Selenium Determination in Serum by Graphite Furnace Atomic Absorption Spectrometry

Selenium concentration in serum has been proposed as the most valuable indicator of human selenium status. In this work, the concentration of selenium in serum is measured by GFAAS using longitudinal Zeeman-effect background correction, a highly sensitive technique that can be used to determine selenium at sub-ppb level. Standard reference materials are analyzed to verify the accuracy and precision of this technique. The direct method proposed in this study is used for the determination of selenium in human serum collected from healthy people of 19–25 years and women of 21–34 years in the First trimester of pregnancy. The method developed in this study, which can quickly and accurately measure serum selenium, is suitable for applications in clinical diagnosis or biological monitoring.     

硒对镉毒性的拮抗与解毒作用实验研究

不同剂量的硒对高剂量镉的拮抗作用引起大鼠全血中谷胱甘肽过氧化物酶活性和心肝、肾脏器相对重量的变化，用以评价硒对镉毒性的缓解作用，实验结果显示，经口给适量的硒对镉引起的毒性有拮抗作用，对机体有保护作用。     

The Application on Determination of Se by Continus Flow Hydride Generation Atomic Absorption Spectrometry in Zhangjiakou Low Se Area of China

Selenium is an essential nutrient trace element for human with established recommended dietary intake levels for different age groups. Low Se status has been reported to be a contributing factor in a number of deficiency diseases, of which the best doucumented is Keshan disease, a cardiomyopathy occurring in certain regions of China. By now,there are still new Keshan disease patients occuring in some area of China such as Zhangjiakou district. In order to assess and monitor the selenium nutrient status in human health, it is necessary to precisely quantify selenium in environment materials especially low Se level materials. This paper reports the analysis method on determination Se in low Se grain samples by continuous flow hydride generation atomic absorption spectrometry (HGAAS).     

天然产物中硒含量测定及形态分析

硒是人体必需微量元素之一，具有抗肿瘤、防衰老、防辐射和增强机体免疫力等多种功能。文章概述了国内近年来硒含量测定方法和国内外对硒形态分析的现状。     

Determination of selenium status using the nail biologic monitor in a canine model

Toenails and fingernails are routinely used to estimate selenium status in epidemiological studies; however, literature validating nail selenium concentration as a surrogate for critical organs is limited. In this study diets of intact male dogs were selenium supplemented at two physiological levels (3 and 6 μg/kg/day) in two different forms, selenomethionine and selenium-enriched bioformed yeast. The selenium-adequate basal diet consumed by the treatment and control groups during the 4-week run-in period and throughout the trial contained 0.3 ppm selenium. After 7 months the dogs in the two treatment groups and the control group were euthanized. Representative tissue samples from prostate, brain, liver, heart and skeletal muscle were collected, rinsed and frozen. Toenail clippings from multiple toes were also collected. Selenium was determined by neutron activation analysis using Se77m (half life = 17.4 s) at the University of Missouri Research Reactor Center. NIST SRM 1577, Bovine Liver was analyzed as a quality control. The analysts were blinded to control and treatment group assignments. As expected, tissue selenium levels increased proportionally with supplementation. A slightly greater increase in tissue selenium was observed for the purified selenomethionine compared to the bioformed yeast; however this trend was significant only for brain tissue. Toenail selenium concentrations and tissue selenium were highly correlated (p < 0.003) with Pearson coefficients of 0.759 (skeletal muscle), 0.745 (heart), 0.729 (brain), 0.723 (prostate), and 0.632 (liver). The toenail biologic monitor accurately assesses selenium status in skeletal muscle, heart, brain, prostate, and liver in the canine model.     

