我国成年人甲状腺碘含量的检测--微堆超热中子活化法测碘

采用微堆仪器超热中子活化分析法,测定了我国南北地区７８例正常年人甲状腺碘的含量,发现存在地区性差异,从而为评价碘对人体健康的影响提供了背景资料。     

The Rapid and Non-Destructive Determination of Vanadium in Carbons by the Neutron Activation Analysis Using Gadolinium as an Internal Standard Material

Abstract

The present work deals with the determination of vanadium in high grade carbons by the thermal neutron activation using a Van de Graaff Accelerator. In this study, gadolinium oxide is used as the internal standard material, and the detection limit of this method is c. a. 1 ppm.     

Determination of Trace Elements in Liquid Fuels by Instrumental Neutron Activation Analysis

Abstract

An instrumental neutron activation analysis with Ge(Li) γ -spectrometry and computer-assisted data reduction, has been developed for the determination of more than 20 elements in different liquid fuels. Organo-metallic standard solutions were mixed to obtain suitable standards. Two neutron irradiations and 4 γ-spectrometric measurements are required for each sample. Corrections were taken into account for a few spectrometric and nuclear interferences. The overall standard deviation for nearly all elements is mainly determined by counting statistics. The following elements can be determined : Na, Al, S, Cl, K, Sc, V, Cr, Fe, Co, Ni, Cu, Zn, As, Se, Br and La whereas the concentration of the following elements are mostly near the limit of detection: Mg, Mo, Sb, Ba, Th and Hg.     

火试金预浓集结合中子活化和电感耦合等离子体质谱法测定铂族元素

建立了两种以火试金预浓集为基础的、可用于准确测定铂族元素的方法;中子活化法和电感耦合等离子体质谱法。讨论了它们的分析检出限、准确度及其适应性。并用这两种方法测定了5种候选地质参考物质中铂族元素的含量。     

一种新的测定铱丰度及其化学形态的放射化学中子活化分析法

本工作建立了一个以长链伯胺N_(1923)萃取为基础的放射化学中子活化分析法,可测定含量低达10~(-12)g/g的Ir。影响Ir萃取率的关键是Ir在水溶液中的化学形态,而不是其价态。此外,我们发展了一个用于地质样品物相分离的化学分相方法,研究了白垩系-第三系界线粘土样品中异常Ir的赋存状态。     

低空白镍锍试金预富集中子活化分析测定地球化学标准物质中的铂族元素

研究了镍锍试金预富集中子活化分析测定岩石样品中的铂族元素。纯化捕集剂氧化镍,大大降低了化学分离全流程铂族元素的空白。取样量为50g时,所需溶剂各元素的空白值为(ng/g):Pt<0.05、Pd<0.05、Os<0.01、Ru<0.05、Rh<0.05、Ir=0.002。用平面锗探测器测定Rh使测定下限降低了两个数量级,对几种国标地球化学标准物质的测定结果与推荐值基本符合。     

Nondestructive Determination of Mercury in Copper by Thermal Neutron Activation Analysis

Abstract

Thermal neutron activation analysis was applied to the nondestructive determination of parts per billion (p.p.b.) quantities of mercury in high purity, oxygen-free high conductivity (OFHC) copper. The data were treated to a five-point gamma spectrum smoothing to reduce the statistical variations due to the low count rates. Linear regression and a statistical evaluation of the data were also performed. Net photopeak counting rates of approximately 43 counts per minute (c.p.m.), compared to a background of approximately 6 c.p.m., were obtained for six two-gram copper samples containing 38 ± 12 p.p.b. mercury.     

Standard Reference Materials to support US regulations for nutrients and contaminants in food and dietary supplements

To address the measurement and standard needs of the food and nutrition communities, the National Institute of Standards and Technology (NIST) has developed a suite of food-matrix Standard Reference Materials (SRMs) characterized for nutrient concentrations. These food-matrix SRMs include infant formula, baby food, and typical diet composites; meat homogenate, oyster, mussel, and fish tissues; baking chocolate; peanut butter; and spinach. Many of these materials were developed based on recommendations of the food industry to populate a nine-sectored triangle, developed by the Association of Analytical Communities (AOAC) International, in which foods are positioned based on their fat, protein, and carbohydrate contents. Value assignment of proximates, vitamins, and elements of nutritional interest in these food-matrix SRMs has been based primarily on the combination of results from measurements at NIST and from a group of collaborating laboratories involved in food measurements. Food-matrix SRMs are now available that are representative of all nine sectors of the AOAC International food-matrix triangle. Current activities are focused on the development of SRMs for dietary supplements including botanical and multivitamin/multielement materials.Presented at the CCQM Workshop on Comparability and Traceability in Food Analysis, 18–19 November 2003, BIPM, Sèvres, France.     

