流动注射化学发光检测盐酸异丙嗪

在碱性介质中,盐酸异丙嗪对luminol-KMnO4发光体系有显著的增强作用.基于此增强作用,建立了一种FI-CL检测盐酸异丙嗪的新方法.在最优化的实验条件下,盐酸异丙嗪的ΔICL强度与其浓度在7.0×10-9~9.0×10-7 mol/L浓度范围内有较好的线性关系.线性方程为ΔICL=35.19+1.19×10-10 c,相关系数r=0.998 4,检出限为4.9×10-9 mol/L.对7.0×10-9 mol/L的盐酸氯丙嗪标准溶液进行11次平行测定,其RSD为2.4%.盐酸异丙嗪加标回收率在89.1%~96.1%之间.     

Study of the forced degradation behavior of prasugrel hydrochloride by liquid chromatography with mass spectrometry and liquid chromatography with NMR detection and prediction of the toxicity of the characterized degradation products

Prasugrel was subjected to forced degradation studies under conditions of hydrolysis (acid, base, and neutral), photolysis, oxidation, and thermal stress. The drug showed liability in hydrolytic as well as oxidative conditions, resulting in a total of four degradation products. In order to characterize the latter, initially mass fragmentation pathway of the drug was established with the help of mass spectrometry/time‐of‐flight, multiple stage mass spectrometry and hydrogen/deuterium exchange data. The degradation products were then separated on a C₁₈ column using a stability‐indicating volatile buffer method, which was later extended to liquid chromatography‐mass spectrometry studies. The latter highlighted that three degradation products had the same molecular mass, while one was different. To characterize all, their mass fragmentation pathways were established in the same manner as the drug. Subsequently, liquid chromatography‐nuclear magnetic resonance (NMR) spectroscopy data were collected. Proton and correlation liquid chromatography with NMR spectroscopy studies highlighted existence of diastereomeric behavior in one pair of degradation products. Lastly, toxicity prediction by computer‐assisted technology (TOPKAT) and deductive estimation of risk from existing knowledge (DEREK) software were employed to assess in silico toxicity of the characterized degradation products.     

原子荧光光谱法测定萤石中的微量铅

以铁氰化钾–盐酸羟胺体系代替铁氰化钾–草酸体系,建立原子荧光法测定萤石中铅含量的方法。对实验条件进行了优化,在负高压280 V,灯电流65 m A,原子化高度8 mm,还原剂3%硼氢化钾溶液(含0.5%Na OH),载流4%盐酸的工作条件下,铁氰化钾–盐酸羟胺体系有明显的增感作用。样品中Ca~(2+)含量在4 g/L之内不影响铅的测定,溶解阶段通过高氯酸冒烟赶尽HF排除氟离子的干扰,并加入硫氰酸钠–邻菲罗啉消除铁和铜等离子的干扰。测定铅的线性范围为0~80 ng/L,相关系数r=0.999 6,方法检出限为0.187μg/L,测定结果的相对标准偏差为0.25%~1.40%(n=12),加标回收率为97.8%~104.5%。该方法测定结果与电感耦合等离子体原子发射光谱法测定结果相符。原子荧光光谱法快速准确,基体干扰少,灵敏度高。     

盐酸吡格列酮与BSA反应机理的荧光猝灭法、同步荧光法比较研究

利用荧光猝灭法和同步荧光法进行了盐酸吡格列酮(PGH)与牛血清白蛋白(BSA)之间反应机理的比较研究.结果表明:两种方法在研究PGH-BSA体系的猝灭类型、结合常数、结合位置、作用力类型、协同性及能量转移距离等方面,得到了相同的结果,表明同步荧光光谱法可以用于药物与蛋白反应机理的研究.     

Absolute quantification of superoxide dismutase in cytosol and mitochondria of mice hepatic cells exposed to mercury by a novel metallomic approach

In the last years, the development of new methods for analyzing accurate and precise individual metalloproteins is of increasing importance, since numerous metalloproteins are excellent biomarkers of oxidative stress and diseases. In that way, methods based on the use of post column isotopic dilution analysis (IDA) or enriched protein standards are required to obtain a sufficient degree of accuracy, precision and high limits of detection. This paper reports the identification and absolute quantification of Cu,Zn-superoxide dismutase (Cu,Zn-SOD) in cytosol and mitochondria from mice hepatic cells using a innovative column switching analytical approach. The method consisted of orthogonal chromatographic systems coupled to inductively coupling plasma-mass spectrometry equipped with a octopole reaction systems (ICP-ORS-MS) and UV detectors: size exclusion fractionation (SEC) of the cytosolic and mitochondrial extracts followed by online anion exchange chromatographic (AEC) separation of Cu/Zn containing species. After purification, Cu,Zn-SOD was identified after tryptic digestion by molecular mass spectrometry (MS). The MS/MS spectrum of a doubly charged peptide was used to obtain the sequence of the protein using the MASCOT searching engine. This optimized methodology reduces the time of analysis and avoids the use of sample preconcentration and clean-up procedures, such as cut-off centrifuged filters, solid phase extraction (SPE), precipitation procedures, off-line fractions insolates, etc. In this sense, the method is robust, reliable and fast with typical chromatographic run time less than 20 min. Precision in terms of relative standard deviation (n = 5) is of 3–5% and detection limits is 0.21 ng Cu g⁻¹.     

