Simple and sensitive method for the determination of trace amounts of thorium using a benzoquinone derivative

A novel simple, sensitive, rapid, direct, and spectrophotometry-based procedure was investigated to determine Th(IV) at trace amounts. The new method is based on Th(IV) chelation with 3,6-dichloro-2,5-dihydroxy-l,4-benzoquinone(DDBQ). The reagent reacts with Th(IV) in 0.1 M HCl to form an orange 1:2 complex. The stability constant value is 6.62×10~4 for the Th(IV)complex. The Th(IV)-DDBQ obtained shows one peak with a maximum at about 346 nm. The chelate forms immediately and the absorbance remains stable for over24 h. Beer's law was obeyed in the concentration range0–10 μg mL^(-1). The molar absorptivity and Sandell's sensitivity were 4.4×10~4 L mol^(-1)cm^(-1) and 0.0053 μg cm^(-2), respectively. Different analytical parameters were tested in detail. Interfering ion(cations and anions) effects were tested. Methods for Th(IV) determination by second and third-derivative spectrophotometry were also introduced at about 344 and 341 nm, respectively. These two derivative orders offer the feature of sensitivity without the necessity for solvent extraction,heating, or pre-concentration steps. Finally, the methods were successfully utilized for Th(IV) determination in monazite, environmental water, and wastewater samples.

Preconcentration of Germanium(IV) on Styrene-Maleic Anhydride Copolymer Modified with Aminobenzoic Acids and Its Spectrophotometric Determination with Bis(2,3,4-trihydroxyphenylazo)benzidine

The styrene-maleic anhydride copolymer was chemically modi?ed, in the presence of formaldehyde, with 4-amino-2-hydroxybenzoic acid or 4-aminobenzoic acid giving sorbents S1 and S2, respectively. The specific sorption behaviour of S1 and S2 towards germanium(IV) was examined and optimized, the preconcentrated germanium(IV) after desorption being spectrophotometrically quantified with bis(2,3,4-trihydroxyphenylazo)benzidine in the presence of hexamethylenetetramine, phenanthroline and 2,2’-bipyridine. The dynamic sorption capacity and detection limits (3σ, n = 17) of germanium were found to be 152.2 and 127.1 mg·g–1, and 0.9 and 1.1 ng·mL–1, for S1 and S2, accordingly. The application of S1 and S2 was demonstrated for the selective preconcentration/determination of germanium in seawater and water obtained after oil pumping.

Determination of the Content of Astragaloside IV in Yikangshu Granules by High Performance Liquid Chromatography

[Objectives]The research aimed to establish a high performance liquid chromatography method for the content determination of astragaloside IV in Yikangshu Granules.[Methods]Kromasil 5μm C18(2),100 A,250 mm×4.6 mm was used;the mobile phase was acetonitrile-water(32∶68);flow velocity was 1.0 mL/min;the temperature of evaporator and sprayer was 80 and 30℃;the column temperature was set at 30℃,and injection volume was 20μL.[Results]Astragaloside IV showed a good linear relationship in the range of 1.01-10.14μg with the peak area,and regression equation was lgY=1.7728lgX+1.597(r=0.9999).The limit of detection for astragaloside IV was 1.96 ng,and the average recovery rate was 95.31%.[Conclusions]This method is sensitive,accurate and reproducible,with good linearity,and it is suitable for the content determination of astragaloside IV in health food Yikangshu Granules.

Th(IV)在高岭土上的吸附行为研究

采用静态批实验的方法,研究了接触时间、pH、离子强度、共存阳离子(Li^+,Na^+,K^+)/阴离子(CO_3^(2-),SO_^(2-)4,PO_4^(3-))、腐殖酸对Th(IV)在高岭土上吸附行为的影响。结果表明,pH和离子强度是影响Th(IV)在高岭土上吸附行为的重要因素,共存阳离子对吸附影响不大,而共存阴离子对吸附有较大的促进/抑制作用。在低pH条件下,HA促进Th(IV)在高岭土的吸附;随着pH升高,HA抑制吸附。表面络合和离子交换是Th(IV)在高岭土上吸附的主要机理。吸附等温线与Langmuir方程可以较好地拟合Th(IV)在高岭土上的吸附等温线。

制备方法对氧化石墨烯氧化程度及对Th(IV)、U(VI)吸附的影响

采用Hummers方法、优化Hummers方法及改进Hummers方法合成氧化石墨烯,并通过FT-IR、TGA、XRD、XPS、SEM以及元素分析等手段对制备产物进行了表征。结果表明,利用优化Hummers方法制备得到的氧化石墨烯具有较高的氧化程度。三种产物对Th(IV)、U(VI)的等温吸附实验结果表明,采用优化Hummers方法制备的氧化石墨烯对Th(IV)的最大吸附量为192.3 mg/g,相比于Hummers方法制备产物的吸附能力提高了38.5%;对U(VI)的最大吸附量为156.2 mg/g,吸附能力提高了28.1%,三种样品对Th(IV)、U(VI)的吸附都更加符合Langmuir等温吸附模型。此外,考察了优化Hummers方法制备的氧化石墨烯吸附Th(IV)、U(VI)的动力学和热力学参数,证实氧化石墨烯吸附Th(IV)、U(VI)符合准二级动力学方程,是自发吸热行为。

