毛细管柱气相色谱法测定白酒中的甜蜜素

建立了毛细管色谱柱气相色谱法测定白酒中甜蜜素的方法。在国标方法的基础上增大取样量,水浴蒸干浓缩,减少衍生后的萃取液体积,增加浓缩倍数,降低方法检出限。甜蜜素浓度在0.02～0.40 g/L范围内与其峰面积呈良好的线性关系,线性相关系数r=0.9998,方法检出限为0.1 mg/kg。该方法适用于白酒中甜蜜素的检测,加标回收率在88%~96%之间,同一样品测定结果的相对标准偏差为4.06%(n=6)。该方法检测结果与高效液相色谱–质谱法测定结果的相对偏差为3.3%~8.3%。     

离子色谱法标定硝酸银标准溶液浓度

建立了离子色谱法标定硝酸银标准溶液浓度的方法。按国家标准方法制备硝酸银标准溶液,混匀后稀释1000倍,注入Dionex Ionpac AS23离子色谱柱,以0.8mmol/L NaHCO3+4.5mmol/L Na2CO3淋洗液等度淋洗,流速为1.0mL/min,抑制电导检测NO3-浓度,外标法峰面积定量,NO3-在1.0~50.0mg/L的范围内与色谱峰面积呈良好的线性关系(R2=0.9994),加标回收率为98.22%~99.11%(RSD0.50%)。方法简便、快速、无干扰,标定准确度高,可替代容量法标定硝酸银标准溶液。     

抑制型电导检测离子色谱法测定饮用水中高氯酸盐

建立抑制型电导检测离子色谱法测定饮用水中的高氯酸盐。选用IonPac^?AS19色谱柱(250 mm×4 mm)，柱温为30℃，电导池温度为35℃，用40 mmol/L氢氧化钾溶液作为淋洗液，氢氧化钾淋洗液由淋洗液发生器在线产生，淋洗液流量为1.0 mL/min，淋洗方式为等浓度淋洗。采用AERS 500(4 mm)型抑制器，抑制器电流为99 mA，进样体积为500μL，高氯酸盐的色谱峰面积与质量浓度在0.030～0.200 mg/L范围内的线性关系良好，相关系数为0.999 2，方法检出限为0.002 mg/L，定量限为0.010 mg/L。7次重复测定结果的相对标准偏差为2.49%～3.78%，样品加标回收率为90.0%～101%。该方法适用于饮用水中高氯酸盐的检测。     

淋洗液在线发生离子色谱法测定血液透析水中的F~–,NO_3~–,SO_4~(2–)

建立血液透析水中F~–,NO_3~–,SO_4~(2–)的淋洗液在线发生–离子色谱检测法。采用ICS–1100型离子色谱仪,Ion Pac AS19型(250 mm×4 mm)色谱柱,淋洗液自动发生装置在线产生高纯度的KOH溶液作为淋洗液,流量为1m L/min,以电导检测器检测,色谱峰面积外标法定量。3种阴离子的质量浓度与色谱峰面积在测定范围内呈良好的线性关系(r≥0.999 8),检出限为0.002~0.01 mg/L,测定结果的相对标准偏差为0.26%~0.88%(n=6),加标回收率为98.0%~101.1%。该法操作简单,分析快速,灵敏度高,重现性好,能够准确检测血液透析水中的F–,NO3–,SO42–,可用于血液透析水的质量控制。     

离子色谱法测定甘草提取物中草酸的含量

建立了用离子色谱测定甘草提取物中残留草酸含量的新方法。选用DionexIonPacAS11-HC阴离子分析柱(250mm×4mmi.d.),淋洗液为18mmol/LNaOH溶液,流速为1.0mL/min,抑制电导检测器检测。草酸色谱峰面积(Y)与浓度(X)在1.004～10.04mg/L内线性关系良好,线性回归方程为Y=0.1939X-0.0326,相关系数r=0.9999,检出限为0.012mg/L。样品回收率为96.8%～98.6%,相对标准偏差为0.78%。该方法简便、快速。     

