粮食、人血中硒蛋氨酸含量测定

利用溴化氰—荧光法对玉米、大米、小麦、大豆和人血中痕量硒蛋氨酸进行了测定，玉米中硒蛋氨酸含量９．２～１９０１４．１ｎｇ／ｇ，其硒蛋氨酸的硒占总硒的比率为４５．５％～８２．０％。同样，大米、小麦和大豆中硒蛋氨酸的硒占各自总硒含量的５４．９％～８６．５％，５０．４％～８１．４％，６２．９％～７１．８％。这些结果表明硒蛋氨酸是所测粮食样品中硒的主要化学形式。血硒含量为５６．４ｎｇ／ｇ和６３．７ｎｇ／ｇ的样品中硒蛋氨酸含量的２８．３ｎｇ／ｇ和５３．４ｎｇ／ｇ，占总硒的２０．２％及３３．８％。     

三氯化铁比色法测定植酸含量的研究

大豆及其加工制品用１．２％ＨＣｌ１０％Ｎａ２ＳＯ４试剂提取，１５％ＴＣＡ试剂沉淀酸性蛋白质，０．７５ｍｏｌ／ＬＮａＯＨ调节上清液ｐＨ值到６．０～６．５，用０．３％磺基水杨酸０．０３％ＦｅＣｌ３６Ｈ２Ｏ试剂比色，于可见光５００ｎｍ处检测，并用标准加入法进行定量分析。结果，测定一种样品１０次变异系数为３．３３％，７种样品回收率范围为８９．８８％～１０３．３８％，１５种样品植酸含量为０．５１％～１．９２％。     

大气中痕量萘的毛细管气相色谱测定法

研究用硅胶管采样，ＣＳ２解吸，ＳＥ－３０毛细管气相色谱ＦＩＤ检测器测定大气中痕量萘，结果表明，检测下限为０．００４ｎｇ，ＲＳＤ为１．５％～７．７％，回收率为９２．３％～９７．６％，解吸效率在９６．２％以上。样品在室温下至少保持３天萘浓度不变     

HCl—NaBH4—K3Fe（CN）6体系气态原子吸收光谱法测定饮料中铅

采用ＶＡ－９０气态原子化装置与ＷＦＸ－１Ｄ原子吸收分光光度计联用测定饮料中铅，采用ＨＣｌ－ＮａＢＨ４－Ｋ３Ｆｅ（ＣＮ）６体系，经Ｌ９（３４）正交试验选择最佳实验条件为：ＮａＢＨ４２０ｇ／Ｌ，Ｋ３Ｆｅ（ＣＮ）６１００ｇ／Ｌ，ＨＣｌ１．５ｍｌ，氩气流量为０．８Ｌ／ｍｉｎ。在０～１００μｇ／Ｌ范围内，相关系数ｒ＝０．９９９６，回收率为９４．１％～１０７．５％，Ｒ·Ｓ·Ｄ％＝３．３～５．２特征浓度和检出限分别为１．２９μｇ／Ｌ／１％和０．０４９μｇ／Ｌ。干扰试验表明，Ｓｎ、Ｈｇ、Ｃｒ、Ｃｕ、Ｍｎ在５００μｇ／Ｌ以下，Ｚｎ、Ａｓ、Ｆｅ、Ｎｉ、Ａｇ在１０００μｇ／Ｌ以下，不干扰测定     

中药中7种微量元素的测定

用原子吸收分光光度法测定莲子、麦冬、山药、甘草、女贞子、当归６种中药中的Ｆｅ、Ｚｎ、Ｃａ、Ｎａ、Ｋ、Ｍｎ、Ｃｕ７种微量元素的含量，回收率在９２．５％～１０５％，ＲＳＤ为０．２％～３．３％，结果满意。     

发硒的催化动力学方法测定

用硒催化Ｎａ２Ｓ．用次甲基蓝的退色反应测定发中硒．催化反应时间与硒含量线０．１～１．０μｇ的范围内。催化反应时间与硒食量线性关系良好，精密度和准确度均很理想，ＣＶ为７．３％，回收率为８７．５～１０６％。     

