基于探针底物法的高效液相色谱-串联质谱法研究蚯蚓体内CYP1A2、CYP2C9与CYP3A4酶活力

按规定方法解剖蚯蚓取得其内脏,经清洗后转移至盛有4mL匀浆缓冲液的组织研磨器中均匀破碎,并将匀浆体积定为6.0mL。将此匀浆液通过差速离心法取其微粒体(即第2次离心后的沉淀物)用3mL保存缓冲液重新悬浮,制得蚯蚓微粒体蛋白悬浮液。将此悬浮液100μL加入于含孵育体系650μL及探针底物混合液(含非那西汀100μmmol·L~(-1)、双氯芬酸钠100μmmol·L~(-1)和睾酮25μmmol·L~(-1))250μL中,升温至37℃,孵化20min,加入甲醇200μL中止反应。离心10min,取其上清液,经0.22μm滤膜过滤。所得滤液流经Acquity HPLC C18色谱柱(50mm×2.1mm,1.8μm),并用不同体积比的(A)每升溶液中含甲酸0.5mL的1mmol·L~(-1)乙酸铵溶液和(B)甲醇组成的混合液作为流动相进行梯度洗脱,使所加入的3种底物被蚯蚓体内的细胞色素P450亚酶的催化作用而相应产生的3种特异代射物分离。然后在电喷雾正离子源和多反应监测模式条件下,用串联质谱法测得其含量。结果表明:所述3种代谢物(对乙酰氨基酚、4′-羟基双氯芬酸、6β-羟基睾酮)的线性范围依次在0.40,0.20,10.0μg·L~(-1)以内,检出限(3S/N)依次为0.008,0.005,0.1μg·L~(-1)。根据所测得3种代谢物的生成量可分别评价蚯蚓体内3种相应的亚酶CYP1A2、CYP2C9和CYP3A4活力。此外,还对受敌敌畏染毒的土壤中培养3d和14d后的蚯蚓样品,按上述方法分析,获得了染毒的土壤对蚯蚓体内上述3种CPY亚酶活力的变化情况。所得结果可作为土壤污染全面诊断的生物标记。     

均相液液萃取-数字成像比色法测定水中痕量六价铬北大核心CSCD

提出了均相液液萃取-数字成像比色法测定水中痕量六价铬的方法。取2.5 mL水样,依次加入0.125 mL十二烷基硫酸钠溶液(20 g·L^(-1))、0.3 mL硫酸溶液(0.5 mol·L^(-1))和0.125 mL含0.04 mol·L^(-1)二苯碳酰二肼的丙酮溶液,摇匀,反应5 min。再用60μL邻苯二甲酸二甲酯和400μL异丙醇的混合液进行萃取,涡旋,离心,通过智能手机比色装置中的Color Grab软件读取萃取层的绿(G)值。结果显示:六价铬标准曲线的线性范围为4~60μg·L^(-1),检出限(3s/k)为1μg·L^(-1);对实际水样进行加标回收试验,本方法所得六价铬测定值与国家标准方法GB 7467-1987的基本一致,回收率为87.8%~109%,测定值的相对标准偏差(n=6)为2.4%~3.7%。     

