fe, Cu, Zn, As, Se, Br and Sr; and flame atomic-absorption spectrometry (FAAS) to analyse Na, Mg, Mn, Cd, Hg and Pb. Significant differences were found in the elemental composition of edible tissues of both species, likely reflecting the distinct physiological role of those tissues: muscle (higher: Na, Mg, Ca and Sr; lower: Fe, Se, Cd); hepatopancreas (higher: Fe, Cu, Br and Cd); gonads (lower: Cl, Ca, Zn and Hg); and roe (higher: Na and Br; lower: K and As). Statistical differences in the elemental composition of each tissue were found between both homarids: Muscle (Na, Se, As and Hg); Hepatopancreas (Na, Mg, Fe, Cu, Se, Br and Hg); and gonads (S and Zn). Since the geographical distribution of both species is different, the differences likely reflect distinct elemental composition in the aquatic environment and, consequently in the feed chain. Both lobster species were rich sources of Na, Cl, Cu, Zn and Se for human consumption. Regarding contaminants, only Cd was detected at high concentrations in the hepatopancreas of both homarids. Despite Cd values were well above the maximum allowed level set by the European Commission for crustaceans’ muscle, so far any limit value was set for crustaceans’ hepatopancreas. Nonetheless, the present study recommends avoiding or moderately consuming this tissue in homarids.     

乙二胺四乙酸四钠中杂质铁的测定

对乙二胺四乙酸四钠中的铁测定,目前主要有两种方法：火焰原子吸收分光光度法和1,10-菲罗琳法。绝大多数用户都采用简便易测的火焰原子吸收分光光度法,但此种方法在不扣除背景的情况下测定结果会因仪器而异。文章通过两台不同型号原子吸收分光光度仪（美国PE-AA100和上海HP-3510）的实验对比表明,在PE-AA100中铁的测定中存在背景吸收,需校正背景,而HP-3510无背景吸收,可直接检测出准确数据。     

火焰原子吸收光谱法测定锡锭中痕量杂质元素

采用空气———乙炔火焰原子吸收光谱法测定纯锡锭中痕量元素铁、铜、铅、铋、锑。以HCl+H2O2沸水浴蒸干排Sn处理,使Sn挥发与待测元素分离消除基体干扰。此方法应用于实际样品的测定,结果令人满意。     

空气—天然气火焰原子吸收光谱法测定气田水中钾钠

对用空气－天然气代替空气－乙炔气做ＡＡＳ的火焰燃气进行了探索。通过改造燃烧器，减小了气流速度，提高了火焰温度，成功地测定了气田水中Ｋ、Ｎａ，并与空气－乙炔气焰的结果进行了对照。     

FAAS法连续测定电解锰阳极板中银和锑

在电解法制锰时，阳极板中微量元素直接影响板的使用寿命和导电性能，其中主要有银和锑。文中用硝酸和酒石酸的混合酸处理样品￣［１］，在不过滤的情况下直接测定，方法快速简便。通过试样分析及方法检验，结果满意。银和锑的加标回收率分别达１０５％，９８％；标准偏差分别为０．００５６，０．００１３；相对标准偏差分别为２．１％，３．３８％。     

硫脲纤维素分离富集火焰原子吸收法测定地质样品中痕量金

在王水介质中，使用硫脲纤维素吸附以除去金矿中其他离子的干扰，被吸附的金用硫脲溶液解脱并用原子吸收光谱测定。本法研究了分离和测定的条件，方法已成功地应用于地质样品中痕量金的测定。     

浊点萃取火焰原子吸收法测定水样中痕量铅的研究

以浊点革取-火焰原子吸收光谱法测定痕量铅,探讨了实验条件对浊点草取及测定灵敏度的影响。在最佳条件下,铅富集倍数达到20倍。该方法可用于自来水、井水及河水中痕量铅的测定。