调味品中氯丙醇的GC/ECD和GC/MS/MS衍生化检测方法研究及应用

报道了调味品中氯丙醇的衍生化气相色谱(GC／ECD)和衍生化气相色谱双串联质谱法(GC／MS／MS)测定。GC／ECD测定酱油中3—氯—1，2—丙二醇(3—MCPD)的检出限达到0．01mg／kg，回收率为91％～104％，变异系数为2．27％～7．96％；GC／MS／MS同时测定酱油中1，3—二氯—2—丙醇、2，3—二氯—1—丙醇和3—氯—1，2—丙二醇，1，3—二氯—2—丙醇、2，3—二氯—1—丙醇的检出限为0．02mg／kg，3—氯—1，2—丙二醇的检出限为0．01mg／kg，回收率在92％～106％，变异系数为3．51％～13．33％。     

在线凝胶渗透色谱-气相色谱-串联质谱非衍生化法测定食品中氯丙醇

建立了食品中氯丙醇类化合物的非衍生化在线凝胶渗透色谱-气相色谱-串联质谱(Online GPC-GCMS/MS)测定方法,目标化合物包括3-氯-1,2-丙二醇(3-MCPD)、2-氯-1,3-丙二醇(2-MCPD)、1,3-二氯-2-丙醇(1,3-DCP)和2,3-二氯-1-丙醇(2,3-DCP).样品中加入氘代同位素内标后,采用ExtrelutTM NT硅藻土进行固相支持液液萃取净化,用正己烷淋洗去除非极性杂质,以乙酸乙酯萃取目标物,萃取液经浓缩后直接采用Online GPC-GC-MS/MS测定.4种氯丙醇在0.005～1.000 mg/L范围内呈良好线性,相关系数均大于0.999,4种氯丙醇的检出限在0.002～ 0.005 mg/kg之间,定量限在0.005～0.01 mg/kg之间.以空白酱油样品为代表性基质的3个水平(0.02,0.1和0.5 mg/kg)的加标回收率和相对标准偏差(RSD,n=6)分别为94.8％～106.3％ (2.2％ ～ 10.3％),91.8％～108.8％(2.1％～10.6％)和83.1％ ～109.4％(1.3％～9.4％).采用本方法分别对酱油、水解植物蛋白液(粉)、料酒、鸡精、面包和糕点样品进行检测,均得到了满意的测定结果.     

气相色谱法测定饼干类食品中氯丙醇类化合物

报道了饼干类食品中3-氯-1，2．丙二醇和1，3-二氯-2-丙醇的测定。采用乙醚索氏提取、甲醇萃取净化，再经N，O-双（三甲基硅烷）三氟乙酰胺（BSTFA）衍生，毛细管气相色谱法分离，FID作检测器。方法检出限为0．01mg／kg，回收率在90％～105％，相对标准偏差为2．2％～9．3％，     

气相色谱-串联质谱法同时测定调味品中3种氯丙醇

建立了气相色谱-串联质谱同时测定调味品中1,3-二氯-2-丙醇(1,3-DCP)、2,3-二氯-1-丙醇(2,3-DCP)和3-氯-1,2-丙二醇(3-MCPD)的分析方法。优化了样品前处理方法及GC-MS/MS分析条件,结果显示,样品经硅藻土净化,正己烷-乙醚(5∶5)洗脱,三氟乙酸酐衍生化后,在GC-MS/MS多反应监测模式(MRM)下测定,3种氯丙醇在0.001～10 mg/L范围内呈良好线性,相关系数分别为0.999 8、0.999 6和0.999 7;检出限(S/N=3)均为0.000 5 mg/kg,加标回收率为88%～97%。该方法简便、快速、溶剂用量少、衍生化试剂价廉易得,且能消除调味品中复杂基质的干扰,结果准确可靠、灵敏度高,适用于调味品中3种氯丙醇的同时测定。     

