高效液相色谱-串联质谱联用测定人血液中的全氟化合物

采用HPLC-ESI-MS/MS联用技术,建立了分析血样中9种全氟化合物(PFCs)的方法.以13C4标记的PFOS (MPFOS)作为内标物.以C18反相柱为分析柱,甲醇、醋酸铵为梯度洗脱淋洗液,9种分析物包括全氟己烷磺酸(PFHxS)、全氟庚酸(PFHpA)、全氟辛酸 (PFOA)、全氟辛烷磺酸(PFOS)、全氟壬酸(PFNA)、全氟癸酸(PFDA)、全氟十一酸(PFUnDA)、全氟十二酸(PFDoDA)和全氟十四酸(PFTA),在15 min内即可达到良好的分离.在血样前处理中,采用MTBE液-液萃取和固相萃取相结合的方法,进一步净化样品以延长色谱柱寿命;比较了4种固相萃取小柱对全氟化合物的萃取性能,最终选定HLB柱(Waters).本研究还讨论了两种C18反相柱Acclaim 120(50 mm×4.6 mm, 3 μm)和Acclaim120 (250 mm×4.6 mm, 5 μm)(Dionex) 对PFCs的分析性能,在本实验条件下,两种色谱柱具有相似的分离性能及检出限,线性范围在0.1～50 μg/L之间 (r≥0.9957);对于血液样品该方法的检出限在0.03～0.8 μg/L之间.本研究将该方法成功地应用于血样实际样品中全氟化合物的测定,加标回收除PFTA较低外,其它化合物均在74.2%～118.1%之间.     

混合无机酸消解-固相萃取-高效液相色谱-串联质谱法分析贝类壳体中的3种全氟磺酸化合物

建立了采用混合无机酸消解-固相萃取(SPE)-高效液相色谱-电喷雾电离串联质谱(HPLC-ESI-MS/MS)分析贝类壳体中的3种全氟磺酸化合物的方法。将贝壳粉经硝酸/盐酸混合酸消解,用氢氧化钠调节消解液的pH值至6后采用Oasis WAX固相萃取柱富集净化,然后采用内标法通过HPLC-ESI-MS/MS在分时段选择反应监测模式下分析上述全氟磺酸化合物。结果表明,该方法对于贝壳中全氟丁烷磺酸、全氟己烷磺酸和全氟辛烷磺酸的检出限(LOD)分别为0.28, 0.42和0.43 ng/g,加标回收率为94.88%～96.24%。采用此方法对渤海湾两种双壳贝类壳体进行的采样分析也表明,贝壳中3种目标污染物的含量范围为＜LOD～0.70 ng/g,比其在贝类软组织中的含量低约1个数量级。实验结果表明混合酸消解-SPE提取是检测贝类壳体中此类污染物的有效前处理方法。     

杂质延迟法去除液相系统中全氟辛酸的干扰

建立了高效液相色谱-串联质谱法(HPLC-MS/MS)对水体中7种全氟烷基酸(C4~C10)和全氟辛烷磺酸的分析方法。水样抽滤除去颗粒物杂质,加入回收率指示物,再使用WAX固相萃取柱富集和净化,提取液浓缩后,使用HPLC/MS/MS分析检测。仪器分析过程中,由于液相系统无法避免含氟材料的使用,引入了较高的全氟辛酸(PFOA)污染。本研究使用杂质延迟法实现了液相系统中PFOA和样品中PFOA的分离。在系统干扰去除后,水体中PFOA的方法检出限降低为0.8 ng/L(取样量500 mL),低定量浓度为3.2 ng/L;其它目标物的方法检出限为0.2~1.2 ng/L,低定量浓度为0.8~4.8 ng/L。本方法具有良好的重现性,6次平行样品测定中各检出化合物的相对标准偏差(RSD)均小于16%,6次基体加标实验中各目标物的回收率为87%~129%,RSD<15%。杂质延迟法有效的去除了系统干扰,降低了方法检出限,提高了方法精密度。     

