高温水解-离子色谱法测定钴酸锂中氯

使用高温水解-离子色谱法对钴酸锂中痕量的氯进行分析测定。样品在1 100℃高温下通入氧气与水蒸气进行水解反应,生成氯化氢气体随载气带出,经冷凝后接收,并通过离子色谱法对氯的含量进行测定。以NaHCO3(4.5mmol/L)与Na2CO3(2.7mmol/L)的混合溶液为淋洗液,经SH-AG-1保护柱及SH-AC-1分离柱分离,Cl-在0.05~5.00mg/L范围内浓度与峰面积呈线性关系,检出限(3S)为0.010mg/L。方法测定氯的加标回收率在92%~96%,相对标准偏差(n=11)在3.0%~5.3%,方法准确、可靠。     

高温水解-离子色谱法同时测定再生锌原料中氟和氯

采用自制的高温水解装置处理样品,结合离子色谱法测定了再生锌原料中氟、氯的含量。试样在1 000℃高温下通入氧气与水蒸汽进行水解反应,以NaHCO_3(6.0mmol/L)与Na_2CO_3(2.4mmol/L)的混合溶液作为淋洗液,经SH-AG-1保护柱及SH-AC-3分离柱分离,测得F-在0~10 mg/L、Cl-在0~50mg/L范围内浓度与峰面积呈线性关系,相关系数分别为r=0.999 8和r=0.999 9,检出限分别为0.020mg/L与0.033 mg/L。分析再生锌原料中氟、氯的加标回收率分别在95.70%~102.5%和96.72%~101.3%,相对标准偏差(n=11)分别在2.1%~6.6%和2.0%~5.8%。方法对再生锌原料中氟(0.010%~1.00%)和氯(0.050%~5.00%)测定,结果满意。     

在线基体消除-离子色谱法测定墨水染料中的氯及硫酸盐

建立了一种在线基体消除的方法,采用离子色谱法测定了墨水染料中的氯和硫酸盐。样品经溶解、稀释后直接进样,在纯水的输送下依次经过DIONEX OnGuard Ⅱ P和IonPac NG1柱,在线实现了墨水样品中染料和疏水性干扰基体的去除,死时间流出的待测阴离子浓缩于阴离子交换柱IonPac AG11-HC。浓缩柱经阀切换进入离子色谱系统,以4.5 mmol/L Na2CO3-0.8 mmol/L NaHCO3作为淋洗液,流速1.2 mL/min,待测离子经IonPac AS23（4 mm×250 mm）分析柱分离,采用DIONEX DS6电导检测器检测,外标法定量。Cl－和SO2-4的线性范围分别为0.05~5.0、0.1~10.0 mg/L,相关系数分别为0.999 8和 0.999 7,加标回收率为94%~103%,相对标准偏差（n=11）小于1.0%,检出限（S/N=3）分别为0.02、0.05 mg/L。该方法用于墨水染料中氯和硫酸盐的测定,结果满意。     

离子色谱法测定聚合物材料中铬(Ⅵ)含量

采用离子色谱法测定聚合物材料中的铬(Ⅵ)含量。取粒径小于250μm的聚合物样品用0.5mol·L-1氢氧化钠溶液提取3h。分取适量提取液经过滤及RP柱净化后,通过IonPac AG19保护柱及DIONEX IonPac AS19阴离子分离柱分离,先后用25mmol·L-1和50mmol·L-1的氢氧化钠溶液淋洗分离柱,采用抑制电导检测器检测。铬(Ⅵ)的质量浓度在0.10~10.0mg·L-1范围内与其峰面积呈线性关系,检出限(3s/k)为7mg·kg-1。对聚氯乙烯(PVC)样品连续测定8次,测定值的相对标准偏差为9.2%。用标准加入法进行方法的回收试验,测得回收率在95.2%~105%之间。     

固相萃取分离-离子色谱法测定化肥中三聚氰胺的含量

采用固相萃取分离-离子色谱法测定化肥中三聚氰胺的含量。化肥样品经10g·L-1三氯乙酸溶液振荡超声提取,离心后,萃取液经阳离子交换固相萃取柱净化。经净化的溶液经IonPac NG1保护柱及Dionex IonPac AS18分离柱分离,以含3mmol·L-1甲基磺酸的乙腈-水(15+85)混合液为淋洗液进行淋洗,所得提取液采用抑制电导检测器进行离子色谱分析。三聚氰胺的质量浓度在5.00~2 000mg·L-1范围内与其峰面积呈线性关系,检出限(3S/N)为0.3mg·kg-1。加标回收率在89.7%~97.8%之间,测定值的相对标准偏差(n=6)在1.9%~4.5%之间。     

