Determination of arsenic in beer by dry ashing, hydride generation atomic absorption spectroscopy

A method has been developed for determination of arsenic in beer. Organic matter is destroyed by the dry-ashing technique, the ash is dissolved in HCl, and hydrides of arsenic are generated by addition of sodium borohydride prior to atomization in a flame-heated quartz cell and atomic absorption spectroscopy measurement. The analytical features of the method are detection limit 0.1 ng/g beer, precision 8%, and recovery 97 +/- 7%. The arsenic contents of different brands from Spain and other European countries were analyzed. In all samples, the arsenic levels found were well below maximum levels allowed in Spanish legislation (100 ng/g). The quantities of arsenic in Spanish beers do not differ from those found in foreign beers. No differences were found between bottled and canned beers, and no correlation exists between metal content and original specific gravity of the beers.     

Determination of arsenic and selenium in whole fish by continuous-flow hydride generation atomic absorption spectrophotometry

A combined wet chemical and dry ash digestion and use of a continuous-flow hydride generator coupled with a flame-heated quartz cell enabled the simple, precise, and highly automated atomic absorption determination of arsenic and selenium in tissues of whole fish. Percent relative standard deviation averaged 4% for each element; method detection limits (micrograms/g dry wt) were about 0.06 for arsenic and 0.04 for selenium. Digestion of samples proceeded with little operator attention and without perchloric acid. Analysis for arsenic as As(V) simplified sample preparation but care had to be exercised to avoid interferences from high concentrations of selenium.     

Determination of arsenic and selenium in environmental and agricultural samples by hydride generation atomic absorption spectrometry

Agricultural and environmental samples are digested with acid, and arsenic and selenium are determined using hydride generation atomic absorption spectrometry. Interelement interferences are eliminated by high acid concentrations or cation-exchange resins. Agreement with standard reference material is excellent. The technique is also applied to actual samples.     

Dry deposition loading of Lake Michigan by airborne particulate matter

A transport model as a function of particle size is presented which couples Chicago area meteorological data through the mixed layer with laboratory and field data on water surface dry deposition. The model is used to (a) estimate a minimum mass transfer efficiency by dry deposition from the Chicago area to Lake Michigan, (b) compare this minimum with the maximum wet deposition likely, and (c) estimate the transfer efficiency of trace metals. Dry deposition is found to cause 15% or more mass transfer efficiency of aerosols to the Lake. This value is considered to be equal to or greater than the efficiency of precipitation scavenging mass transfer. However, dry deposition as a function of particle size is such that the transfer of trace metals by this mechanism appears to be a few percent or less. Consequently, precipitation scavenging appears to be the dominant mechanism for trace metal transfer to Lake Michigan.     

Quantitative monitoring of airborne lead pollution by a foliose lichen

The potential use of lichens as quantitative monitors of airborne heavy metal pollution has been demonstrated by measurements of Po²¹⁰, Pb, Cd, Zn, and V levels in sequential growth of the foliose lichen Pseudoparmelia baltimorensis from three localities in the greater Washington, D.C. area. Samples were dated using the growth rate measured by Lawrey and Hale (1977). Po²¹⁰, Pb, and V increase with age in a given colony. Higher levels of Pb, V, Cd, and Zn are present in samples from the two more polluted sites. The retention of heavy metals is consistent with trapping by an ion exchange mechanism. Since Po²¹⁰ is the daughter product of in situ decay of Pb²¹⁰, accumulated from atmospheric fallout of known rate, its levels can be used to calculate trapping efficiencies of Pb and retrospective fallout rates. These rates are similar to published data from rural and urban areas.     

Extraction of organic compounds from airborne particulate matter

The extraction of organic compounds from airborne particulate matter, obtained by glass fiber filtration, has been studied with different solvents and has been followed as a function of time. For many compounds, almost quantitative extraction was obtained after S h. Polyaromatic hydrocarbons and polar compounds often yielded higher extraction efficiencies with methanol than with benzene. The gas chromatographic mass spectrometric determination of these compounds is somewhat simplified by a separation of the sample into neutral, acidic and basic fractions. The efficiency of this procedure was tested on a mixture of compounds representative for the actual aerosol composition. It was concluded that the basic fraction yielded poor results. The techniques for these measurements included quantitative gas chromatography with electronic integration for standard mixtures and quantitative mass chromatography for natural sample extracts.     