离子色谱法检验尸体心血中草甘膦

建立了离子色谱检测人血中草甘膦的方法。血液样品使用乙腈沉淀蛋白质,离心后取上清液过Dionex OnGuard II RP 柱和Dionex OnGuard IIAg柱后,经IonPac AS-19阴离子色谱柱(25 mm×4 mm)分离,用KOH淋洗液自动发生器(EG)进行梯度淋洗,抑制器采用外加水模式,电导检测器检测。结果表明,草甘膦在10～100 mg/L范围内线性关系良好(相关系数r2=0.9999)。以信噪比(S/N)为3确定方法检出限为0.12 mg/L,以S/N=10确定方法定量限为0.39 mg/L;方法回收率为95.2%～109.1%,相对标准偏差(n=5)为1.2%～3.7%,检测实发案件中死者心血中草甘膦质量浓度为508 mg/L。该方法操作简便,结果准确,适用于血中草甘膦的定量检测,能快速为案件的侦破提供可靠的线索和依据,可满足公安工作的需要。     

离子色谱柱后补液-积分脉冲安培法检测阿立哌唑中三乙胺残留

采用离子色谱柱后补液-积分脉冲安培法建立了测定阿立哌唑原料药中三乙胺残留量的新方法。色谱柱为Dionex IonPac CS17(4 mm×250 mm),保护柱为Dionex IonPac CG17(4 mm×50 mm)。对淋洗液的浓度、检测电位和柱后补液流速进行了优化选择,确定淋洗液为30 mmol/L甲烷磺酸,流速为1.0 mL/min;柱后补液为500 mmol/L NaOH溶液,流速为0.2 mL/min;检测电位为氨基酸电位。结果表明,三乙胺在0.1315~1.315 mg/L范围内线性关系良好(R2=0.9994),加标回收率在101.7%~105.9%之间,相对标准偏差(RSD)为1.9%,建立的方法适用于阿立哌唑原料药中三乙胺的残留量测定。     

离子色谱安培法测定尿液中的胱氨酸

建立离子色谱安培法检测尿液中胱氨酸的分析方法。将尿液稀释处理后,过OnGuardⅡRP前处理柱,去除尿液中的有机物,选用低容量阳离子交换柱IonPac CS17进行分离,以甲烷磺酸梯度淋洗,柱后用300 mmol/L NaOH溶液衍生,离子色谱脉冲安培法检测,外标法定量。胱氨酸的质量浓度在0.1~5.0 mg/L范围内与其色谱峰面积呈良好的线性,线性相关系数r^2=0.999 9,检出限为0.05 mg/L。测定结果的相对标准偏差为0.71%(n=6),样品加标回收率为94%~108%。该方法具有操作简单,专属性强,灵敏度高等优点,可用于临床快速检测尿液中的胱氨酸。     

高效液相色谱法分析生物样品中的敌鼠

 研究用阴离子交换、氰基及硅胶柱固相萃取技术分离提取血、尿、肝及肾中的敌鼠。以香豆素作内标 ,用高效液相色谱 二极管阵列检测器方法进行分离鉴定。色谱条件 :分析柱为HypersilBDSC18(5 μm ,15 0mm× 4 6mmi.d .) ,保护柱为PhenomenexODS(4mm× 3 0mmi.d .) ;流动相 :A为 0 5 %离子对A水溶液 ,B为 0 5 %离子对A甲醇溶液 ,以梯度淋洗程序分离 ;检测波长为 2 86nm。当敌鼠的质量浓度在 1mg/L～ 10 0mg/L范围时 ,其浓度同其峰面积与内标物的峰面积之比有良好的线性关系 (r=0 9999) ,最小检出限量为 5ng(按S/N =3计 )。     

离子色谱法测定酱油中乙酰丙酸

建立了离子色谱法测定酱油中乙酰丙酸含量的方法,并用于实际样品的检测.样品经前处理后,进入离子色谱系统进行分析,乙酰丙酸能有效地分离.选择色谱条件为:AS18 HC离子色谱分析柱,KOH等度淋洗,抑制型电导检测.采用外标法定量,乙酰丙酸浓度与其峰面积在一定浓度范围内有良好的线性关系,相关系数为0.9998.该方法的检出限(S/N=3)为O.015 mg/L,RSD 小于5.8%,回收率为92.0%～102.4%.     

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.