Electrochemical immunosensing of low-density lipoprotein based on sol-gel encapsulation

Abstract Lipoprotein monitoring is desirable in the management of medical conditions such as atherosclerotic cardiovascular disease and coronary artery disease, in which controlling the concentration of these chylomicrons is crucial. Current clinical methods are complex and present poor reproducibility between laboratories. For these reasons, recent guidelines discard the assessment of low-density lipoprotein cholesterol (LDL-C) as a routine analysis during lipid-lowering therapies. Concerning the importance of monitoring this parameter, the authors present an electrochemical immunosensor constructed from a simple and easy-to-reproduce platform that allows detecting and quantifying LDL nanoparticles directly from human serum samples. The performance of the biosensor was studied by scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. The biosensing platform displays good stability and linearity between 30 mg dL-1 and 135 mg dL-1 with a detection limit of 20 mg dL-1. The proposed biosensor can be easily employed for monitoring LDL concentration in clinical treatments.

ZnO: SnO2 nanocomposite efficacy for gas sensing and microbial applications

The unique characteristics of 2-dimensional hetero structure offers efficient gas sensing with high selectivity to identify gases from the interference gases which is quite difficult. In the present work, ZnO: SnO2Nano composite clusters (NCC) is prepared. A resistive metal oxide volatile organic compound (VOC) gas sensor is fabricated with nullifying the effect of humidity by increasing temperature optimally. A single-step SOL-GEL (SG) synthesis is used to prepare ZnO: SnO2 NCC with maximum Zn/Sn molar concentration ratio of 3. The morphological studies through Scanning Electron Microscopy (SEM), electrical properties due to oxygen vacancies and energy band variations of Nanocomposite are measured. The enhancement of gas sensor sensitivity due to highly mesoporous nature of the composite is observed. From the findings, the abundant mesopores in the range of 2 nm-14 nm and specific surface area of 54.2 m2 g?1 with the average crystal size of 14.236 nm, and polar surface area of the composite 25.9651Åis achieved. When compared to bare ZnO and SnO2 gas sensors, the present gas sensor offers the higher selectivity with enhanced performance due to the mesoporous structure. Fast repeatability rate of 2200 sec at 350?C to ethanol is attained and the overall selectivity of the sensor increased twice as 2.085. The NCC compound is tested firstly with micro organisms such as B. subtilis (B. S), Bacillus cereus (B. C), B. coagulans (B. C), Pseudonymous auriginosa (P. A) are considered for antimicrobial activity. From the findings, zinc stannate compound showed good efficacy towards B. cereus Gram positive and P.A gram-negative. A bacterial growth is arrested highly with B. cereus.

Synthesis of ureasil-polyether film forming materials by using environmentally friendly solvent

Organic inorganic hybrids present several advantages as drug release systems, such as: high flexibility, high mechanical and thermal resistance, transparency, and low water solubility. These hybrids are synthesized through a chemical route named sol-gel that usually uses as solvente tetrahydrofuran (THF). Objetives: To develop film formers from hybrid materials replacing THF with ethanol, a less toxic solvent for skin application and for the environment. Methods: Four polymers were used: two based on polyethylene oxide (PEO) with molecular weight of 500 and 1900 g mol-1 and two based on polypropylene oxide (PPO), with molecular weight of 400 and 2000 g mol-1. The structural analysis was performed by FTIR, 1H-NMR and 29Si-NMR, and the thermal-mechanical analysis by DSC and TG-DTA. Results: The results of the thermo-mechanical analysis revealed that the solvent replacement did not affect the thermal stability and flexibility of the di-ureasil hybrid. Conclusions: Structural characterization confirmed the formation of hybrids both in THF and in ethanol. Therefore, ethanol is an excellent solvent for the synthesis of these hybrid matrices, since it allows obtaining the same material without changing its characteristics, with some advantages, however, over THF. Furthermore, this paper describes the efficiency of ethanol as a solvent, which is environmentally friendly, to replace THF in the physical-chemical characteristics of these filming former materials.

