液液萃取/液相色谱-串联质谱法分析海水中的短裸甲藻毒素

建立了基于液液萃取/液相色谱-串联质谱法定量分析海水中3种短裸甲藻毒素(BTX-1、BTX-2、BTX-3)。利用液相色谱-串联质谱的高灵敏度,将海水的分析体积减至20 mL;通过响应面优化确定了海水中短裸甲藻毒素的最佳提取条件:加6 g氯化钠,旋涡时间60 s,用5 mL乙酸乙酯提取2次。3种短裸甲藻毒素的线性范围为1～200μg/L,其检出限均为0.02μg/L,定量下限均为0.05μg/L,平均回收率为95.4%～104%,日内相对标准偏差(RSD)为2.2%～5.3%,日间RSD为3.0%～4.5%。方法降低了样品的分析体积,提高了前处理效率,且时效性和适用性强,实现了污染海水中短裸甲藻毒素的高效率痕量分析。     

离心式微固相萃取与液相色谱-质谱联用测定生物样品中新型合成大麻素

建立了离心式微固相萃取与液相色谱-质谱(LC-MS)联用，同步测定尿样和血样中5种新型合成大麻素的分析方法。尿样和血样稀释后在离心条件下通过C18离心式固相萃取柱，甲醇洗脱后LC-MS检测。结果显示，尿液基质中，5种合成大麻素在0.1～10μg/L浓度范围内线性关系良好，相关系数(R²)大于0.994，检出限(LODs)为0.01～0.02μg/L，定量限(LOQs)为0.05～0.08μg/L。全血基质中，5种合成大麻素在0.5～10μg/L浓度范围内线性关系良好，R²大于0.992, LODs为0.05～0.15μg/L, LOQs为0.18～0.50μg/L。在尿样和全血中分别添加0.5, 2, 10μg/L 3个浓度水平的合成大麻素，回收率分别为81.9%～108.3%和75.0%～95.5%，相对标准偏差(RSDs)低于10%。该方法可以满足生物样品中新型合成大麻素的分析需求。     

QuEChERS/高效液相色谱-四极杆-飞行时间质谱法测定巧克力中的18种合成大麻素

建立了检测巧克力中18种合成大麻素的QuEChERS/高效液相色谱-四极杆-飞行时间质谱方法。通过优化提取溶剂种类、提取条件和净化条件，确定200.0 mg巧克力采用1 mL甲醇超声提取10 min，取上层清液加入0.05 g C₁₈和0.05 g PSA净化后，以乙腈和0.1%甲酸水溶液为流动相进行梯度洗脱，采用ZORBAX Eclipse Plus C₁₈(3.0 mm×100 mm,1.8μm)色谱柱进行色谱分离，利用四极杆-飞行时间质谱检测。18种合成大麻素在11 min内实现了分离，5F-EMB-PICA与5F-MDMB-PICA同分异构体通过色谱保留时间和二级质谱碎片实现分辨；5F-EMB-PINACA与5F-ADB同分异构体通过二级质谱碎片实现分辨。18种合成大麻素在1～200μg/L范围内呈良好线性关系，相关系数均不小于0.997 0，检出限为0.02～0.20μg/L，定量下限为0.07～0.66μg/L，在50、100、150μg/kg加标水平下样品的回收率为86.2%～104%，仪器的相对标准偏差(RSD)为0.040%...     

液-液萃取/气相色谱-串联质谱测定纸制食品接触材料中9种挥发性全氟化合物前体物的迁移量

采用气相色谱-串联质谱(GC-MS/MS)技术建立了纸制食品接触材料中全氟脂肪醇、全氟丙烯酸酯和全氟磺酰胺等9种挥发性全氟化合物前体物的测定方法。样品采用欧盟(EU) 2017/752中食品模拟物3%乙酸、10%乙醇、50%乙醇和橄榄油浸泡,水基模拟物用二氯甲烷萃取,橄榄油浸泡液用乙腈萃取,DB-5MS(30 m×0. 25 mm×0. 25μm)色谱柱分离后,采用多反应监测(MRM)模式进行检测。9种化合物在5~500μg/L质量浓度范围内与峰面积呈线性关系。在3%乙酸、10%乙醇、50%乙醇及橄榄油食品模拟物中的方法定量下限分别为3. 3~4. 4、3. 5~4. 2、3. 3~4. 9μg/L和4. 2~5. 1 ng/g。样品加标回收率为85. 0%~115%,相对标准偏差(RSD,n=6)≤7. 8%。该法快速可靠、准确简便,适用于纸制食品接触材料中全氟化合物前体物的分析检测。     