某些地方性疾病地区环境中硒的研究──硒的水平及形态

于全国８省市自治区内克山病、大骨节病氟中毒和硒中毒等地方病区，癌症和肝炎地区性的高发区及正常地区内的３０个调查点，采集空气、水、土壤等环境样品，分析硒水平及硒存在形态。调查结果为空气硒：室内以陕西永寿大骨节病区最低３．３ｎｇ／ｍ３，湖北建始县硒中毒区最高６１４．２μｇ／ｍ３；室外空气硒浓度以云南宣威肺癌多发区最低为０．３ｎｇ／ｍ３，仍是建始县的最高３７１．１ｎｇ／ｍ３；室内外空气颗粒物中硒９０％存于＞１０μｍ的细颗粒物中。室外空气中气态硒的百分比（均值为２３．３％）高于室内（均值为９．７％）；颗粒物中不同价态硒分布云南的以Ｓｅ（Ⅵ）为主占６３．５％，陕西以Ｓｅ（Ⅳ）为主占５６．７％，湖北的以Ｓｅ（＜Ⅳ）为主占７９．５％，土壤硒为５８（克山病区）～９０３７ｎｇ／ｇ（硒中毒区），水溶性硒占总硒的百分比以硒中毒、氟中毒、克山病及大骨节病等地区较低，多在５％以下，其它地区的较高，多在１０％以上；其不同价态硒的百分比分布与空气颗粒物的基本一致。水中硒含量大部分在０．３ｎｇ／Ｌ以下，只有高硒和硒中毒地区为１～６８３ｎｇ／Ｌ。不同价态硒的百分比的分布以Ｓｅ（Ⅵ）为主均值７１．４％，Ｓｅ（Ⅳ）均值１８．５％，Ｓｅ（＜Ⅳ）均?     

荧光光度法测定全血硒的研究

本文介绍用２,３—二氨基萘荧光法在９３０荧光光度计上测定全血硒的探讨,最低检出限为７．９９ｎｇ。用０～０．２００μｇ硒的标准溶液做反复测定,其相关系数为０．９９９６,检出值的相对标准差为３．２～９．２％。测定全血中硒含量的相对标准差为１４．５％,平均...     

示波极谱法测定口服液中微量锗

本文采用回流消化法处理样品。选用Ｈ２ＳＯ４—焦性没食子酸—钒（ＩＶ）—ＥＤＴＡ—抗坏血酸体系。锗与焦性没食子酸络合产生灵敏的极谱波，测定口服液中微量锗，使方法的灵敏度显著提高。锗浓度在０～４ｎｇ／ｍｌ范围内与峰高呈良好的线性关系（γ≥０．９９９）。样品加标回收率为８０．４％～１１９．７％，相对标准偏差为１．６％～３．０５％。用本法对市售有机锗饮料进行测定，结果令人满意。     

亚硒酸钠与硒蛋氨酸对砷诱导人外周血淋巴细胞遗传毒性保护作用比较

为了探讨硒作为拮抗砷毒害的化学干预剂，拮抗砷对机体损伤，降低肿瘤发病率的机理，我们采用ＳＣＥ实验和ＤＮＡ合成抑制实验，研究证实预加５×１０－７、１×１０－６ｍｏｌ／ＬＮａ２ＳｅＯ３和同时加１×１０－６ｍｏｌ／Ｌ硒蛋氨酸能明显减轻Ａｓ２Ｏ３诱导人外周血淋巴细胞ＳＣＥ频率。预加５×１０－６ｍｏｌ／ＬＮａ２ＳｅＯ３和同时加１×１０－６、５×１０－６ｍｏｌ／Ｌ硒蛋氨酸能明显拮抗Ａｓ２Ｏ３对ＤＮＡ合成抑制作用。硒对砷损伤人细胞遗传物质保护作用的机理尚待进一步研究。     

Metabolism of selenite and selenomethionine in the rhesus monkey

Female rhesus monkeys were fed a commercial monkey diet and given selenium (Se) as either selenite or selenomethionine (SeMet) in the drinking water for 11 mo. Muscle and liver biopsies were taken initially and at the end of the experiment for determination of Se levels and glutathione peroxidase (GPX) activity. Blood was collected at monthly to bimonthly intervals, and the plasma and erythrocytes were subjected to gel filtration to determine the distribution of Se among proteins of various molecular weights. At the end of the experiment, there was significantly more Se in liver, muscle and hair from the monkeys given SeMet than in tissues from those given selenite, but there were no differences in liver or muscle GPX activity between the two treatment groups. The erythrocyte and plasma Se levels were significantly higher in the monkeys given SeMet than in those receiving selenite, but there were no differences in the GPX levels between these groups. About 68% of erythrocyte Se was associated with GPX in monkeys given selenite whereas only 34% was associated with GPX in those administered SeMet. The correlation coefficient for blood Se level and erythrocyte GPX activity was 0.92 in monkeys given selenite but only 0.37 in those given SeMet. Gel filtration of plasma revealed only one Se peak for plasma from the monkeys given selenite but at least two major Se peaks for plasma from monkeys receiving SeMet. The possible implications of these results for humans are discussed, including the reasons for poor correlations of GPX activity and blood Se levels.     