高效液相色谱-串联质谱法测定医用口罩中8种全氟化合物

采用高效液相色谱-串联质谱(LC-MS/MS)技术建立了医用口罩中全氟辛酸、全氟辛烷磺酸钾、全氟十一酸、全氟十二酸、全氟辛烷磺酸胺、全氟十三酸、全氟十四酸、N-乙基全氟辛烷磺酸胺8种全氟化合物的测定方法。样品以甲醇为溶剂,超声提取,采用C₁₈(150 mm×2.1 mm, 5μm)色谱柱分离,流动相为甲醇和乙酸铵,梯度洗脱,多反应监测(MRM)模式进行分析检测,外标法定量。结果表明：8种全氟化合物的定量限(LOQ,以信噪比>10计)为0.50～1.58μg/kg,在0.5～10μg/L时标准曲线线性关系良好(r>0.9979),样品加标回收率为98.4%～102.3%,相对标准偏差为1.55%～7.44%。该方法前处理简单,回收率高,精密度好,适用于医用口罩中全氟化合物的检测。     

固相萃取-超高效液相色谱-三重四极杆质谱联用同时测定水中菊酯类农药多残留

应用固相萃取-超高效液相色谱-三重四极杆质谱(UPLC-MS/MS)联用技术,建立了水中20种菊酯类农药多残留的分析方法。通过对固相萃取柱、淋洗液、流动相等条件的优化,确定以Oasis HLB为固相萃取柱、正己烷-丙酮(9∶1,V/V)为淋洗液、0.1%乙酸水溶液-乙腈(7∶3,V/V)为流动相做水样预处理。在最优实验条件下,目标物的回收率为73.4%~124.5%,相对标准偏差(RSD)在5.7%~9.1%之间,线性范围均在1~2 000μg/L,各目标物标准品在UPLC-MS/MS系统中有效的线性相关(R2)为0.999以上。该方法具有检测限低、回收率高等优点,经实际样品测试,可适用于水中20种菊酯类农药多残留的同时检测。     

固相萃取-超高效液相色谱/串联质谱法同时测定水中27种磺酰脲类除草剂

采用固相萃取,用超高效液相色谱-串联质谱法(UPLC-MS/MS)建立了水中27种磺酰脲类除草剂的分析方法。通过对固相萃取柱、淋洗液、流动相等的优化,确定以Oasis HLB固相萃取柱、乙腈为淋洗液、0.1%乙酸-甲醇(7∶3,V/V)为流动相做水样预处理。在最优条件下,目标物回收率均为79.8%~124.5%,相对标准偏差(RSDs)为6.9%~9.6%,线性范围均为1~2 000μg/L,线性相关系数(R2)在0.999以上。该方法具有检测限低、回收率高等优点,经实际样品测试,可适用于水中27种磺酰脲类除草剂残留的同时检测。     

复合分子印迹固相萃取-HPLC-MS/MS法测定植物源性食品中多种农药残留

建立了复合分子印迹固相萃取(CMISPE)-高效液相色谱-三重四级杆串联质谱(HPLC-MS/MS)同时检测多种植物源性食品中20种三嗪类和磺酰脲类除草剂残留的分析方法。样品经乙腈提取后,利用液液萃取及复合分子印迹固相萃取小柱净化。液相色谱以乙腈和1%甲酸溶液作为流动相梯度洗脱,C8色谱柱分离,在多反应监测(MRM)正离子电喷雾扫描模式下进行HPLC-MS/MS分析。结果表明:20种除草剂在0.5~20 ng/m L范围内线性关系良好,相关系数均在0.99以上。对玉米样品进行3个水平的加标回收试验(5,10,20μg/kg),20种目标化合物的回收率在62.7%~117.4%之间,相对标准偏差(n=6)为1.7%~13.9%。检出限(S/N≥3)均小于0.63μg/kg,定量限(S/N≥10)均小于2.1μg/kg。方法适用于植物源性食品中20种三嗪类及磺酰脲类农药残留的检测。     

