简单火焰共振原子吸收光谱仪的研究(英文)

本主研究火焰共振检测器在原子吸收光谱法中的应用,设计了分别以线性光源火焰共振光谱及连续光源火焰共振光谱为基础的两种简单廉价原子吸收光谱仪。本文也研究了仪器的光学特性、操作条件,可检测性及样品的分析。

702型光电自准直仪用于X射线吸收谱的测量

702型光电自准直仪主要用于精密机械的直线度、平面度和小角度等参数的静态测量。本文作者经过多年研究,将该仪器用在 X 射线吸收谱仪之中,实现了自动跟踪的多点动态测量。

频谱分析在共振系统中的应用

采用频谱分析的方法对机械系统中的振动模式进行分析，使系统中的共振模式的测定规范化、定量化．此方法应用于液体切变波共振吸收谱仪的研制中，取得了良好的效果．

8mm波段圆柱螺旋腔的研制

为了用８ｍｍ波段傅里叶变换谱仪测量气体的转动吸收谱线，研制了一个用作气体样品池的圆柱螺旋腔．讨论了如何通过选择腔体结构和耦合方式抑制干扰模，并对腔的模式纯度和有载ＱＬ值进行了测试．

羊毛辐射接枝甲基丙烯酸缩水甘油脂研究

对甲醇溶液中甲基丙烯酸缩水甘油脂在羊毛纤维上的γ射线辐射接枝反应作了系统研究。考察了气氛、剂量、剂量率、单体浓度等实验条件对接枝反应的影响,发现气氛对接技反应的影响很小,而接枝率随辐照剂量和单体浓度的增大而提高,接枝效率则随单体浓度的增大而减小。在剂量大于11kGy后接枝率达到平稳状态。用红外吸收谱仪(IR)和扫描电镜(SEM)分析发现单体均匀地接枝在羊毛上。

Effect of PSA tin plating process on trace lead in tin coating

In this paper,effects of conditions in phenol sulfonic acid(PSA) plating for tin coating of MR low carbon aluminum killed steel on trace Pb were examined.Trace Pb was measured by atomic absorption spectrometry(AAS)and glow discharge spectrometry,and coating morphology was observed by scanning electronic microscopy(SEM).Corrosion resistance of the tin coating was analyzed by electrochemical methods.The results indicated that Pb content in the tin coating reduced as bath temperature increased.When the temperature exceeded40 ℃,the grains in the coating were coarse and loose,reducing the corrosion resistance.As current density increased,Pb content increased rapidly,while low current density plating could lead to drain regions.The plating speed had no obvious effect on trace Pb in tin coating.In the tin plating layer,Pb was enriched at the surface and gradually reduced to zero along the depth.At bath temperature of 40 ℃ and current density of 20 A·dm^(-2),the amount of Pb could be less than 100 mg·kg^(-1) with excellent corrosion resistance.

Heavy Metal Biosorption Sites Studies of Laminaria japonica

The role played by the functional groups of Laminaria japonica treated by methanol and formaldehyde in biosorption of the heavy metals was investigated. Infrared spectroscopy analysis and biosorption experiments show that both carboxyl and amino groups join in the sorption; chemical treatment decreased the biosorption efficiency of the heavy metals.

Detection of Total Phenols, Essential and Toxic Elements in Latvian Whole Grain Bread

A survey was carried out with the aim of assessing the level of the total phenolic compounds （TPC）, essential （Na, K, Ca, Mg, Cu, Zn） and toxic （Cd and Pb） elements in 10 Latvian whole grain rye and/or wheat flour bread samples, obtained from the local market. The quantities of the TPC were determined by spectrophotometry. Mineral content was determined by flame photometry, flame atom absorption spectrometry （FAAS） and electrothermal atomic absorption spectrometry （ETAA） after wet digestion in concentrated HNO3. The values were comparable to the literature data. The average content in all the samples was （on a basis of weight of the product） 547 ± 28 mg/100 g for Na; 280 ±20 mg/100 g for K; 32 ± 2 mg/100 g for Ca; 88 ±5 mg/100 g for Mg; 0.49 ± 0.09 mg/100 g for Cu; 1.6 ±0.2 mg/100 g for Zn. Both Pb and Cd were determined below the limit of detection （LOD 5 0.10 mg/100 g）. The LOD values were determined for each element. The TPC content in defatted samples was slightly lower than the non-defatted ones, showing the dependence on the sample preparation. The calculated average levels of the elements were compared with the maximum levels recommended or regulated by the national legislation.

