Hydride generation atomic absorption spectrometric (HGAAS) determination of selenium in term and preterm infant formulae available in the United Kingdom

A simple and sensitive hydride generation atomic absorption spectrometry method is described for the determination of total selenium in infant formulae. Decomposition of the composite sample matrix involved overnight digestion with a nitric-perchloric acid mixture (10:2 ml) then heating at 150 °C (30 min) and 220 °C (60 min). No apparent matrix interferences were encountered. The selenium levels in infant formulae, reported for the first time, ranged from 0.034 to 0.093 μ/g (dry wt) for bovine casein and whey-based term powdered infant products, 0.023–0.093 μg/g (dry wt) for preterm powdered formulae and 0.027–0.049 μ/g (wet wt) for hospital administered low birth weight ready-to-feed formulae. These values are dependent on geographic origin of bovine milk and exhibit variation between batches. Routine QC analysis and fortification by manufacturers is recommended.     

微波消解氢化物原子荧光光谱法测定食品中的硒

目的优化微波消解-氢化物原子荧光光谱法检测食品中的微量元素硒。方法采用不同前处理方法对检测结果影响进行研究,分别对质控样经微波消解后是否赶酸作对比,赶酸时是否加盐酸作对比,微波消解与电热板湿法消解作对比,用氢化物原子荧光光度仪测定其含量。结果用微波消解,赶酸后加盐酸继续赶酸,用原子荧光光谱仪进行检测,检出限为0.425μg/kg,定量限为1.42μg/kg,精密度为2.67%,回收率为93%～109%。结论该方法简便、快速、准确度高,可用于食品中硒的检测。     

UV-photolysis assisted digestion of food samples for the determination of selenium by electrothermal atomic absorption spectrometry (ETAAS)

An UV-oxidation procedure has been developed to completely digest biological/food samples for the determination of trace levels of selenium. A combined use of UV photolysis and hydrogen peroxide in the presence of an oxidant (HNO₃), results in the complete oxidation of the organic matter. This method is simpler and requires fewer reagents when compared with other sample pre-treatment procedures. The clear solution obtained was analysed for the selenium content by graphite furnace atomic absorption spectrometry. Unreduced palladium-nitrate modifier was used in all cases. However, in case of samples that are known to contain sulfur (like mushroom, Brazil nut, etc.), reduced palladium was used as modifier. The method was verified using three standard reference materials i.e., Whole egg powder-8415, Tuna fish-IAEA 350, Oyster tissue-1566a, and the results were in agreement at 95% confidence level. By using standards addition as calibration method, accurate results were obtained for the certified reference material, the precision for the CRM’s were in the range of 3.5–8%. The characteristic mass of selenium is assessed as 10 pg. The detection limits were in the range of 35–40 ng/g.     

Comparison of graphite furnace and hydride generation atomic absorption spectrometry for the determination of selenium status in chicken meat

Four different procedures for the determination of selenium in chicken meat by atomic absorption spectrometry were investigated. They consisted on conventional ambient pressure acid digestion carried out before and after sample drying, associated or not with fat extraction. For all procedures muscle and skin were analyzed separately. Drying was carried out in a conventional oven at 65 °C for 24 h. For fat extraction different solvents and solvent mixtures were investigated considering both extraction yield and sample adequacy for further AAS measurement. Acid digestions were carried out with mixtures of HNO₃ and HClO₄. After digestion, selenium was measured either by Hydride Generation (HGAAS) or by Graphite Furnace Atomic Absorption Spectrometry (GFAAS). For the reduction of Se(VI) prior to the HGAAS determination, 8% (w/v) NaBr, 6 mol/l HCl (both with and without sulfamic acid), as well as UV radiation were investigated. Tests with spiked samples have shown that either UV radiation (pH 8) or NaBr/sulfamic acid presented good recoveries. In this way the HGAAS determination of selenium in tissue was carried out without interference whereas for the fatty fraction the results were satisfactory only if GFAAS was used. The results showed that drying the sample and extracting the fat prior to digestion is advantageous once the amount of acid necessary can be significantly reduced. The precision, expressed as relative standard deviation, was about 6.5% and 0.8% for GFAAS and HGAAS measurements, respectively. The limits of detection for HGAAS and GFAAS, based on three times the standard deviation of the blanks were 1 μg/l and 0.6 μg/l, respectively. The results have shown that in chicken meat 59% of the selenium is found in the muscle tissue while the skin responds for 41%.     

