气相色谱-质谱法同时快速测定血清中5种剧毒灭鼠剂

建立了同时快速测定血清样品中毒鼠强、氟乙酰胺、氟乙酸钠、甘氟Ⅰ与甘氟Ⅱ 5种灭鼠剂的气相色谱-质谱联用法。在pH 2.0条件下,以N,N-二乙基对苯二胺为衍生剂,N,N'-二环己基碳二亚胺为催化剂,氟乙酸钠在室温下振荡衍生5 min,衍生物与毒鼠强、氟乙酰胺、甘氟Ⅰ、甘氟Ⅱ一并被乙酸乙酯萃取,经50 ℃下氮吹浓缩后用气相色谱-质谱同时测定,采用选择离子监测(SIM)模式,基质标准外标法定量。方法选用SLB-IL59离子液体毛细管柱(30 m×0.25 mm×0.20 μm,最高温度:300 ℃),流速1.0 mL/min,经程序升温在15 min内成功地分离了5种灭鼠剂。结果显示,血清中氟乙酰胺的线性范围为0.02~2.0 mg/L,毒鼠强的线性范围为0.02~10 mg/L,其他目标物的线性范围为0.01~1.0 mg/L;检出限为0.001~0.002 mg/L (S/N=3),相关系数R²>0.995。在3个加标水平下,方法加标回收率介于84.0%和110.0%之间,相对标准偏差(n=6)介于2.9%和7.5%之间。方法操作简便、准确,灵敏度高,适于中毒病人的快速诊断检测。     

铒甘氨酸配位化合物和铒组氨酸配位化合物的EXAFS谱研究

本文用EXAFS谱研究了三个固体铒甘氨基酸配位化合物, 得到铒甘氨酸和铒组氨酸的第一配位层Er-O键长分别为2.35和2.32A, 配位数分别为8.3和8.0. 并进一步用EXAFS径向结构函数图, 讨论了与其结构类型的关系, 推测出铒氨基酸配位化合物晶体的所属可能结构类型。     

铒甘氨酸配位化合物和铒组氨酸配位化合物的EXAFS谱研究

本文用EXAFS谱研究了三个固体铒甘氨基酸配位化合物,得到铒甘氨酸和铒组氨酸的第一配位层Er—O键长分别为2.35和2.32 A,配位数分别为8.3和8.O。并进一步用EXAFS径向结构函数图,讨论了与其结构类型的关系,推测出铒氨基酸配位化合物晶体的所属可能结构类型。     

超高效液相色谱法测定水产品中甲砜霉素和氟甲砜霉素残留

建立了一种同时测定水产品中甲砜霉素和氟甲砜霉素药物残留的超高效液相色谱(UPLC)方法。样品经乙酸乙酯提取,正己烷液-液分配除脂,过HLB固相萃取小柱,用3mL10%甲醇淋洗,5mL100%甲醇洗脱,洗脱液用氮气吹干,残渣用1mL10%乙腈水溶液定容。采用超高效液相色谱分离,二极管阵列检测器检测,外标法定量。甲砜霉素在0.05~2.0mg/L,氟甲砜霉素在0.025~1.0mg/L范围线性关系良好,相关系数分别为0.9996、0.9999;样品加标平均回收率分别为80.0%、95.8%;相对标准偏差分别为5.6%、11.2%,甲砜霉素、氟甲砜霉素检出限分别为10μg/kg、5μg/kg。     

液液微萃取-甲基衍生化/气相色谱法对水中氯代酸除草剂的测定

在pH大于12的条件下使水样中的氯代除草剂全部水解为盐,用正己烷和甲基叔丁基醚混合溶剂提取有机杂质,再在酸性条件下经5 mL甲基叔丁基醚提取,重氮甲烷甲基衍生化30 min后用带微电子捕获检测器的毛细管气相色谱分析,以4,4-二溴八氟联苯为内标物进行定量.茅草枯、麦草威、2,4-D、五氯苯酚的质量浓度分别在5.0 ～500、1.0 ～200、5.0 ～500、0.5 ～100 μg/L范围内与色谱峰面积呈良好的线性关系(r= 0.994 5 ～0.998 0),检出限分别为1.0、0.5、1.0、0.1 μg/L.用该法测定南京玄武湖水样中的茅草枯,其质量浓度为7.1 μg/L,4种被测组分在高、中和低添加水平下的回收率分别为102% ～105%、96% ～110%、87% ～109%.同时建立了一种生产重氮甲烷的新原料--N-亚硝基-N-甲基脲的简易方法.     

