微柱分离-ICP-MS测定高纯氧化钆中14种稀土杂质

研究了采用自制微柱分离装置分离Gd2O3基体的条件。99．9％以上基体被分离，分离周期为36min。建立了高纯Gd2O3中分离Gd后测定Yb、Lu以及内标补偿法直接测定其它12种稀土杂质的ICP—MS分析方法.定量下限为0．08～0．80μg／g，加标回收率为85％～115％，相对标准偏差为1．1％～8．5％、方法可满足快速测定99．999％ Gd2O3中14种稀土杂质的要求。     

高纯氧化铈中稀土元素杂质的测定

使用特效萃取剂P538分离氧化铈,用JY38P型等离子光谱仪进行稀土元素杂质的测定,杂质总量的测定下限为3.6ppm。研究了输出功率、分离效率及非稀土杂质对测定的影响。方法精密度为12％相对误差小于15％     

植物中酞酸酯的分析测定研究

建立了二氯甲烷超声提取、小粒径硅胶住色谱项分离、UV-HPLC测定植物中酞酸酯的方法,简便、快速,可使酞酸酯与杂质有效分离,回收率为85％～101％。用于实际植物样品中酞酸酯的测定,结果满意。     

多波长线性回归导数分光光度法同时测定饮料中糖精钠和苯甲酸

测定了同时测定两组分的多波多线性回归导数分光光度法,无需进行化学分离。方法用于模拟样品和饮料样品中糖精钠和苯甲酸的同时测定,回收率为９８％￣１０１％,相对标准偏差〈３．０％。     

流动注射在线萃取色谱分离原子吸收光谱法测定痕量铂

研究了流动注射在线分离富集原子吸收光谱法测定痕量铂的方法。以自制的GDX501-TBP萃取树脂为微型分离柱，在优化后的分离富集条件下，进样时间为60s，洗脱时间为45s。在线分离测定时间为3min，方法检出限为0．25μg/L，线性范围10—600μg/L，加标回收率为97．8％-103．6％，相对标准偏差3．49％-4．25％。方法已用于矿物管理样中铂的测定。     

反相高效液相色谱法分析刺儿菜中维生素K_1

报道了用高效液相色谱法快速测定刺儿菜中维生素Ｋ１的方法。ＮｏｖａｐａｋＣ１８柱为分离柱,甲醇－异丙醇（７０３０）为流动相。方法操作简便,分离条件较好,回收率在９５％以上,变异系数小于１．２３％。     

在线柱分离ICP-MS测定高纯Eu2O3中Tm

报道了一种在线柱分离ICP－MS快速测定高纯氧化铕中杂质铥的方法，采用一种新型膦酸类萃取剂，大大降低了林洗酸度，洗脱液中的Tm直接进入ICP－MS进行在线测定。整个分离测定周期为40min，方法检出限为0．12ng/mL，加示加收率为91．5％－98％，RSD为4．1％，该方法快速，简便。用于高纯氧化铕中杂质铥的测定，结果满意。     

电泳毛细管的改性及其在酶和单克隆抗体分离分析中的应用

用壁处理办法对高性能毛细管电泳的毛细管柱进行改性,在Bio-Rad HPE-100中用肽测得组分的平均柱效为200000/m,使用寿命在200次以上。对纤维素酶.尿酶等一系列的样品作了分离和测定,尿酶5次重复测定的相对标准偏差小于1％。在10min内分离并测定了由细胞瘤培养的实际样品中的抗乙肝抗体(HBsAG),反映迁移时间重复性的相对标准偏差为1.87％,并作出了相应校正曲线。     

高效液相色谱法测定河道底泥中的多环芳烃

用高效液相色谱法分离测定河道底泥中的多环芳烃，通过梯度淋洗使多种多环芳烃完全分离，并分别得到14种多环芳烃的检出限和线性范围，被试验的4种多环芳烃的回收率为94.1％～103．1％，相对标准偏差为1.00％。2．87％（n=7）。用该方法对小清河东营段的实际底泥样品中多环芳烃的含量进行了测定。     

金属材料分析方法的选择和施行 第四讲：金属材料中钛的测定（续）

(2)变色酸光度法测定钢铁中钛(摘自NF A06-313-87) 适用范围:含钴、铜或钒量ω(％)<6％,钼量<2.5％,铌量<0.2％且不含钨的钢铁试样可不分离直接测定,超过规定范围的试样应经过树脂交换分离。 测定范围:ω(Ti)0.010％-3.00％ 方法提要:此标准方法分为两部分,第一部分为     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.