Selenium bioavailability from buckwheat bran in rats fed a modified AIN-93G torula yeast-based diet

Selenium (Se) is an essential nutrient for humans and animals. The Se RDA for adult humans is 55 mug/d; however, dietary amounts as high as 200 mug/d in the highly available form of selenomethionine in yeast were shown to reduce the incidence of certain cancers. A number of natural foods contain relatively high amounts of Se; for the most part, however, the availability of food Se for absorption and utilization is unknown. This experiment was conducted to determine the bioavailability of Se from a high-protein, high-fiber bran-isolate of buckwheat groats that contains Se. The method used was based on the ability of Se from buckwheat bran to restore Se-dependent enzyme activities and tissue Se concentrations in Se-deficient rats. The responses produced from buckwheat bran Se were compared with a standard response curve generated by feeding graded amounts of Se as sodium selenite (Na(2)SeO(3); Na selenite) or selenomethionine (SeMet) in a newly reformulated AIN-93G-Torula yeast diet with a more balanced nutrient composition than older diets of this nature. Relative bioavailability was determined by using the slope-ratio assay method for enzyme data, or the parallel lines assay method for tissue Se concentration data. Results showed that Se availability from buckwheat bran based on the restoration of plasma Se was 70-80% as high as Na selenite or SeMet. However, when based on the restoration of muscle Se, buckwheat bran was 90% as high as Na selenite, but only 60% as high as SeMet. When using the ability of dietary Se to restore whole blood and liver glutathione peroxidase activity, buckwheat bran Se was 75-80% as high as Na selenite or SeMet. However, for the restoration of liver thioredoxin reductase, buckwheat bran Se was only 40% as high as Na selenite and 70% as high as SeMet. The relative bioavailability of Se from buckwheat bran with all variables considered was approximately 73% whether measured against Na selenite or SeMet. Although some variables indicated low bioavailability of Se from buckwheat bran, other factors such as Se speciation in the bran, digestibility of the bran, the cooking process, and combinations with other foods in the diet should be considered and analyzed before firm conclusions can be reached.     

水及食品中微量镉的微波消解氢化物发生-原子荧光光谱测定法

目的 探讨生活饮用水及食品中微量镉的微波消解氢化物发生原子荧光光谱测定法.方法 样品经微波消解后,以硼氢化钾为还原剂,稀盐酸为载流,加入钴离子,使镉与硼氢化钾反应生成镉的挥发性物质,以原子荧光光谱法进行测定.并探讨了实验条件.结果 方法的线性范围为0.1～100 ng/ml(r＞0.999 3),检出限为0.1 ng/ml,回收率为96.9%～104.0%,RSD为1.54%～2.03%.结论 该方法灵敏度高、选择性好、操作方便、快速,适用于批量样品分析.

Abstract：

Objective To develop a method for the determination of trace cadmium in drinking water or food using microwave digestion-hydride generation-atomic fluorescence spectrometry. Methods The microwave digestion method was used. Cobalt was added in the carrying liquid, the cadmium volatile matter was determined by atomic fluorescence spectrometry. Results The detection limit of this method was 0.1 ng/ml ,the liner range of cadmium was 0.1-100 ng/ml (r>0.999 3), the recovery rate was 96.9%-104.0%,RSD was 1.54%-2.03%. Conclusion The method is simple and rapid, with good sensitivity and selectivity, and it is applicable to the determination of trace cadmium in drinking water or food.     

Differential responses to selenomethionine supplementation by sex and genotype in healthy adults

A year-long intervention trial was conducted to characterise the responses of multiple biomarkers of Se status in healthy American adults to supplemental selenomethionine (SeMet) and to identify factors affecting those responses. A total of 261 men and women were randomised to four doses of Se (0, 50, 100 or 200 μg/d as L-SeMet) for 12 months. Responses of several biomarkers of Se status (plasma Se, serum selenoprotein P (SEPP1), plasma glutathione peroxidase activity (GPX3), buccal cell Se, urinary Se) were determined relative to genotype of four selenoproteins (GPX1, GPX3, SEPP1, selenoprotein 15), dietary Se intake and parameters of single-carbon metabolism. Results showed that supplemental SeMet did not affect GPX3 activity or SEPP1 concentration, but produced significant, dose-dependent increases in the Se contents of plasma, urine and buccal cells, each of which plateaued by 9-12 months and was linearly related to effective Se dose (μg/d per kg0·75). The increase in urinary Se excretion was greater for women than men, and for individuals of the GPX1 679 T/T genotype than for those of the GPX1 679 C/C genotype. It is concluded that the most responsive Se-biomarkers in this non-deficient cohort were those related to body Se pools: plasma, buccal cell and urinary Se concentrations. Changes in plasma Se resulted from increases in its non-specific component and were affected by both sex and GPX1 genotype. In a cohort of relatively high Se status, the Se intake (as SeMet) required to support plasma Se concentration at a target level (Se(pl-target)) is: Se(in) = [(Se(pl - target) - Se(pl))/(18.2ng d kg?.??/ml per mu g)] .     

