由3-二茂铁-2-丁烯酸根和1,10-邻菲啰啉构筑的一维链状铅(II)配位聚合物的合成、晶体结构及电化学性质

Pb(OAc)₂•3H₂O, 3-二茂铁-2-丁烯酸钠以及1,10-邻菲啰啉在甲醇中反应得到了铅的配位聚合物: [Pb(m-OOCCH＝C(CH₃)Fc)(m₂-OOCCH＝C(CH₃)Fc)(phen)]_n (Fc＝(h⁵-C₅H₅)Fe(h⁵-C₅H₄); phen＝1,10-邻菲啰啉). 单晶测试表明: 每个铅离子为六配位, 其中4个氧原子来自4个3-二茂铁-2-丁烯酸根, 另2个氮原子来自邻菲啰啉; 相邻的铅离子通过3-二茂铁-2-丁烯酸根的单齿和双齿氧原子桥连形成了一个无限的一维长链. 研究了标题化合物在DMF溶液中的电化学性能.     

5,10,15-三苯基-20-吡啶基卟啉荧光猝灭法测定痕量铅

:试验制备了一种荧光试剂5,10,15-三苯基-20-吡啶基卟啉(TPPyP),该试剂激发光谱(λ_(ex))为420nm时,在650nm波长处有发射光谱(λ_(em))峰。当试剂与铅(Ⅱ)反应时产生荧光猝灭现象。提出了以此试剂为荧光探针测定痕量铅(Ⅱ)的荧光光度法。在邻苯二甲酸盐-盐酸缓冲溶液中,一定量的十六烷基三甲基溴化铵(CTMAB)存在下,通过测定样品溶液和空白溶液在发射波长650nm的荧光强度,计算得反应液荧光强度的降低程度△F;结果表明:△F值与铅(Ⅱ)的质量浓度在1.0×10~(-4)～1.5×10~(-3)mg·L~(-1)范围内呈线性关系,方法的检出限(3s/k)为4.0×10~(-5)mg·L~(-1)。此方法用于膨化食品中铅(Ⅱ)的测定,回收率在95.0%～107.0%之间,相对标准偏差(n=6)小于3%。     

新型荧光试剂1-(8-喹啉)-3-(3,5-二溴-2-吡啶)-三氮烯的合成及其应用

将具有荧光特性的杂环8-氨基喹啉和吡啶类试剂结合,并引入三氮烯结构,合成了新型荧光试剂1-(8-喹啉)-3-(3,5-二溴-2-吡啶)-三氮烯(QBPyT)。其结构经元素分析、红外光谱、核磁共振波谱证实。研究结果表明,在pH 9.5硼酸-氢氧化钠缓冲溶液的介质存在下,该试剂在λex/λem=248nm/496nm处产生强荧光,并且能与铅(Ⅱ)形成配合物从而使荧光增强。据此建立了三氮烯测定铅(Ⅱ)的新型荧光分析法。铅的浓度在5.0×10-7～1.2×10-5 mol.L范围内与其荧光强度呈线性关系,检出限(3S/N)为9.5×10-8 mol.L。将其应用于水样中铅(Ⅱ)的测定,测得回收率在92.6%～94.0%之间,测定值的相对标准偏差(n=5)小于3.5%。     