Simultaneous determination of antimony and bismuth in soils by continuous hydride generation—atomic absorption spectrometry

A method for the simultaneous determination of Sb and Bi in soils using an automated hydride generation system with an electrically heated quartz cell atomizer, and an atomic absorption spectrophotometer is described. Five g of the air-dried soil was placed in a 100 mL Erlenmyer flask fitted with a Liebig condenser and boiled gently with 20 mL 6 M HCl for 1 hr on a sand bath. The extract was then filtered into a 100 mL volumetric flask. The two elements in the sample solution (<30 mL) placed in a 50 mL volumetric flask are prereduced by potassium iodide and ascorbic acid solutions. Reduction of Sb and Bi ions to stibine and bismuthine is obtained by sodium tetrahydroborate solution. Detection limits (S/N = 2) are 7 ng g^?1 dry soil for Sb and 0.7 ng g^?1 dry soil for Bi. The effects of 19 diverse ions on the absorbances of Sb and Bi were investigasted, and it was found that the errors by these ions will be within 5% in the ordinary unpolluted or even polluted soils. In order to examine the accuracy of the proposed method, Sb and Bi in the four Canadian reference soils and NBS-4355 from the National Bureau of Standards in the USA were determined. The values obtained in this work are close to the recommended or the not-certified values. The amounts of Sb, Bi and the related elements in the soils near a smelter were also analyzed.     

Features of airborne breathable particulate in a remote rural and in an urban area

In order to define the atmosphere pollution role in the lung cancer etiology it is necessary to carefully measure the composition of airborne pollutants. The evaluation of atmosphere pollution by analytic electron microscopy technique has made it possible to analyze the morphology and composition of airborne breathable particulate and to characterize the sources. The comparative study of a rural area and a downtown area in Rome has shown qualitative and quantitative differences in the pollution pattern. In the urban area the data we have obtained point out motor vehicle traffic as the greatest source of pollution. A large amount of heavy metals and mineral fibers, potentially noxious for health, was observed.     

微波消解-GFAAS测定肥料中铅、镉含量的方法

通过多个实验的研究分析建立了微波消解法作为样品前处理,原子吸收石墨炉(GFAAS)法同时测定肥料中铅、镉含量的方法。结果表明,铅的检出限为1.6μg/L,镉的检出限为0.11μg/L;7次平行相对标准偏差3%;3个浓度水平加标回收率均在90%～110%。微波消解-GFAAS法对肥料中铅镉测定结果准确、稳定,且更节约人力、物力以及时间,可作为推荐方法。     

应用氢化物发生-原子吸收分光光度法和直接测汞仪测定肥料中汞含量的方法比对研究

肥料中的汞元素是重要的重金属污染物之一,研究肥料中汞元素的快速测定方法对于肥料的安全生产意义重大。研究通过正交设计试验,方法检出限、精密度和准确性试验,优化了仪器条件,确定了直接测汞仪测定肥料样品中汞含量的最佳仪器条件,并与GB/T 23349-2020《肥料中砷、镉、铬、铅、汞含量的测定》中规定的氢化物发生-原子吸收分光光度法进行比对。研究结果表明,正交试验确定的直接测汞仪法的最佳分析条件组合为“干燥温度250℃,催化分解温度700℃,开始测定温度300℃”。该方法具有良好的二次曲线关系,方法检出限为0.0023 ng,加标回收率在93.8%～103.9%之间,相对标准偏差在3.2%～6.3%之间。通过与国家标准对比表明,直接测汞仪法与氢化物发生-原子吸收分光光度法无显著性差异,该法具备简便、快速、准确、灵敏度高等特点,适合不同肥料品种中汞元素的测定。     

Determination of inorganic tin in biological samples by hydride generation-atomic absorption spectrometry after silica gel cleanup

A method is described for the determination of inorganic tin in biological samples by hydride generation-atomic absorption spectrometry (HG-AAS). A sample is extracted with ethyl acetate after addition of HCl and NaCl. The concentrated extract is passed through a silica gel column. The column is washed with ethanol, water, and 0.2N HCl successively, and then inorganic tin is eluted with 2N HCl and measured by HG-AAS. Recoveries from fish muscle spiked with 0.1 micrograms/g Sn4+ are 78.9 +/- 4.2% (average +/- standard deviation, n = 5). The detection limit is 0.01 micrograms/g as Sn.     

