钨(Ⅵ)-2-羟基-3-甲氧基苯基荧光酮-溴化十六烷基三甲铵体系显色反应及其应用

研究了在溴化十六烷基三甲胺(CTMAB)存在下,2-羟基-3-甲氧基苯基荧光酮与钨(Ⅵ)显色反应的条件。结果表明,在0.32 mol/L硫酸介质中,2-羟基-3-甲氧基苯基荧光酮与钨(Ⅵ)形成一种桔红色的络合物,其最大吸收峰位于516 nm,表观摩尔吸光系数为1.3×105L.mol-1.cm-1,在25 mL溶液中,钨量在0~12μg范围内符合比尔定律。分析方法可用于合金钢中微量钨的测定,相对标准偏差为1.6%~5.3%,结果与认定值相符合。     

钇—8-羟基喹啉—表面活性剂三元体系中的荧光反应

荧光光度法测定钐,铕和铽已有报道,但对钇的报导尚不多见。 本文较为系统地研究了钇—8—羟基喹啉(QX)溴化十六烷基三甲基铵(CTMAB)三元体系中的荧光反应,并拟定了可供实用的测定方法。 一、主要试剂与仪器 实验中配制标准溶液用的Y_2O_3纯度为99.99％,以盐酸溶解之,其余试剂均为分析纯。 测量仪器为日立MPF-4型荧光分光光度计及pHS-2型酸度计。     

9-(2-羟基-5-偶氮对甲苯)苯基荧光酮与钼显色反应的研究及应用

合成了新显色剂9-(2-羟基-5-偶氮对甲苯)苯基荧光酮(HMAPPF),并采用红外、核磁和质谱分析确定其分子结构。在研究新试剂与钼Ⅵ显色反应基础上,建立了测定合金钢中微量钼的光度分析方法。在盐酸、磷酸及CTMAB存在下,钼Ⅵ与HMAPPF室温立即反应,生成红色络合物,体系至少可以稳定12h以上。钼络合物的最大吸收峰位于522nm,表观摩尔吸光系数达1.54×105L.mol-1.cm-1,在25mL溶液中,钼Ⅵ量在0～12μg范围内符合比尔定律。此外,该显色反应体系具有良好的选择性,绝大多数金属离子有较     

9-(3,5-二溴)水杨基荧光酮—钼—CTMAB三元络合物显色反应的研究及应用

本文研究了9-(3,5-二溴)水杨基荧光酮(简称DBSF)—钼—CTMAB显色反应的主要条件,它是一种新的三元络合物体系,λmax在527nm,但试剂λmax为467nm,对比度为60nm,ε=1.44×10~5。荧光酮类显色剂与金属离子的反应大多数是在弱骏(或弱碱)液中进行,但与钼可在强酸介质中显色,选择性好,可不必分离,加入抗坏血酸掩蔽大量的铁,测定合金钢中的钼,获得了很满意的结果。     

4,5-二溴苯基荧光酮—溴化十六烷基三甲铵荧光猝灭法测定微量钽的研究

本文提出了用4,5-二溴苯基荧光酮和CTMAB荧光猝灭法测定微量钽高灵敏度的分析方法,激发波长和发射波长分别为400nm和510nm,当Ta_2O_5的含量在0～8μg/25ml范围内,线性关系良好.直线回归方程为:y=100-4.05x,线性相关系数r=0.9995,对8份样品平行测定,相对标准偏差为4%,用本法测定样品中的微量钽,结果满意     

新试剂3,5-二溴-4-偶氮-8-羟基喹啉苯基荧光酮与锆(Ⅳ)显色反应的研究及应用

研究了新显色剂3,5-二溴-4-偶氮-8-羟基喹啉苯基荧光酮(DBAHQPF)在溴化十六烷基三甲铵(CTMAB)存在下,与锆(Ⅳ)形成红色络合物的条件,其λ_(max)~(MR)=538nm,ε_538nm=1.72×10~5,锆(Ⅳ)浓度在0～10μg/25ml 范围内服从比尔定律。拟定方法已用于直接测定铝合金样品中痕量锫,结果满意。     

对氯苯基荧光酮光度法测定微量铝

研究了在表面活性剂溴化十六烷基三甲铵(CTMAB)存在下,铝(Ⅲ)与对氯苯基荧光酮(pClPF)的显色反应和光度性质。在 pH6.0的 HAc-NaAc 缓冲溶液中,铝(Ⅲ)与试剂形成1:2的络合物。络合物在波长563nm 处的表观摩尔吸光系数ε=1.10×10~5。铝(Ⅲ)含量在0～6.0μg/25ml 范围内符合比尔定律。拟定方法法用于铝铁黄铜及石灰石样品中微量铝的测定,结果满意。     