Construction and Validation of New Electrochemical Carbon Nanotubes Sensors for Determination of Acebutolol Hydrochloride in Pharmaceuticals and Biological Fluids

A simple, rapid and a highly selective method for direct electrochemical determination of acebutolol hydrochloride (AC) was developed. The developed method was based on the construction of three types of sensors conventional polymer (I), carbon paste (II) and modified carbon nanotubes (MCNTs) carbon paste (III). The fabricated sensors depend mainly on the incorporation of acebutolol hydrochloride with phosphotungstic acid (PTA) forming ion exchange acebutolol‐phosphotungstate (AC‐PT). The performance characteristics of the proposed sensors were studied. The sensors exhibited Nernstian responses (55.6 ± 0.5, 57.14 ± 0.2 and 58.6 ± 0.4 mV mol L^?1) at 25 °C over drug concentration ranges (1.0 × 10^?6‐1.0 × 10^?2, 1.0 × 10^?7‐1.0 × 10^?2 and 5.0 × 10^?8‐1.0 × 10^?2 mol L^?1 with lower detection limits of (5.0 × 10^?7, 5.0 × 10^?8 and 2.5 × 10^?8 mol L^?1 for sensors (I), (II) and (III), respectively. The influence of common and possible interfering species, pharmaceutical additives and some related pharmacological action drugs was investigated using separate solution method and no interference was found. The stability indicating using forced degradation of acebutolol hydrochloride was studied. The standard addition method was used for determination of the investigated drug in its pharmaceutical dosage forms and biological fluids. The results were validated and statistically analysed and compared with those from previously reported methods.     

Cloud point variation of amphiphilic drug promethazine hydrochloride with added surfactants

In this paper we report clouding phenomenon occurring in an amphiphilic phenothiazine drug promethazine hydrochloride (PMT) in presence of surfactants. Cationic and nonionic surfactants increase the CP of 75 mM PMT solutions (prepared in 10 mM sodium phosphate buffer). These surfactants form mixed micelles with PMT. Anionic surfactants also form mixed micelles with the drug but the CP behavior is different by showing a peaked behavior. At low concentrations, anionic surfactants hinder micelle formation by forming ion-pairs whereas the usual CP decreasing effect at higher concentrations is due to mixed micellization. The CP behavior of 75 mM PMT+50 mM TBAB+surfactant systems is also explored which is found similar to PMT+surfactant systems with the difference only in magnitude of the clouding temperature.     

Aggregation behavior and interaction of an amphiphilic drug imipramine hydrochloride with cationic surfactant cetyltrimethylammonium bromide: light scattering studies

The aggregation behavior and interaction of an amphiphilic antidepressant drug imipramine (IMP) hydrochloride with the cationic surfactant cetyltrimethylammonium bromide (CTAB) have been studied using light scattering (both static and dynamic) techniques. Due to rigid tricyclic hydrophobic moiety present in the molecule, the drug shows interesting association behavior. The static light scattering measurements show that the self-association of IMP commenced above a well-defined critical micellar concentration (CMC), which decreases with increasing the mole fraction of the CTAB surfactant. Both the excess Gibbs energy (ΔG(ex)) and the Gibbs energy of micellization (ΔG(M)°) are negative, and decrease with increasing mole fraction of the surfactant. The hydrodynamic diameters (d(h)) of the micellar aggregates were also evaluated using the dynamic light scattering measurements. The data indicate formation of larger aggregates by IMP and CTAB due to mixed micellization and subsequent micellar growth. The results have been analyzed using different models (viz., Clint, Motomura, Rosen, Rubingh, etc.) for mixed micelle formation.     

脲和盐酸胍诱导的卵清溶菌酶分子去折叠过程中各稳定构象态的分布和过渡

以内源荧光光谱和荧光相图法研究了脲和盐酸胍诱导的卵清溶菌酶分子的去折叠过程,结果表明,当变性液中脲和盐酸胍的浓度分别约为4.0和3.0 mol/L时,卵清溶菌酶分子的去折叠过程均存在一个折叠中间态,这两个去折叠过程均符合"三态模型".在卵清溶菌酶分子"三态"去折叠过程的基础上,通过变性剂分子和卵清溶菌酶分子之间的缔合一...