液液萃取-气相色谱-质谱法测定地下水中32种半挥发性有机化合物

建立液液萃取–气相色谱–质谱法测定地下水中32种半挥发性有机化合物的方法。采用二氯甲烷和正己烷为萃取溶剂,经DB–5MS UI型色谱柱(30 m×0.25 mm,0.25μm)分离,选择离子扫描模式监测,内标法定量。32种半挥发性有机化合物的质量浓度在2-100μg/L的范围内与色谱峰面积具有良好的线性关系,相关系数均大于0.995,方法检出限为0.001-0.006μg/L,平均回收率为76.0%-126%,测定结果的相对标准偏差为2.30%-14.1%(n=6)。该方法能够满足地下水中32种半挥发性有机化合物的同时测定。     

液相色谱-串联质谱法测定水产品中亮绿、亚甲基蓝及其代谢物残留量

建立了水产品中亮绿、亚甲基蓝及其代谢物残留量同时测定的液相色谱-串联质谱(LC-MS/MS)方法。样品经乙酸铵缓冲溶液和乙腈提取,二氯甲烷液液萃取,PRS固相萃取柱净化,氮吹浓缩,定容后测定。以2 mmol/L乙酸铵(含0. 1%甲酸)、乙腈和甲醇为流动相,CAPCELL PAK C_(18)色谱柱进行分离,在选择反应监测(SRM)模式下测定,外标法定量。在最佳实验条件下,5种化合物在1. 0～100. 0μg/L范围内线性关系良好(r~2 0. 999),检出限(LOD,S/N≥3)均为1. 0μg/kg,定量下限(LOQ,S/N≥10)均为2. 0μg/kg;在水产品中加标水平为1. 0、5. 0、10. 0μg/kg时,回收率为70. 3%～92. 1%,相对标准偏差(RSD,n=6)为2. 3%～13%。该方法灵敏度高,能有效检测水产品中亮绿、亚甲基蓝及其代谢物的残留量。     

QuEChERS-高效液相色谱串联质谱法测定鱼血浆中喹烯酮的残留

建立了分散固相萃取-高效液相色谱-串联质谱(QuEChERS-HPLC-MS/MS)测定鱼血浆中喹烯酮残留的分析方法。血浆样品经乙腈萃取,采用乙二胺-N-丙基硅烷(PSA)与石墨化炭黑(GCB)为吸附剂进行固相分散净化。用Xtrerra C18(3.5μm,4.6 mm i.d.×150 mm)色谱柱分离,电喷雾正离子(ESI+)模式电离,多反应监测模式检测,外标法定量。方法在5～100μg/L范围内有较好的线性关系,相关系数大于0.998,方法检出限为1.5μg/L,定量限为5μg/L。采用该方法对空白血浆检测并进行加标回收实验,在5和25μg/L两个添加水平下,加标回收率大于90%,相对标准偏差(n=3)低于7.2%。     

液-液萃取气相色谱法测定地表水中痕量苯酚

建立了液-液萃取气相色谱法测定地表水中痕量苯酚的方法。用盐酸调节水样至pH2左右,以二氯乙烷-乙酸乙酯(体积比为2∶1)混合溶液为萃取剂,以CD-5色谱柱进行分离,氢火焰离子化检测器检测苯酚的含量。苯酚的质量浓度在1.00~20.0μg/L范围内与其色谱峰面积呈良好的线性关系,线性相关系数r=0.999 3,检出限为0.03μg/L。样品加标回收率为93.0%~97.0%,测定结果的相对标准偏差小于2%(n=7)。该方法检出限低,精密度和准确度高,操作简便,适用于地表水中微量苯酚的分析。     

分散液液微萃取-气相色谱-质谱法测定水样中4种嗅味物质

以四氯乙烯作萃取剂,以丙酮为分散剂对水样中4种嗅味物质,二甲基异莰醇、土臭素、β-环柠檬醛和β-紫罗兰酮进行分散液液微萃取,提取液供气相色谱-质谱仪分析。在选择离子监测模式下,4种嗅味物质的线性范围均为0.05～20μg.L-1。二甲基异莰醇、土臭素、β-环柠檬醛和β-紫罗兰酮的检出限(3S/N)分别为0.03,0.01,0.02,0.01μg.L-1。方法用于自来水和河水样品分析,4种嗅味物质的回收率在87.7%～102%之间,测定值的相对标准偏差(n=6)在1.8%～7.8%之间。     

液液萃取-气相色谱-质谱法测定墨水中的16种多环芳烃

采用液液萃取-气相色谱-质谱法测定墨水中的16种多环芳烃。样品经二氯甲烷液液萃取后,使用固相萃取技术进行纯化。在气相色谱分离中用DB-5MS色谱柱为固定相,在质谱分析中采用选择离子监测模式。16种多环芳烃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/N)在5.0~30μg·kg-1之间。以空白样品为基体进行加标回收试验,所得回收率在60.6%~116%之间,测定值的相对标准偏差(n=6)在1.5%~5.3%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.     

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.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.