Assessment of Selected Heavy Metals in Street Dust Samples from Jazan City, KSA （Kingdom of Saudi Arabia）

In this work, Jazan province （Saudi Arabia） was examined for its heavy metals content. Therefore, 15 street dust samples were collected, digested and analyzed in order to investigate the levels of selected heavy metals and propose the causes for the presence of these metals. All collected samples were digested using Leeds Public Analyst method. The concentrations of heavy metals （Fe, Cu, Mn, Zn, Cd, Co and Pb） were analyzed using atomic absorption spectroscopy. Six heavy metals （Fe, Cu, Mn, Zn, Co and Pb） were measured in all samples; the concentration of Cd was not detected in Jazan dust by atomic absorption spectroscopy. The heavy metals levels in Jazan street dust increase according to the following sequence： Fe 〉 Mn 〉 Zn 〉 Cu 〉 Pb 〉 Co. The correlation coefficients and enrichment factors relative to earth crust abundances of heavy metals were calculated in order to predict the possible sources in dust.

Content of Cadmium in Poppy Seeds and Poppy Seeds Containing Products Marketed in Czech Republic

Concentration of cadmium in poppy seeds, semi-finished products and baked goods with poppy seeds was determined by graphite furnace atomic absorption spectrometry （GF-AAS）. Homogenous samples of poppy seeds and products containing poppy seeds were digested by means of microwave digestion system by using of nitric acid and hydrogen peroxide as reagents. The measurements were carried out using an atomic absorption spectrometer with Zeeman background correction. Detection limit was 0.003 mg/kg. A total of 208 samples of poppy seeds （from years 2004-2009） and 17 samples of semi-finished and baked goods were analysed. The average content was 0.64 mg/kg （median 0.64 mg/kg） for poppy seeds and 0.079 mg/kg （median 0.069 mg/kg） for semi-finished and baked goods. The relative standard deviation was lower than 5% for all measurements.

FLAME ATOMIC ABSORPTION DETERMINATION OF COPPER IN CEREALS FOOD SAMPLES WITH THE PRECONCENTRATION OF POTASSIUM TETRATITANATE WHISKER

A simple and reliable method has been developed for separation and preconcentration of trace amounts of copper ions in cereals food for subsequent measurement by flame atomic absorption spectrometry （FAAS）. The Cu^2＋ ions are adsorbed selectively and quantitatively during the passage. The retained copper ions were desorbed from the potassium tetratitanate whisker with 10.0mL of 2mol/L sulphuric acid solutions as eluent and were determined by FAAS. The linear range was 0.05μg/mL-0.20μg/mL in the original solution with a correlation coefficient of 0.9998. The detection limit of the proposed method is 2. lng/mL in the original solution （3σ, n=9）. Determination of copper in standard ions showed that the proposed method has good accuracy （recovery was more than 95%）. The method was successfully applied for recovery and determination of copper in cereals food samples

Hygienic Quality of Fish Depending of Cadmium （Cd） and Lead （Pb） Content in Bottom Sediments of Water Reservoirs Kolinany

Analysis of bottom sediments in water reservoir Kolifiany from the aspect of Cd and Pb contents, the determination of observed heavy metal contents in different parts of carp body （meat muscle, liver and kidney） and the evaluation of hygienic status and suitability of fish meat for the human consumption were performed. For analysis, each tissue sample was dissolved in a solution of nitric acid p.a. （HNO3：HzO = 2：1）; sediment sample in solution of acids （HF-HNO3-HCIO4） and analyzed for presence of Cd, Pb by the atomic absorption spectrophotometer （AAS） Varian Duo 240FS and 240Z. Our results confirmed hygienic harmless of bottom sediments in water reservoir Kolifiany. The Cd, Pb contents in sediments represent no risk within their input into the fish organisms. The Cd content in fish meat is lower than maximum available amount given by legislative norms, and the contents of Pb in fish meat too. The results of Cd, Pb content determination in carp body confirmed that fish muscles belong to suitable foodstuff for the human consumption.

C2H2 Overtones Near 12300 cm^-1 Revisited with a Very Sensitive Cavity Ring-down Spectrometer

A cavity ring-down spectrometer （CRDS） is constructed with a single-mode continuous-wave Ti：Sapphire laser. It allows attaining a minimum detectable absorption of 1.8× 10^-10cm^-1. The spectrometer is applied to record the overtone spectrum of ^12C2H2 in the 12240- 12350 cm-1. Compared with the previous CRDS and intra-cavity laser absorption spectroscopy studies in the same region, the present measurement achieved better sensitivity and better precision as well. As a result, the ro-vibrational parameters of the high overtone bands of acetylene at 12290.12, 12311.82, and 12350.61 cm^-1 have been refined. The advantages of the present CRD spectrometer is also demonstrated by the newly observed and well characterized perturbation on the f component of the very weak band near 12289 cm^-1. The quantitative measurement capability of the spectrometer is verified with the measurement of the water lines and employed to give the absolute band intensities of those three acetylene bands.