2-羟基和4-羟基-3,5-二硝基吡啶铅盐的热行为、分解机理、非等温分解反应动力学及其在推进剂中的应用

在程序升温条件下 ,用DSC ,TG ,慢速裂解 /傅里叶红外 ,研究了 2 羟基 3 ,5 二硝基吡啶铅盐 ( 2HDNPPb)和 4 羟基 3 ,5 二硝基吡啶铅盐 ( 4HDNPPb)的热行为、机理和动力学参数 ,提出了它们的热分解机理 ,计算了热爆炸临界温度 ,考察了它们对RDX改性双基推进剂的催化效果 .结果表明 :2HDNPPb和 4HDNPPb主放热分解反应的表观活化能和指前因子值分别为 2 5 2 .3 4kJ·mol-1,10 19.3 0 s-1和 187.3 9kJ·mol-1,10 13 .74s-1.由加热速率 β→ 0的DSC曲线的初始温度 (Te)和峰温 (Tp)算得 2HDNPPb和 4HDNPPb的热爆炸临界温度值分别为 3 2 7.64 ,3 3 6.5 7和 3 2 3 .90 ,3 3 3 .96℃ .2HDNPPb的热稳定性优于4HDNPPb .0 .1MPa时 ,它们的放热分解过程动力学方程可表示为 :　　对 2HDNPPb　　dα/dT =10 2 0 .48( 1-α) [-ln( 1-α) ] 3 /5e-3 .0 3 51× 10 4 /T　　对 4HDNPPb　　dα/dT =10 15.0 0 ( 1-α) [-ln( 1-α) ] 2 /3 e-2 .2 53 9× 10 4 /T对含RDX改性双基推进剂 ,它们都具有催化燃烧和降低压力指数的作用 .2HDNPPb的催化效果明显优于 4HDNPPb .羟基在分子中所处的不同位置是影响热稳定性和催化效果的主要因素     

氢化物发生-原子吸收光谱测定钢铁中痕量铅

对氢化物发生-原子吸收光谱(HG-AAS)测定铅的预氧化问题和铅的氢化物发生的新机理作了理论上的探讨。发现铅氢化物发生最佳条件同酸、碱等物质的量浓度的中和相关。对柠檬酸的络合、缓冲作用作了研究。发现K3Fe(CN)6的光敏作用能消除钢中有关化学元素对测量铅的干扰。提出了简便准确的钢中0.000 0x%铅的直接测定方法。应用此法分析了5个标样中的铅含量,结果与标准值一致,得RSD为2.0%(n=4,wPb6.2×10-5%)及1.5%(n=14,wPb1.3×10-3%),方法的测定限为w(Pb)5×10-6%。     

浊点萃取-氢化物发生-原子荧光光谱法测定水样中痕量铅

提出了氢化物发生-原子荧光光谱法测定水中痕量铅的方法。以双硫腙为络合剂,在pH 8.0的硼砂溶液中,用非离子表面活性剂Triton X-114浊点萃取样品溶液中痕量铅。选用15.0 g·L~(-1)硼氢化钾溶液作为产生氢化铅的还原剂,氢化物发生反应在盐酸(1+99)介质中进行,铅的质量浓度在0.05～3.2μg·L~(-1)范围内与其相应的荧光强度呈线性关系。方法的检出限(3S/N)为0.016μg·L~(-1)。应用此方法测定了水中铅的含量,测得回收率在96.5%～104.6%之间,相对标准偏差(n=6)均小于5%。     

2,6-二溴-4-氯偶氮胂与铅、铋显色反应

1　引　　言含卤素的不对称变色酸双偶氮类试剂是稀土元素的优良显色剂 ,这类试剂用于铅、铋的测定也有一些报道。有文献用 2 ,6 二溴 4 氯偶氮胂在 1 .2ｍｏｌ Ｌ高氯酸中测定了铜合金及粗铜中微量铋 (ε为 9.0× 1 0 4Ｌ·ｍｏｌ- 1 ·ｃｍ- 1 )。实验发现 ,该试剂在 3 0ｍｏｌ ＬＨＣｌＯ4介质中与铋显色反应有更高的灵敏度 (ε为 1 .0 5× 1 0 5Ｌ·ｍｏｌ- 1 ·ｃｍ- 1 )。在该条件下 ,Ｐｂ2 +不干扰Ｂｉ3 +的测定 ;在 0 .1ｍｏｌ ＬＨＣｌＯ4中 ,两者均与试剂显色 ,其摩尔吸光系数分别为 4 .4 6× 1 0 4和 1 .0 3×1 0 5Ｌ·ｍｏｌ…     

新型显色剂Meso-四(4-羟基-3-乙氧基苯基)卟啉的合成及其应用

合成了四(4-羟基-3-乙氧基苯基)卟啉, 用元素分析、质谱、紫外-可见光谱、红外光谱及核磁共振氢谱进行了表征, 研究了该卟啉与铅离子的显色反应条件. 结果表明, 当pH=11.0时, 在十二烷基磺酸钠存在下, 沸水浴加热5 min反应完全, 在473 nm处测得配合物的表观摩尔吸光系数为2.08×105 L/(mol·cm), 铅量在0~12 μg/25 mL范围内符合比尔定律, 用此法成功地测定人发标准物质中的微量元素铅的含量.     

