GC–MS法同时测定聚氨酯塑胶跑道中16种多环芳烃

建立气相色谱–质谱法同时测定聚氨酯塑胶跑道中16种多环芳烃如萘、苊、二氢苊、芴、菲、蒽、荧蒽、苯并[b]荧蒽、芘、苯并[a]蒽、屈、苯并[k]荧蒽、苯并[a]芘、茚并[1,2,3-cd]芘、1-甲基奈、2-甲基萘的检测方法。样品采用甲苯为提取剂,经超声提取和硅胶柱净化后,用气相色谱–质谱法测定16种多环芳烃残留量。16种多环芳烃的质量浓度在0.2~10.0 mg/kg范围内与色谱峰面积呈良好的线性,线性相关系数r20.998,检出限为5.0~60.0μg/kg。回收率为72.4%~101.6%,测定结果的相对标准偏差为0.9%~7.2%(n=6)。该方法准确度高、精密度好,适用于聚氨酯塑胶跑道中多环芳烃多残留检测。     

冷冻研磨超声浸提分离-气相色谱-质谱法测定充油丁苯橡胶中8种多环芳烃的含量

为从充油丁苯橡胶样品中分离提取其中所含8种多环芳烃化合物(PAHs,包括苯并[a]蒽、艹屈、苯并[b]荧蒽、苯并[j]荧蒽、苯并[k]荧蒽、苯并[e]芘、苯并[a]芘及二苯并[a,h]蒽),采用了冷冻研磨、超声浸提法。试验选择了5件样品分别将其粉碎至约2mm~3的颗粒,并取一定量的颗粒样品置于研磨仪中进行冷冻研磨至粉末状态。称取加工成粉末状的样品1.00g,加入正己烷-丙酮(1+1)混合溶液10mL,在40℃超声提取35min。将所得提取液氮吹浓缩至近干,用正己烷1mL溶解残渣,所得溶液经滤膜过滤,滤液供气相色谱-质谱分析。采用VB-17MS毛细管色谱柱,在90～300℃温度区间按程序升温模式进行分离。在质谱分析中,用电子轰击离子源和选择离子监测模式。测得8种PAHs的线性范围均在0.05～5.0mg·L~(-1)之间,检出限(3S/N)在0.01～0.02mg·L~(-1)之间。在样品溶液中加入混合标准溶液进行回收试验,测得回收率在84.5%～106%之间,并从测定值计算其相对标准偏差(n=6)在1.6%～4.9%之间。     

气相色谱质谱法测定化妆品中9种多环芳烃

建立了气相色谱质谱法测定化妆品中9种多环芳烃的分析方法。化妆品中的萘、苯并[a]蒽、、苯并[b]荧蒽、苯并[j]荧蒽、苯并[k]荧蒽、苯并[e]芘、苯并[a]芘、二苯并[a,h]蒽等9种多环芳烃用甲醇超声提取后,用环己烷液-液萃取后浓缩,经硅胶-中性氧化铝柱净化后,采用气相色谱-质谱测定。多环芳烃浓度在0.05～2 mg/L范围内,质量浓度与其峰面积呈良好的线性关系。在低、中、高3个添加水平下,9种多环芳烃化合物的平均回收率为81.6%～100.2%,相对标准偏差为1.3%～5.8%。方法可用于化妆品中多环芳烃的检测。     

气相色谱-串联质谱法同时测定卷烟滤嘴中15种多环芳烃

建立了气相色谱-串联质谱同时检测卷烟滤嘴中15种多环芳烃的方法。卷烟滤嘴用二氯甲烷振荡萃取后,经0.22μm有机相滤膜过滤,采用DB-5MS色谱柱(30 m×0.25 mm,0.25μm)进行分离,电子轰击源、正离子模式下以多反应监测模式进行检测,内标法进行定量。15种多环芳烃(苊烯、苊、芴、菲、蒽、荧蒽、芘、苯并[a]蒽、屈、苯并[b]荧蒽、苯并[k]荧蒽、苯并[a]芘、二苯并[a,h]蒽、苯并[g,h,i]苝和茚并[1,2,3-c,d]芘)的线性关系良好,相关系数(R~2)为0.991 4~0.999 9。15种多环芳烃在低、中、高3个添加水平下的平均回收率为81.6%~111.2%;除了芴在低添加水平时相对标准偏差为19.2%外,其他相对标准偏差均小于16%。15种多环芳烃的检出限为0.02~0.24 ng/滤嘴,定量限为0.04~0.80 ng/滤嘴。方法前处理简便,具有快速、准确、灵敏度高及重复性好的优点,适用于卷烟滤嘴中多环芳烃的分析。     

配位聚合物固相萃取/气相色谱-质谱联用法测定环境水样中的6种多环芳烃

制备了一种二维的[Zn(benzotriazole)2]n配位聚合物,并经过XRD、SEM及元素分析法的表征,将其用于富集萃取环境水样中的6种重质多环芳烃,该配合物对于含多苯环的化合物显示出较强的吸附力。实验中分别对填料用量、淋洗剂、洗脱剂的种类及用量、穿透体积等参数进行考察,并将其与同等上样量及加标量的C18固相萃取小柱进行对比,建立了水样中6种多环芳烃的气相色谱-质谱联用检测方法。结果表明,使用200mg[Zn(benzotriazole)2]n配合物作为固相萃取填料,以10%甲醇为淋洗剂,0.5mL丙酮和5mL二氯甲烷作为洗脱剂,在上样体积为200mL、流速为4mL/min的条件下,6种多环芳烃均具有较高的回收率。荧蒽(Flan)、苯并(b)荧蒽(BbF)、苯并(g,h,i)芘(BghiP)的质量浓度在20～1000μg/L范围内,苯并(k)荧蒽(BkF)、苯并(a)芘(BaP)、茚并(1,2,3-Cd)芘(InP)在10～500μg/L范围内与峰面积呈良好线性关系,相关系数为0.9968～0.9993。方法的检出限为0.45～10.7ng/L,加标回收率为77%～112%,相对标准偏差为3.8%～8.5%。结果表明,该方法具有成本低、灵敏度高等特点,能够满足实际水样中6种多环芳烃的测定要求。     

