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。     

同位素稀释-气相色谱-质谱法测定食用植物油中总氯丙醇脂肪酸酯

建立了食用植物油中总氯丙醇脂肪酸酯(氯丙醇酯)的同位素稀释-气相色谱-质谱(GC-MS)检测方法。样品经甲醇钠-甲醇溶液水解,硅藻土小柱净化,七氟丁酰咪唑(HFBI)衍生后,GC-MS 检测,同位素内标法定量。3-MCPD 酯、2-MCPD 酯、1,3-DCP 酯和2,3-DCP 酯在0.050~2.000 mg/ L 浓度范围内,均呈良好线性相关,相关系数(R)均大于0.9995。3-MCPD 酯、2-MCPD 酯、1,3-DCP 酯和2,3-DCP 酯的检出限分别为0.015,0.015,0.030和0.030 mg/ kg,定量限分别为0.050,0.050,0.100和0.100 mg/ kg。以空白特级初榨橄榄油为空白基质的加标回收实验的平均回收率为87.0%~110.5%,相对标准偏差(RSD)均小于10.1%。在74份食用植物油样品中,3-MCPD 酯、2-MCPD 酯和1,3-DCP 酯的检出率分别为94.6%,63.5%和5.4%,未检出2,3-DCP 酯;3-MCPD 酯、2-MCPD 酯和1,3-DCP 酯的含量分别在未检出(ND)~10.646 mg/ kg、ND ~3.617 mg/ kg 和ND ~0.089 mg/ kg 之间。本方法简便、准确、可靠,适用于食用植物油中总氯丙醇酯的测定。     

微乳电动毛细管色谱法分离检测酱油中的氯丙醇

建立了微乳电动毛细管色谱分离3种氯丙醇的方法。以十二烷基硫酸钠(SDS)作为表面活性剂,系统考察了pH值、缓冲溶液类型和浓度、SDS浓度、助表面活性剂浓度、油相浓度、温度和运行电压对3-氯-1,2-丙二醇(3-MCPD),1,3-二氯-2-丙醇(1,3-DCP),2,3-二氯-1-丙醇(2,3-DCP)分离的影响。结果表明,最佳微乳缓冲液为1%(V/V)正庚烷,100 mmol/L SDS,10%(V/V)正丁醇和8 mmol/L磷酸二氢钠-硼砂溶液(pH 8.50),检测波长为192 nm,温度20℃,分离电压为15 kV。3种氯丙醇的线性范围为2.0×10-6～3.2×10-5 mol/L,相关系数大于0.996,检出限(S/N=3)为0.95～1.9μmol/L。酱油样品经乙醚液液萃取,萃取平均回收率为93.2%～103.0%,相对标准偏差小于6.5%。本方法应用于实际样品和加标后样品中三氯丙醇的检测,结果满意。     

固相萃取-同位素内标-气相色谱-质谱法测定纸质食品接触材料中4种氯丙醇的迁移量

<正>1 引言氯丙醇是丙三醇结构上的羟基被氯原子取代而成的一类化合物,主要包括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),具有急、慢性毒性作用,易引起某些实验动物肿瘤,造成肾脏和生殖系统损伤, 是国际公认的食品污染物。纸质材料可以制成杯、碟、碗等,被广泛用作食品容器和包装材料餐具等。纸制品生产过程中,常添加环氧氯     

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％。     

固相萃取-气相色谱-质谱法测定酱油中3-氯-1,2-丙二醇

建立了酱油中3-氯-1,2-丙二醇(3-MCPD)残留量的同相萃取-气相色谱-质谱(GC/MS)分析方法.利用SampliQ OPT固相萃取柱净化样品,考察了乙醇、丙酮、乙醚、乙醚-正已烷(9:1,V/V)4种洗脱液对3-MCPD回收效果的影响.洗脱液在室温下经氮气吹干后用双(三甲基硅烷基)三氟乙酰胺-三甲基氯硅烷(B...     