石墨烯纳米筛负载钴铁双金属层状氢氧化物的制备及其在重金属离子电化学传感中的应用北大核心CSCD

本文采用自组装-碳热造孔-刻蚀的方法将钴铁双金属层状氢氧化物(Co_(3)FeLDH)与石墨烯纳米筛(HG)复合,进而制备了基于Co_(3)FeLDH/HG复合材料的电化学传感器,用于同时检测水中Pb^(2+)、Cd^(2+)和Zn^(2+)。由于HG的高比表面积、多孔性和良好的导电性,以及Co_(3)FeLDH阵列结构对重金属离子的强亲和性,所制备传感器表现出良好的分析性能。实验结果显示,Pb^(2+)与Cd^(2+)的峰电流与浓度在1~1500μg·L^(-1)、Zn^(2+)峰电流与浓度在5~1800μg·L^(-1)范围线性关系良好,方法对Pb^(2+)、Cd^(2+)和Zn^(2+)的检测限分别达2.41 nmol·L^(-1)、4.45 nmol·L^(-1)和15.38 nmol·L^(-1),大大低于世界卫生组织(WHO)允许的生活水中3μg·L^(-1)(27 nmol·L^(-1))、10μg·L^(-1)(48 nmol·L^(-1))和1 mg·L^(-1)(33 mmol·L^(-1))的阈值。所制备的电化学传感器具有良好的稳定性和重现性,在环境分析检测方面具有良好的应用前景。     

UPLC-MS/MS结合多探针底物方法研究刺五加叶中黄酮苷类成分对CYP450活性的影响

利用超高效液相色谱-串联质谱联用(UPLC-MS/MS)的多反应监测(MRM)技术结合多探针底物方法, 研究了刺五加叶中的主要黄酮苷类化合物槲皮苷、金丝桃苷及芦丁对肝细胞色素P450酶(CYP450)亚型CYP1A2, CYP2C, CYP2E1, CYP2D和CYP3A活性的影响. 结果表明, 3种化合物对各CYP亚型酶均有抑制作用, 其中金丝桃苷和槲皮苷对CYP1A2催化的非那西丁的O-脱乙基反应抑制的IC₅₀值分别为46.53和49.75 μmol/L, 金丝桃苷和芦丁对CYP2E1催化的氯唑沙宗的6-羟基化反应抑制的IC₅₀值分别为99.87和86.36 μmol/L. 机理性抑制实验结果表明, 3种化合物对2种亚型酶的抑制作用是随着预孵时间延长而增强的机理性抑制.     

自制的苄氧基葫芦脲[6]应用于荧光光度法测定商业制剂中头孢曲松钠的含量北大核心CSCD

制备了苄氧基葫芦脲[6]([BnO]_2CB6),并应用于商业制剂中头孢曲松钠(CTRX)的荧光光度法测定。在pH 6.5的Britton-Robinson缓冲溶液中,[BnO]2CB6与CTRX形成包结物(包结比为1∶1),使体系发生光诱导的电子转移作用,导致明显的荧光猝灭现象。荧光反应的激发波长和发射波长依次为405,495nm。CTRX的浓度在40μmol·L^(-1)以内与其对应的荧光猝灭程度呈线性关系,检出限(3S/N)为17nmol·L^(-1)。方法用于CTRX商业制剂样品的分析,CTRX的测定值与高效液相色谱法(HPLC)测得的结果相符,加标回收率为98.0%~101%,测定值的相对标准偏差(n=6)为3.0%~7.2%。     

CYP3A4酶对土茯苓黄酮类成分代谢的影响

以土茯苓6种黄酮类成分为底物,研究了不同孵育时间、不同CYP3A4酶浓度对6种成分代谢的影响。通过土茯苓6种黄酮类成分的酶促动力学,得到米氏常数(K_m)、最大反应速度(V_(max))和代谢清除率(Cl_(int))。结果表明,以表儿茶素、新落新妇苷、落新妇苷、异落新妇苷、黄杞苷、白藜芦醇为底物时,K_m分别为1.39,1.38,2.37,1.59,0.79,2.01μmol/L; V_(max)分别为0.02,0.01,0.02,0.02,0.01,0.02μmol/(L·min); Clint分别为(1.14,0.96,0.90,0.99,1.42,0.97)×10~(-2)min~(-1)。     

