络天青S—CPB—Brij35胶束增溶吸光光度法测人发中微量铜

在阳离子表面活性剂ＣＰＢ和非离子表面活性剂Ｂｒｉｊ３５存在下,ｐＨ７．５的弱碱性介质中,二价铜离子与络天青Ｓ形成灵敏度高的１：２络合物。应用吸光度法测定人发中微量铜,铜含量在０．０２～２．０ｍｇ·Ｌ＾－１遵守比耳定律,方法检出限为限为０．０１ｍｇ·Ｌ＾－１,平均回收主继１００．５％±０．２１％,ＲＳＤ为０．２１％。此法用于人发中微量铜的测定。结果满意。     

氢化物发生—冷阱捕获—色谱分离—原子吸收法测定天然水中坤的形态

研究建立了氢化物发生－冷阱捕获－色谱分离－原子吸收方法测定天然水中四种主要砷形态，测试系统自行组装，色谱柱填料采用ＣｈｒｏｍｏｓｏｒｂＧＡＷ－ＤＭＣＳ（粒径０．３～０．４５ｍｍ），其上涂布３％ＯＶ－１０１。方法的检出限以砷计分别为：Ａｓ（Ｖ）０．５１ｎｇ，Ａｓ（Ⅲ）０．４３ｎｇ，ＭＭＡ０．３８ｎｇ，ＤＭＡ０．６７ｎｇ；１２ｎｇ砷标准偏差为Ａｓ（Ⅴ）４．２１％，Ａｓ（Ⅱ）３．５６％，ＭＭＡ３．２３％     

二极管阵列检测—偏最小二乘吸光光度法同时测定铜锌

研究了以２－（５－溴－２－噻唑偶氮）５－二乙氨基苯酚（５－Ｂｒ－ＰＡＤＡＰ）作显色剂,ＣＣＤ（Ｃｈａｒｇｅ Ｃｏｕｐｌｅｄ Ｄｅｖｉｃｅ,电荷耦器件）二极管阵列检测分光光度装置采及收光谱,用偏最小二乘法解析,同时测定了粮食中铜和锌。方法的线性范围锌为０．０５～０．４０μｇ．ｍｌ＾－１,铜为０．０２～０．６０μｇ．ｍｌ＾－１;检出限铜为０．０２μｇ．ｍｌ＾－１,平均加标回收率锌为９３．３％～９５．７     

用离子抑制色谱法分析二(2,2,6,6-四甲基-4-哌啶基)马来酸酯合成反应液

建立了用离子抑制色谱法分析二（２,２,６,６－四甲基－４－哌啶基）马来酸酯合成反应液的方法。平均回收率为９８．８％,相对标准偏差为０．５６％,测量的平均相对偏差不大于５．０％。方法简单、快速,可用于工艺条件的选择和质量检测。     

气相色谱／氢火焰检测器检测HL—60细胞DNA中氧化损伤产物8—羟基鸟嘌呤的

用０．４ｍｍｏｌ／ＬＨ２Ｏ２处理ＨＬ－６０细胞株２４ｈ,采用气相色谱／氢火焰检测器检测ＤＮＡ氧化损伤产物８－羟基鸟嘌呤,并用气相色谱－质谱仪选择性离子检测对其进一步鉴定。所用方法的平均回收率为８１．７％,ＲＳＤ小于５％。     

流动注射—二极管阵列检测分光光度法同时测定铅和镉

建立流动注射－电荷耦合器件二极管阵理分光光度法装置，研究了以ｍｅｓｏ－四（４－三甲铵苯基）卟啉为显色剂同时测定铅和镉的方法，镉和铅测定的线性范围为０～２．０ｍｇ／Ｌ和０～２．５ｍｇ／Ｌ镉的检出限为０．０１４ｍｇ／Ｌ，铅为０．０１５ｍｇ／Ｌ。进样频率为６０次／ｈ，对合成样品和陶瓷食具容器浸泡液中铅和镉进行了同时测定，获得满意的结果，样品的平均标准加入回收率为１００．９％，相对标准偏差小于８．８％。     

