气相色谱-质谱联用对纺织品中16种含氯酚及邻苯基苯酚、β-萘酚残留量的测定

建立了气相色谱-质谱(GC-MS)测定纺织品中16种含氯酚及邻苯基苯酚、β-萘酚残留量的方法.样品经甲醇超声提取、浓缩后,用0.1 mol/L硼砂溶液溶解,再经乙酸酐乙酰化后正己烷提取,用GC-MS测定,内标法定量.在0.025 ~1.0 mg/L范围内,方法的线性关系良好,相关系数为0.999 3 ~0.999 9,添加回收率为83% ~112%,相对标准偏差为0.26% ~8.82%.该方法简便、快速、灵敏度高,完全可满足进出口纺织品中16种含氯酚及邻苯基苯酚、β-萘酚残留量检测的要求.     

衍生化-分散液液微萃取-气相色谱/质谱法同时测定纺织固体废物中含氯苯酚和邻苯基苯酚

建立了衍生化-分散液液微萃取-气相色谱/质谱(DLLME-GC/MS)方法,并将其用于纺织固体废物中18种含氯苯酚和邻苯基苯酚的分析检测。方法对衍生化体系、乙酸酐用量、衍生化温度和时间、萃取剂种类及用量、分散剂种类及用量进行了筛选和优化。确定最佳条件为:纺织固体废物样品用0.15 mol/L的K_2CO_3溶液超声提取后定容,加入0.12 mL乙酸酐,于温度60℃条件下衍生35 min,取6 mL样品提取液,加入0.7 mL体积比为2∶5的四氯化碳(提取剂)和丙酮(分散剂)的混合溶剂分散萃取后,于8 000 r/min下离心3 min,取下层有机相进行GC/MS分析。18种含氯苯酚和邻苯基苯酚在0.002～0.160 mg/L范围内均呈良好的线性关系,相关系数为0.9991～1.0000,检出限为0.07～0.76μg/kg,定量限为0.28～3.04μg/kg,样品加标回收率在84.2%～105.0%范围,相对标准偏差在0.6%～6.4%之间。该方法简单、灵敏,适用于纺织固体废物中18种含氯苯酚和邻苯基苯酚的分析。     

纺织品中19种含氯苯酚的气相色谱-质谱联用测定及其迁移行为

建立了气相色谱-质谱联用(GC-MS)同时测定纺织品中19种残留含氯苯酚的分析方法。以棉贴衬纺织品为基底材料,采用0.1 mol/L K_2CO_3溶液作为萃取液及衍生化介质,乙酸酐乙酰化,正己烷萃取后进行GC-MS测定,采用选择离子监测进行确证,外标法定量。检出限为2μg/kg,线性范围为0.0004~1.0 mg/L,线性相关系数R~2大于0.999,加标回收率为88.6%~107.6%,相对标准偏差(RSDs,n=7)为1.8%~7.6%,方法可满足纺织品及其制品中19种含氯苯酚类物质的同时检测需求。研究了棉纺织品中含氯苯酚的迁移行为,表明纺织品表面涂层性质、厚度等均对此迁移行为产生一定的影响。     

同位素稀释-气相色谱三重四极杆质谱法测定水性内墙涂料中的苯酚与氯代苯酚防霉杀菌剂

建立了同位素稀释-气相色谱串联三重四极杆质谱(GC-MS/MS)测定水性内墙涂料中苯酚及氯代苯酚(2-氯苯酚、2,4-二氯苯酚、2,4,6-三氯苯酚、2,3,4,6-四氯苯酚、五氯苯酚、邻苯基苯酚和六氯芬)防霉杀菌剂的方法。样品加入同位素内标,经甲醇超声提取,乙酸酐衍生后正己烷提取,采用GC-MS/MS测定,内标法定量,方法检出限均为0.005 mg/kg。目标物在0.02~1 mg/kg范围内线性良好,相关系数大于0.99,添加回收率为75.3%~107.6%,相对标准偏差为4.3%~14%。方法可以满足以丙烯酸、聚醋酸乙烯-丙烯酸和聚苯乙烯-丙烯酸为基材的水性内墙涂料中氯酚类防霉杀菌剂残留的检测要求。     

气相色谱-质谱法测定水产品中19种氯代酚及其钠盐

建立了用气相色谱-质谱(GC-MS)联用法测定水产品中19种氯代酚及其钠盐的分析方法。试样用H_2SO_4消解后,用环己烷-乙酸乙酯提取酸解液中的氯代酚,利用酚类易溶于稀碱溶液的性质,将氯代酚提取到稀碱液中,调稀碱液pH至微酸性,用二氯甲烷-正己烷溶液萃取,无水Na_2SO_4脱水,浓缩定容并硅烷化衍生后,用GC-MS仪EI源选择离子模式检测,氘代4-氯-3-甲基酚(PCMC-d_2)和氘代2,4,6-三溴苯酚(2,4,6-TBP-d_2)为内标,内标法定量。氯代酚在2.0~70.0μg/L范围内,其浓度和峰面积呈良好的线性相关(r≥0.999);水产品中添加量为1.00μg/kg、2.00μg/kg、3.00μg/kg和7.00μg/kg时,回收率一氯酚(MCP)为55.2%~88.8%,二氯酚(DCP)为63.0%~114%,三氯酚(TCP)为76.0%~116%、四氯酚(TeCP)为78%~125%,五氯酚(PCP)为83.2%~104%;方法检出限在0.2~0.4μg/kg之间。     