5-安替比林偶氮水杨基荧光酮的合成及其与钨显色反应的研究

报道了新试剂5-安替比林偶氮水杨基荧光酮(APASF)的合成方法,研究了在表面活性剂十六烷基三甲基溴化铵(CTMAB)存在下试剂与钨的显色反应。将4-氨基安替比林重氮化制得重氮盐溶液,然后水杨醛与重氮盐反应合成安替比林偶氮水杨醛,将事先合成的偏三酚三乙酸酯与安替比林偶氮水杨醛反应合成APASF,并用红外光谱分析法对其进行表征。产率为40%。在酸性介质中,表面活性剂十六烷基三甲基溴化铵(CTMAB)存在下,试剂与钨生成络合物的最大吸收波长为520 nm,表观摩尔吸光系数为7.4×104L.mol-1.cm-1,钨的质量浓度在0.1～1.0μg/mL范围内符合比尔定律。方法用于标准钢样中钨的测定,测得值与认定值相符。     

镧Ⅲ-9-(3,5-二溴)水杨基荧光酮-溴化十六烷基三甲铵三元络合物显色反应的研究与应用

研究了在阳离子表面活性剂溴化十六烷基三甲铵(CTMAB)存在下,9-(3,5-二溴)水杨基荧光酮(DBSAF)与镧(的显色反应及光度性能,建立了测定镧(的新方法。在pH 10.5NH3.H2O-NH4Cl缓冲溶液中,La(与DBSAF及CTMAB形成摩尔比为1∶2∶4的紫红色三元络合物,其最大吸收峰位于566.0 nm波长处,表观摩尔吸光系数为1.03×105L.mol-1.cm-1,在25 mL溶液中镧(量在0~24μg范围内符合比尔定律。该法已用于电子工业钛酸镧烧结中游离氧化镧的测定。     

3,5-二溴-4-氨基苯基荧光酮与铬显色反应及其应用

研究了在CTMAB存在下,3,5-二溴-4-氨基苯基荧光酮(DBAPF)与铬(Ⅵ)的显色反应条件和光度性质,确定在pH5.0～6.5范围内,铬(Ⅵ)与试剂形成稳定的1:2络合物,其最大吸收波长为589nm,表观摩尔吸光系数为1.36×10~5L·mol~(-1)·cm~(-1),铬(Ⅵ)浓度在0～11μg/25ml范围内符合比尔定律。拟定方法用于普钢样品中铬的测定,结果满意。     

4，5－二溴邻硝基苯基荧光酮光度法测定微量镓

研究了镓与4,5-二溴邻硝基苯基荧光酮（DBON-PF）的显色反应,在盐酸—氯化钾介质中,有CTMAB存在下,显色反应灵敏,镓与DBON-PF络合物的最大吸收波长在757nm,络合物的表观摩尔吸光系数ε＝8.2×10     

Heteroaryl analogues of AMPA. 2. Synthesis, absolute stereochemistry, photochemistry, and structure-activity relationships

We have previously shown that (S)-2-amino-3-(3-hydroxy-5-phenyl-4-isoxazolyl)propionic acid [(S)-APPA, 2] is a weak agonist at (RS)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptors, specifically activated by (S)-AMPA (1), whereas (S)-2-amino-3-[3-hydroxy-5-(2-pyridyl)-4-isoxazolyl]propionic acid [(S)-2-Py-AMPA, 5] and (RS)-2-amino-3-[3-hydroxy-5-(2-thiazolyl)-4-isoxazolyl]propionic acid (4) are potent AMPA agonists. On the other hand, (R)-APPA (3) and (R)-2-Py-AMPA (6) have been shown to be weak AMPA antagonists. We now report the synthesis of 2-Py-AMPA (7a) and the isomeric compounds 3-Py-AMPA (7b) and 4-Py-AMPA (7c) as well as the 7a analogues, (RS)-2-amino-3-[3-hydroxy-5-(6-methyl-2-pyridyl)-4-isoxazolyl]p ropion ic acid (7d) and (RS)-2-amino-3-[3-hydroxy-5-(2-quinolinyl)-4-isoxazolyl]propionic acid (7e). Furthermore, (RS)-2-amino-3-[3-hydroxy-5-(2-furyl)-4-isoxazolyl]propionic acid (2-Fu-AMPA, 7f) and its 5-bromo-2-furyl derivative (7g) were synthesized, and (S)-2-Fu-AMPA (8) and (R)-2-Fu-AMPA (9) were prepared by semipreparative chiral HPLC resolution of 7f. HPLC analyses and circular dichroism spectroscopy indicated the absolute stereochemistry of 8 and 9 to be S and R, respectively. This was confirmed by an X-ray crystallographic analysis of 9.HCl. In receptor binding (IC50 values) and rat cortical wedge electrophysiological (EC50 values) studies, 7c (IC50 = 5.5 +/- 0.6 microM; EC50 = 96 +/- 5 microM) was shown to be markedly weaker than 7a (IC50 = 0.57 +/- 0.16 microM; EC50 = 7.4 +/- 0.2 microM) as an AMPA agonist, whereas 7b,d,e were inactive. The very potent AMPA agonist effect of 7f (IC50 = 0.15 +/- 0.03 microM; EC50 = 1.7 +/- 0. 2 microM) was shown to reside exclusively in 8 (IC50 = 0.11 +/- 0.01 microM; EC50 = 0.71 +/- 0.11 microM), whereas 9 did not interact significantly with AMPA receptors, either as an agonist or as an antagonist. 8 was shown to be photochemically active and is a potential photoaffinity label for the recognition site of the AMPA receptors. Compound 7g turned out to be a very weak AMPA receptor agonist (IC50 = 12 +/- 0.7 microM; EC50 = 160 +/- 15 microM). None of these new compounds showed detectable effects at N-methyl-d-aspartic acid (NMDA) or kainic acid receptors in vitro. The present studies have emphasized that the presence of a heteroatom in the 2-position of the heteroaryl 5-substituent greatly facilitates AMPA receptor agonist activity.     

