反相高效液相色谱法快速检测大豆素火腿中5种防腐剂

建立一种快速检测大豆素火腿中的苯甲酸、山梨酸、脱氢乙酸、羟苯甲酯、羟苯乙酯5种防腐剂含量的反相高效液相色谱法。大豆素火腿样品用水-甲醇(2∶1)超声振荡提取,提取液沉淀蛋白后,用0.45μm滤膜过滤,以Angilent Zorbax SB-C18色谱柱分离,梯度洗脱,用二极管阵列检测器检测。5种防腐剂得到良好的分离,质量浓度在0.1~5.0μg/mL范围内与色谱峰面积线性相关,相关系数(r2)均大于0.995,加标回收率为80.8%~115.2%,方法检出限为0.03~0.17μg/mL,定量限为0.10~0.54μg/mL,重复性相对标准偏差为1.35%~3.78%(n=6)。该方法样品处理简单,准确度高,重复性好,检出限低,适用于大豆素火腿中防腐剂含量的监测。     

高效液相色谱法测定化妆品原料中N-乙酰神经氨酸

建立高效液相色谱法测定化妆品原料中N-乙酰神经氨酸含量的方法。以体积分数为50%的乙酸溶液为水解溶剂,样品于80℃水浴中加热30 min,以CAPCELL PAK SCX柱（250 mm×4.6 mm,5μm）为分析柱,流动相为乙腈-0.1%磷酸水溶液（体积比为80∶20）,等度洗脱,流量为1.0 mL/min,柱温为35℃,采用高效液相色谱二极管阵列检测器测定,以色谱峰面积外标法定量。检测波长为205 nm,进样体积为10μL。N-乙酰神经氨酸的色谱峰面积与质量浓度在10.0～500.0μg/ml范围内线性关系良好,相关系数为0.999 9,方法检出限为0.12μg/mL,定量限为0.4μg/mL。样品加标平均回收率为97.7%～98.9%,测定结果的相对标准偏差为0.37%～1.36%(n=6)。该方法样品处理简便、高效,适用于化妆品原料中N-乙酰神经氨酸的含量测定。     

高效液相色谱法同时测定蜜饯中5种常见食品添加剂

建立同时测定蜜饯中安赛蜜、苯甲酸、山梨酸、糖精钠、脱氢乙酸的反相高效液相色谱法,用于监测蜜饯产品,提高时效性.安赛蜜、苯甲酸、山梨酸、糖精钠、脱氢乙酸分别在1.2～100 μg/mL、0.2～100 μg/mL、1.1～100μg/mL、6.2～140 μg/mL和2.7～100 μg/mL浓度范围内线性良好,相关系数分别为0.9997、0.9999、0.9996、0.9998和0.9993,检出限分别为15、1.2、18、50和20 ng;平均回收率均在95%以上,相对标准偏差均小于2.8%.此法样品处理简便易行,适于同时测定蜜饯中的安赛蜜、苯甲酸、山梨酸、糖精钠、脱氢乙酸.     

气相色谱法测定乙酸阿比特龙中1,1,3,3-四甲基胍

建立气相色谱测定乙酸阿比特龙原料药中1,1,3,3-四甲基胍的方法。选择乙酸乙酯为溶剂溶解样品，以安捷伦CP-Volamine毛细管柱（30 m×0.32 mm,0.45μm）作为分离色谱柱，采用氢火焰离子化检测器（FID）进行检测，外标法定量分析。1,1,3,3-四甲基胍的质量浓度在10.22～204.38μg/mL范围内与色谱峰面积线性关系良好，相关系数为0.999 4，定量限为10.22μg/mL。样品加标回收率为97.9%～113.7%,9份样品测定结果的相对标准偏差为5.0%。该方法操作简单，可用于乙酸阿比特龙原料中1,1,3,3-四甲基胍的测定。     

多功能柱净化-高效液相色谱法检测麦类中赭曲霉毒素A

本文提出了一种采用高效液相色谱/荧光检测法(HPLC/FLD)测定麦类样品中赭曲霉毒素A的方法.样品经V(乙腈):V(水)=84:16提取,多功能柱净化,C18色谱柱(4.6×250 mm,5μm)分离,V(水):V(乙腈):V(乙酸)=102:96:2作流动相,流速1.0 mL/min.结果表明,标准工作液在浓度1.0～50.0μg/L范围内,峰面积与浓度成良好的线性关系,线性相关系数＞0.9999,样品在3.0,10.0,50.0 ng/g添加水平的回收率为60%～85%,相对标准偏差为7.9%～8.8%(n=8),方法检出限为3.0 ng/g(S/N＞10).本法快速、准确、操作简单,可满足大批麦类样品的检测需要.     