分散固相萃取结合气相色谱-高分辨质谱快速筛查酱油中多种氯丙醇

建立了酱油中1，3-二氯-2-丙醇、2，3-二氯-1-丙醇、3-氯-1，2-丙二醇和2-氯-1，3-丙二醇的分散固相萃取-气相色谱-高分辨质谱快速筛查检测方法。样品采用乙酸乙酯提取，提取液浓缩后经N-丙基乙二胺净化，气相色谱-高分辨质谱测定，内标法定量。结果表明，该方法对于酱油中4种氯丙醇的定量限为0.5~10 μg/kg。在3个浓度水平下的加标回收率为78%~103%；相对标准偏差均不大于8.8%。该方法快速、简便、准确、灵敏，可作为酱油中4种氯丙醇的有效检测方法。     

气相色谱-三重四极杆串联质谱法同时测定调味品中的氨基甲酸乙酯和氯丙醇

建立了气相色谱-三重四极杆串联质谱(GC-MS/MS)同时测定调味品中氨基甲酸乙酯(EC)和氯丙醇(3-氯-1,2-丙二醇(3-MCPD)和2-氯-1,3-丙二醇(2-MCPD))的方法。样品添加同位素内标后,采用Extrelut^TM NT有机硅藻土填料进行基质固相分散萃取,先用正己烷淋洗除杂,再用乙酸乙酯-乙醚(20:80, v/v)混合溶剂洗脱被测物,洗脱液经浓缩后采用GC-MS/MS多反应监测(MRM)模式测定。EC、3-MCPD和2-MCPD的方法检出限依次为2、5和5 μg/kg,线性范围依次为5~1000 μg/kg(r=0.9997)、10~1000 μg/kg(r=0.9991)和10~1000 μg/kg(r=0.9995)。酱油、料酒(黄酒)、沙拉酱和方便面调味料4种基体中在20、100和400 μg/kg 3个水平加标测定的平均回收率和相对标准偏差(RSD,n=7)范围分别为EC: 87.7%~104%(RSD为4.3%~10.7%)、3-MCPD: 90.1%~109%(RSD为2.6%~10.2%)、2-MCPD: 90.9%~103%(RSD为3.0%~9.5%)。在部分酱油、料酒和方便面调味料中同时检测到了EC、3-MCPD和2-MCPD,在部分沙拉酱中检测到了EC或3-MCPD。该法准确、快速,适用于调味品中EC、3-MCPD和2-MCPD的同时检测。     

分散固相萃取法对鸡精中3-氯-1,2-氯丙醇的测定

氯丙醇(chloropropanols,CPDs)是丙三醇结构上的羟基被氯原子取代的一类化合物,包括3-氯-1,2-氯丙醇(3-MCPE))、2-氯-1,2-氯丙醇(2-MCPD)、1,3-二氯-2-丙醇(1,3-DCP).食品添加剂和污染物联合专家委员会对CPDs进行了评价,发现3-MCPD危害广泛,可损害人体的肝、肾、神经系统等器官[1],因此制定3-MCPD的暂定每日最大耐受量(TDI)为2μg/kg.     

固相萃取-气相色谱/负化学电离-质谱法测定酸水解植物蛋白及酱油中的3-氯-1,2-丙二醇

建立了酸水解植物蛋白及酱油中3-氯-1,2-丙二醇(3-MCPD)的固相萃取-气相色谱/质谱测定方法。样品经Aoisa-HBL固相萃取柱萃取,正己烷-乙酸乙酯净化提取,七氟丁酰咪唑衍生,衍生物经气相色谱/负化学电离-质谱（GC/NCI-MS）选择离子模式(SIM)检测,外标法定量。3-MCPD的定量检测限为0.5 μg/kg,平均回收率为92.2%～97.4%,相对标准偏差为3.6%～10.9%。该方法检测灵敏度高,定性定量准确。     

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.     

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.     

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.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

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.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

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.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

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.