固相微萃取-气相色谱法测定鱼肉中五氯酚

经匀浆的鱼肉样品置于20 mL顶空瓶中,加入氯化钠3.0 g,水1 mL及pH 2.0硫酸溶液9 mL,于40℃超声萃取30 min。将顶空瓶放入带固相微萃取装置的Combi PAL全自动进样器中,于90℃温度下加热20 min后,用85μm聚丙烯酸酯萃取头固相微萃取10 min,于280℃热解3 min,用HP-5毛细管柱分离后,用气相色谱法(电子捕获检测器)测定五氯酚的含量。五氯酚的线性范围在0.05~100μg.L-1之间,方法的检出限(3S/N)为0.02μg.L-1。在3个浓度水平(1.0,5.0,50.0μg.kg-1)上对方法的回收率进行试验,测得回收率在81.2%~89.4%之间,测定值的相对标准偏差(n=6)在4.2%~7.1%之间。     

分散液相微萃取-分光光度法测定水样中痕量肼

建立了分散液相微萃取-分光光度法测定痕量肼的新方法.在0.2 mol/L HCl介质中,以对二甲氨基苯甲醛(PDAB)为显色剂,三氯甲烷为萃取剂,乙醇为分散剂分离富集溶液中痕量肼.优化了反应酸度、萃取剂与分散剂的选择和用量、显色剂用量、显色时间和萃取时间等影响因素.最佳实验条件下,方法的线性范围0.80~120μg/L(r=0.999 5),检出限0.26μg/L.应用于实际水样测定,回收率在98.0%~103.4%之间,RSD在2.7%~3.2%之间.     

蔬菜中甲胺磷等5种有机磷农药残留量的分散液-液微萃取/气质联用技术检测

建立了分散液-液微萃取/气相色谱质谱(DLLME/GC-MS)联用技术分析蔬菜样品中甲胺磷、甲拌磷、甲基对硫磷、毒死蜱和乐果5种有机磷农药残留的新方法。优化后的萃取条件:10μL氯苯为萃取剂,1.0 mL丙酮为分散剂,萃取时间为3 m in。5种有机磷农药均具有良好的线性关系,相关系数不低于0.995,加标回收率为60%~95%,相对标准偏差为2.8%~9.1%,检出限为0.001~0.140 mg/kg。应用于蔬菜中有机磷农药残留的检测,结果满意。     

盐酸甲醇溶液提取-气相色谱-质谱法测定水生动植物样品丁基锡

采用四乙基硼酸钠(NaBEt4)为衍生剂,建立简单、高效的生物样品有机锡气相质谱(GC-MS)分析方法。结果表明,冷冻干燥生物样品粉末0.1 g经15 mL 0.035 mol/L盐酸甲醇振荡提取1 h,定量提取液加入乙酸盐缓冲溶液(pH 4.8)调节溶液酸度,用含内标物正己烷2 mL和0.5 mL 2%(m/V)NaBEt4水溶液衍生萃取30 min后,GC-MS同时测定一丁基锡(MBT)、二丁基锡(DBT)、三丁基锡(TBT)。在0.5~50μg/L范围内,线性良好,3种有机锡加标回收率均在80%以上。此方法能快速简单对复杂生物样品中的有机锡进行分析,其检出限约为0.01μg/L,3个平行样测量值标准偏差都在10%以内。     

离子液体-分散液液微萃取/高效液相色谱法用于猪肾脏中3种四环素类抗生素的检测

建立了分散液液微萃取(DLLME)技术进行样品前处理,高效液相色谱(HPLC)法测定猪肾脏中土霉素(OTC)、四环素(TC)、金霉素(CTC)3种四环素类抗生素(TCs)残留量的方法。考察了分散剂种类、离子液体用量、分散剂用量、样品溶液p H值、萃取时间、盐效应等因素对萃取效率的影响。优化后的实验条件为:以丙酮为分散剂,离子液体([BMIM]PF6)用量为50μL,分散剂用量为140μL,样品溶液p H值为3.0,萃取时间为15 min,不添加盐。该方法在0.1~10.0 mg/L范围内线性关系良好(r2≥0.999 5),土霉素、四环素和金霉素的相对标准偏差(RSD)为2.2%~3.1%,检出限(LOD)为54~93μg/L,富集倍数为7.0~27.8,且样品的加标回收率达99.5%~101.1%。该法准确度和精密度均满足分析方法的要求,实现了对猪肾脏中土霉素、四环素、金霉素3种四环素类抗生素残留量的快速、绿色、灵敏和准确检测。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

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.