高效液相色谱-电感耦合等离子体质谱法测定化妆品中2-溴-2-硝基-1,3-丙二醇

建立了高效液相色谱-电感耦合等离子体质谱(HPLC-ICP-MS)测定化妆品中2-溴-2-硝基-1,3-丙二醇的方法。采用ZORBAX RX-C_8色谱柱(150×2.1 mm,5μm)进行分离,以甲醇-水-5%磷酸(10∶985∶5,用2 mol/L NaOH调至pH 3.0)为流动相,流速为0.7 m L/min,柱温为室温。结果显示,2-溴-2-硝基-1,3-丙二醇在2.5 min处出峰,其线性范围为0.01~1.0 mg/L,相关系数为0.999 9。不同基质化妆品的方法检出限均为1.0μg/g,回收率为94.6%~101.3%,相对标准偏差(RSD,n=6)为1.5%~4.5%。该方法快速、准确、灵敏、无干扰,适用于化妆品中2-溴-2-硝基-1,3-丙二醇的定性定量测定。     

基于QuEChERS提取的高效液相色谱-串联质谱法同时测定4种不同基质类型化妆品中15种硝基咪唑类禁用药物

建立了同时测定4种不同基质类型化妆品中15种硝基咪唑类(NMZs)禁用药物的高效液相色谱-串联质谱法(HPLC-MS/MS)。样品经溶剂超声提取,改良的QuEChERS方法净化后,过0.22μm滤膜上机检测。采用XSelect CSH C_(18)色谱柱(2.1 mm×150 mm,3.5μm)进行分离,以0.1%甲酸乙腈-0.1%甲酸水溶液作为流动相梯度洗脱,流速为0.25 mL/min。采用正离子模式电喷雾电离(ESI~+),多反应监测(MRM)模式检测,基质匹配标准曲线外标法定量。结果表明,15种硝基咪唑类药物在5～500μg/L范围内线性良好,相关系数(r~2)0.99,检出限(LOD)和定量下限(LOQ)分别为0.8～200μg/kg和4～400μg/kg。3个不同浓度加标水平下,平均加标回收率为86.8%～115%,相对标准偏差(RSD)为0.3%～8.4%。该方法前处理简单、分离效果好、回收率高,适用于化妆品中硝基咪唑类禁用药物的测定。     

高效液相色谱法同时测定婴儿湿巾中9种防腐剂

称取0.500 0g湿巾样品,剪碎后,加入80%(体积分数)甲醇溶液5.00mL,漩涡振荡提取3min,经0.22μm滤膜过滤,以Diamonsil C_(18)(2)色谱柱(4.6mm×250mm,5μm)分离滤液中的9种防腐剂,流动相为甲醇-0.1%(质量分数)磷酸溶液,梯度洗脱。采用二极管阵列检测器,咪唑烷基脲、5,5-二甲基海因、2-溴-2-硝基丙烷-1,3-二醇、苄索氯胺和苯扎氯铵的检测波长为210nm,氯苯酣醚的检测波长为230nm,醋酸氯己定、山梨酸钾和氯化十六烷基吡啶的检测波长为254nm。9种防腐剂的质量浓度在一定范围内与对应的色谱峰面积呈线性关系,检出限(3S/N)在0.01～0.5mg·L~(-1)之间。对空白样品进行加标回收试验,回收率在77.2%～100%之间,测定值的相对标准偏差(n=6)在1.2%～8.4%之间。应用该方法分析了20批次婴儿湿巾样品,有15批次的样品中检出咪唑烷基脲、5,5-二甲基海因、2-溴-2-硝基丙烷-1,3-二醇、醋酸氯己定、山梨酸钾或苄索氯胺。     

高效液相色谱法同时测定化妆品中9种4-羟基苯甲酸酯类防腐剂

建立同时测定化妆品中9种4-羟基苯甲酸酯类防腐剂的高效液相色谱法。样品经甲醇溶解,超声提取,使用Waters Symmtery C_(18)(2.1 mm×250 mm,5μm)色谱柱,用0.1%磷酸溶液–乙腈为流动相进行梯度洗脱,采用二极管阵列检测器进行检测,检测波长为254 nm,外标法定量。9种防腐剂的质量浓度在0.1~100μg/mL范围内与对应的色谱峰面积线性关系良好,相关系数为0.9993~0.9997,检出限为0.65~2.22μg/g,定量限为2.18~7.39μg/g。样品在25、50、250μg/g 3个加标水平时的平均回收率为95.73~104.06%,测定结果的相对标准偏差为0.58~5.28%(n=6)。该方法简单、准确、灵敏,可用于化妆品中9种4-羟基苯甲酸酯类防腐剂的测定。     

高效液相色谱-三重四极杆串联质谱法同时测定化妆品中24种香豆素类化合物

建立了高效液相色谱-三重四级杆串联质谱法同时测定化妆品中24种香豆素类化合物含量。水基、乳液、膏霜类样品和唇膏、粉饼等固态类样品分别采用甲醇、甲醇-四氢呋喃(1∶1)混合溶液超声提取后,经Agilent Poroshell120 SB-C₁₈色谱柱(100 mm×4.6mm,2.7μm)分离,以甲醇-5 mmol/mL甲酸铵(含0.1%甲酸)溶液作为流动相进行梯度洗脱,流量为0.5 mL/min,多反应监测模式检测。24种香豆素类化合物在各自质量浓度范围内与色谱峰面积线性关系良好,相关系数均不小于0.999 5,检出限为0.002～0.8μg/kg,定量限为0.004～3μg/kg。在低、中、高三个浓度加标水平下,样品平均加标回收率为84.8%～112.9%,测定结果的相对标准偏差为1.2%～9.8%(n=6)。该方法操作简便、灵敏度高、准确性好,可用于化妆品中香豆素类化合物的定性筛查和定量测定。     