Degrading enzyme modified molecularly imprinted xerogel for selective adsorption and degradation of dopamine / 药学学报

In recent years, the overexpression dopamine (DA) due to the use of addictive drugs has caused concern and urgently needs to be addressed. The method used in our study is known as biomimetic sol-gel synthesis. We undertook the experiment to develop molecularly imprinted xerogel polymers (MIXPs) through template molecules dopamine polymerized with polyethyleneimine (PEI), then self-assembled and crosslinked with tetramethoxysilane (TMOS) in the form of non-covalent hydrogen bonds by using biomimetic sol-gel process, and then eluted template DA will leave a blotting site. Monoamine oxidase immobilized MIXPs (MAO-MIXPs) was obtained by coating monoamine oxidase onto MIXPs. The synthesis optimization of MAO-MIXPs was finally set as the ratio of DA template, PEI and MAO coating (DA 40 mg, PEI 0.6 mL, MAO 2.5 mg·g-1) to achieve highly selective adsorption toward DA in artificial cerebrospinal fluid based on the adsorption performance and degradation performance. The micromorphologies and physical-chemical properties of MAO-MIXPs were characterized by scanning electron microscopy, differential scanning calorimeter and Fourier transform infrared spectroscopy, and then amount of adsorption was calculated with adsorption equation. Simultaneously, the Brunner-Emmet-Teller (BET) and Langmuir model were simulated. It was found that the adsorption behavior tended to be monolayer adsorption. This new molecularly imprinted polymer demonstrated potential dopamine expression regulation for highly selective recognition, adsorption and degradation of dopamine.

Photocatalytic Degradation of Textile dye Orange-122 Via Electrospray Mass Spectrometry

Abstract This work reports the study of the potential application of Zn/TiO2 catalysts, obtained by the sol-gel method, in processes of environmental decontamination through the reactions of photodegradation of textile dye, followed by electrospray mass spectrometry. The catalysts synthesis was performed according to a 2² factorial design with repetition at the central point. The characterization techniques used were: N2 adsorption measurements (BET method), scanning electron microscopy with energy dispersive X-ray (MEV/EDS), X-ray diffraction and point of zero charge (PZC). The photocatalytic tests were performed in batch in the presence of sunlight, and to evaluate the degradation kinetics study, a rapid direct injection electrospray mass spectrometry (DI-ESI-MS) method has been developed. By the photocatalytic tests, the calcination temperature of 400 °C has shown the best results of discoloration for the reactive Orange-122 dye (99.76%) in a reaction time of 2h. The discoloration kinetics were a pseudo-first order, and a statistical analysis was performed to investigate the effects of the variables and to optimize the conditions of discoloration to the dye. After the reactional time of 2 h, an ion of m/z 441.5 was detected by ESI-MS, indicating that the photocatalytic process was effective for the degradation of the dye to secondary compounds.

Síntesis y caracterización de nanocompuestos Fe3O4/Ag: su efecto contra Enterobacter aerogenes y Enterococcus faecaiis / Synthesisandcharacterization of nanocompounds Fe3O4/Ag: its effect against Enterobacter aerogenes and Enterococcus faecaiis / Síntese e caracterização de nanocompósitos Fe3O4/Ag: seu efeito contra Enterobacter aerogenes e Enterococcus faecaiis