Analysis of the selenium species distribution in cow blood by size exclusion liquid chromatography–inductively coupled plasma collision cell mass spectrometry (SEC–ICPccMS)

A method for performing rapid semiquantitative screening of the distribution of Se species in the blood of cows fed with a diet enriched in selenized yeast was optimized. The method was based on direct injection of a blood sample onto a high resolution size exclusion chromatographic column and fractionation of the selenium species. Selenium was detected on-line by ICP-MS with a collision cell. The concentrations of selenized haemoglobin and free selenomethionine were estimated using the chromatogram. The method was applied to a study involving 15 control and 15 treated dairy cows at four different supplementation time points. The increase in the selenomethionine and selenized haemoglobin was a linear function of the total selenium concentration. A threshold value of 600 ng ml(-1) of total Se was established beyond which selenomethionine could not be incorporated into the protein. No inorganic selenium was found to be present. The total selenium in cow blood correlated well with that in milk. The selenium supplementation did not change the protein distribution profiles for other essential elements (Cu, Fe, Mn, Zn).     

Characteristics of selenium in australian marine biota

The occurrence, distribution and speciation of selenium in Australian marine biota is discussed. Biochemical pathways for the accumulation of selenium by marine organisms are also postulated. Comparison of the levels of selenium in macroalgae, fish, crustaceans and molluscs indicates that preferential accumulation of selenium by particular taxa does not occur. Phaeophyta have significantly lower selenium concentrations than Rhodophyta and Chlorophyta. Fish have lower selenium contents in muscle tissues than molluscs and crustaceans. Marine animals with different dietary intake (planktonic vs herbivorous vs carnivorous) are not observed to have significantly different levels of selenium (P>0.05). Selenium in all the organisms studied was predominantly associated with free amino-acids or protein residues and was not present as characterizable inorganic selenium species (SeO₃^2?, SeO₄^2?). These results indicate that selenium is probably only incorporated into biota for specific biochemical purposes with any exces selenium being excreted or eliminated.     

生物和环境样品中硒元素的形态分析研究

金属组学是继基因组学/蛋白质组学和代谢组学后提出的一种新的组学,其研究重点在于对所研究的金属和类金属元素的各种存在形态进行分析。硒是生物环境中存在的一种重要的类金属元素。形态与浓度不同的硒化合物可能是生物体的必需元素,同时也可能导致中毒。本文对目前存在的硒元素形态分析方法的研究现状进行了总结,并对前景进行了展望。     

克山病和大骨节病患者红细胞免疫功能与血硒水平的对比研究

对潜在型克山病和大骨节病患者的红细胞免疫功能、血清红细胞免疫粘附调节因子和全血硒含量进行了检测。结果表明：克山病和大骨节病患者的红细胞Ｃ３ｂ受体花环率和全血硒含量均明显低于非病区居民，血清红细胞免疫粘附抑制率均高于非病区居民，免疫复合物花环率和血清红细胞免疫粘附促进率与非病区居民无明显差异；但两病患者上述参数之间无明显差异。提示潜在型克山病和大骨节病患者红细胞免疫功能低下，可能均与低硒状态和血清红     

硒的抗突变性作用与机体免疫功能的研究

研究了在三氯甲烷致突变性试验中加入硒的影响。结果显示硒能减少Ａｍｅｓ试验中三氯甲烷诱变的回变菌落数，能使小鼠骨髓嗜多染红细胞微核率和鳙鱼外周血有核红细胞微核率明显下降。并研究了硒在细胞免疫试验中的作用，结果显示硒能使正常鼠和荷瘤鼠的肺和脾的ＮＫ细胞活性提高，能促进其脾Ｔ淋巴细胞的增殖反应，还能增加外周血Ｔ淋巴细胞数。     

Use of enriched <Superscript>74</Superscript>Se and <Superscript>77</Superscript>Se in combination with isotope pattern deconvolution to differentiate and determine endogenous and supplemented selenium in lactating rats

A quantitative methodology has been developed to differentiate between endogenous and supplemented selenium in lactating rats using two enriched selenium isotopes. Lactating rats were fed for 2 weeks with formula milk containing one enriched Se isotope, ⁷⁷Se, as the metabolic tracer. The isotopic composition of selenium in serum and urine samples was then measured by collision cell ICP-MS after the addition of a solution containing another enriched isotope, ⁷⁴Se, as quantitation tracer, before analysis. Isotope pattern deconvolution allowed the transformation of measured Se isotopic abundances into concentrations of natural abundance (endogenous) selenium and enriched ⁷⁷Se (supplemented) present in the samples. The proposed methodology was validated using serum and urine reference materials spiked with both ⁷⁷Se and ⁷⁴Se. The obtained results are discussed in terms of selenium exchange and half-life in lactating rats (11–12 days) and selenium levels in serum in comparison with non-supplemented rats and control rats after maternal feeding.     