Determination of selenium in human milk by hydride cold-trapping atomic absorption spectrometry and calculation of daily selenium intake.

A technique of hydride cold-trapping atomic absorption spectrometry following microwave digestion was developed and optimized for the determination of selenium in human milk. The method was validated by the analysis of two standard reference materials (CRM milk powder). The detection limit was 0.5 ng mL(-)(1). The method was then used to analyze 78 milk samples from 38 Austrian mothers throughout their first 10 months of lactation. The mean concentration of selenium in the mother's milk decreased with the days postpartum from 23.9 +/- 12.0 microg L(-)(1) in colostrum to a plateau of 11.4 +/- 3.0 microg L(-)(1) in mature milk. On the basis of the milk selenium concentrations, the selenium intakes of the fully breast-fed infants and the lactating mothers were calculated. The selenium intake of the infants during their first 3 months of life was >8.2 microg day(-)(1). The selenium intake of the lactating mothers was 48 microg day(-)(1). Compared to the recommended dietary allowance, the fully breast-fed infants received sufficient selenium but the lactating mothers obtained less than the recommended.     

Determination of cadmium, lead, and copper in margarines and butters by galvanostatic stripping chronopotentiometry

A galvanostatic stripping chronopotentiometric (GSCP) method for the simultaneous determination of cadmium, lead, and copper in commercial margarines and butters is described. Quantitative analyses of heavy metals in the mineralized fat samples, except standard addition method, were carried out automatically. The mean concentrations of Cd(II), Pb(II), and Cu(II) in different types of margarines and butters varied from 9.1 to 26.2, 9.2-14.2, 298.2-364.0 microg x kg(-)(1), respectively, that is below the legal requirements. The detection limits are 0.02, 0.02, and 0.06 microg x L(-)(1) for Cd(II), Pb(II) and Cu(II), while the reproducibilities are 3.3, 5.7, and 2.0%, respectively. The comparable precision (RSD = 0.76-4.5 and 0.87-4.9%) and recovery (96.7-102.2% and 96.1-103.2%) for the proposed GSCP and standard GFAAS methods, demonstrate the benefit of GSCP method in the routine analysis of heavy metal ions in fats.     

Determination of cadmium, copper, and lead in sodium chloride food salts by flame atomic absorption spectroscopy

A method for determination of Cd, Cu, and Pb in sodium chloride food salt samples has been developed. It consists of extraction in 4-methyl-2-pentanone of the complexes formed with ammonium pyrrolidine dithiocarbamate and further analysis of the extracts by flame atomic absorption spectroscopy. Detection limits in ng/g salt were 0.2 for Cd, 0.7 for Cu, and 10.0 for Pb. The coefficients of variation of 12 independent analyses were 13% for Cd (at a level of 0.4 ppb), 18% for Cu (1.6 ppb), and 5% for Pb (40 ppb). The recoveries were 100 +/- 0% for Cd, 115 +/- 14% for Cu, and 100 +/- 13% for Pb.     

氢化物发生——原子荧光光谱法同时测定肥料中砷、汞的研究

通过对消化体系的选择及双道原子荧光光度计测试条件的优化，建立了氢化物发生-原子荧光光谱法同时测定肥料中砷、汞的方法。方法线性范围宽（As0-100μg／L；Hg0-10μg／L），检出限低（As0．05μg／L和Hg0.07μg／L）。无机肥料中As回收率为98．8％-100．4％，Hg回收率为98．9％-102．2％；有机肥料中As回收率为94．4％-105．6％，Hg回收率为97．6％-103．8％。