预富集-氢化物发生原子吸收光谱法测定水产品中的痕量硒

研究了预富集-氢化物发生原子吸收光谱法测定水产品中的痕量硒的新方法。用吡咯烷二硫代氨基甲酸铵(APDC)作配位剂,在pH4.0～6.5的条件下,用固体硅胶捕集、膜滤纸抽滤分离Se-APDC配合物,然后用0.1moL/L盐酸从膜滤纸上洗下硅胶,得到能够直接用氢化物原子吸收光谱法测定的硒悬浊液。该法操作简便,富集速度快。100mL溶液,特征质量为1.5×10-11g/1%。在最佳条件下,用这个方法测定了水产品中的痕量硒,当n=6时,标准偏差为0.0027～0.0054,变异系数为0.012～0.028,样品的加标回收率在95.2%～104.6%之间,结果较为满意。     

湿法消解-氢化物发生原子荧光光谱法测定动物性农产品中硒含量

目的 通过对消解条件、预还原方式、铁氰化钾屏蔽效果、硼氢化钾浓度、氢化反应酸度等反应条件的比较分析,建立湿法消解-氢化物发生原子荧光光谱法测定肉蛋奶等动物性农产品中硒含量的分析方法.方法 牛奶、鸡蛋、猪肉、鱼肉样品经混合酸消解后,加入6 mol/L的盐酸溶液低温预还原,于氢化物原子荧光光谱仪上进行检测.结果 方法检出限...     

氢化物发生-原子荧光光谱法测定富硒麦芽中的硒含量

建立了氢化物发生-原子荧光光谱法测定富硒麦芽中硒的分析方法.研究了仪器的工作条件、试剂对硒测定的影响,探讨了消化试剂对样品消化的影响和共存离子的干扰及消除.在优化的工作条件下,硒的检出限(σ=3)为0.167μg/L,相对标准偏差(RSD)为1.203%,线性范围为0～100μg/L.应用该方法测定了不同富硒麦芽中的硒含量为11.729～32.746μg/g,加标回收率为94.1%～101.6%.     

氢化物发生原子荧光法测定灰树花中硒含量

采用氢化物发生-原子荧光光谱法测定灰树花中硒含量。用硒标准溶液考察了载流盐酸浓度、硼氢化钠浓度、酸介质浓度对荧光强度的影响。比较了样品的两种前处理方式,得出了最佳测定条件。结果表明采用微波消解消化较为完全,优于湿法消解;该方法线性范围为1～10ng/mL,检出限为0.002ng/mL,精密度为1.3%～4.1%(n=10),回收率为94.96%～97.94%(n=5),测得灰树花中硒的含量为0.2242μg/g。本方法准确、灵敏、简便、快速,可用于灰树花中硒含量的测定。     

氢化物原子荧光光度法测定无机砷方法的探讨

通过对氢化物原子荧光光度法测定食品中无机砷含量的整个测定过程进行研究,系统分析了该方法中标准溶液系列随着存放时间的长短其荧光强度的变化。结果显示,无机砷浓度在0-30．Oμg／L,冰箱里0-4℃存放1个月,能有效控制测定结果的准确性,确保检验工作的质量。     

微波消解-氢化物原子荧光光谱法测定大米中的总砷

针对《食品中总砷及无机砷的测定》GB 5009.11-2014对食品中总砷的测定方法进行了改进.根据国家标准GB 5009.11 2014总砷的测定中氢化物原子荧光光谱法,分别采用微波消解与湿法消解对质控样品和试样样品处理后进行总砷含量的测定.结果 表明:总砷在0～10.0 μg/L线性范围的相关系数为0.999 8,...     

Comparison of electrothermal and hydride generation atomic absorption spectrometry for the determination of total arsenic in broiler chicken

The purpose of this study was to estimate total arsenic concentration in different tissues (leg, breast, liver and heart) of broiler chicken by hydride generation atomic absorption spectrometry (HGAAS) and graphite furnace atomic absorption spectrometry (GFAAS), prior to microwave assisted acid digestion. The accuracy of the techniques was evaluated by using certified reference material DORM-2. The percentage recoveries of total As were observed as 100.6% and 99.4% for HGAAS and GFAAS, respectively. The precision of the techniques, expressed as relative standard deviation, was observed as 1.71% and 4.18% for HGAAS and GFAAS measurements, respectively. The limits of detection for HGAAS and GFAAS were 0.025 μg/g and 0.052 μg/g, respectively. The concentrations of total arsenic in different tissues of broiler chicken were found in the range of 2.19–5.28, 2.15–5.22, 2.97–7.17 and 2.68–6.36 μg/g for leg, breast, liver and heart tissues, respectively. At a mean level of chicken consumption (60 g/person/day), people may ingest in the range of 72.0–85.1 μg arsenic/person/day from chicken alone.     

氢化物发生-原子荧光光谱法测定富硒发芽糙米中的硒含量

对氢化物发生-原子荧光光谱法(HG-AFS)测定富硒发芽糙米硒含量的方法.研究表明:其检出限为0.2μg/L,相对标准偏差RSD为0.94%,平均回收率为99.74%,精密度高、稳定性好、简便快速,适合于富硒发芽糙米中硒的定量分析.通过测定采用不同浓度亚硒酸钠溶液富硒处理的发芽糙米的总硒、有机硒和无机硒含量,确定选择硒浓度为50 mg/L的溶液富硒处理后的发芽糙米品质较好.     