氧弹燃烧灰化法测定有机物中氯

采用氧弹燃烧灰化法进行样品预处理，使有机物中的氯转化为氯离子，然后用AgNO3滴定法测定氯的含量Ⅲ。通过测定面粉、虾米以及固体卤代芳烃，结果表明，方法准确、重现性好，灵敏度高，回收率为97．5％～102％，可用于有机物中氯的测定。     

气相色谱法检测汤中氯丙醇类化合物

应用毛细管柱-气相色谱法测定汤料中氯丙醇类化合物.汤料试样中氯丙醇类化合物在索氏抽取器中用乙醚萃取,于萃取液中通入氮气吹干乙醚,残留物用每次1 mL甲醇萃取两次以净化氯丙醇类化合物.收集并合并甲醇萃取液,蒸发除去甲醇后用N,O-双(三甲基硅烷)-三氟乙酰胺进行衍生化,所得衍生物经毛细管色谱柱分离,用氢火焰离子化检测器(FID)检测,方法的检出限为0.01 mg·kg-1.对精密度及回收率作了试验,得到的回收率在95%～102%之间,RSD(n=5)值小于4.5%.     

氯丙醇分子印迹自组装胶束的制备及其电化学传感性能

以双亲性无规聚合物和氯丙醇为组装基元,在选择性溶剂中制得氯丙醇分子印迹胶束,并将其电沉积在金电极表面得到分子印迹电化学传感器。采用Zeta电位及纳米粒度分析仪、透射电子显微镜表征了组装环境对形貌的影响。乳酸量、盐浓度和氯丙醇浓度对印迹胶束的组装行为有较大影响,当氯丙醇浓度为10~(-10)~10~(-4) mmol/L时制得的电化学传感器具有良好的线性响应。     

衍生化气相色谱—质谱法测定水中的路易氏剂及砷酸

本文研究了用气相色谱－质谱法测定水中微量路易氏剂及砷。在酸性条件下，路易氏剂及水解产物２，３－二巯基丙醇迅速反应形成挥发性的衍生物，大大提高了测定灵敏度。用选择性离子检测定量，最小检测量为每升水中１μｇ，路易氏剂的加标回收率为９５．６２％～１０５．８８％之间，砷的加标回收率为９６．３５％～１０６．０３％之间。     

衍生化气相色谱－质谱法测定水中的路易氏剂及砷酸

本文研究了用气相色谱－质谱法测定水中微量路易氏剂及砷。在酸性条件下，路易氏剂及水解产物２，３－二巯基丙醇迅速反应形成挥发性的衍生物，大大提高了测定灵敏度。用选择性离子检测定量，最小检测量为每升水中１μｇ。路易氏剂的加标回收率为９５．６２％～１０５．８８％之间，砷的加标回收率为９６．３５％～１０６．０３％之间。     

氯丙醇双酯在四极杆/静电场轨道阱高分辨质谱中的裂解规律研究及应用

通过直接采集碎片离子的高精度质量数（分辨率> 70 000,m/z 200），利用元素模拟得到碎片离子的元素组成，进而探究氯丙醇双酯的质谱裂解规律。结果表明：氯丙醇双酯存在以脂肪酸或酮基形式的中性丢失，形成一系列的碎裂片段：[RCH2COOH+H]+,[RCH==CO+H]+和[*g-H2O]+等，这些离子可用于鉴定脂肪酸链组成。在高碰撞能下，脂肪酸链的骨架结构形成一系列Δ=14 u的碎片离子，质荷比分布为100～210 u。值得注意的是，氯丙醇双酯在一定的碰撞能量范围内，sn-1/3位酰基链形成的碎裂片段总大于sn-2位对应的离子碎片，该结论可实现对氯丙醇双酯酰基链位置的准确鉴定。基于上述裂解规律，在植物油中共鉴定出9种3-氯丙醇双酯，含量为（7.12±0.54）～(24.24±2.01) mg/kg。     

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.     

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.     

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.     

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.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.