Sample vial influences on the accuracy and precision of carbon and oxygen isotope ratio analysis in continuous flow mass spectrometric applications

Due to the small amounts of sample gas involved in continuous flow mass spectrometric analysis, care should be taken to evaluate the influence of sample containers on the carbon and oxygen isotope ratios of samples. Data indicate that Na-glass and borosilicate glass vials, equipped with butyl rubber septa, can cause significant changes in the isotopic composition of CO(2) gas, even where sample gases are stored within the vial for less than one day. The magnitude of these changes varies from vial to vial. Given the leverage that contamination can potentially exert on small gas samples, each researcher should carefully evaluate the effect of sample vials in order to eliminate unknown and unwanted changes in the composition of samples. Copyright 2000 John Wiley & Sons, Ltd.     

Single vial formulation for theranostic radiopharmaceutical preparation

The present work was aimed at development of pharmaceutical grade single vial kit like formulation of somatostatin analogue, DOTA–Tyr³–Thr⁸-Octreotide (DOTATATE) suitable for radiolabeling with both diagnostic (⁶⁸Ga) and therapeutic (¹⁷⁷Lu) radioisotope. Single vial kit like formulation of DOTATATE was prepared. Radiolabeling methods with ⁶⁸Ga and ¹⁷⁷Lu were standardized. The pharmaceutical purity and stability of formulation was studied over a period of 6 months. Pharmacokinetics of radiolabeled preparations was studied in Swiss mice. DOTATATE formulation with 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid buffer was successfully prepared. Both ⁶⁸Ga–DOTATATE and ¹⁷⁷Lu–DOTATATE complexes were formed with >95 % radiochemical purity. Biodistribution studies of ⁶⁸Ga–DOTATATE and ¹⁷⁷Lu–DOTATATE complexes in Swiss mice revealed fast clearance of activity via renal route. Single vial kit like formulation suitable for easy preparation of ⁶⁸Ga–DOTATATE and ¹⁷⁷Lu–DOTATATE at hospital radiopharmacy was successfully demonstrated.     

Radioactivity measurement with a plastic scintillation vial

Liquid scintillation counting is widely used to measure radioactivity, but it generates radioactive organic liquid waste. Not to generate the liquid waste using a liquid scintillation counter, novel counting method with a plastic scintillation vial was designed. The counting efficiency for ³²P was 10–40% and that for ¹²⁵I was 4–8%. The efficiency depended on the sample volume. The color quenching effect was negligible. No radioactive liquid waste was generated by this method. In addition, you can reuse the measured sample.     

Directly suspended droplet microextraction in a rotating vial

In this paper, a novel suspended droplet microextraction method was developed for the detection of trace of organic compounds in water samples. The process was executed in a rotating extraction vial without the use of a stir bar. A single drop of octan-1-ol placed on top of the water sample was used as the solvent. The droplet remained on top of the water sample as a thin layer with an expanding surface area during the extraction stage, while during the sampling stage, the droplet was collected and sampled by inserting a needle. The volume of the microdroplet used was 3 μL or less, to ensure high organic compound sensitivity. The microextraction experimental setup was simple, utilizing centrifugal forces and possesses the advantages of low cross-contaminant/interference and applicability to water samples apt to emulsification. Nitrobenzene was selected as a model organic compound, and samples were analyzed using gas chromatography (GC) or UV-vis spectrometry. Analysis of the microextraction method results showed a relative standard deviation (RSD) less than 3.82%.     

Single vial kit formulation for preparation of PET radiopharmaceutical: 68Ga-DOTA-TOC

This paper describes the development of a lyophilized cold kit of DOTA-[Tyr³]-Octreotide (DOTA-TOC) for instant compounding of ⁶⁸Ga-DOTA-TOC, suitable for diagnosis of neuroendocrine tumors. The work involved formulation of DOTA-TOC kits, optimization of radiolabeling, quality control of ⁶⁸Ga-DOTA-TOC and animal biodistribution studies. The prepared kits enable a reliable method for preparation of ⁶⁸Ga-DOTA-TOC of high radiochemical purity and excellent stability. Availability of such kits along with ⁶⁸Ge/⁶⁸Ga generators is expected to stimulate the widespread use of ⁶⁸Ga-DOTA-TOC in nuclear medicine practice in developing countries.     