流动注射光度法同时测定血清中NO3^—和NO2^—

采用流动注射分析技术、以分光光度计为检测器,建立了同时测定血清中ＮＯ３和ＮＯ２的方法。以α－萘胺－７－磺酸为显色剂,在５２０ｎｍ比色,测定流路中装有锌－镉还原柱,将ＮＯ３在线还原为ＮＯ２。分析速度达４５样·ｈ＾－１,ＮＯ３和ＮＯ２的检出限分别为０．０１ｍｇ·Ｌ＾－１、０．００３ｍｇ·Ｌ＾－１,相对标准偏差分别为１．０％、０．５％。     

Zn—5Br—PAN—6S—Tritox X—100三元体系测定铝合金中微量锌

５Ｂｒ－ＰＡＮ－６Ｓ和Ｔｒｉｔｏｎ Ｘ－１００在ＰＨ８．８－９．０与锌形成三元配合物，其最大吸收峰在５８５ｎｍ处，表观摩尔吸光系数ε５８５为６．０５×１０＾４，在２５ｍＬ显色液中含锌５－３０μｇ，符合比耳定律。用于测定铝合金中微量锌，简便易行，其标准偏差在０．００７－０．０１２之间，相对标准偏差为１．４％－４．１％。     

流动注射—胶束荧光法快速测定葡萄糖中的微量铝

本提出Ａｌ－Ｃａｌｃｅｉｎ－ＣＴＭＡＢ－Ｔｗｅｅｎ－８０体系，用流动注射－胶束荧光法快速测定葡萄糖中微量铝的方法。荧光最大激发波长和发射波长分别为４７８．０和５０９．０ｎｍ．Ａｌ＾３＋的浓度在０－６μｇ／ｍＬ范围内标准曲线呈线性关系，方法检出下限为８．４２×１０＾－３μ／ｍＬ。方法已用于测定葡萄糖中微量铝，相对标准偏差为１％左右，回收率为９５－１０１％，进样频率为１４０次／ｈ，进样量为０．４４３     

5—（5—硝基—2—吡啶偶氮）—2,4—二氨基甲苯与钌的显色反应及其应用

报道以５－（５－硝基－２－吡啶偶氮）－２，４－二氨基甲苯（５－ＮＯ２－ＰＡＤＡＴ＿作为测定钌的分光光度法。在４０％乙醇存在下ＰＨ４．０－６．５乙酸－乙酸钠缓冲溶液中５－ＮＯ２－ＰＡＤＡＴ与Ｒｕ（Ⅱ）形成稳定的红色络合物。该络合物的无机酸作用下，可转变为另一型人有较高吸收特性的络合物，适宜酸度范围分别为０．１２－２．０ｍｏｌ／ＬＨＣｌ，０．１２－１．２ｍｏｌ／ＬＨＣｌＯ４，０．１２－１．０ｍｏｌ／Ｌ     

硒酵母中有机硒及硒代氨基酸含量的测定方法

报道了人工培养硒酵母中有机硒及硒代胱氨酸（ＳｅＣｙｓ）和硒代蛋氨酸（ＳｅＭｅｔ）含量的测定方法。采用透析处理法使硒酵母中的无机硒和有机硒得以分离,并采用催化分光光度法测定了硒酵母中有机硒的含量;采用氨基酸自动分析仪测定了硒酵母中ＳｅＣｙｓ和ＳｅＭｅｔ的含量。     

柱前衍生化-HPLC法测定恩施3种富硒蔬菜中硒氨基酸

采用HPLC与ICP-MS间隙联用的方法,以柱前衍生化-HPLC法进行定性定量分析,使用ICP-MS鉴定,建立一种富硒蔬菜中硒氨基酸的分离检测方法。结果表明:所测定的硒代氨基酸在其线性范围内呈现良好的线性关系(R2>0.999)。该方法中硒代蛋氨酸和硒代胱氨酸的检出限分别为0.204 mg/L和0.680 mg/L,加标回收率分别为97.4%和94.0%,RSD分别为2.1%和0.69%。检测恩施富硒蔬菜样品,白菜、萝卜叶和苋菜含有硒代蛋氨酸和硒代胱氨酸。此方法可用于富硒蔬菜中硒代氨基酸的含量检测。     

Selenium speciation by high-performance liquid chromatography with on-line detection by atomic absorption spectrometry

