双体系多波长Rosenbrock算法同时测定镧,铈,镨的研究

用计算分光光度法同时测定混合物中各组分含量已有不少报道。但是,对于镧、铈、镨等相邻稀土混合物体系,计算分光光度法一般难以给出令人满意的结果。这是由于相邻稀土元素的化学性质过于相似,其配合物的吸收光谱严重重叠,致使测量模型(线性方程组)呈现严重的病态性质。解决这一问题可从寻找较好的显色体系,以扩大各组分光学性质的差异     

多波长线性回归—导数吸光光度法同时测定三组分混合物

提出了等吸收点-多波长线性回归-(导数)吸光光度法同时测定三组分混合物的原理,以5-Br-PADAP-溴代十六烷吡啶(CPB)-金属离子显色体系为例,通过测定合成样品及铝合金中的锰、铜、锌.对方法的可行性进行了验证,结果良好.     

迭代目标转换因子分析光度法同时测定钇和其它稀土合量

以三氯偶氮胂为显色剂，根据钇(Y^3 )与其它稀土组分的显色络合物吸收光谱差别较大的特点，提出应用迭代目标转换因子分析光度法同时测定钇和其它烯土合量的计算光度分析法，通过对不同组成的人工模拟样品和龙南稀土氧化物标准样中的钇和其它稀土合量的测定，取得了满意的结果。     

双显色双波长分光光度法测定稀土的研究——镧与钇、总稀土与钇的同时测定

本文将双显色双波长分光光度用于稀土多元素同时分析,以铬天青S-二甲酚橙体系测定镧与钇,以偶氮肿Ⅲ-偶氮氯膦-mA体系测定非钇稀土合量与钇。     

铅(Ⅱ)-钇组稀土(Ⅲ)-BPR-乙酸根-TPB-乙醇体系共显色效应的研究

本文报道了铅(Ⅱ)与钇组稀土在Pb(Ⅱ)-RE(Ⅲ)-BPR-Ac~--TPB-EtOH体系中的共显色效应。探索了共显色效应的最佳条件及共显色体系的杂多核配合物的性质。此体系可用于测定铅及钇组稀土,灵敏度高,在0—30μg钇组稀土/25ml或0—60μg铅/25ml的范围内服从比尔定律。测定了杂多核配合物组成并讨论了它的形成机理。研究了外来离子的干扰情况及其分析应用。     

人工神经网络算法分光光度法同时测定锰和镍

采用甲醛肟-锰、镍显色体系,应用人工神经网络分光光度法,对吸收光谱严重重叠的两组分锰、镍同时进行测定。应用于工业废水中锰（Ⅱ）和镍（Ⅱ）的同时测定,回收率在95％～102％之间。     

用改进回归正交试验法从混合稀土-偶氮胂Ⅲ-EDTA显色体系中测定四种单一稀土的研究

本文应用回归正交试验法,在混合稀土-偶氮胂Ⅲ-EDTA显色体系中,对La,Ce,Pr,Nd四种稀土进行四因子一次回归正交实验。在650nm处得到吸收峰高与稀土浓度间的回归方程。再用标准系列加入法得到各稀土浓度对吸收峰高的变化率(偏偏微)。由回归方程求得偏徽方程组,求解该方程组可得四种单一稀土的含量。这种新方法由于应用正交优化原理,故比其他单一稀土测定方法具有明显的优点:不必分离即可同时测定单一稀土。对包头和龙南混合稀土的测定结果表明,该法可靠,误差≤2％。     

双波长K系数-标准加入-导数分光光度法同时测定重油中的钴镍

本文提出了一种同时测定两组分混和物的新方法，即双波长Ｋ系数－标准加入－导数分光光度法，该法同时进行两组分的标准加入，以两个组分的峰值波长为测定波长，又互为参比波长，利用Ｋ系数法以一套吸光度数据同时完成两个组分的测定。本文以ＯＰ－５－Ｂｒ－ＰＡＤＡＰ为显色体系，同时测定了重油中的钴、镍，结果令人满意。本方法简便，灵敏度高。     

双波长K系数—导数吸光光度法同时测定重油中钴和镍

提出了双波长K系数-导数吸光光度法,以样品中两组分的峰值波长互为测定波长和参比波长,以一套导数值数据进行两组分的同时测定,具有简便、灵敏度高的优点.以三正辛胺萃取分离干扰离子,OP—5-Br-PADAP显色体系同时测定了重油中的钴、镍.结果令人满意.     