Compensation of the siphoning effect in nonaqueous capillary electrophoresis by vial lifting

Increasing the sample load in nonaqueous capillary electrophoresis through the use of wide-bore capillaries is a good way to scale up analytical separations to semipreparative level. However, obtaining high efficiency requires the use of special instrumentation to eliminate siphoning. When wide-bore capillaries are employed, relatively large solvent volumes are transported from inlet to outlet vial, and due to the difference in liquid levels a siphoning flow from outlet to inlet is established. Siphoning induces a deviation from the plug-like flow profile and adversely affects the separation efficiency. In this study the use of wide-bore capillaries in nonaqueous capillary electrophoresis was examined with compensation for siphoning by lifting of the inlet vial. The inlet vial is raised at a speed appropriate for maintaining equal levels of liquid in the inlet and outlet vials. The optimal lift rate was determined empirically from a series of runs in which the lift rate was varied. As well, a simple theoretical model was devised for the calculation of lift rates. The model was successfully applied for the 200 microm and 320 microm ID capillaries but for the 530 microm ID capillary the predicted optimal lift rate was too low. Evidently this was because the theory was unable to account for the effect of siphoning on the migration times. Three model compounds, bumetanide, furosemide and ethacrynic acid, were separated using an acetonitrile-ethanol mixture (50:50, v/v) with potassium acetate (1 mM) or ammonium acetate (5 mM) as electrolyte. Good separation of bumetadine and ethacrynic acid was obtained even with a 530 microm ID capillary when the lift rate was carefully optimized. Without elimination of siphoning the peaks would not have been detectable. The viscosities and electrical conductivities of the electrolyte solution measured at different temperatures showed that viscosity as well as conductivity decreased with increasing temperature. The temperature dependence of the conductivity was used to estimate the temperature inside the CE capillary.     

碳纳米管填充技术研究

本文在回顾碳纳米管填充技术研究进程的基础上,结合自身的研究工作对碳纳米管的填充方法及相关微观机制进行了归纳和总结,并对碳纳米管填充在相关领域的应用前景及尚待开展的工作进行了评述和展望。     

Simple and fast near-infrared spectroscopic analysis of hydroxyl number of polyol using a disposable glass vial

Hydroxyl (OH) number of polyol was measured using near-infrared (NIR) spectroscopy with the use of a disposable glass vial as a sample container. Polyols are viscous, so disposable vials are advantageous when spectroscopic methods are employed. Due to the curvature of the vial walls, a narrow aperture was used to minimize the spectroscopic deviations. The narrow aperture attenuated the NIR radiation and increased the spectral noise in the collected polyol spectra. Wavelet transformation (WT) was employed to reduce this noise and partial least squares (PLS) calibration model was developed. The overall prediction results compare well with those from conventional wet analysis that requires time (1–3 h) and large amounts of chemical reagents. NIR spectroscopy with the use of disposable vials can be utilized for a simple and fast quality assurance of polyol in actual industrial settings.     

Development of vial wall sorptive extraction and its application to determination of progesterone in human serum

A novel sample preparation method, vial wall sorptive extraction (VWSE), which uses a vial whose internal wall is coated with polydimethylsiloxane (PDMS), was developed. The method was applied to the determination of progesterone in human serum sample. Human serum sample (0.5 mL) spiked with progesterone-¹³C₂ was pipetted into the VWSE device and vortex mixing was performed for 30 min. Then, the serum sample was removed and the vial rinsed with purified water. Fifty microliter of methanol as liquid desorption (LD) solvent was pipetted into the VWSE device and vortex mixing was performed for 10 min. Then, the extract was analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The correlation coefficient (r) of the calibration curve over the concentration range of 0.5–200 ng mL⁻¹ was 0.999. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.1 and 0.5 ng mL⁻¹, respectively. The relative recoveries were 97.9% (RSD: 4.4%, n = 6) and 102.8% (RSD: 1.1%, n = 6) for progesterone spiked at 5 and 50 ng mL⁻¹, respectively. This simple, accurate, sensitive, and selective analytical method is applicable to the trace analysis of a minute amount of sample.     

齿科充填复合材料研究进展

齿科充填复合材料是由高分子基质、无机填料及光引发剂体系组成的复合物,主要用于齿科的修复。本文综述了近几年齿科充填复合材料的进展情况,并着重对该类材料中单体的研究进展进行分析和归纳。     

封孔镀铜过程中JGB作用机理研究

采用极化曲线和电化学交流阻抗法测试,研究了封孔镀铜过程中整平剂JGB的作用机理,同时利用质谱和液体核磁共振谱确定了通电过程中JGB分解产物A的结构。结果表明,JGB是一种非常不稳定的物质,在较低的阴极极化电位下JGB通过断开-N=N-双键同时加氢来实现它向产物A的转化,转化过程中JGB从电极表面脱附。相对JGB而言,产物A比较稳定,它在阴极表面的吸附强度随电位负移而增强。封孔镀过程中,因印制线路板(PCB)表面的工作电位一般都较JGB的脱附电位更负,而在此电位下,产物A可稳定吸附于电极表面,所以JGB的分     