Resumen En el presente trabajo, se reporta la síntesis y caracterización de nanopartículas magnéticas de magnetita/plata (Fe3O4/Ag) para el estudio de sus propiedades antibacterianas frente a las bacterias Enterobacter aerogenes (Gram-negativa) y Enterococcus faecaiis (Gram-positiva). Las nanopartículas magnéticas de magnetita (MNPs) se sintetizaron por el método de solgel, usando bromuro de cetiltrimetilamonio (CTAB) como surfactante. Posteriormente, en la dispersión coloidal de magnetita, se llevó a cabo la reducción química in situ de iones de plata, usando glucosa como agente reductor y polivinilpirrolidona (PVP) como agente dispersante, para obtener un nanocompuesto magnético Fe3O4/Ag. El análisis morfológico y espectroscópico de las nanopartículas de Fe3O4 y del nanocompuesto de Fe3O4/Ag fue realizado mediante la espectroscopia infrarroja con transformada de Fourier (FTIR), Raman, y Mössbauer (MS), además de la técnica de difracción de rayos X (DRX), la microscopía electrónica de barrido (SEM) y espectroscopia de energía dispersiva de rayos X (EDS). Las nanopartículas de Fe3O4 resultaron esféricas con un diámetro medio de 10 nm y el nanocompuesto de Fe3O4/Ag con un tamaño medio de 28 nm, el test antibacteriano indicó que el uso del nanocompuesto de Fe3O4/Ag a una concentración de 5 mg'mL-1 permite una inhibición total del crecimiento de los microorganismos estudiados a partir de una concentración inicial 108 bacterias mL-1.

Abstract In the present study, we report the synthesis and characterization of magnetite/silver magnetic nanoparticles (Fe3O4/Ag) and the study of their antibacterial properties against the bacteria Enterobacter aerogenes (Gramnegative) and Enterococcus faecaiis (Grampositive). Magnetite magnetic nanoparticles (MNPs) were prepared by a sol-gel method using cetyltrimethylammonium bromide (CTAB), as a surfactant, followed by in-situ chemical reduction of silver ions by glucose, and polyvinylpyrrolidone (PVP), as a dispersive agent, to obtain the antibacterial nanocomposite of Fe3O4/Ag. Morphological and spectroscopic studies of magnetite nanoparticles and nanocomposite were carried out using the Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Mössbauer spectroscopy (MS), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Spherical Fe3O4 MNPs showed an average diameter of 10 nm and the average size for nanocomposite was 28 nm. The antibacterial test indicated that the use of the nanocomposite of Fe3O4/Ag at a concentration of 5 mg'mL-1 allowed a total inhibition of the growth of the microorganisms studied from an initial concentration of 108 bacteria mL-1.

Resumo No presente trabalho, relatamos a síntese e caracterização de nanopartículas magnéticas de magnetita/prata (Fe3O4/Ag) e o estudo de suas propriedades antibacterianas contra as bactérias Enterobacter aerogenes (Gram-negativo) e Enterococcus faecaiis (Gram-positiva). Nanopartículas magnéticas de magnetita (MNPs) foram sintetizadas pelo método solgel usando o bromuro de cetiltrimetilamonio (CTAB) como surfactante. Posteriormente, na dispersão coloidal de magnetita, a redução química in situ dos íons de prata foi realizada utilizando-se glicose, como agente redutor, e polivinilpirrolidona (PVP), como agente dispersante, para obter um nanocompósito magnético Fe3O4/Ag. A análise morfológica e espectroscópica das nanopartículas de Fe3O4 e do nanocompuesto de Fe3O4/Ag conduziu-se através da espectroscopia infravermelha com transformada de Fourier (FTIR), Raman, e Mössbauer (MS), además da técnica de raio X da deformação (DRX), a microscopia eletrônica de barrido (SEM) e a espectroscopia de energia dispersiva de raios X (EDS). As nanopartículas de Fe O têm formas esféricas com um diâmetro médio de 10 nm e o nanocompósito de Fe3O4/Ag com um tamanho promédio de 28 nm. O teste antibacteriano indicou que o uso do nanocompósito Fe3O4/Ag na concentração de 5 mg'mL-1 permitiu inibir totalmente o crescimento dos microrganismos estudados a partir de uma concentração inicial de 108 bactérias mL-1.