5-苯基偶氮-8-(4-羧基苯偶氮氨基)喹啉与铜(Ⅱ)显色反应研究

合成了5-苯基偶氮-8-(4-羧基苯偶氮氨基)喹啉(PACPAQ)。在pH8.2的硼砂缓冲介质中,在CTMAB存在下,铜(Ⅱ)与PACPAQ形成1:4紫红色络合物,λ_(max)为540nm,ε=6.9×10~4·L·mol~(-1)·cm~(-1),铜量在0～10μg/25ml范围内符合比尔定律.用于粗铅和水中铜的测定,结果满意。     

流动注射-火焰原子吸收光谱法测定痕量铅——磷酸盐沉淀吸附在线富集

在流动注射-火焰原子吸收光谱法(FI-FAAS)测定铅(Ⅱ)的流路中设计了铅(Ⅱ)的磷酸盐沉淀在线富集的编结反应器,痕量铅(Ⅱ)与2.0×10-9mol·L-1磷酸二氢钾溶液在微酸性条件下在反应器中反应.当试样溶液的进样体积固定为8.00 mL,采用的富集流速为4.4 mL·min-1,富集时间为90 S,生成的铅(Ⅱ)的磷酸盐沉淀吸附于聚四氟乙烯反应管的内壁,毋需过滤,直接用2.0 mol·L-1硝酸流入管内使铅(Ⅱ)的沉淀溶解,溶液中铅(Ⅱ)按选定条件进行FAAS检测.按上述条件,可使增强系数(N)达到20,铅(Ⅱ)的检出限(3σ)达到23μg·L-1.对铅(Ⅱ)0.50 mg·L-1的标准溶液平行测定6次,算得测定结果的相对标准偏差为3.1%.用此方法分析了2件粉饼样品,测定值的相对标准偏差(n=6)分别为2.2%和4.1%.以此样品作基体进行回收试验,测得平均回收率为91%.     

Spectrophotometric determination of nickel in biological samples using 1-azobenzene-3-(3-hydroxyl-2-pyridyl)-triazene

A new sensitive and selective chromogenic reagent, 1-azobenzene-3-(3-hydroxyl-2-pyridyl)-triazene (ABHPT), was synthesized. It has been found that ABHPT reacts with nickel(II) in a borax buffer solution (pH 10.0) to form 2: 1 red complexes with the maximum absorption at 530 nm. The apparent molar absorptivity of the complex is 2.6 × 10⁵ L/(mol cm). Most metal ions can be tolerated in considerable amounts, whereby only zinc and mercury may interfere with the determination of nickel(II). Nevertheless, this can be easily eliminated by prior separation with sulfhydryl dextran gel. A new method for the spectrophotometric determination of trace nickel(II) was developed. Beer’s law is obeyed for 0–15 μg of nickel(II) in 25 mL of solution. The limit of quantification, limit of detection, and relative standard deviation are 0.74 ng/mL, 0.25 ng/mL, and 1.0%, respectively. The method has been applied to the determination of trace nickel(II) in biological samples with satisfactory results. The text was submitted by the authors in English.     

Synthesis of meso-tetra-(3,5-dibromo-4-hydroxylphenyl)-porphyrin and its application to second-derivative spectrophotometric determination of lead in clinical samples