New Inorganic Components for Dental Filling Composites

Summary. Dental composite filling materials are improved by incorporating nanofillers. They impart increased hardness and wear resistance to composites. In addition, they produce better polishing results than macrofillers. If the particles are sufficiently small, transparent composite pastes are obtainable, independent of the refractive index of the polymerisable monomers. In this context, organosols, non-agglomerated nanoparticles in organic liquid media, are especially interesting. Some of our own results on organosols are presented in this paper. Their relatively low viscosity enables the preparation of composites with a high filler load, thus reducing the shrinkage of the dental composite during polymerisation and improving the mechanical properties. Inorganic–organic hybrids are an attractive class of materials for dental fillings. The synthesis of different polymerisable ormocers for dental composites is reviewed in the second part. Ormocers can be applied as a polymerisable matrix, improving biocompatibility and wear resistance. Their use as inorganic fillers improves the thermodynamic compatibility of the filler with the matrix and enhances the polishability. Functionalised inorganic clusters used as new additives combine the properties of very small nanoparticulate fillers and well-designed highly functional monomers with high crosslinking capabilities. Xerogel colour pigments are advantageous alternative additives to conventional pigments. 3-D structural colour pigments, which are obtained by the self-assembly of monodisperse spherical particles, produce an opalescent effect resembling that of the natural enamel in highly aesthetic composites.This revised version was published online in February 2005. In the previous version the issue was not marked as a special issue, and the issue title and the editor was missing     

New Inorganic Components for Dental Filling Composites

Dental composite filling materials are improved by incorporating nanofillers. They impart increased hardness and wear resistance to composites. In addition, they produce better polishing results than macrofillers. If the particles are sufficiently small, transparent composite pastes are obtainable, independent of the refractive index of the polymerisable monomers. In this context, organosols, non-agglomerated nanoparticles in organic liquid media, are especially interesting. Some of our own results on organosols are presented in this paper. Their relatively low viscosity enables the preparation of composites with a high filler load, thus reducing the shrinkage of the dental composite during polymerisation and improving the mechanical properties. Inorganic–organic hybrids are an attractive class of materials for dental fillings. The synthesis of different polymerisable ormocers for dental composites is reviewed in the second part. Ormocers can be applied as a polymerisable matrix, improving biocompatibility and wear resistance. Their use as inorganic fillers improves the thermodynamic compatibility of the filler with the matrix and enhances the polishability. Functionalised inorganic clusters used as new additives combine the properties of very small nanoparticulate fillers and well-designed highly functional monomers with high crosslinking capabilities. Xerogel colour pigments are advantageous alternative additives to conventional pigments. 3-D structural colour pigments, which are obtained by the self-assembly of monodisperse spherical particles, produce an opalescent effect resembling that of the natural enamel in highly aesthetic composites.     

Eco-friendly micellar HPTLC technique for the simultaneous analysis of co-formulated antibiotic cefoperazone and sulbactam in pure form and vial pharmaceutical formulation

JPC – Journal of Planar Chromatography – Modern TLC - A rapid, sensitive, and eco-friendly micellar high-performance thin-layer chromatography (HPTLC) technique for the simultaneous...     

Glass microballoons: Filling agents for polyurethane elastomers

Combustibility of polyurethanes in the presence of inert filling agents: glass microballoons of a sodiumborosilicate nature, was studied. The expediency of their use in the composition of elastomers for reduction of fire danger was considered, and the effect of glass materials on their mechanical characteristics was studied.     

超级化学镀铜填充微道沟的研究

超级化学铜填充技术不仅可以应用于半导体超大集成电路铜互连线, 而且可以应用于三维封装. 研究了不同浓
度、不同分子量的PEG 对以甲醛为还原剂的化学镀铜溶液中铜的沉积速率的影响. 随着添加剂PEG 浓度和分子量的
增大, 化学铜的沉积速率明显降低. 电化学研究结果表明PEG 通过抑制甲醛的氧化反应降低化学铜的沉积速率, PEG
分子量越大, 对化学铜的抑制作用越强. 利用PEG-6000 对化学铜的抑制作用和在溶液中低的扩散系数, 采用添加
PEG-6000 的化学镀铜溶液, 成功地实现了宽度在0.2 μm 以下微道沟的超级化学填充. 就PEG 的分子量、微道沟的深
径比等因素对超级化学铜填充的影响也做了研究.