近岸及河口海水中全氟化合物的固相萃取富集/超高效液相色谱-串联质谱测定

建立了近岸及河口海水中全氟辛基磺酸(PFOS)、全氟辛酸(PFOA)、全氟十一酸(PFUn A)、全氟十二酸(PFDo A)、全氟十三酸(PFTr DA)、全氟十四酸(PFTA)6种全氟化合物(PFCs)的超高效液相色谱-串联质谱(UHPLC-MS/MS)测定方法。使用C18固相萃取小柱对500 m L水样中的目标物进行富集后,用15 m L甲醇-乙酸乙酯混合淋洗液(4∶1)进行洗脱,浓缩,定容至1.0 m L后,用Kinetex XB-C18色谱柱以均含5.0mmol/L甲酸铵的甲醇-水为流动相梯度洗脱方式进行分离,电喷雾负离子模式(ESI-)电离,多重反应监测模式(MRM)以及内标法对6种PFCs进行定性定量测定。优化了固相萃取、色谱分离及质谱测定条件,考察了海水盐度对方法回收率的影响。在优化实验条件下,方法在2.0,5.0,10.0 ng/L加标水平下,实际海水样品的回收率为80.1%~117.4%,在2.0 ng/L加标水平的相对标准偏差(RSD,n=7)为8.2%~12.1%。6种PFCs的线性范围为0.5~50.0μg/L,相关系数大于0.999 0;方法的定量下限(LOQ,S/N=10)为0.5~1.5 ng/L。该方法具有样品前处理简单、分析速度快、选择性好的特点,适用于近岸及河口海水中全氟化合物的快速测定。     

UPLC-MS/MS法检测肉类组织中的11种全氟化合物

建立了肉类组织中11种常见全氟化合物(全氟丁烷磺酸、全氟己烷磺酸、全氟庚酸、全氟辛酸、全氟辛烷磺酸、全氟壬酸、全氟癸酸、全氟十一酸、全氟癸烷磺酸、全氟十二酸、全氟十四酸)的Waters OasisHLB固相萃取净化/超高效液相色谱-串联质谱(UPLC-MS/MS)分析方法。肉类组织中加入内标,经乙腈均质、提取后,用玻璃纤维真空抽滤,再用乙腈饱和的正己烷除脂净化,经Waters Oasis HLB固相萃取小柱富集净化,氮吹浓缩,超高效液相色谱(UPLC)分离,以2 mmol/L醋酸铵-2 mmol/L醋酸铵甲醇溶液为流动相,使用串联四极杆电喷雾离子源负离子扫描,多反应监测(MRM)模式检测,内标法定量。11种全氟化合物在0.50～20.0μg/L范围内线性关系良好,方法的检出限为0.014～0.060μg/kg,定量下限为0.047～0.199μg/kg,回收率为70.9%～107.1%,相对标准偏差(RSD,n=6)为0.4%～11.4%。该方法具有净化效果好、定量准确、灵敏度高的特点,适用于肉类组织中11种常见全氟化合物的快速确认和准确定量。     

液相色谱-串联质谱法测定小型家用电器塑料部件中全氟辛酸

建立了高效液相色谱-串联质谱(HPLC-MS/MS)结合加速溶剂萃取测定小型家用电器塑料部件中全氟辛酸(PFOA)的分析方法。样品冷冻粉碎后采用甲醇作溶剂进行快速溶剂萃取,萃取液经C18固相萃取柱富集净化后,以C18柱为分离柱,以甲醇-水为流动相,梯度洗脱,电喷雾负离子模式下多反应监测(MRM))模式检测。PFOA在0.5～100.0μg/L范围内线性关系良好(r2=0.998 9),回收率为93%～107%,相对标准偏差为2.9%～7.6%,检出限(S/N=3)为0.5μg/kg。该方法操作简便、灵敏度高,适用于小型家用电器塑料部件中全氟辛酸残留分析。     

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.