Directional separation of active ingredients of dehydrotumulosic acid from Guizhi Fuling Capsule by molecular imprinting technique / 中草药

To establish a method for directional separation of dehydrotumulosic acid from the extracts of Guizhi Fuling Capsule with molecular imprinting technique (MIT). Molecular imprinting polymer (MIP) was prepared by sol-gel process with dehydrotumulosic acid as molecular template to study the absorption property. The dehydrotumulosic acid was achieved from Guizhi Fuling Capsule by one-step separation with polymer as filler. The structure of dehydrotumulosic acid was identified on the basis of the spectral data and physicochemical property. The maximum binding capacity (Qmax) of MIP was 9.10 mg/g measured by Scatchard equation and the purity of dehydrotumulosic acid was 90.76% by HPLC. The established MIT for the directional separation of dehydrotumulosic acid from Guizhi Fuling Capsule is simple and benefit to reducing the solvent use during the separation process, which could offer a novel method for the separation and purification of dehydrotumulosic acid.

Extraction of Paeoniflorin and Its Derivatives fromGui-Zhi Fu-Ling Capsule Using Molecular Imprinting Technology / 世界科学技术-中医药现代化

Paeoniflorin and its derivatives are main active compounds inGui-Zhi Fu-Ling Capsule (GZFLC). In this study, molecular imprinted polymer (MIP) was prepared by sol-gel process to obtain paeoniflorin and its derivatives in GZFLC. The static adsorption capacity of MIP was measured by scatchard equation. The results showed that the maximum apparent absorbing capacity of MIP was 52.28 mg·g-1. One-step separation of paeoniflorin from 4 g methanol samples of GZFLC was 197 mg with the purity of 89.3%. It was concluded that paeoniflorin MIP can be used to separate phaoniforin and its analogues from GZFLC.

Synthesis of Dihydroartemisinin using Ni/TiO2 catalyst Prepared by Sol Gel Method.

Artemisinin is a δ-sesquiterpene lactone that incorporates an endoperoxide moiety. This compound was isolated as the active compound of Artemisia annua L. Dihydroartemisinin is the simplest semisynthetic derivative of artemisinin and is more potent than artemisinin. Combined with piperaquine, curently this compound is the drug of choice to treat malaria. The objective of this research is to modify the structure of artemisinin into dihydroartemisinin. A new way to modify the structure of artemisinin into dihydroartemisinin, had been successfully conducted using hydrogenation process with Ni/TiO2 catalyst. The yield of the reaction was 16.58%. LC-MS analysis showed that the compound had mainly a peak with retention time tR 2.2 minutes and mass spectrum showed that the molecular weight of the compound was 284.29 which was the molecular formula of dihydroartemisinin, C15H24O5. The IR spectrum showed that there was a spectrum from C-O in a wave number of 1034.14 cm-1. Hydrogenation reaction did not destroy the endoperoxide group. This was proven by the existing of C-O-O-C in a frequency of 1091.71; 875.68; 844.82 cm-1. 1H- and 13C-NMR data and comparison to the authentic sample, showed that the compound was a racemic mixture of /dihydroartemisinin. The dihydroartemisinin resulted from this process was also proven for its antimalarial activity, in vitro assay using cultured Plasmodium falciparum clone 3D7 with its IC50= 2x10-7M.

Produção de I-124 com uso de nanomateriais e sua biodistribuição em animais / Production of I-124 with the use of nanomaterials and their biodistribution in animals