2-[(对-苯偶氮苯)-三氮烯]苯甲酸与锑的显色反应研究及其应用

合成了新显色剂2-[(对-苯偶氮苯)-三氮烯]苯甲酸(PABTB),并研究了该试剂在阳离子表面活性剂CTMAB存在下与锑离子的显色反应。将邻氨基苯甲酸重氮化得到重氮盐溶液,然后重氮盐与对氨基苯偶氮苯发生偶联反应,产物经提纯和重结晶后得到PABTB。通过元素分析和红外光谱检验确认其为目标产物。在pH 10.18的硼砂和氢氧化钠缓冲溶液介质中,锑与该试剂形成摩尔比为1∶2的红色络合物,其表观摩尔吸光系数为1.686×105L.mol-1.cm-1,锑离子的浓度在0~0.7 mg/L范围内符合比尔定律。用该试剂成功地测定了矿样中微量锑。     

Studies on substances with antiblastic activity. IX. Anthramycin and analogs. IX. Synthesis of 7-methoxy-8-hydroxy-10,11-dihydro-5H-pyrrolo[2,1-c] [1,4] benzodiazepine and other compounds related to oxotomaymycin

The synthesis of some pyrrolobenzodiazepine derivatives related to oxotomaymycin, an antibiotic recovered together with tomaymycin from fermentation broths of Streptomyces achromogenes var. tomaymycetics, is described. Reaction between 2-nitro-4-benzyloxy-5-methoxybenzylbromide and pyrrole-2-carboxyaldehyde afforded 1-(2-nitro-4-benzyloxy-5-methoxybenzyl)pyrrole-2-carboxyaldehyde. Catalytic reduction of this compound with hydrogen in the presence of Pd/C gave 10,11-dihydro-8-hydroxy-7-methoxy-5H-pyrrolo[2.1-c] [1,4]benzodiazepine. Amides obtained from condensation between 2-nitro-4-benzyloxy-5-methoxybenzoic acid chloride and proline or hydroxyproline were reduced catalytically to 2,3-dihydro-8-hydroxy-7-methoxy-1H-pyrrolo [2,1-c] [1,4]benzodiazepine-5,11 (10H, 11aH)-dione and its 2-hydroxyderivative respectively. The synthesis of 10,11-dihydro-8-hydroxy-9-methoxy-5-pyrrolo [2,1-c] [1,4]benzodiazepine is also reported.     

Ferulic acid dehydrodimers from wheat bran: isolation, purification and antioxidant properties of 8-O-4-diferulic acid