20α-羟基孕酮对土拨鼠肾上腺微粒体甾体羟基化反应的抑制作用

本文研究了20α-羟基孕酮对土拨鼠肾上腺微粒体P-450催化甾体羟基化的抑制作用。探明了17α-羟基孕酮作底物时,20α-羟基孕酮对P-450_(C_(21))催化的C_(21)羟基化反应及P-450_(17αlyase)催化的C_(17)—C_(20)键断裂的反应均表现出拮抗抑制。抑制常数分别为1.73μmol/L(P-450_(C_(21)))和1.37μmol/L(P-450_(17lyase))。比较了分别以孕酮和17α-羟基孕酮作底物时,20α-羟基孕酮对P-450_(17αlyase)催化C_(17)—C_(20)键断裂的不同影响,由此推论出雄甾烷二酮在肾上腺微粒体中生成的连续反应机理。     

氨基改性Fe_(3)O_(4)纳米材料修饰电极同时测定Cd^(2+)和Pb^(2+)北大核心CSCD

采用溶剂热法一步合成氨基改性的Fe_(2)O_(4)(NH_(2)-Fe_(3)O_(4))纳米材料,通过扫描电镜、红外光谱、X射线衍射等方法对合成纳米材料进行表征,并将NH_(2)-Fe_(3)O_(4)滴涂在玻碳电极(GCE)表面制成电化学传感电极(NH_(2)-Fe_(3)O_(4)/GCE)。结果发现,NH_(2)-Fe_(3)O_(4)/GCE在最优条件下可以同时测定Cd^(2+)和Pb^(2+),Cd^(2+)在1.2×10^(-8)~9.6×10^(-5)mol·L^(-1)浓度范围内与峰电流值呈良好的线性关系(R=0.9949),检测限为1.4×10^(-9)mol·L^(-1);Pb^(2+)在4.8×10^(-8)~9.6×10^(-5)mol·L^(-1)时浓度范围内与峰电流值呈良好的线性关系(R=0.9843),检测限是2.7×10^(-9)mol·L^(-1)。     

表面增强拉曼光谱法测定牛奶中青霉素G钠的残留量北大核心CSCD

青霉素G钠(NaBP)溶液的常规拉曼光谱信号微弱.将制备的浓缩银纳米粒子(AgNPs)20μL与不同浓度(1×10^(-9)~1×10^(-1)mol·L^(-1))的青霉素G钠溶液(pH 6)20μL混合,所得混合液的表面增强拉曼光谱(SERS)信号显著增强,在上述混合液中加入1×10^(-2)mol􀅰L^(-1)硫酸镁溶液8μL,青霉素G钠SERS增强效果最佳.据此,提出了以AgNPs为基底,硫酸镁为凝聚剂,采用SERS测定青霉素G钠含量的方法,并用于加标牛奶样品的检测.结果表明,青霉素G钠浓度为1×10^(-8)~1×10^(-3)mol·L^(-1)时,其浓度的对数值与相应的SERS信号强度呈线性关系,检出限(3s/k)为8.2×10^(-9)mol·L^(-1).按标准加入法进行回收试验,回收率为80.0%~96.0%,测定值的相对标准偏差(n=5)为2.3%~6.5%.     

吗啉基修饰的新型香豆素Fe~(3+)荧光探针化合物的合成及其性能

间苯二酚与乙酰乙酸乙酯经亲核取代反应制得7-羟基-4-甲基香豆素(1);1与碘甲烷在乙醚中反应制得7-甲氧基-4-甲基香豆素(2);2与N-溴代丁二酰亚胺在四氯化碳中经2步反应制得3-溴-4(溴甲基)-7-甲氧基香豆素(4);4在四氢呋喃溶剂中与吗啉反应合成了一种新型的基于香豆素的荧光探针化合物——3-溴-7-甲氧基-4-(吗啉代)-2H-吡喃-2-酮(5),其结构经~1H NMR,~(13)C NMR和MS表征。光学性能和金属离子识别性能研究结果表明:5的激发波长为340.15 nm,发射波长为408.35 nm;5对Fe~(3+)有良好的识别作用,在1.0×10-5mol·L~(-1)~9.0×10~(-5)mol·L~(-1)可定量检测Fe~(3+)含量。     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.