O iodo-124 é um emissor de pósitron com 4,2 dias de meia vida física. Seu decaimento dá-se por emissão de pósitrons (23,3 por cento) e captura eletrônica (76,7 por cento). Suas características físicas e químicas o tornam um isótopo atrativo para aplicações médicas. O desenvolvimento de novas técnicas de imagens, melhorias na tecnologia de Tomografia por Emissão de Pósitrons (PET), o desenvolvimento de novos detectores e métodos computacionais de processamento de sinal, abrem novas perspectivas para a sua aplicação. Os crescentes usos da tecnologia PET em oncologia, em estudos de farmacocinética e de metabolismo de drogas, fazem dos radiofármacos marcados com 124I uma ferramenta de grande interesse e utilidade. O uso de moléculas marcadas com 124I destaca-se especialmente devido à conveniente meia-vida do 124I. Esta característica possibilita diagnósticos por imagens, em centros PET longe do local de produção de radionuclídeos. Dentro deste contexto, este trabalho apresenta um método de produção e separação de 124I. Este método é inovador e pioneiro no país. Baseia-se no desenvolvimento e utilização de alvos de natTeO2 nanoestruturados. Estes alvos são irradiados em um acelerador de partículas carregadas, de energia variável, o cíclotron CV-28 do IEN. As irradiações são realizadas com feixes de prótons de 24 MeV de energia inicial.Na preparação dos alvos nano particulados o destaque foi a simplicidade do método, que usa a técnica de sol-gel para obtenção de nano partículas, o TeCl4 como precursor e a água como solvente. O 124I produzido foi separado do material alvo por destilação seca e capturado numa solução de NaOH (0,02M), em sistema automatizado. O rendimento de alvo grosso foi de 6,81 MBq/μAh, sendo o rendimento da síntese de aproximadamente 90%. O 124I obtido foi então utilizado em estudos preliminares de biodistribuição. Estes estudos foram realizados em um MicroPET, modelo LabPET 4 do CDTN, em camundongos tipo Swiss. Os resultados da aplicação de Na124I mostraram alta qualidade de imagem PET da tireoide, sendo que a máxima captação deu-se 6 h após injeção.

Fabrication of Molecularly Imprinted Electrochemiluminescence Sensor and Its Application in Heroin Detection / 分析化学

An electrochemiluminescence (ECL) sensor with molecularly imprinted polymer (MIP) film was prepared for the determination of heroin. The sensor was prepared by re-modifying the molecular imprinting membrane onto the Ru ( bpy ) 2+3 modified glassy carbon electrode. The electrochemical and electrochemiluminescence behavior of the sensor was investigated. The proposed sensor displayed high sensitivity and excellent selectivity for the target molecule heroin. Under the optimum conditions (0. 1 mol/ L PBS (pH 7. 0) at a scan rates of 100 mV/ s and incubation time of 5 min), a linear response was observed with the concentrations of heroin from 1. 0 × 10-14 mol/ L to 1. 0 ×10-10 mol/ L and the detection limit was 4. 0 × 10-15 mol/ L. The sensor was successfully applied to the determination of heroin in urineand saliva samples with the recoveries from 97% to 104% .

Fabrication and Cell Imaging of Room Temperature Phosphorescent Silica Nanomaterials / 分析化学

Aphosphorbasedonsilicananoparticleswaspreparedusingasol-gelmethod.Thecontrollable synthesis, spectroscopic properties, cytotoxicity and cell imaging of these nanomatericals were examined by using photoluminescence spectra, TEM, XRD, confocal microscopy and other characterized measurements. The results demonstrated that the obtained sample was silica with diameter about 50 nm. The maximum fluorescence excitation and emission wavelengths of the silica nanomatericals were 280 nm and 335 nm, and the maximum phosphorescence excitation and emission wavelengths of the silica nanomatericals were 280 nm and 440 nm. The obtained silica sample possessed room temperature phosphorescence that was stable against environmental changes. The obtained sample was stored in air at ambient conditions and its phosphorescence remained unchanged after 3 month demonstrated its long-term stability. The result of methyl thiazolyl tetrazolium ( MTT) and cell imaging experiments suggested that the synthesized silica nanoparticles were feeble cytotoxicity and could be uptaken by cells at the lysosomal compartment. Therefore these nanoparticles could serve as bioprobes for cell imaging.