多体系计算光度法测定稀土混合物中的微量单一稀土

多组分体系的计算分光光度法是化学计量学中一个十分活跃的研究领域。近年来,由于许多新的数学方法不断引入,已经形成了多元光度分析代替常规单变量方法的趋势。稀土元素化学性质十分相似,在实验上表现为标准光谱的“共线性”问题,故计算分析法测定混合稀土比较困难。本文采用多显色体系的实验方法来扩大各组分光谱的差异性,即减弱标准光谱的线性相关性;同时采用数值稳定性较好的可变容差法进行计算。测量对象为难于分离的Eu-Gd二元及Sm-Eu-Gd三元体系。     

F-对沸石分子筛双四元环影响的量子化学计算

采用PM3量子化学计算方法研究了沸石分子筛及无机微孔晶体结构中双四元环内含F^-及不含F^-的8种模型簇的几何结构、电子结构以及稳定性,考察了F^-对双四元环结构和性质的影响,发现F^-的存在依次增强了纯硅、磷铝和磷镓双四元环的稳定性,而降低了硅铝的稳定性,F^-在双四元环中所处位置的计算值与实验晶体数据基本吻合.     

O-17 NMR spectra of ring compounds. Correlation of 17O and 13C methyl substitution parameters

The ¹⁷O NMR spectra of 22 1,3-dioxanes, four exanes, four 4-heterooxanes, four tetrahydrofurans and four 1,3-dioxolanes have been recorded and methyl substitution parameters determined for the 1,3-dioxanes. The parameters, including γ_a, correlate linearly with corresponding ₁₃C parameters for methyloxanes.     

Ytterbium Coordination Polymer with Four Different Coordination Numbers：The First Structural Characterization of Lanthanide Phthalate Complex

The novel ytterbium coordination polymer is a t4wo-dimensional framework in which the central metal ions have four different coordination numbers and form four kinds of coordination poly-hedra,The four kinds of coordination polyhedra connect into infinite chains by sharing oxygen atoms.     

径向基函数神经网络光度法同时测定苯酚、邻苯二酚、间苯二酚和对苯二酚

对吸收峰重叠严重的苯酚、邻苯二酚、间苯二酚和对苯二酚4组分体系进行研究,以径向基函数神经网络光度法建立校正模型,同时测定了水样中的苯酚、邻苯二酚、间苯二酚和对苯二酚的含量,回收率为95.7％～109.2％。     

Synthesis of four‐armed poly(ε‐caprolactone)‐block‐poly(ethylene oxide) by diethylzinc catalyst

Biodegradable, amphiphilic, four‐armed poly(?‐caprolactone)‐block‐poly(ethylene oxide) (PCL‐b‐PEO) copolymers were synthesized by ring‐opening polymerization of ethylene oxide in the presence of four‐armed poly(?‐caprolactone) (PCL) with terminal OH groups with diethylzinc (ZnEt₂) as a catalyst. The chemical structure of PCL‐b‐PEO copolymer was confirmed by ¹H NMR and ¹³C NMR. The hydroxyl end groups of the four‐armed PCL were successfully substituted by PEO blocks in the copolymer. The monomodal profile of molecular weight distribution by gel permeation chromatography provided further evidence for the four‐armed architecture of the copolymer. Physicochemical properties of the four‐armed block copolymers differed from their starting four‐armed PCL precursor. The melting points were between those of PCL precursor and linear poly(ethylene glycol). The length of the outer PEO blocks exhibited an obvious effect on the crystallizability of the block copolymer. The degree of swelling of the four‐armed block copolymer increased with PEO length and PEO content. The micelle formation of the four‐armed block copolymer was examined by a fluorescent probe technique, and the existence of the critical micelle concentration (cmc) confirmed the amphiphilic nature of the resulting copolymer. The cmc value increased with increasing PEO length. The absolute cmc values were higher than those for linear amphiphilic block copolymers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 950–959, 2004     