微波消解-石墨炉原子吸收光谱法测定花生中镉含量

本文研究了高脂肪高蛋白材料花生中镉含量测定方法。采用微波消解法处理花生样品,使用石墨炉原子吸收光谱法测定花生中镉含量。从广东、湖北和辽宁3省随机抽取收获的9个花生样品进行检测,镉含量范围为0．061～0．529mg／kg,RSD为1．22％-8．75％（n=6,c=0．859—7．409ng／mL）,该方法检出限为0．00019mg／kg,加标回收率为95．4％～100．1％,具有灵敏、快速、准确的特点,可用于高脂肪高蛋白样品中镉含量的测定。     

Optimisation of digestion method for determination of arsenic in shrimp paste sample using atomic absorption spectrometry

The microwave digestion method was developed and verified for the determination of arsenic in shrimp paste samples. Experimental design for five factors (HNO₃ and H₂O₂ volumes, sample weight, microwave power and digestion time) were used for the optimisation of sample digestion. For this purpose, two level half factorial design, which involves 16 experiments, was adopted. The concentration of arsenic was analysed by graphite furnace atomic absorption spectrometry. Design Expert® 7.0 software was used to interpret all data obtained. The combination of 2 mL HNO₃ and 1 mL H₂O₂ volumes, 0.1 g sample weight, 1400 W power and 5 min digestion time was found to be the optimum parameters required to digest the shrimp paste samples. Tests with spiked samples presented good recoveries with relative standard deviations between 0.32% and 5.35%.     

Simultaneous multi-channel hydride generation atomic fluorescence spectrometry determination of arsenic,bismuth, tellurium and selenium in tea leaves

A novel, rapid and sensitive method for the simultaneous multi-channel hydride generation atomic fluorescence spectrometry (HG-AFS) determination of total arsenic (As), total bismuth (Bi), total tellurium (Te) and total selenium (Se) in tea leaves was proposed. The operating parameters of self-made multi-channel HG-AFS were optimised, including negative high voltage of photo multiplier tube (PMT), the flow rates of carrier and shield gas, observation height and lamp currents. The conditions of hydride generation for As, Bi, Te and Se were studied in details. Under optimal conditions, the method detection limits (MDL) for As, Bi, Te and Se in tea leaves were 0.0152 μg g⁻¹, 0.0080 μg g⁻¹, 0.0022 μg g⁻¹ and 0.0068 μg g⁻¹, respectively. The proposed method was successfully applied to the simultaneous determination of As, Bi, Te and Se in various tea leaves and the spike recoveries were in the range of 90–103%. The accuracy of method was validated by analysing a tea certified reference material. The obtained values were consistent with the certified ones.     

顺序注射氢化物发生-原子荧光光谱法同时测定大蒜中的硒和砷

建立了一种顺序注射氢化物发生-原子荧光光谱法测定大蒜中Se和As含量的方法,同时讨论了共存离子的干扰情况。在最佳实验条件下,Se和As的检出限分别为0.13μg/L和0.090μg/L,加标回收率为93.6%～103.8%。     

GFAAS determination of selenium in infant formulas using a microwave digestion method

A method for determining the selenium content of infant formulas is proposed. It includes wet digestion with nitric acid and hydrogen peroxide in medium pressure teflon bombs in a microwave oven and determination by graphite furnace atomic absorption spectrometry (GFAAS). The absence of interferences is checked. Values obtained for the limit of detection (19.4 ng/g), precision (RSD = 2.2%) and accuracy by analysis of a reference material show that the method is reliable.     

原子荧光光谱法测定饲料中镉

介绍氢化物发生-原子荧光光谱法对饲料中镉的定量分析方法，样品干法灰化后用硫酸溶解，以二硫脲—四氯化碳去除离子干扰，最佳工作条件下，该法测定线性范围0～70ng／mL，加标回收率为90％～103％，RSD为2．24％～3．41％，最低检测限为0．15ng／mL，标准曲线相关系数为0．9996，该法具有精密度高、准确性好、检出限低等优点。     

氢化物发生原子荧光法测定大豆卵磷脂中的砷

采用氢化物发生原子荧光法测定大豆卵磷脂中的砷,确定了仪器的最佳条件,探讨了还原剂溶液浓度介质酸浓度,预还原剂,载气流量等对测定砷的影响.在选定的操作条件下,砷的最低检出限为0.29 ng/mL,相对标准偏差为2.3%.用建立的方法测定大豆卵磷脂中的砷,操作简单、快速、灵敏度高.     

氢化物发生-原子荧光法测定食用醋中的As

为准确测定食用醋中As的含量,采用了氢化物发生原子荧光法测定方法。通过实验确定了仪器的灯电流40mA、负高压315V和还原剂KBH4浓度0．12％为最佳条件。在此条件下,As的最低检出限为0．08μg／L,相对偏差为1．8％,线形范围1．0μg／L～200μg／L。用该法测其结果符合国家食品卫生标准。