Comparison of Mosses as Bioindicator of Heavy Metal Pollution in Aramoko-Ekiti and Are-Ekiti, Nigeria

The increasing global concern over the public health impacts attributed to environmental pollution led us to investigate and compare the deposition of some heavy metals in mosses from an urban area, Aramoko Ekiti and a rural area, Are Ekiti. Both towns are located in the SouthWest, Nigeria. Moss samples were collected at different sites in the two towns. These samples were then digested in acid and analysed for Cd, Cr, Ni, Pb and Cu, using a flame atomic absorption spectrometer. The results of the study show variations in the concentrations of the heavy metals among the different sites in each town as well as between the two towns. Apart from cd which was suspected to have originated from natural sources in the investigated samples, the relatively higher concentrations of the other metals in Aramoko-Ekiti suggests an important anthropogenic source which we suspect to be automobiles since there are little or no industrial or mining activities within the town. Furthermore, the relatively higher concentrations of the metals exhibited by moss samples collected around locations prone to higher traffic situations in the two towns such as roadsides, filling stations and garages stresses the significance of traffic density in heavy metal pollution of the environment. These places （filling stations and garages） should be sited far away from residential areas. Also, residences should be sited at considerably far distances from major roads. These will prevent the bioaccumulation of the heavy metals in residents. Though, the results show that Aramoko-Ekiti is more polluted with the heavy metals than Are-Ekiti, the concentration of the heavy metals were still within the permissible limits. Given the results of this work and similar ones, there is need to evaluate the pollution status of the environment from time to time especially the urban areas and high traffic areas.

Effect of Socio-Demographic Factors on Zinc Status of Infants and Preschool Children in East Gojjam, Amhara Region of Ethiopia

Zinc deficiency is a public health concern and is the most prevalent micronutrient deficiencies in developing countries. The main objective of this study was to assess the prevalence and risk factors of zinc deficiency among infants and preschool children. Based on a community, the cross-sectional study was conducted in East Gojjam between October 2011 and April 2012. Two hundred and forty infants and preschool children were randomly selected in the study. Data on potential determinants of zinc deficiency were collected using a structured questionnaire. Serum zinc concentration was measured using atomic absorption spectrometer. Statistical analysis was done using ANOVA, independent sample student＇s t-test and linear regression model. The mean serum zinc concentration of infants and preschool children was 62.98 （±13.03） μg/dL in 95% confidence interval （CI） between 61.32 and 64.63 （i.e., 95% CI： 61.32, 64.63）. About 57,1% of the subjects were zinc deficient. The main determinants of low serum zinc status of infants and preschool children were age and number of family members living on the same land. Zinc status of older children was 3.67 μg/dL （95% CI： -5.58, -1.77） lower than children who were aged 6-10 months. Serum zinc status of infants and preschool children is decreased by 0.83 p.g/dL （95% CI： -1.36, -0.30） with each additional family member. Food insecurity, dietary diversity, sex, child health, anthropometric indices, maternal education and wealth index were not associated with serum zinc status. Zinc deficiency among infants and preschool children is highly prevalent. Such potential deficiencies require urgent attention, including complementary food preparation education, traditional phytate reduction method and family planning implementation recommended in the study area.

Cross-Validation of a Mobile N20 Flux Prototype （IPNOA） Using Micrometeorological and Chamber Methods

Within a LIFE＋ project IPNOA （improved flux prototype for n2o emission from agriculture）, LIFE11 ENV/IT/302 is a mobile prototype was developed to evaluate at field scale N20 emissions using a fast chamber technique. Main challenge was to develop a mobile system capable of moving on various field surfaces, equipped with very reliable N20 gas analyser （Los Gatos Research Inc.）, electrically autonomous （with batteries） and enough robust to face up to field conditions. In this paper, we report the major features of this prototype studied during two field campaigns. The N20 flux IPNOA prototype was compared with other methodological implementations： first, during an INGOS （integrated non-CO2 greenhouse gas observing systems） campaign on a grazed grassland at Easter Bush （Scotland） by Eddy correlation method, and then after on an arable crop at Grignon （France） using automatic and manual chambers fitted with QC-TILDAS （Quantum Cascade Tunable Infrared Laser Differential Absorption Spectrometer, Aerodyne Research Inc.）, with the 46C model of thermo-instrument analyser or with a GC （gas chromatography） analysis.