盐酸超声-氟离子选择电极法测定复合肥中氟含量

为快捷有效地测定复合肥中氟的含量,采用盐酸浸取过夜、盐酸超声、碱熔、纯水煮沸四种方法提取复合肥中的氟离子,用氟离子选择电极进行测定,全程加标回收;结果发现盐酸超声提取法测得值与碱熔提取法测定值非常接近,并且加标回收率为98.4%~104.2%,相对标准偏差为1.9%;则用盐酸超声提取法测定复合肥中的氟含量方法可靠,方便快速,能够满足复合肥中氟含量的测试要求。     

大体积进样气质联用法同时检测毒鼠强和氟乙酰胺

建立了气相色谱-质谱法同时检测食品中毒鼠强和氟乙酰胺的方法,重点探讨了具有溶剂排空模式的程序升温汽化(PTV)进样口对大体积进样的作用。通过对分流排空流量、吹扫时间、PTV温度及其最大进样体积等PTV参数的优化,选择离子模式和大体积进样能够将检出限提高2～3个数量级,两种灭鼠药的回收率均为83.7%～105%,相对标准偏差为1.5%～6.2%,毒鼠强最低检出限为1.0 μg/kg ,氟乙酰胺最低检出限为5.0 μg/kg ,用外标法定量,在质量浓度为5～100 μg/kg 时,毒鼠强和氟乙酰胺的线性     

流动注射化学发光法测定3种氟喹诺酮类药物

研究发现,氟喹诺酮类药物对可溶性Mn(-甲醛化学发光体系有强烈的增敏作用,结合流动注射技术,建立了3种氟喹诺酮类药物诺氟沙星、氧氟沙星和环丙沙星的流动注射化学发光新方法。在优化的实验条件下(2×10-4molMn(-3%甲醛-3mol/L磷酸),本方法测定诺氟沙星、氧氟沙星和环丙沙星的线性范围分别为1.0×10-7～1.0×10-5mol/L,1.0×10-7～1.0×10-5mol/L和3.0×10-7～5.0×10-5mol/L;检出限分别为3×10-8mol/L,3×10-8mol/L,1×10-7mol/L;相对标准偏差(5.0×10-6mol/L氟喹诺酮类药物,n=11)分别为2.6%,1.6%和2.8%。该方法已用于诺氟沙星胶囊中诺氟沙星的含量测定。     

超高效液相色谱-串联质谱法测定人血浆中蘑菇毒肽的含量

提出了用超高效液相色谱-串联质谱法测定人血浆中6种蘑菇毒肽含量的方法。取人血浆样品1.0mL,先后用乙腈-甲醇(1+1)混合溶液(每次用3mL)超声提取10min,离心5min,合并2次上层提取液,于50℃吹氮至近干,加入甲醇和5%(体积分数)氨水(1+4)的混合溶液溶解残渣,并定容至1.0mL,此溶液经0.22μm滤膜过滤,取滤液进行色谱分离和质谱测定。选用BEH C_(18)色谱柱作为固定相,并用不同比例的(A)甲醇和(B)5%(体积分数)氨水的混合液作为流动相进行梯度洗脱。质谱分析时,选择电喷雾离子源正离子(ESI+)模式在弱碱性条件下,用多反应监测(MRM)模式测定6种蘑菇毒肽(α-鹅膏毒肽、β-鹅膏毒肽、γ-鹅膏毒肽、二羟基鬼笔毒肽、羧基二羟基鬼笔毒肽和羧基三羟基鬼笔毒肽)的含量。上述6种蘑菇毒肽标准曲线的线性范围均在3.12～125μg·L~(-1)之间,其测定下限(10S/N)在2.0～5.0μg·L~(-1)之间。回收试验测得回收率在78.4%～106%之间,测定值的相对标准偏差(n=6)在2.3%～14%之间。     

小体积液相萃取-气相色谱-质谱法测定唾液中鸦片类毒品的含量

提出了小体积液相萃取-气相色谱质谱法测定唾液中鸦片类毒品含量的方法。在pH9的磷酸盐缓冲溶液中,1 mL的唾液试样(其中加入乙基吗啡为内标)用150μL的氯仿进行超声提取10min,使吗啡、6-单乙酰吗啡和可待因进入有机相,离心分离,取上清液80μL加入N-甲基-双-三氟乙酰胺试剂进行衍生化,所得衍生化产物的溶液做气相色谱-质谱法检测。唾液中吗啡、6-单乙酰吗啡、可待因的检出限(3S/N)分别为0.005,0.003,0.002mg·L~(-1),标准曲线线性范围均为0.01～1.0mg·L~(-1)。在唾液试样中添加0.01,0.10,1.00mg·L~(-1)L混合标准溶液,测得平均回收率:吗啡为38.1%～50.0%,6-单乙酰吗啡为81.5%～88.8%,可待因为89.9%～109.8%,相对标准偏差(n=5)在6.7%～18.4%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.