A new very sensitive and selective chromogenic reagent, meso-tetra-(3,5-dibromo-4-hydroxylphenyl)porphyrin [T(DBHP)P], was synthesized and studied for the determination of trace lead in detail. In 0.10 mol l-1 NaOH medium, lead reacts with T(DBHP)P to form a 1:2 yellow complex, which gives a maximum absorption at 479 nm; 0-0.48 microgram ml-1 Pb(II) obeyed Beer's law. The molar absorptivity of the complex and Sandell's sensitivity are 2.5 x 10(5) 1 mol-1 cm-1 and 0.000812 microgram cm-2, respectively. Second-derivative spectrophotometry is better than conventional spectrophotometry in sensitivity and selectivity, and its limit of quantification, limit of detection and relative standard deviation are 0.70 ng ml-1, 0.21 ng ml-1 and 1.0%, respectively. Ca (3250-fold), Mg (2000-fold), Sr (1000-fold), Ba (750-fold), Al (1000-fold), Bi (500-fold), Fe (2000-fold), Co (750-fold), Ni (1000-fold), Cu (750-fold), Zn (1250-fold), Cd (2500-fold) and Ag (550-fold) do not interfere with the determination of lead. The chromogenic system is remarkably superior to other reagents, especially porphyrin compounds. The influence caused by oxygen in air or in solution can be easily eliminated by adding Na2SO3. The reaction is very stable, the stability constant of the complex being 1.2 x 10(45). The chromogenic reaction is completed within 1 min at room temperature when 8-hydroxylquinoline is used as catalyst. The proposed method has been applied to the direct determination of trace lead in clinical samples. The accuracy and precision are both very satisfactory.     

季胺盐型表面活性剂与镉试剂显色反应的研究及应用

在三乙醇胺存在下，季铵盐型表面活性剂溴化十六烷基三甲铵，溴化十二烷基二甲基苄铵和溴化十六烷基吡啶分别与１－（４－硝基苯基）－３－「４－苯基偶氮）苯基」－三氮烯形成离子缔合物显色，吸收光谱红移，离子缔合物；ＮＰ－ＰＡＰＴ与ＤＤＭＢＡＢ来１：２与ＣＴＭＡＢ，ＣＰＢ均为１：３；测定了显色体系的ＣＴＭＡＢ，ＤＤＭＢＡＭ，ＣＰＢ的临界胶束浓度，符合比尔定律的范围，表观摩尔吸光系数δｍａｘ，探讨了微量ＣＴＭＡ     

The mucic acid as chromogenic agent

The absorption spectra in the infrared and vis-uv regions of mucic acid were established. The analytical behavior of mucic acid as a potential chromogenic reagent for the spectrophotometric determination of trace materials was studied. Interactions with iron(III), copper(II), cobalt(II) and (III), nickel(II), vanadium(IV), and uranyl(II) in basic medium were observed.     

Uramyldiacetic acid (UDA) as absorptiometric agent

The analytical behavior of uramyldiacetic acid as potential chromogenic reagent for the spectrophotometric determination of trace materials is studied. As a result, interesting reactions with copper (II), uranium (VI), iron (II), iron (III), cobalt (II), cerium (II), and nickel (II) in neutral or acidic medium were observed. The absorption spectrum of UDA is established.     

羧基化碳纳米管在荧光酮光度法测定铅中的应用

研究了羧基化碳纳米管(c-MWNT)存在下二溴羟基苯基荧光酮(DBH-PF)与铅离子的显色反应. 结果表明, 在pH=9.4～10.0的硼酸盐缓冲介质中, 二溴羟基苯基荧光酮和铅离子在羧基化碳纳米管的存在下能形成稳定的浅红色配合物, 最大吸收波长为558 nm, 表观摩尔吸光系数为5.62×104 L·mol-1·cm-1. 当含量在(1～50 μg)/25 mL范围内时, 满足朗伯-比尔定律.     

Spectrophotometric determination of copper in alloys using naphthazarin

Naphthazarin (5,8-dihydroxy-1,4-naphthoquinone; Naph) is proposed as a chromogenic reagent for the spectrophotometric determination of copper(II). The polynuclear complex has a mole ratio of Cu:Naph=4:6 in a 50% v/v ethanol/water medium containing 0.1 M ammonium acetate and 1.5% (w/v) sodium dodecyl sulfate. The copper-naphthazarin complex shows an absorption maximum at 330 nm with a molar absorptivity of 1.84x10(4) l mol(-1) cm(-1). Beer's law is obeyed up to 4.5 ppm of copper(II). The method was applied for copper determination in alloy samples with satisfactory results.     