Several approaches to the determination of selenomethionine, selenocystine, selenite and selenate by high-performance liquid chromatography with online detection by atomic absorption spectrometry are described. The N?2,4-dinitrophenyl derivatives of selenomethionine, selenoethionine, selenocystine and phenylmercury(II) cystineselenoate were recovered from aqueous solution, separated on a Nucleosil 5-NO₂ reversed-phase HPLC column with a methanolic mobile phase containing acetic acid and triethylamine, and detected with a quartz thermochemical hydride-generating interface–atomic absorption spectrometry (AA) system. The restriction of having to perform chromatography with an organic mobile phase (to support the combusion process) was overcome with a new interface design capable of operation with either organic or aqueous HPLC mobile phases. Using aqueous acetic acid (0.015% v/v) containing 0.1% (w/v) ammonium acetate delivered at 0.5cm³ min^?1, selenate, selenite, selenomethionine, selenocystine and selenoethionine were separated virtually to baseline on a cyanopropyl-bonded phase HPLC column. Other selenium compounds which were investigated included methane seleninic and methane selenonic acids as well as the crude oxidation product mixtures resulting from the treatment of selenomethionine and selenocystine with hydrogen peroxide. A procedure for extracting selenate, selenite, selenomethionine, selenocystine and selenoethionine from spiked water or ground feed supplement into liquefied phenol resulted in acceptable recoveries for the latter four analytes but was unacceptably low for selenate.     

Selenium speciation in animal tissues after enzymatic digestion by high-performance liquid chromatography coupled to inductively coupled plasma mass spectrometry

A procedure is described for the enzymatic digestion of tuna and mussel samples that allows the determination of selenium species by high-performance liquid chromatography in conjunction with inductively coupled plasma mass spectrometry. The species were extracted by two-step enzymatic hydrolysis with a non-specific protease (subtilisin). The selenium species were separated on a Spherisorb 5 ODS/AMINO column using two different chromatographic conditions, namely phosphate buffers at pH 2.8 and pH 6.0 as mobile phases. The method determines organic (trimethylselenonium, selenocystine, selenomethionine and selenoethionine) and inorganic selenium species (selenite and selenate), but only organic selenium species were found in the samples. The sum of identified selenium species in the sample was about 30% of the total selenium present in the enzymatic extract despite the fact that recoveries of total hydrolysed selenium were 93-102%. Trimethylselenonium ion and selenomethionine were found in both tuna and mussel samples and an unknown selenium species was also found in tuna samples.     

Determination of Selenium Species in Cordyceps militaris by High-performance Liquid Chromatography Coupled to Hydride Generation Atomic Fluorescence Spectrometry

The purpose of this work is to develop a high-efficiency extraction method for determining the selenium species in Cordyceps militaris. Six extraction solutions, including hot water, HCl, methanol–water, ammonium acetate, protease XIV, and protease K, combined with ultrasound-assisted extraction, were utilized in the measurements. The selenium species in the extracts were separated and characterized by high-performance liquid chromatography. Their concentrations were subsequently determined by hydride generation atomic fluorescence spectrometry. The 25?mM ammonium acetate was selected as the extraction solution due to its advantages in cost and efficiency. Validation was performed, and the selenium species recoveries were 69–97% for selenocystine, selenite, selenomethionine, and selenate with good linearity and precision. The major selenium species in C. militaris were selenocystine and selenomethionine that accounted for almost 73.1?±?1.6% of the total selenium.     

Selenoamino acid speciation using HPLC–ETAAS following an enzymic hydrolysis of selenoprotein

A high-pressure liquid chromatography–electrothermal atomic absorption spectroscopy (HPLCETAAS) hyphenated technique was used for the determination of seleno compounds present in a selenium-enriched yeast. Conditions were optimized for the separation and quantification of the selenoamino acids, selenocystine and selenomethionine, in the presence of other compounds. The separation was achieved by ion-pairing chromatography using sodium heptanesulphonate as the anionic counterion. On-line detection was carried out using electrothermal atomic absorption with palladium(II) as a matrix modifier. Different extraction procedures were tested on a seleniumenriched yeast. A 92% recovery of the total selenium present in the material was obtained. Attempts to evaluate selenium speciation were carried out; selenomethionine and selenocystine were identified as the major components (42% and 35% respectively).     