Uptake and speciation of selenium in garlic cultivated in soil amended with symbiotic fungi (mycorrhiza) and selenate

The scope of the work was to investigate the influence of selenate fertilisation and the addition of symbiotic fungi (mycorrhiza) to soil on selenium and selenium species concentrations in garlic. The selenium species were extracted from garlic cultivated in experimental plots by proteolytic enzymes, which ensured liberation of selenium species contained in peptides or proteins. Separate extractions using an aqueous solution of enzyme-deactivating hydroxylamine hydrochloride counteracted the possible degradation of labile selenium species by enzymes (such as alliinase) that occur naturally in garlic. The selenium content in garlic, which was analysed by ICP–MS, showed that addition of mycorrhiza to the natural soil increased the selenium uptake by garlic tenfold to 15 μg g⁻¹ (dry mass). Fertilisation with selenate and addition of mycorrhiza strongly increased the selenium content in garlic to around one part per thousand. The parallel analysis of the sample extracts by cation exchange and reversed-phase HPLC with ICP–MS detection showed that γ-glutamyl-Se-methyl-selenocysteine amounted to 2/3, whereas methylselenocysteine, selenomethionine and selenate each amounted to a few percent of the total chromatographed selenium in all garlic samples. Se-allyl-selenocysteine and Se-propyl-selenocysteine, which are selenium analogues of biologically active sulfur-containing amino acids known to occur in garlic, were searched for but not detected in any of the extracts. The amendment of soil by mycorrhiza and/or by selenate increased the content of selenium but not the distribution of detected selenium species in garlic. Finally, the use of two-dimensional HPLC (size exclusion followed by reversed-phase) allowed the structural characterisation of γ-glutamyl-Se-methyl-selenocysteine and γ-glutamyl-Se-methyl-selenomethionine in isolated chromatographic fractions by quadrupole time-of-flight mass spectrometry.     

Profile of selenium in soil and crops in seleniferous area of Punjab,India by neutron activation analysis

In the Nawanshahr–Hoshiarpur region of Punjab, India, more than 1000 hectares of agricultural land is significantly affected by high levels of selenium (Se). Studies were carried out to examine Se levels in soil and crops such as wheat grains, wheat husk, rice, maize and mustard using neutron activation analysis. The Se concentrations in soil and crop products were found to be ranging from 2.7 to 6.5 mg kg⁻¹ and 13 to 670 mg kg⁻¹, respectively, indicating significantly high selenium in these crop products. Two reference materials were analysed for Se contents by INAA as controls.     

ESR study of radiation resistance of some aza- and thiacrown ethers at 77 K

The objective of this study was to determine if a stable enriched tracer of Se-76 could be used to establish the delay time between a dietary intake of selenium and its appearance in various matrices. Selenium, an essential trace element, has been investigated at the Missouri University Research Reactor (MURR) for several years. Several matrices have been studied to determine selenium status in humans; these include fingernails, toenails, blood, hair, and urine. A cohort of five women and seven men was utilized for this study. Each subject ingested selenium supplements which were enriched in Se-76 (96.48%). Fingernails, toenails, whole blood, and blood sera were collected as biochemical indicators. Selenium concentrations and glutathione peroxidase activities were determined in blood sera and whole blood to monitor the effect of the selenium supplement in these matrices. Selenium concentrations were determined in fingernails and toenails prior to supplementation and for several months afterward to determine the delay time for the appearance of selenium. The effects of the selenium supplement on the selenium concentrations of the fingernails, toenails, whole blood, and blood sera and the effect of the supplement on glutathione peroxidase activity will be reported.     