Spectrophotometric determination of lead in traditional Chinese medicines with dibromo<Emphasis Type="Italic">p</Emphasis>-methyl-acethylsulfonazo

A new highly sensitive and selective chromogenic reagent dibromo-p-methyl-acethylsulfonazo (DBMASA) has been synthesized and purified. A method has been proposed for the spectrophotometric determination of lead with DBMASA in traditional Chinese medicines. The content of lead in the samples was low, so we used sulfhydryl cotton fiber (SCF) to separate and enrich trace Pb(II), which lead to a satisfactory result. In 0.25 M phosphoric acid medium, which greatly increased the selectivity, lead reacted with DBMASA to form a 1: 2 blue complex, having an intense absorption peak at 640 nm. Under the optimal conditions, Beer’s law is obeyed over the range 0.01–1.0 μg/mL of Pb(II) and the apparent molar absorptivity is 1.06 × 10⁵ L/mol cm. The detection limit and variation coefficient are found to be 2.1 ng/mL and 1.3%, respectively. The method has been applied to the determination of lead in traditional Chinese medicines with satisfactory results.     

The Color Reaction of Mercury(II) with the New Reagent 2-Methylthiophenyldiazoaminoazobenzene and Its Application

A new and very sensitive and selective chromogenic reagent, 2-methylthiophenyldiazoaminoa-zobenzene (MTDAA), was synthesized and studied in detail for the determination of trace mercury(II) in water samples. The method is based on the color reaction between MTDAA and mercury(II). It was found that mercury(II) reacts with MTDAA in Na₂B₄O₇-NaOH buffer solution (pH = 10.0) to form 1 : 2 red complexes; these show maximum absorption at 520 nm. Beer’s law is obeyed in 0–15 µg of mercury(II) in 25 mL of solution. The apparent molar absorptivity of the complex is 1.33 × 10⁵ L/(mol cm); its limit of quantification, limit of detection, and relative standard deviation are 0.75 ng/mL, 0.27 ng/mL, and 1.0%, respectively, giving better sensitivity. The influence of the reaction variables and the effect of interfering ions are reported; most of the metal ions in water samples can be tolerated in considerable amounts. Only a few ions can interfere with the determination of trace mercury(II), but these can be eliminated by prior extraction. The proposed method is sensitive, simple, and rapid. It has been applied to the determination of trace mercury(II) in water samples with satisfactory results.__________From Zhurnal Analiticheskoi Khimii, Vol. 60, No. 7, 2005, pp. 703–706.Original English Text Copyright © 2005 by Guo, Din, Tian, Liu, Chang, Meng.The text was submitted by the authors in English.     

Use of a novel medium, the ionic liquid 1-butyl-3-trimethylsilylimidazolium hexafluorophosphate, for liquid-liquid extraction of lead in water and its determination by graphite furnace atomic absorption spectrometry

The ionic liquid 1-butyl-3-trimethylsilylimidazolium hexafluorophosphate, abbreviated as [C4tmsim][PF6], was developed as a novel medium for liquid-liquid extraction of lead(II) in water, in which dithizone was used as a metal chelator to form a neutral lead-dithizone complex. Under optimal conditions, the complex was extracted into the [C4tmsim][PF6] phase from aqueous solution and back-extracted with nitric acid solution into the aqueous phase that was used directly for the subsequent determination of Pb. The system using the ionic liquid demonstrated good extraction performance; the extraction and back-extraction efficiencies were 99.8 and 99.7%, respectively, for Pb(II) at 20 microg/L. The above procedure, including the extraction and back-extraction, was used to enrich trace levels of Pb(ll) in a relatively large volume of water samples (1000 mL water), and an enrichment factor of 400 was obtained. The enrichment coupled with graphite furnace atomic absorption spectrometry was successfully applied to the determination of Pb in water. The calibration graph was linear at levels near the detection limits up to > or = 100 ng/L Pb(II). The limits of quantitation and detection for lead in real water samples were 2.5 and 1.0 ng/L, respectively. Lead recoveries of 96.2-103.8% from spiked samples demonstrate the accuracy of the proposed method.