Rapid Determination of Benzo[a] pyrene in Edible Vegetable Oil Using a New Type of Solid Phase Extraction Column

研究了Bond Elut ENV新型固相萃取柱在食用植物油中苯并[a]芘快速检测中的应用,建立了快速测定食用植物油样品中苯并[a]芘残留量的固相萃取/液相色谱/荧光检测法.样品用正己烷溶解,固相萃取净化,SUPELCOSILTM LC - PAH(25 cm×4.6 mm,5μm)色谱柱分离,以乙腈-水(95:5)为流动相,荧光检测(λ(n) =297 nm,λem=408 nm),外标法定量.苯并[a]芘的检出限为0.3μg/kg,在1.0 ～50.0 μg/L范围内线性关系良好,相关系数为0.9996,方法的回收率为79％～102％,相对标准偏差不高于9.4％.该方法准确、实用、简便、快速,在食用植物油的苯并[a]芘残留量检测方面有广泛的应用前景.     

分散式固相萃取结合高效液相色谱法快速测定油脂制品中苯并(a)芘

1引言苯并(a)芘(BaP)具有强致癌和致突变作用[1]。油脂制品中的苯并(a)芘主要源自不合理的加工方式:如温度过高的油料焙炒、高温压榨等工艺过程均可导致油脂受热分解,环化聚合生成苯并(a)芘[2]。目前,关于食品中苯并(a)芘较为普遍的检测方法主要有薄层色谱法[3]、高效液相色谱法(HPLC)[4]、气相色谱-质谱法[5]等。提取净化方法主要有凝胶渗透色谱法[6]、液液萃取法[7]、固相萃取法[8]、层析柱法等[9]。本研究采用高效液相色谱荧光检测法,应用分散式固     

超声提取-高效液相色谱法测定纺织品中5种同分异构CMR物质

采用超声提取结合高效液相色谱同时测定纺织品中5种同分异构CMR物质[苯并(j)荧蒽(BjF)、苯并(e)芘(BeP)、苯并(b)荧蒽(BbF)、苯并(k)荧蒽(BkF)和苯并(a)芘(BaP)]的含量。样品0.500 g经20 mL体积比为1:1的甲醇-四氢呋喃混合溶剂于30℃超声提取30 min,提取液在Agilent Eclipse PAH色谱柱上分离,以乙腈-水混合液为流动相进行梯度洗脱,采用荧光检测器进行检测。结果表明:5种同分异构CMR物质的质量浓度在5.0～150 μg·L~(-1)内与其峰面积呈线性关系,检出限(3S/N)均为1.0 μg·L~(-1)。加标回收率为98.6%～103%,测定值的相对标准偏差(n=6)为 2.9～3.7%。     

用固体基质室温燐光法分析环境样品中多环芳烃的研究

用滤纸基质室温燐光法分析多环芳烃。以醋酸铊TlAc/醋酸铅Pb(Ac)_2(1∶1mol)的乙醇水(50％V/V)溶液为重原子微扰剂,对国产分析滤纸,玻璃纤维滤膜和醋酸纤维滤膜等9种不同的基质材料测定芘的燐光信号强度并进行了比较。对芘、荧蒽、苯并(e)芘、苯并(a)芘、苯并(ghi)芘和晕苯的混合物样品进行了测定。对煤飞灰和燃煤排放物样品中的芘和苯并(a)芘进行了定量分析,并用高效液相色谱法对测定结果进行验证。对芘和苯并(a)芘的检测限分别达到10~(-10)和10~(-9)g数量级。本文还对进一步提高灵敏度的问题进行了讨论。     

固相微萃取-气相色谱串联质谱法检测北京大气细颗粒物中的多环芳烃

采用固相微萃取与气相色谱串联质谱联用,建立了快捷测定大气细颗粒物(PM2.5)中16种优控多环芳烃的方法.目标物先用二氯甲烷富集浓缩,然后用100 μm聚二甲基硅氧烷萃取纤维,通过超声萃取方式,在60℃条件下,萃取30 min.在优化的在多反应监测模式下,方法回收率在56.8％ ～ 106.0％之间,检出限为0.022～0.056 ng/m3.应用此方法检测了清华大学采样点采取的2013年1月1到15日北京PM2.5空气样品中的16种PAHs,实验结果表明,PAHs总质量浓度在290～1812 ng/m3之间,其中四环PAHs的总质量浓度最大(145 ～937 ng/m3),其次是五环PAHs(总质量浓度81.1～664.5 ng/m3),分子质量浓度较高的依次是荧蒽、芘、苯并(b)荧蒽、(蕴)、苯并(a)芘、苯并(k)荧蒽、苯并(a)蒽和菲,PAHs的污染主要来源于化石燃料燃烧和机动车排放.     

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.     

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.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

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.