固相萃取-高效液相色谱法同时测定豆制品中的碱性嫩黄O、酸性橙Ⅱ和碱性橙Ⅱ

建立了一种固相萃取-高效液相色谱法同时测定豆制品中的碱性嫩黄O、酸性橙Ⅱ和碱性橙Ⅱ等3种黄色工业染料的方法。样品经体积分数70%乙醇水溶液(含1.0%氨水)涡旋超声提取后,采用Strata-X-AW固相萃取(SPE)小柱净化,洗脱液用氮气吹至近干后用甲醇溶解并定容,过PTFE滤膜后在Kromasil C18色谱柱上,以V(甲醇):V(20 mmol/L乙酸铵)=65:35的溶液为流动相进行分离,检测波长为450 nm。结果表明,在最优的色谱条件下,各目标化合物的加标回收率在89.0%~94.7%之间,相对标准偏差在2.2%~4.6%之间。3种染料在0.2~20.0 mg/L内呈现良好的线性关系,相关系数r≥0.999,豆制品中碱性嫩黄O、酸性橙Ⅱ和碱性橙Ⅱ的检出限分别为0.06、0.06和0.09 mg/kg。该方法用于实际样品的检测取得了满意的效果。     

固相萃取-高效液相色谱-串联质谱法测定辣椒中碱性橙类染色剂

建立了固相萃取/高效液相色谱串联质谱测定辣椒中碱性橙2、碱性嫩黄、碱性橙21和碱性橙22的方法。样品用体积分数2%甲酸乙腈溶液提取,经Waters MCX混合型阳离子固相萃取柱净化后,以C18柱为分离柱,乙腈和体积分数0.1%甲酸水溶液为流动相,多反应(MRM)监测模式进行检测。4种物质在1.0~50.0μg/L内线性关系良好(r2>0.99),方法的检出限和定量限分别2.0μg/kg和5.0μg/kg;添加量分别为5.0,10.0,20.0μg/L时的回收率为71.3%~92.5%,相对偏差为5.8%~14%。方法可用于辣椒中碱性橙2,碱性嫩黄,碱性橙21和碱性橙22的同时测定。     

高效液相色谱-串联质谱法同时测定食品中五种黄色化工染料

采用高效液相色谱-串联质谱法(HPLC-MS/MS)建立了食品中非法添加的碱性橙、碱性嫩黄、酸性橙I、酸性橙II和酸性黄36这5种黄色工业染料的定量定性分析方法。使用Agilent ODS C18分离柱(50 mm×2.0 mm, 1.8 μm),以5 mmol/L乙酸铵水溶液(0.1%甲酸)-乙腈(3:2, v/v)为流动相,流速为0.3 mL/min。采用电喷雾离子化源,以多反应监测(MRM)方式分别在正、负离子模式下进行检测。在最佳检测条件下,得到了较宽的线性范围和较低的定量检出限。碱性橙和碱性嫩黄的线性范围均为5.0～80.0 mg/L;酸性橙I、酸性橙II及酸性黄36的线性范围均为10.0～160.0 μg/L。食品中碱性橙、碱性嫩黄、酸性橙I、酸性橙II及酸性黄36的定量限分别为20、20、40、40、40 ng/g。该方法重现性较好,保留时间和峰面积的相对标准偏差分别不大于0.50%和2.14%。本研究还测定了鸡肉、豆制品和黄鱼中添加的5种化工染料,回收率在79.8%~95.2%之间,结果令人满意。     

高效液相色谱法同时测定食品中7种非食用色素

建立了高效液相色谱法同时测定食品中7种非食用色素(碱性嫩黄O、碱性橙、酸性橙Ⅱ、酸性金黄、玫瑰红B、对位红、苏丹红Ⅰ)的方法。依次采用乙腈、甲醇和碱性甲醇提取豆制品和肉制品;采用乙腈和70%乙腈依次提取调味品。采用SunFireTMC18色谱柱(250 mm×4.6 mm,5μm),以甲醇-50 mmol/L乙酸铵水溶液(H3PO4调至pH 4.5)为流动相,梯度洗脱,流速1 mL/min,测定波长为450和520 nm。7种非食用色素的在各自相应浓度范围内线性相关系数均大于0.998;检出限(LOD)在0.01～0.1 mg/L之间;定量限(LOQ)在0.18～1.2 mg/kg之间。平均回收率均大于80%;相对标准偏差(RSD,n=3)在2.0%～5.7%之间。     

碱性橙与蛋白间的特异性与非特异性作用荧光光谱比较

将碱性橙与抗体的作用、碱性橙与牛血清白蛋白(BSA)间的作用分别作为特异性作用和非特异性作用模型,采用荧光光谱法固定激发波长为280 nm,扫描不同温度下碱性橙与抗体和牛血清白蛋白两种相互作用,在300～600 nm的发射波长,比较了两种相互作用的差异.结果表明,碱性橙与抗体结合为单一的静态猝灭过程,二者之间的作用力主要为静电作用力;在溶液中,二者以摩尔比1∶1结合,结合常数为3.88×104 L/mol(25.C),3.73×104 L/mol(37.C)和2.35×104 L/mol (45.C);碱性橙距抗体分子色氨酸残基最短距离(r)为5.52 nm.碱性橙与BSA的结合也为静态猝灭,作用力为静电作用力.但碱性橙与抗体作用过程中形成了激基复合物,与BSA则不形成激基复合物.     