四种荧光素酯的化学物理性质

在紫外线的照射下,荧光素酯能与生物体细胞作用发出鲜艳的黄绿色荧光,由于生物体细胞的生活力不同,细胞内水解酶的含量也不同,因而显出的荧光强度不同。借此性质可以测定细胞内荧光素水解酶的活性以及细胞的生活状态。由于它们是一类选择性好,灵敏度较高的生物荧光染色剂,所以深入研究四种荧光素酯的化学物理性质是有意义的。四种荧光素酯的分子结构可用下面通式表示。     

Characterization of acridone dyes for use in four-decay detection in DNA sequencing

Four acridone dyes and dye-labeled primers were characterized for use in four-decay DNA sequencing. In the four-decay scheme, fluorescence lifetime replaces spectral ("color") selectivity for distinguishing between four base-specific labels in a single-lane capillary electrophoresis (CE) separation of the DNA fragments. Prior to the introduction of the acridone dyes, a major obstacle to four-decay detection was the lack of four suitable dyes with resolvable lifetimes. The four acridone dyes, whether free in solution or tethered to DNA primer, exhibit significant differences among their lifetimes and are well-suited to use together in four-decay sequencing. The lifetimes of the four dye-labeled DNA primers that were sequentially injected and detected on-the-fly in a 2% POP6 sequencing gel were 4, 6, 11 and 14 ns. A 405 nm violet laser diode provides optimal excitation of the four dyes.     

超高效液相色谱-串联质谱法测定鸡肉中的4种聚醚类抗球虫药物残留

采用乙腈直接提取、石墨化碳黑固相萃取小柱净化、UPLC快速分离,串联质谱检测、成功建立了鸡肉中莫能菌素、马杜菌素、盐霉素、拉沙洛西等4种抗球虫药物的多残留检测方法.对样品提取、净化过程和仪器条件进行了优化改进,经Waters C18 columm分离、正离子电喷雾电离模式测定,4种药物的检测限为0.2μg/kg,最低定量限为0.5μg/kg.选取0.5、1.0、2.0μg/kg 3个质量分数进行空白添加回收率实验,回收率为71.9%～100.9%.批内RSD 2.7%～15%,批间RsD为1.7%～10%.各项技术指标满足国内外法规的要求,适合大量样品中聚醚类抗球虫药物残留的确认检测.     

Construction of polymeric and oligomeric lanthanide(III) thiolates from preformed complexes [(TMS)2N]3Ln(mu-Cl)Li(THF)3 (Ln = Pr, Nd, Sm; (TMS)2N = Bis(trimethylsilyl)amide)

The complex [{(TMS)2N}4(mu4-Cl)Sm4(mu-SPh)4(mu3-Cl)Li(THF)] has been formed by protonolysis of [(Me3Si)2N]3Sm(mu-Cl)Li(THF)3 with 1 equiv of HSPh, which contains a square array of Sm(III) ions connected by a central mu4-Cl ligand. The edges of the square Sm4 array are bridged by four mu3-Cl and four mu-SPh ligands. The four Sm atoms and Li atom are connected by four mu3-Cl ligands.     

微波消解-液相色谱-原子荧光光谱联用(LC-AFS)法测定稻米样品中砷形态

建立了稻米中4种砷元素形态的液相色谱-原子荧光光谱联用法(LC-AFS),样品用0.15mol/L的硝酸溶液微波提取50min,提取液经离心分离后,采用Hamilton PRP-X100色谱柱,45mmol/L KH2PO4-5mmol/L Na2HPO4缓冲液为流动相,砷形态4个组分能够在7min内达到基线分离,且无需调pH。优化了氢化物发生条件,使用了更低浓度的载流和还原剂。方法学实验结果表明,各组分在2~10ng/mL范围内线性关系良好,相关系数为0.9988~0.9998,各组分的检出限分别为0.29 ng/mL、0.47 ng/mL、0.62 ng/mL和1.16 ng/mL;各组分峰面积的相对标准偏差均低于3.11%;加标回收率为85.3%～112.8%;对稻米标准物质的分析测定结果表明该方法定值准确。最后,与GB 5009.11-2014中使用的提取及测量条件进行对比,表明该方具备法快速、环保、高效的特点。