微量元素硒的检测方法进展

介绍了硒的各种检测方法，报道了它们在中草药、食品、环境和生物样品中的应用和检测结果．     

低硒克山病病区和非病区居民红细胞免疫功能的对比测定

对比测定了低硒克山病病区和非病区居民的红细胞免疫功能、血清红细胞免疫粘附调节因子和血硒含量。结果表明，低硒病区和非病区居民红细胞Ｃ３ｂＲ花环率和血硒水平显著低于对照非病区，而血清红细胞免疫粘附花环抑制率显著高于对照非病区；３组居民的红细胞免疫复合物花环率和血清红细胞免疫粘附花环促进率无明显差异；低硒病区和非病区居民上述各参数值均相似。研究说明，克山病病区居民红细胞免疫功能低下和血清红细胞免疫粘附抑     

硒的营养卫生及其检验方法

概述了微量元素硒在动、植物和人体内的分布、镉、硒拮抗及其对人体健康的影响，并介绍和比较了硒的测定方法。     

硒的土壤化学及其生物有效性

硒是重要的生命元素。高硒和低硒均会引起动物发生各种疾病，硒由土壤进入植物体，通过食物链控制着动物的硒营养状况，因此研究硒的土壤化学及其对生物的有效性对维护人类健康和牲畜生产是十分有意义的，本文拟就土壤中硒的含量、形态、有效性影响因素，硒的保健作用和调节措施等方面作一综述。     

Influence on elemental status by hip-endoprostheses

For many clinical purposes various artificial devices are applied, which contact human tissue and can thus cause adverse reactions between prosthetic surfaces and body components. Of the many materials applied for orthopaedic joint replacements the most common are cobalt-chromium-molybdenum alloys. In these cases considerable amounts of cobalt-chromium-molybdenum wear particles are released from the prostheses which have to be regarded as a cause of long-time problems for the patient.Since these particles are dissolved in body fluids of the surrounding area they are distributed in the whole body via blood. Elevated metal concentrations have been found in blood and urine of persons with endoprostheses. Partly the metals are excreted via urine, but to some extend they accumulate in different organs.Therefore this study dealt with the development of an analytical method for the determination of seven relevant trace elements, namely Al, Co, Cr, Mo, Nb, Ni, and Ti in nine kinds of human tissue (brain, heart, kidney, liver, lung, muscle, lymphatic nodes, spleen, body fat) starting with drawing of the sample, sample work up and finally analysis by means of atomic spectrometry. The optimized method was then applied to determine the metal contents in organs of persons (post mortem) with total hip replacements with metal on metal bearing surfaces. Comparison of the data obtained with those of persons without hip-endoprostheses shows that brain and lung are the main targets for elemental accumulation in persons with hip-endoprostheses. Mo and Nb represent the elements with the highest tendency to be accumulated.     

Low volume microwave digestion for the determination of selenium in marine biological tissues by graphite furnace atomic absorption spectroscopy

A microwave digestion method for the determination of marine biological tissues has been developed to allow determination of selenium in small sample sizes (< 0.1 g). The benefits of this technique include maintaining concentrates in extracts without the subsequent over dilution encountered when using larger vessels, increased sample throughput and reduced loss of volatile material. Freeze dried biological material (< 0.1 g) and nitric acid (1 ml) were placed into 7 ml screw top Teflon vessels which are completely sealed on capping. Two 7 ml vials were placed into larger 120 ml vessels fitted with a Teflon spacer and 10 ml of distilled water. The effects of microwave power and time, and sample mass on selenium recovery from three marine standard reference materials (NIST SRM 1566a Oyster Tissue, NRCC DORM-1 Dogfish Muscle and NRCC TORT-1 Lobster Hepatopancreas) were examined. The optimum conditions: 600 W, 2 min; 0 W, 2 min; 450 W, 45 min, allowed quantitative recoveries of selenium from these and three other standard reference materials (NRCC DOLT-1 Dogfish liver, NIST RM-50 Albacore tuna and IAEA MA-A-2 fish flesh). Studies on sample mass showed that the analysis of sample masses from 0.025 to 0.1 g gave selenium concentrations within the certified range. Six species of selenium: selenite, selenate, selenomethionine, selenocysteine, selenocystamine, and trimethyl selenonium were added to oyster, dogfish, and lobster tissues. Recoveries were near quantitative for all species (94–105%) except trimethyl selenonium (90–101%).