液相色谱-串联质谱法测定生活饮用水中4种卤代乙酸的含量

提出了液相色谱-串联质谱法测定生活饮用水中二氯乙酸、三氯乙酸、一碘乙酸和二碘乙酸等4种卤代乙酸含量的方法。取0.5 mL过滤后的水样,与0.5 mL乙腈混合。以Torus DEA色谱柱为固定相,以体积比10∶90的含1.0 mmol·L^-1乙酸铵的2.0%(体积分数)氨水溶液-乙腈混合液为流动相进行等度洗脱。分离后的4种目标物经电喷雾离子源负离子模式扫描,采用多反应监测模式进行检测,外标法定量。结果显示：4种卤代乙酸的质量浓度在5～100μg·L^-1内与定量离子峰面积呈线性关系,检出限(3S/N)为0.3～3.0μg·L^-1;对自来水水样进行3个浓度水平的加标回收试验,回收率为70.1%～114%,测定值的相对标准偏差为(n=6)为0.90%～5.8%;方法用于10份末梢水分析,其中一碘乙酸、二碘乙酸和三氯乙酸均未检出,有8份样品检出二氯乙酸,检出量为2.0～4.4μg·L^-1。     

大体积固相萃取-气相色谱法测定水中17种氯代有机物

建立水中17种氯代有机物的大体积固相萃取–气相色谱检测方法。样品以3.0 mL/min的流量经大体积样品采样器Cleanert PS固相萃取柱富集,真空抽干后用10.0 mL丙酮洗脱,挥干洗脱液,用1.0 mL正己烷定容,在选定的色谱条件下进行分析。17种氯代有机物的质量浓度在0～100μg/L内与色谱峰面积呈良好的线性关系,相关系数均大于0.999,方法检出限为0.002 5～0.074μg/L。样品加标回收率为81.0%～116.0%,测定结果的相对标准偏差为0.56%～6.80%(n=6)。该方法快速、灵敏、准确,重现性好,具有一定的实用价值,适用于水中17种氯代有机物的同时测定。     

离子色谱-抑制电导法测定卷烟爆珠中挥发性脂肪酸

建立离子色谱法同时测定卷烟爆珠中甲酸、乙酸、丙酸、丁酸、戊酸、己酸的分析方法。500 mg样品用1mL 0.1 mol/L KOH溶液固定,压碎爆珠壁,用超纯水溶解,涡旋振荡提取,过SPE-C₁₈柱和0.22μm滤膜后,以5 mmol/L KOH淋洗液等度洗脱,流量为1.0 mL/min,在柱温45℃条件下,经SH-AP-4型阴离子色谱柱分离,采用电导检测器检测,色谱峰面积外标法定量。6种脂肪酸在0.1～10 mg/L的质量浓度范围内与色谱峰面积线性关系良好,相关系数均大于0.999,方法检出限为0.876 4～10.23μg/L,测定结果的相对标准偏差为0.63%～3.00%(n=6),样品加标回收率为84.75%～115.4%。该方法可用于卷烟爆珠中挥发性脂肪酸的检测。     

高效液相色谱法测定食品中的姜黄素

食品中的姜黄素经甲醇提取、净化后,以液相色谱-紫外检测器外标法定量检测.色谱条件:反相C<,18>色谱柱(250 mm x4.6 mm,5μm),以乙腈-0.05%乙酸氨水溶液为流动相等度洗脱,流速为1.0 mL/min.姜黄素质量浓度在0.5-50.0μg/mL范围内与峰面积呈线性关系,回归方程y=7440x-295...     

气相色谱法测定交联透明质酸钠凝胶的修饰度

建立一种气相色谱测定交联透明质酸钠凝胶中修饰度的分析方法。通过沸水酸解的方法提取凝胶中的丙三醇物质，以丙三醇为外标，采用气相色谱法进行定量分析。采用PEG-20M毛细管柱（30.0 m×0.32 mm,0.50μm），柱温为250℃，采用氢火焰离子化检测器（FID）检测，检测器温度为290℃，载气流量为30 mL/min，载气为高纯氮气，流量为3.0 mL/min。丙三醇质量浓度在8.16～122μg/mL范围内与色谱峰面积线性关系良好，线性方程为y=3 266.9x-8 404.7，相关系数r=0.999 7，方法检出限为0.037μg/mL，定量限为0.83μg/mL，样品加标回收率为99.17%～99.94%，测定结果的相对标准偏差为0.77%(n=6)。     

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%.     

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.     

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.     

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.     

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.     

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.