超声辅助酶法提取-原子荧光光谱法测定富硒黑木耳中硒形态

建立了富硒黑木耳中硒代胱氨酸、硒代半胱氨酸、亚硒酸、硒蛋氨酸、硒酸5种硒形态的液相色谱-原子荧光光谱分析方法。通过链酶蛋白酶E酶解,结合超声提取后,选取Hamilton PRP-X100离子交换色谱柱(250 mm×4.1 mm,10μm),40 mmol/L的磷酸氢二铵为流动相,在16 min内,5种硒形态完全达到基线分离。5种硒形态在线性范围内相关系数R为0.9990~0.9999;加标回收率为76.1%~108%;检出限分别为硒代胱氨酸0.35μg/L、甲基-硒代半胱氨酸0.46μg/L、亚硒酸0.26μg/L、硒代蛋氨酸0.64μg/L、硒酸3.06μg/L;方法应用于富硒黑木耳中硒形态的分析,精密度高、重现性好、方法稳定、准确可靠,是测定富硒黑木耳中硒形态含量的有效方法。     

Retention study of inorganic and organic selenium compounds on a silica-based reversed phase column with mixed ion-pairing reagents

Summary Separation of seven inorganic and organic selenium compounds, namely selenic acid [Se(VI)], selenous acid [Se(IV)], trimethylselenonium iodide (TMSe⁺), selenocystine (SeCys), selenomethionine (SeMet), selenoethionine (Seet), and selenocystamine (SeCM), has been performed on a LiChrosorb C 18 column by using mixed ion-pair reagents; 1-butanesulfonic acid and tetramethylammonium hydroxide. Flame atomic absorption spectrometry (FAAS) was used as an element-specific detector. The retention behaviors of selenium compounds in terms of several chromatographic parameters, such as pH of the mobile phase, the concentrations of ion-pair reagents, and the content of organic modifier (methanol) were investigated. It was found that the separation of both inorganic and organic selenium compounds can be achieved within 12 min with a mobile phase of 10 mM 1-butanesulfonic acid −4 mM tetramethylammonium hydroxide −4 mM malonic acid −0.05% methanol adjusted to pH 4.5 at a flow rate of 1.0 mL min⁻¹. The results obtained in this study showed that the use of mixed ion-pair reagents is very useful to improve the separation of selenium compounds. The applicability of this technique for the speciation of selenium compounds in real samples was demonstrated by the determination of selenium compounds in a selenium nutritional supplement. The results were found to be in good agreement with those obtained by ion-exchange HPLC-ICP-MS.     

Speciation of selenoamino acids by on-line HPLC ETAA spectrometry

An analytical method was developed to determine selenoamino acids in the presence of other compounds. Separation has been achieved by High Performance Liquid Chromatography (HPLC) using electrothermal atomic absorption (ETAA) spectrometry as a very sensitive and element-specific detector. On-line HPLC ETAAS speciation of selenocystine and selenomethionine has been studied, using a laboratory made interface. Analytical characterization of the method has been realized with standard solutions. Using a 100μl sample loop, the detection limits were calculated as 8 μgl^?1 for selenomethionine and 10 μgl^?1 for selenocystine with repeatability and reproducibility of 4% and 7% respectively. The method has been applied to the determination of selenoamino acids in an extract of white clover (CRM402) certified for total selenium.     

ASSIMILATION,DISTRIBUTION, AND METABOLISM OF (75Se)-SELENITE,SELENATE, AND SELENOAMINO ACIDS BY ESCHERICHIA COLI

Abstract

Assimilation of selenium (Se) by Escherichia coli as (⁷⁵Se)-selenite, selenate, selenomethionine, selenocystine and Se?CH₃-selenocystine revealed that (a) selenoamino acids from a culture media are more completely assimilated than selenite or selenate and (b) that the amount of selenite is assimilated three to four times selenate. Most (>95%) of the Se assimilated by E. coli could not be solubilized by sonication and ethanol extraction but much (28% to 70%) of the Se, except Se from selenomethionine, was removed by alkaline dialysis. Se from selenocystine and from Se?CH₃-selenocystine dialyzed from intact cells, whereas Se from selenite and selenate did not. Dialyzable Se is that Se probably present in selenotrisulfide (R?S?Se?S?R) bonds or bound nonspecifically. Analysis of the soluble Se metabolites from selenite, selenate, selenomethionine and selenocystine showed that E. coli produces at least one major metabolic product common to all substrates which upon chromatography appeared to be selenocysteic acid. In monogastric animals selenite and selenate Se does not enter the primary protein structure as amino acids yet metabolites of selenite, selenate and selenocystine produced by E. coli could enter the primary protein structure of animals in minute amounts.