Fluorescence determination of platinum with dibromohydroxyphenyl-fluorone in microemulsion after separation and enrichment by sulfhydryl dextrose gel

A new fluorescence quenching method has been developed for the determination of platinum in nonionic microemulsion medium.This method is based on the fact that platinum can form a stable chelate with dibromohydroxyphenyl-fluorine（DBHPF） when they are in the molar ratio of 1：2 in the nonionic microemulsion medium.Under optimum conditions,the system,having the maximum excitation and emission wavelengths at 468 nm and 532 nm,respectively,shows constant fluorescence intensity in the pH range of 3.5-4.0 and high selectivity and sensitivity as well as low interference from foreign ions.Furthermore,this fluorescence intensity is a linear function of Pt（IV） concentration in the range of 0.002-1.00 μg·mL^-1 and the limit of detection is 2.90 ng·mL^-1.

Content Determination of Astragaloside Ⅳ in Astragalus from Three Different Regions by HPLC

[Objectives] The content of astragaloside in Astragalus membranaceus(Fisch.) Bge.var.mongholicus(Bge.) Hisao from three different regions was determined.[Methods] Referring to the method recorded in the Chinese Pharmacopoeia(2015 edition),the content of astragaloside IV in A.membranaceus was determined by HPLC.[Results] There were great differences in the astragaloside IV content of A.membranaceus among different regions.The content of astragaloside IV in A.membranaceus cultivated in Inner Mongolia was highest(0.155%),followed by that(0.143%) in A.membranaceus cultivated in Gansu,and the content of astragaloside IV in A.membranaceus cultivated in Shanxi was lowest(0.080%).The contents of astragaloside IV in A.membranaceus from different regions were all in line with the standard(not less than 0.040%) of Chinese Pharmacopoeia(2015 edition).[Conclusions]The content of astragaloside IV in A.membranaceus cultivated in three different regions met the medicinal standards.

响应面法优化改性β-环糊精聚轮烷对Th(IV)的动态吸附

通过使用响应面分析法(RSM)的Box-behnken设计来优化聚轮烷对Th(IV)的吸附过程,考察pH、吸附时间、初始浓度和吸附剂用量等因素对吸附过程的影响;同时对各种相互影响因素建模和拟合,并对实验数据进行处理。实验结果表明:各独立因素均为Th(IV)吸附过程的显著因素,通过相关系数和方差分析发现预测值和实验值基本一致,在pH值=3.72,吸附时间为35.4 min,钍离子初始浓度为22.8 mg/L,吸附剂用量为30 mg时,Th(IV)的最大吸附量为13.62 mg/g。Langmuir,Freundlich和Dubinin-Radusckevich(D-R)的等温吸附模型表明,吸附过程更符合Langmuir等温吸附模型,且为自发吸附过程。综上可知,聚轮烷在水相低浓度Th(IV)吸附方面是一种优良的吸附材料。

A RAPID FLUORIMETRIC DETERMINATION OF TYROSINE IN SERUM BY THE REACTION WITH CERIUM (Ⅳ)

A fluorimetric method for the determination of tyrosine in serum was proposed. The fluoriscence intensity is a linear function of tyrosine content in the range 0-1. 44ug/ml. The percentage of recovery was satisfactory.

RAP ID FIUORIMETRIC DETERMINATION OF TRYP TOP HAN BY THE R(?)ACTION WITH CERIUM (Ⅳ)

A flmorimetric method for determination of t typ top han was proposed. This method is very simple, rapid in determination of tryp top han in aqueous medium. The percentage of recovery was satisfactory.

THE STUDY ON THE WATER SOLUBLE PEPTIDES IN PAPAVER SOMNIFERUM POLLEN EXTRACTION,PURIFICATION,SEQUENCE DETERMINATION AND SYNTHESIS

Four peptides PSPP1,PSPP2,PSPP3 and PSPP4 were purified from the water-extract of Papaver somniferum pollen.Their sequences,with 21,17,13 and 16 amino acid residues respectively,have been determined by Edman degradation-N-terminal dansylation.PSPP2, PSPP3 and PSPP4 were synthesized using solid phase method.The immunopromotive activities of PSPP1,PSPP2,PSPP3,PSPP4 and the initially separated sample PSPP have been also observed by the methods of counting erythrocyte rosette forming cells(ERFC) and T-lymphocyte transformation test in vitro.

Extraction of Th(IV) from nitric acid with 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione

The BMPPT (4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione)was synthesized from BMPP. Its m.p. is 106-108℃. The results of the element analysis are as follows: C, 68.51%, H, 4.51%, N, 9.26%, S, 11.47%, which are in conformity with the theoretical value (C, 69.15%, H, 4.76%, N, 9.52%, S, 10.90%). The solvent extraction of Th4+ from nitric acid solution by BMPPT in benzene was studied. The extraction ability of BMPPT is not so high as that of its parent (BMPP). The Th4+ distribution ratio (DTh) increases with the increasing pH of the aqueous phase, and pH1/2 for Th4+ was 3.2 ([BMPPT]=0.10 mol/L). When the pH increases, the distribution ratio of Th4+ increases linearly with the slope of 1 .59. When the concentration of BMPPT increases, the distribution ratio of Th4+ increases rapidly. The lgDTh-lg[BMPPT] is linear with the slope of 1.42 and the extraction mechanism is the cation ion-exchange.