Pyrohydrolysis Coupled to Ion Chromatography for Sensitive Determination of Iodine in Food-Related Materials

For the determination of iodine in food-related materials, the biological sample was decomposed using a pyrohydrolytic procedure. A sample vessel made from mullite, in which an aliquot of sample was taken, was placed in a quartz tube, and heated at 100°C through 820°C step by step under wet oxygen flow. Iodine in the sample was separated by evaporation as hydrogen iodide and collected in a dilute sodium hydroxide solution. After the basic solution containing the analyte was neutralized by adding hydrochloric acid, iodine in the solution was determined by using ion chromatography with ultraviolet absorption detection. The operating conditions for the pyrohydrolytic decomposition procedure were examined. Under the optimized conditions, organic constituents in the sample were completely decomposed since the analyte species were converted to the iodide ion. The detection limit of 0.01 µg g^?1 iodine was established with a reproducibility of 1.2% when a sample of 500 mg was taken. This method was applied to the determination of iodine in various certified reference materials and food samples with satisfactory results.     

用中子活化分析法研究25种元素在人体肝脏亚细胞组分中的分布

采用差速离心分离技术与中子活化分析法（ＮＡＡ）相结合的方法分析了人肝２５５中元素,并用标准参考物保证结果的准确性。分析结果表明,大多数元素在各亚细胞组分中并非均匀分布。Ａｓ、Ａｕ、Ｃｏ、Ｉ、Ｍｇ、Ｓｂ、Ｓｅ在细胞核和线粒体浓度最高。Ａｌ、Ｓｓ、Ａｕ、Ｂａ、Ｆｅ、Ｉ、Ｍｇ、Ｍｏ、Ｓｂ、Ｓｃ在细胞核和线粒体浓度最高。Ａｌ、Ａｓ、Ａｕ、Ｂａ、Ｆｅ、Ｉ、Ｌａ、Ｍｇ、Ｍｎ、Ｓｂ、Ｓｅ在胞液中深度最低,生物体     

Short- and long-time neutron activation analysis of egyptian phosphate reference materials

Three Egyptian phosphate reference materials (S1, S2 and S3) were investigated using short-term activation analysis. The precision of the determination of Dy, Sc, Gd, Yb, Mg, V, F, Al, Mn, and Ca by this method ranged from 2 to 5% due to the homogeneity factor. Another 11 elements were determined by NAA using medium and long-lived nuclides. Most results were in good agreement with the recommended values. The values of Dy and Gd are reported.     

免疫亲和柱净化-柱后光化学衍生-高效液相色谱法同时检测粮谷中的黄曲霉毒素、玉米赤霉烯酮和赭曲霉毒素A

建立了同时检测粮谷中黄曲霉毒素(B1、B2、G1和G2)、玉米赤霉烯酮和赭曲霉毒素A的免疫亲和柱净化-柱后光化学衍生-高效液相色谱方法。样品经过甲醇-水(体积比为80∶20)提取,通过免疫亲和柱富集和净化,采用Waters Nova-Pak色谱柱(3.9 mm i.d.×150 mm,4 μm),以甲醇、乙腈和1%的磷酸溶液为流动相,梯度洗脱,柱后光化学衍生、改变波长荧光检测。黄曲霉毒素(B1、B2、G1和G2)、玉米赤霉烯酮和赭曲霉毒素A检出限分别为0.24,4.0和0.5 μg/kg,标准曲线的线性范围分别为0.24~6.0,4.0~100.0和0.5~40.0 μg/L;在小麦、玉米、黑麦样品中,平均加标回收率为70.8% ~94.0%,相对标准偏差为2.79% ~9.38%。     

Determination of Elements in Japanese Standard Soil Materials by Means of Insturmental Neutron Activation Analysis

Instrumental neutron activation analysis (INAA), and inductively coupled plasma mass spectroscopy (ICP-MS) were applied to the determination of major elements and rare earth elements in Japanese Standard Soil Materials (NDG-1 to -8). Eight major elements, Al, Fe, Ti, Ca, Mg, Mn, K, and Na were determined by INAA. A comparison of the data for rare earth elements obtained by INAA and ICP-MS shows that the data of the contents determined by the two different analytical methods are in fairly good agreement with each other.     