分散固相萃取净化/液相色谱-串联质谱法测定化妆品中7种氨基苯甲醚

建立了同时测定化妆品中7种氨基苯甲醚类化合物(邻氨基苯甲醚、间氨基苯甲醚、对氨基苯甲醚、2,4-二氨基苯甲醚、2,5-二氨基苯甲醚、3,4-二氨基苯甲醚、3,3'-二甲氧基联苯胺)的分散固相萃取净化液相色谱-串联质谱(LC-MS/MS)分析方法。样品用甲醇-水(1∶1,含0.1%甲酸)溶液提取,经PSA分散固相萃取净化后,样液经Welch Ultimats XB-C_(18)(4.6 mm×150 mm,5μm)色谱柱分离,多反应监测(MRM)模式检测,以保留时间和特征离子对定性,外标法定量。结果表明,7种氨基苯甲醚类化合物在0.10~200.0μg/L浓度范围内线性关系良好,相关系数均大于0.998;方法检出限(S/N=3)为0.4~10.9μg/kg。样品日内回收率为64.7%~98.1%,相对标准偏差(RSD,n=6)为1.2%~10.6%;日间精密度(n=5)为2.3%~9.8%。对30个不同水剂类化妆品检测发现,其中1个样品检出3,3'-二甲氧基联苯胺,含量为5.3μg/kg。该方法准确可靠,适用于化妆品中7种氨基苯甲醚的同时测定。     

HPLC-ICP-MS法检测化妆品中的硫柳汞和苯基汞

建立了化妆品中硫柳汞和苯基汞的高效液相色谱分离,电感耦合等离子体质谱法(ICP-MS)测定的检测方法。方法采用SB C18反相色谱柱(4.6×150mm,5μm)分离,流动相为甲醇-60 mmol/L乙酸铵溶液(含0.1%L-半胱氨酸),经过梯度洗脱,ICP-MS测定组份中的202Hg,以保留时间定性,外标法定量。结果表明,在此条件下,硫柳汞和苯基汞在0～100μg/L范围内线性良好,两种有机汞的检出限分别为5.76μg/L和4.41μg/L,不同类型化妆品中硫柳汞和苯基汞的平均回收率在82.0%～118.7%范围内。方法适用于化妆品中硫柳汞和苯基汞的测定。     

QuEChERS-超高效合相色谱-串联质谱法测定化妆品中45种糖皮质激素

建立了QuEChERS处理,超高效合相色谱-串联质谱(UPC~2-MS/MS)测定化妆品中45种糖皮质激素(GCs)含量的方法。样品经NaCl饱和溶液分散、乙腈涡旋提取、QuEChERS法净化后,以Torus 2-PIC色谱柱(100 mm×3.0 mm,1.7μm)为分析柱,以超临界CO_2为主要流动相,0.1%(V/V)甲酸甲醇溶液为共溶剂梯度洗脱,以97%甲醇溶液(V/V,含0.1%甲酸)为补偿液,电喷雾电离源的三重四极杆质谱在正离子、多反应监测模式下测定,外标法定量。结果表明:45种GCs在0.20～100μg/L浓度范围内线性关系良好(R~2≥0.9935),检出限为0.05～0.10μg/kg,定量限为0.15～0.30μg/kg;在3个加标水平下的平均回收率为74.4%～110.7%,相对标准偏差为2.9%～11%。该法为化妆品中多种GCs的测定提供了技术支持。     

超高效液相色谱-四极杆/静电场轨道阱高分辨质谱快速分析化妆品中17种喹诺酮类药物

建立了一种水剂、乳液和非蜡基膏霜类化妆品中17种喹诺酮类药物的超高效液相色谱-四极杆/静电场轨道阱高分辨质谱(UPLC-Q Orbitrap HRMS)分析方法。样品采用0.1%甲酸(体积分数)乙腈混合溶液超声提取,正己烷液液萃取脱脂,经Agilent Poroshell EC C_(18)(4.6 mm×150 mm,2.7μm)色谱柱分离后,以全扫描/二级离子扫描(Full Scan/dd-MS~2)进行定性筛查和定量检测,内标法定量。结果表明,17种喹诺酮类药物均在0.05～20.0μg/L范围内呈良好的线性关系(r~20.996 0),检出限和定量下限分别为0.5、1.0μg/kg。在2、4、20μg/kg 3个加标水平下,回收率为82.3%～108%,相对标准偏差(RSD,n=6)为3.5%～8.6%。该方法快速准确,灵敏度高,可用于化妆品中喹诺酮类药物的测定。     

分散固相萃取净化/高效液相色谱-串联质谱法测定水产品中的5种硝基咪唑类药物残留

建立了水产品中5种硝基咪唑类药物的高效液相色谱-串联质谱检测方法。样品经含0.1%氨水乙腈提取,加无水硫酸钠、C18-N以及NH2-PSA净化剂后涡旋振荡对样品进行净化,以Merck Chromolith Performance RP-18e(4.6 mm×100 mm)色谱柱分离,甲醇和0.1%甲酸水溶液为流动相梯度洗脱,正离子模式电喷雾电离,配合多反应离子扫描(MRM)定性定量分析目标化合物。考察了提取剂中氨水和净化剂的用量对加标回收率的影响,在优化实验条件下,5种硝基咪唑类药物在20~500μg/L范围内线性关系良好,r2≥0.998 9;3个加标水平下的方法回收率为77.2%~94.8%;定量下限为0.7~2.0μg/kg。该方法快速、简单、准确,适用于水产品中5种硝基咪唑类药物残留的检测。     

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.     

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.     

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.     

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.