微波消解—原子荧光光谱法测定富硒精米中硒

目的建立微波消解—氢化物发生原子荧光光谱法测定富硒精米中硒的方法。方法富硒精米样品经微波消解后,用氢化物原子荧光光谱法测定富硒精米中硒的浓度。结果本法在硒浓度为0～10μg/L范围有良好的线性关系,相关系数r=0.9997,检出限为0.002 mg/kg;相对偏差为0.57%～2.7%;回收率为99.8%～101.0%。结论该方法具有简便、快速、灵敏度高等优点,适合日常批量检测。     

膳食维生素B_6对硒的生物利用率影响的研究──Ⅲ．对成年大鼠组织中硒和谷胱甘肽过氧化物酶水平的影响

１２周龄雄性大鼠饲缺维生素Ｂ６（ＶＢ６）缺硒酪蛋白蔗糖基础膳食，３周后按体重把动物分成６组。分别喂饲三种膳食，即基础膳食、基础膳食中补充硒０．２５ｍｇ／ｋｇ的亚硒酸钠或ＤＬ－硒蛋氨酸，在此基础上每种膳食又分为补充（２．５μｇ／ｇ）或不补充盐酸吡哆醇两组。实验期为１４周。补Ｖ８６各组的红细胞和骨骼肌中硒水平和谷胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ）活性均显著高于相应缺ＶＢ６各组，ＶＢ６对饲亚硒酸钠大鼠肝硒和ＧＳＨ－Ｐｘ水平没有影响；但当补充硒蛋氨酸时，与补ＶＢ６大鼠相比缺ＶＢ６大鼠的肝硒水平较高而ＧＳＨ－Ｐｘ活性则显著降低。这些研究结果进一步证明，ＶＢ６与血浆硒的转运和硒的利用有关，并且可能参与了硒蛋氨酸在肝脏中的代谢过程。     

Selenium from selenium-rich Spirulina is less bioavailable than selenium from sodium selenite and selenomethionine in selenium-deficient rats

The bioavailabilty of selenium (Se) from selenium-rich Spirulina (SeSp) was assessed in Se-deficient rats by measuring tissue Se accumulation and glutathione peroxidase (GSH-Px) activity. For 42 d, rats were subjected to dietary Se depletion by consumption of a Torula yeast (TY)-based diet with no Se; controls were fed the same diet supplemented with 75 microg Se/kg diet as sodium selenite. Se-deficient rats were then repleted with Se (75 microg/kg) by the addition of sodium selenite, selenomethionine (SeMet) or SeSp to the TY basal diet. Selenium speciation in SeSp emphasized the quasi-absence of selenite (2% of total Se); organic Se comprised SeMet (approximately 18%), with the majority present in the form of two selenoproteins (20-30 kDa and 80 kDa). Gross absorption of Se from SeSp was significantly lower than from free SeMet and sodium selenite. SeMet was less effective than sodium selenite in restoring Se concentration in the liver but not in kidney. SeSp was always much less effective. Similarly, Se from SeSp was less effective than the other forms of Se in restoring GSH-Px activity, except in plasma and red blood cells where no differences were noted among the three sources. This was confirmed by measuring the bioavailability of Se by slope-ratio analysis using selenite as the reference form of Se. Although Se from SeSp did not replenish Se concentration and GSH-Px activity in most tissues to the same degree as the other forms of Se, we conclude that it is biologically useful and differently metabolized due to its chemical form.     

食物及饲料中泛酸的测定

建立食物及饲料中泛酸的微生物测定法。利用Lactobacillusplantarum(ATCC 80 14)的生长对泛酸的依赖性 ,通过光密度法测定细菌生长和繁殖的强度来间接地测定食物或饲料样品中的泛酸含量。本方法的灵敏度为 0 5 μg L。批内RSD为 2 8%～ 6 0 % ,批间RSD为 3 0 %～ 5 7% ,回收率为 90 2 %～ 10 5 8% ,RSD为 2 8%～ 5 9%。本方法重现性好、准确度高 ,适用于各种食物及饲料中泛酸的测定     

PXC和EMR-Lipid QuEChERs技术在动物源性食品中多种β-受体激动剂残留检测的前处理效果对比

目的 比较PXC和EMR-Lipid QuEChERs(简称EMR-L)萃取法对动物源性食品中多种β-受体激动剂残留检测效果的影响.方法 利用UPLC-MS/MS分析技术,使用PXC固相萃取小柱和EMR-Lipid QuEChER两种前处理材料,对相同样品的检测结果进行对比和分析.结果 两种前处理方法在0.5～10 n...