固相萃取―离子色谱法测定工业废水中卤素

采用LC-C18柱-IC-Na柱串联,对样品进行固相萃取,以离子色谱法对工业废水中的卤素进行快速测定。选定的色谱条件是Ion Pac AS22离子交换柱、4.5 mmol/L(Na_2CO_3)+1.4 mmol/L(NaHCO_3)混合液作淋洗液,流速为1.2 m L/min,抑制型电导检测。氟、氯、溴、碘四种卤素在0~10.0 mg/L的浓度范围内线性关系良好,相关系数均大于0.999 0,检测限(3倍噪声比)分别为0.015、0.017、0.025和0.034 mg/L,相对标准偏差分别为0.98%、0.76%、0.82%和0.69%,回收率为95.02%~97.85%。该方法具有简便、准确、灵敏等特点,可较方便地应用于工业废水的质量检测和控制。     

氧弹燃烧-离子色谱法测定原油中氯和溴

采用氧弹燃烧法对原油样品进行燃烧,然后用碳酸钠-碳酸氢钠溶液作为吸收液进行吸收,并提出了离子色谱法分离测定原油中氯和溴的含量的方法。以Dionex IonPac AS23型分离柱为离子交换柱,以4.8mmol·L-1碳酸钠-1.0mmol·L-1碳酸氢钠溶液为淋洗液等度洗脱。氯和溴的质量浓度均在0.01～1mg·L-1范围内与其峰面积呈线性关系,方法的检出限(3S/N)分别为0.3mg·kg-1与0.7 mg·kg-1。方法用于原油样品分析,测定值的相对标准偏差(n=6)在3.5%～4.2%之间,回收率在91.8%～109%之间。     

氧弹燃烧-离子色谱法测定涂料中氯和溴的含量

涂料中有机化合物通过氧弹燃烧转化为无机离子,其中可溶性氯和溴离子被吸收液吸收后,经离子色谱仪测定。采用IonPacAS22(4 mm×250 mm)阴离子色谱柱,IonPacAG22保护柱,以4.5 mmol/L Na2CO3-1.4 mmol/L NaHCO3为流动相,流速为1.0 mL/min。氯和溴离子的质量浓度在1～20 mg/L范围内分别与色谱峰面积呈良好的线性关系,相关系数均大于0.999,平均加标回收率为94.7%～96.2%,测定结果的相对标准偏差小于1.0%(n=6)。该方法检测时间短、损失量少,适用于涂料中氯和溴含量的测定。     

反相离子对高效液相色谱法测定心肌组织中的三磷酸腺苷

 采用反相离子对高效液相色谱法测定心肌组织中三磷酸腺苷 (ATP)的含量。样品经高氯酸溶液沉淀蛋白 ,上清液用KOH溶液中和后用反相离子对高效液相色谱法分离测定。色谱柱为SpherisorbODS2柱 ,流动相为甲醇 KH2 PO4缓冲液 (内含 5mmol/LIPR A离子对试剂 ) ,在 2 59nm波长处检测。方法最低检测限为 2mg/L,在 5mg/L～ 1 0 0 mg/L范围内有良好的线性关系 (r=0 9998) ,方法的回收率为 97 8%～ 1 0 4 % ,日内精密度 <4 85% ,日间精密度 <8 81 %。方法准确、灵敏、快速 ,适用于动物和人心肌组织中ATP含量的测定。     

离子色谱法测定不同地区家庭饮用井水中的阴、阳离子

采用离子色谱法测定不同地区家庭饮用井水中氟离子、氯离子、硝酸根、硫酸根、钠离子、钾离子、镁离子和钙离子等8种阴、阳离子的含量。样品经IonPac AS11-HC型分离柱及IonPac AG11-HC型保护柱分离,以30mmol·L-1氢氧化钾溶液为淋洗液(阴离子分析);样品经IonPac CS12A型分离柱及IonPac CG12A型保护柱分离,以20 mmol·L-1甲基磺酸溶液为淋洗液(阳离子分析);采用电导检测器检测。8种离子在一定的质量浓度范围内与其峰面积呈线性关系,方法的检出限(3s)在0.002~0.034mg·L-1之间。对井水样品进行测定,测定值的相对标准偏差(n=6)在0.59%~2.0%之间。用标准加入法做方法的回收试验,计算得回收率在98.3%~109%之间。     

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.