Aroma Properties of Selected Local Spices of Akwa Ibom State of Nigeria

Some famous local spices were selected to determine their potentials in terms of their aroma and utilization. They included Tea Bush （Ocimum basilicum）, Guinea Black Pepper （Piper guineense）, African Pepper （Xylopia aethiopica）, Alden Tree （Tetrapleura tetraptera） and the African Meg Nut or Onion Tree （Blighia unijugata）. Essential oils were extracted from the samples and used for aroma absorption test in a uv-visible spectrometer V2.03. The intensity of aroma was indicated at some peak values of absorption at particular wavelengths. The compounds responsible for the aroma at this peak values were identified by matching their wavelengths with those of known compounds at similar wavelengths of absorption. Thus, a compound such as Quinoline that has hot strong aroma and little bleaching effect was proved to be present in Guinea black pepper ;at the wavelength of 313.0 nm. Benzene with hot strong aroma and flammable effect was also indicated in this spice at the wavelength of 253.0 rim. Proximate analysis carried out showed that these spices have high nutritive values. Some of them such as Guinea black pepper, African Nutmeg and Ethiopian （African） pepper had high ether extract of 20.01, 25.97 and 31.25 respectively, and could be regarded as oil seeds, they contain much of essential oils.

Separation and characterization of petroleum asphaltene fractions by ESI FT-ICR MS and UV-vis spectrometer

Using heptane, toluene, and tetrahydrofuran （THF） as eluant, asphaltenes were fractionated into five fractions based on their polarity and solubility. The molecular composition of polar heteroatom species in both asphaltene and its fractions were ana- lyzed by negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry （ESI FT-ICR MS）. The application of UV-vis spectrometer in characterizing asphaltene composition and measuring asphaltene concentration was discussed. About 11.9 wt% asphaltene components adsorbed permanently on silica gel in the extrography column after exces- sive elution with various solvents. In negative FT-ICR MS, the mass spectra show that acidic and neutral nitrogen-containing compounds such as N1 and NIS1 mainly existe in the first three less polar fractions, while oxygen-containing compounds such as 02, O2S, O2S2, 03, and 04 show high relative abundance in more polar fractions. These results suggest oxygen-containing compounds have stronger adsorption ability with silica gel. It was observed that the double bond equivalence （DBE） distribu- tion of N1 class species in the fractions shifted to higher values while the carbon number shifted to smaller numbers as polarity of fractions increased. This indicates that acidic and neutral Nl compounds with longer carbon chain and less aromaticity have less polarity compared with those with shorter carbon chain and stronger aromaticity. UV-vis absorbance indicats that fractions containing the most aromatic and most polar asphaltene have better absorbance at long wavelength, while the fractions that consist of least aromatic and least polar asphatlenes show high absorbance at short wavelength.

Epigallocatechin-3-gallate affects the growth of LNCaP cells via membrane fluidity and distribution of cellular zinc

Objective:To evaluate effects of epigallocatechin-3-gallate (EGCG) on the viability, membrane properties, and zinc distribution, with and without the presence of Zn2+, in human prostate carcinoma LNCaP cells. Methods: We examined changes in cellular morphology and membrane fluidity of LNCaP cells, distribution of cellular zinc, and the incorporated portion of EGCG after treatments with EGCG, Zn2+, and EGCG+Zn2+. Results: We observed an alteration in cellular morphology and a decrease in membrane fluidity of LNCaP cells after treatment with EGCG or Zn2+. The proportion of EGCG incorporated into liposomes treated with the mixture of EGCG and Zn2+ at the ratio of 1:1 was 90.57%, which was significantly higher than that treated with EGCG alone (30.33%). Electron spin resonance (ESR) studies and determination of fatty acids showed that the effects of EGCG on the membrane fluidity of LNCaP were decreased by Zn2+. EGCG accelerated the accumulation of zinc in the mitochondria and cytosol as observed by atomic absorption spectrometer. Conclusion: These results show that EGCG interacted with cell membrane, decreased the membrane fluidity of LNCaP cells, and accelerated zinc accumulation in the mitochondria and cytosol, which could be the mechanism by which EGCG inhibits proliferation of LNCaP cells. In addition, high concentrations of Zn2+ could attenuate the actions elicited by EGCG.

Size-controlled chalcopyrite CuInS_2 nanocrystals:One-pot synthesis and optical characterization

Chalcopyrite ternary CulnS2 semiconductor nanocry stals have been synthesized via a facile one-pot chemical approach by using oleylamine and oleic acid as solvents. The as-prepared CuInS2 nanocrystals have been characterized by instrumental analyses such as X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, transmission electron microscopy （TEM）/high-resolution TEM （HRTEM）, energy-dispersive X-ray spectroscopy （EDS）, UV-vis absorption spectroscopy （UV-vis） and photoluminescence （PL） spectroscopy. The particle sizes of the CuInS2 nanocrystals could be tuned from 2 to 10 nm by simply varying reaction conditions. Oleylamine, which acted as both a reductant and an effective capping agent, plays an important role in the size-controlled synthesis of CulnS2 nanocrystals. Based on a series of comparative experiments under different reaction conditions, the probable formation mechanism of CulnS2 nanocrystals has been proposed. Furthermore, the UV-vis absorption and PL emission spectra of the chalcopyrite CulnS2 nanocrystals have been found to be adjustable in the range of 527-815 nm and 625-800 rim, respectively, indicating their potential application in photovoltaic devices.