Th(Ⅳ)在高庙子膨润土上的吸附行为

采用静态批式法研究了Th(Ⅳ)在高庙子膨润土上的吸附行为。探讨了接触时间、pH、离子强度、固液比以及腐殖酸对吸附的影响。测定了293.15 K下的吸附等温线。实验结果表明,pH和离子强度对Th(Ⅳ)吸附的影响很大,腐殖酸在低pH下促进Th(Ⅳ)在高庙子膨润土上的吸附,而在高pH下几乎没有影响;Th(Ⅳ)在高庙子膨润土上的吸附主要通过表面络合和离子交换进行;Langmuir方程可以很好的拟合吸附等温线。

徐黄合剂的制备工艺优化及含量测定

优化徐黄合剂最佳提取工艺并建立制剂含量测定方法。以黄芪甲苷含量为提取工艺及含量测定评价指标,采用L_(9)(3^(4))正交试验法,选取加水量、煎煮时间及煎煮次数为考察因素确定最佳提取工艺,并考察常压浓缩和减压浓缩对黄芪甲苷含量的影响。另外建立黄芪甲苷高效液相色谱测定方法并进行方法学考察。结果显示,最佳提取工艺为加6倍量水,沸后提取1 h,提取2次;两种不同的浓缩方法对制剂含量影响无显著性差异;黄芪甲苷在0.048 16~0.963 20 mg/mL范围内线性关系良好,阴性样品无干扰,精密度、重复性、稳定性测得的RSD<3%;平均加样回收率为101.85%(RSD=2.54%,n=9),表明该含量测定方法灵敏、准确。

海水中^(234)Th的超低水平液闪谱仪测定

本文提出了利用超低水平液闪谱仪测定海水中234Th的方法.海水经氢氧化铁吸附共沉淀富集后,接着用阴离子交换和TBP/煤油萃取进行Th同位素的分离与纯化.对一系列测定条件进行了详细的研究,提出了测定海水中234Th的适宜程序,即在含有234Th和产额示踪剂230Th的纯化后的5mol/dm3HNO3溶液中加入TBP/煤油进行萃取,然后用0.1mol/dm3HNO3反萃取,后者是先用契伦柯夫计数法测量234Th(通过234mPa),后加入闪烁液Hisafe3用α/β模式测量α放射体230Th.对于α和β放射体液闪谱仪的计数效率分别为100%和55.7%±2.7%.234Th的化学回收率和总探测效率分别为70%～80%和30%～45%.该法测定海水中的234Th快速、简便和高效.

海洋样品中^(231)Pa和U,Th同位素的联合分离测定

本文结合已报道的U,Th分离方法和^(231)Pa分离条件建立了Th-Pa-U联合分离流程和测试技术,并用以分离测定一个锰结核和一个深海沉积物样品中的^(231)Pa,U和Th同位素含量的深度分布。用^(231)pa_(ex),^(230)Th_(ex)和^(230)Th_(ex)/^(232)Th法分别计算该锰结核的生长速率为1.5,0.9和1.5mm/Ma。U,Th和^(231)Pa的化学回收率(％)分别为40—80,80—92和60—86。

不平衡铀系定年的新技术突破──高精度、高灵敏度￣（238）U—￣（234）U—￣（230）Th同位素质谱测定和应用

８０年代中期发展起来的高精度、高灵敏度不平衡铀系热电离质谱定年新技术是同位素定年技术的一次革命性突破，并已在古气候、古环境、古海洋、考古学以及近代火山—岩浆作用研究中取得了一系列重要成果，本文介绍了这方面的研究进展。这一新技术已引起越来越广泛的重视，显示出巨大的应用前景。尽快开展不平衡铀系热电离质谱定年技术的应用，对提高我国的高分辩率第四纪年代学分析技术和应用研究水平有重要意义。

Th(Ⅳ)盐沉淀-EDTA滴定法快速测定污水中总磷研究

研究了快速测定污水中磷含量的Th（Ⅳ）盐沉淀-EDTA滴定的分析方法。水样用HNO3及H2SO4消解为PO4^3-并在掩蔽干扰离子后的酸性溶液中，先加入已知量且过量的Th（NO3）4标准溶液．当Th、（PO4）4沉淀完全并在pH2-3滤液中。以二甲酚橙为指示剂，用乙二胺四乙酸二钠盐（EDTA）标准溶液滴定剩余的Th（NO3）4至终点、测定结果的相对标准偏差小于2．5％，加标回收率在94．7%-101．2％之间。结果表明，改进后的方法简单、快捷、干扰小．测定结果与国家标准方法相符，相对偏差均小于2．0％。