Wheat bran contains several ester-linked dehydrodimers of ferulic acid, which were detected and quantified after sequential alkaline hydrolysis. The major dimers released were: trans-5-[(E)-2-carboxyvinyl]-2-(4-hydroxy-3-methoxy-phenyl)-7-methoxy-2, 3- dihydrobenzofuran-3-carboxylic acid (5-8-BendiFA), (Z)-beta-[4-[(E)-2-carboxyvinyl]-2-methoxyphenoxy]-4-hydroxy-3-methox ycinnamic acid (8-O-4-diFA) and (E,E)-4,4'-dihydroxy-5,5'-dimethoxy-3,3'-bicinnamic acid (5-5-diFA). trans-7-hydroxy-1-(4-hydroxy-3methoxyphenyl)-6-methoxy-1,2-dihydro - naphthalene-2,3-dicarboxylic acid (8-8-diFA cyclic form) and 4,4'-dihydroxy-3,3'-dimethoxy-beta,beta'-bicinnamic acid (8-8-diFA non cyclic form) were not detected. One of the most abundant dimers, 8-O-4-diFA, was purified from de-starched wheat bran after alkaline hydrolysis and preparative HPLC. The resultant product was identical to the chemically synthesised 8-O-4-dimer by TLC and HPLC as confirmed by 1H-NMR and mass spectrometry. The absorption maxima and absorption coefficients for the synthetic compound in ethanol were: lambda max: 323 nm, lambda min: 258 nm, epsilon lambda max (M-1 cm-1): 24,800 +/- 2100 and epsilon 280 (M-1 cm-1): 19,700 +/- 1100. The antioxidant properties of 8-O-4-diFA were assessed using: (a) inhibition of ascorbate/iron-induced peroxidation of phosphatidylcholine liposomes and; (b) scavenging of the radical cation of 2,2'-azinobis (3-ethyl-benzothiazoline-6-sulphonate) (ABTS) relative to the water-soluble vitamin E analogue, Trolox C. The 8-O-4-diFA was a better antioxidant than ferulic acid in both lipid and aqueous phases. This is the first report of the antioxidant activity of a natural diferulate obtained from a plant.     

2,6-吡啶-二羧酸—溴化十六烷基三甲基铵体系荧光分光光度法测定痕量铕

提出了在表面活性剂存在下 ,2 ,6-吡啶 -二羧酸 (DPA)体系荧光分光光度法测定痕量铕 ,研究了最佳反应条件 ,铕的检出限可达 0.0 4 5ng/mL ,可允许存在一定量的其他共存稀土离子 ,并考察了Al3+,Fe3+,Ca2 +,Mg2 +离子对测定的影响 ,该法用于测定包头混合稀土氧化物中痕量铕 ,获得了较满意的结果。     

铝酸钡与氢氧化钡脱硫过程比较

用铝酸钡和氢氧化钡对种分母液进行脱硫试验,对脱硫渣进行XRD分析,并比较脱硫过程。结果表明,氢氧化钡的脱硫效果更好,脱硫完成时间更短,速率更快;铝酸钡先与碱液反应生成2BaO.Al2O3.5H2O,再与硫碱和碳碱反应,而氢氧化钡直接与硫碱和碳碱反应,脱硫过程均可用未反应核模型描述。     

稀土铅中铅的络合滴定法测定

在一定条件下用氟化钠分离稀土元素，硫酸铅钾沉淀分离其它干扰元素，在pH5．8的醋酸－醋酸钠缓冲溶液中用EDTA滴定铅。     

5—Br—DMPAP测钢铁及合金中铋

利用斐了子型表面活性剂ＯＰ存在下,５－Ｂｒ－ＤＭＰＡＰ与铋的反应来测钢铁及合金中铋。干扰元素用ＤＤＴＣ－ＤＤｌ４萃取法分离,ＨＣｌ（１＋１）反萃取后随铋主的微量铁以抗坏血酸掩蔽,反应适宜酸度为ｐＨ３左右。采用０．１Ｍ－氯醋酸和Ｍ醋酸钠（１＋１）混合液为缓冲液,络合物Ｂｉ－５－Ｂｒ－ＤＭＰＡＰ最大吸收峰在５７５ｎｍ处。     

银纳米粒子-锌(Ⅱ)协同双催化动力学荧光法测定电镀工业废水中痕量锌

在含有十六烷基三甲基溴化胺(CTMAB)的磷酸盐(PBS)缓冲溶液中,Zn²⁺对高碘酸钠氧化荧光桃红的反应具有显著的催化效应,催化的结果是导致其荧光强度显著减弱。据此建立了基于Zn²⁺和银纳米粒子协同双催化效应动力学荧光法测定痕量Zn²⁺的新方法。实验结果表明pH 7.8的磷酸盐缓冲溶液中,当荧光桃红、NaIO₄、银纳米粒子、CTMAB溶液浓度分别为2.0×10^-6 mol/L,5.0×10^-3 g/L,5.0×10^-6 mol/L ,1.5×10^-3 g/L时,Zn²⁺的浓度在5×10^-8 ~ 100×10^-8 g/L范围内与体系的荧光强度改变值呈良好的线性关系,检出限为1.88×10^-8 g/L。应用于电镀工业废水中Zn²⁺的检测,测定值与双硫腙光度法基本一致,相对标准偏差(RSD,n=6)≤2.5%。