泡沫塑料预富集中子活化测定铜矿中的铼

介绍了泡沫塑料(泡沫塑料)预富集中子活化测定铜矿中的铼的分析流程,研究了泡沫塑料在HF介质中对铼的吸附性能。全流程对铼的吸附率大于97%,对铼的富集倍数为1×104。并对标样铜银矿GBW07164(GSO3)、精铜矿GBW07166(GSO5)进行了分析,其分析精度RSD(n=6)分别为4.4%和3.6%。测定结果与参考值基本吻合,结果令人满意。     

人体子宫癌活组织中微量元素的中子活化分析

本文利用样品的低温干燥预处理技术和仪器中子活化分析方法,同时测定了人体子宫癌活组织中的29种微量元素,并分别与宫颈炎组织和正常组织比较,初步研究结果表明,子宫癌组织,宫颈炎组织和正常组织中Au,I,Se等微量元素有显著差异。     

Determination of Silver in Plants by Flameless Atomic Absorption Spectrometry and Neutron Activation Analysis

Abstract

Three analytical techniques suitable for determining silver concentrations in plants are presented and compared. Graphite furnace atomic absorption spectrometry performed directly on sample digests was the most sensitive and convenient. Neutron activation analysis, measuring ^110mAg gave good reproducibility, but lower sensitivity. A cyclic activation scheme to generate and detect the short-lived isotope ¹¹⁰Ag was useful as a quick reconnaissance technique, but interference from ⁷⁶As reduced its effectiveness.

Data are presented on the silver content of terrestrial plants. Background silver concentrations for lichens and bryophytes collected from Wales, U.K. were <0.07μgg^?1. Samples collected from areas contaminated by derelict metal mines contained between 0.1-1.0μAgg^?1. The aerial portions of vascular species usually contained less silver than bryophytes growing on the same substrate. Fungi are shown to bioconcentrate silver to a greater extent than cadmium, copper or lead.     

Determination of Arsenic and Mercury in Various Environmental Matrices by Chemical Neutron Activation Analysis

Chemical neutron activation analysis was developed for determining trace amounts of arsenic and mercury in a variety of environmental matrices, including water, sediment, rock, plants, animal organs, etc: The adsorption procedure via magnesium oxide as the agent was applied to preconcentrate arsenic from the digested environmental matrices where arsenic in the form of As(V) ion could be highly efficiently adsorbed by hydrous magnesium oxide. On the other hand, the extraction procedure via lead diethyldithiocarbamate as the agent was applied to preconcentrate mercury from the digested environmental matrices where mercury in the form of Hg(II) ion could be highly efficiently extracted into the solution of lead diethyldithiocarbamte in dichloromethane. Both of the preconcentrated materials prepared ultimately in the solid states, i.e., arsenic in magnesium oxide and mercury in lead diethyldithiocarbamte were taken to be neutron irradiated. The γ spectra of the preconcentrated samples irradiated generally showed clear peaks of the product radionuclides from arsenic or from mercury by the different separation procedures. The possible interfering elements such as Na, Br, etc., were prominently minimized in respect of most of the preconcentrated samples. The reliability and accuracy of the proposed analytical methods for detecting arsenic and mercury can be confirmed by the assay of commercial standard reference materials including sediment, rock, plants, and animal organs.     

Determination of Ga,Th, and U in Bauxite and Coal Ash by Epithermal Neutron Activation Analysis

Neutron activation analysis is applied to the determination of Ga, Th and U in Bauxite and coal ash; thermal and epithermal irradiations are used. The other analytical methods are also quantitatively surveyed for gallium. The results indicate that epithermal neutron activation is prefered for those trace elements because the former method is more simple and quick.     

粒度分析及粒度标准物质研究进展

综述了当前粒度分析测试方法的研究进展,并简单介绍了各种测试方法的基本原理以及包括美国、欧洲、中国在内的国家和地区在粒度标准物质方面的研究概况。     

The Determination by Neutron Activation Analysis of Selected Elements in Cigarettes

Abstract

Neutron activation analysis was used for the determination of Na, Al, CI, K, Ca, Sc, Mn, Cu, Br, and La in the tobacco, mainstream smoke condensate, paper, and dropped ash of the Kentucky Reference Cigarette (IRI). The procedure requires no sample transfers prior to activation and no radiochemical separations before counting.