低共熔溶剂萃取超高效液相色谱法检测调味油中酸性橙Ⅱ、碱性橙21和碱性橙22

建立了低共熔溶剂萃取结合超高效液相色谱仪快速检测调味油中酸性橙II、碱性橙21和碱性橙22的分析方法。以辣椒油、胭脂树橙油、姜黄油、番椒油、花椒油、十三香精油等6种调味油作为分析对象,由氯化胆碱和乙二醇合成的低共熔溶剂对样品进行萃取,乙酸铵缓冲溶液-乙腈作为流动相梯度洗脱,采用ACQUITY UPLC?BEH C18色谱柱进行分离,二极管阵列检测器于490 nm波长进行测定。结果表明,上述3种禁用染料可在6 min内有效分离,且在0.02~2 mg/L范围内呈良好的线性关系,相关系数均大于0.999;检出限为0.03 mg/kg,所测调味油样品的平均回收率为90.3%~99.6%。方法适用于基质复杂的调味油样品中酸性橙II、碱性橙21和碱性橙22 3种工业染料的检测。     

某些功能饮料中共存胭脂红及酒石黄的检测

建立了一种简便、准确测定某些功能饮料中共存胭脂红和酒石黄的酸度控制吸收光谱法。在pH 3.80 Tris-HCl条件下,胭脂红和酒石黄与碱性艳绿反应生成离子缔合物。胭脂红和酒石黄的定量测定波长分别选在520 nm和426 nm,它们的表观摩尔吸收系数分别为1.26×10⁴ L/(mol·cm)、2.63×10⁴ L/(mol·cm),检测限、定量限及线性范围分别为0.032 mg/L、0.56 mg/kg、0.05～12.4 mg/L(胭脂红体系)和0.036 mg/L、0.62 mg/kg、0.05～11.8 mg/L(酒石黄体系)。加标回收率和相对标准偏差(RSD,n=5)胭脂红体系分别为98.3%～103%和1.3%～2.7%,酒石黄体系97.7%～103%和1.6%～2.3%。该方法用于某些功能饮料中共存胭脂红和酒石黄的测定,结果较好。     

固相萃取结合超高效液相色谱-串联质谱法同时检测食品中的6种工业染料

建立了超高效液相色谱-串联质谱(UPLC-MS/MS)同时检测食品中6种工业染料含量的方法。样品用含50%甲醇和1%甲酸的50 mmol/L乙酸铵溶液进行提取、WAX弱阴离子交换固相萃取柱进行净化后,采用多反应监测(MRM)模式进行检测,基质曲线外标法定量。其中酸性橙Ⅱ采用负离子模式检测,其余5种染料采用正离子模式检测。碱性橙Ⅱ、罗丹明B、碱性嫩黄O、罗丹明6G、碱性桃红T的定量限为1.6 mg/kg,酸性橙Ⅱ为6.0 mg/kg;碱性橙Ⅱ、罗丹明B、碱性嫩黄O、罗丹明6G、碱性桃红T的线性范围为1.0~100.0 mg/L;酸性橙Ⅱ的线性范围为5.0~100 mg/L,线性相关系数均大于0.999。6种染料的回收率为70.3%~109.2%;相对标准偏差(RSD)为2.6%~14.1%。本方法灵敏度高,操作简单高效,适合于食品中6种非法添加工业染料的定量及确证分析。     

利血平与玫瑰精B的高灵敏显色反应及分析应用

研究了利血平与玫瑰精B的显色反应,建立了测定利血平的高灵敏分光光度法。在酸性条件下,利血平的水解产物和玫瑰精B形成具有正、负吸收峰的红色离子缔合物,最大正吸收波长位于490 nm,最大负吸收波长位于520 nm,表观摩尔吸光系数(ε)分别为1.20×105L.mol-1.cm-1(正吸收)和1.83×105L.mol-1.cm-1(负吸收),利血平在0～5.0μg/mL范围内遵从比尔定律。若采用正、负峰叠加测定,灵敏度可达3.00×105L.mol-1.cm-1。探讨了适宜的反应条件、主要分析特性及方法的精密度和可靠性。该法可用于市售利血平注射液中利血平含量的测定。     

双波长分光光度法同时测定水样中的Cr(Ⅲ)和Cr(Ⅵ)

以EDTA为显色剂,在pH 3.5~4.0,75℃水浴加热条件下,用双波长分光光度法同时测定水中Cr(Ⅲ)和Cr(Ⅵ)。选择测定Cr(Ⅵ)的波长对为352nm和441 nm,测定Cr(Ⅲ)的波长为542 nm,Cr(Ⅵ)的线性范围和检出限分别为0~120 mg/L和0.025 mg/L;Cr(Ⅲ)线性范围和检出限分别为0~140 mg/L和0.007 mg/L。Cr(Ⅵ)和Cr(Ⅲ)加标回收率分别为96.4%~100.4%和99.8%~104.5%。     

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.