Amperometric L-lactate Biosensor Based on Sol-Gel Film and Multi-walled Carbon Nanotubes/Platinum Nanoparticles Enhancement / 分析化学

An electrochemical L-lactate biosensor was fabricated by combining Platinum nanoparticles (Pt-nano) with multi-walled carbon nanotubes(MWCNTs).L-lactate oxidase(LOD) was immobilized on the surface of the glassy carbon electrode (GCE) modified with MWCNTs and Pt-nano.The surface of resulting LOD/MWCNTs/Pt-nano electrode was covered by a thin layer of sol-gel to avoid the loss of LOD and to improve the anti-interference ability.The cyclic voltammetric results indicated that MWCNTs/Pt-nano catalyst displayed a higher performance than MWCNTs.Under the optimized conditions, i.e., applied potential of 0.5 V, pH 6.4, 25 ℃, the proposed biosensor's determination range was 0.2-2.0 mmol/L, response time was within 5 s, and the sensitivity was 6.36 (A/(mmol/L).It still kept 90% activity after 4 weeks.The fabricated biosensor had practically good selectivity against interferences.The results for whole blood samples analyzed by the present biosensor showed a good agreement with those analyzed by spectrophotometric method.

Preparation and Characteristics of Patterned TiO2 Thin Film onTC4 Made by Sol-gel Method / 医用生物力学

Objective To improve the long-term biocompatibility and mechanical stability of Titanium alloy implants. Method micro-nano patterned TiO2 thin films have been prepared on TC4 substrates via a sol-gel dip-coating method with Ti(OC4H9)4 (TEOT) as precursor and polyethylene glycol (PEG) as organic template. The influence of PEG concentration upon the morphology of the target films has been studied by using AFM. The wettability and tribological properties of the target films have been studied by means of optical contact angle measuring instrument and UMT-2. Results When increasing the PEG concentration to 3.5g/100mL, a parallel arranged groove structure can be obtained on the surface of the sample; compare with TiO2 sol-gel film without adding organic template, the wear resistance of the patterned film is better. Conclusions The feature of the patterned TiO2 films can be controlled by adding different amount of organic template; and it has been proved that a certain kind of patterned structure can improve the wear resistance of the film.

Preparation and characteristics of patterned TiO_2 thin film on TC4 made by sol-gel method / 医用生物力学

Objective To improve the long-term biocompatibility and mechanical stability of Titanium alloy implants.Method Micro-nano patterned TiO_2 thin films have been prepared on TC4 substrates via a sol-gel dipcoating method with Ti(OC_4H_9)_4(TEOT)as precursor and polyethylene glycol(PEG)as organic template.The Influence of PEG concentration upon the morphology of the target films has been studied by using AFM.The wettability and tribological properties of the target films have been studied by means of optical contact angle measuring instrument and UMT-2.Results When increasing the PEG concentration to 3.5 g/100 mL,a parallel arranged groove structure can be obtained on the surface of the sample;compared with TiO_2 sol-gel film without adding organic template,the wear resistance of the patterned film is better.Conclusions The feature of the patterned TiO_2 films can be controlled by adding different amount of Organic template;and it has been proved that a certain kind of patterned structure can imeprove the wear resistance of the film.

Preparation and characteristics of patterned TiO_2 thin film on TC4 made by sol-gel method / 医用生物力学

Objective To improve the long-term biocompatibility and mechanical stability of Titanium alloy implants.Method Micro-nano patterned TiO_2 thin films have been prepared on TC4 substrates via a sol-gel dipcoating method with Ti(OC_4H_9)_4(TEOT)as precursor and polyethylene glycol(PEG)as organic template.The Influence of PEG concentration upon the morphology of the target films has been studied by using AFM.The wettability and tribological properties of the target films have been studied by means of optical contact angle measuring instrument and UMT-2.Results When increasing the PEG concentration to 3.5 g/100 mL,a parallel arranged groove structure can be obtained on the surface of the sample;compared with TiO_2 sol-gel film without adding organic template,the wear resistance of the patterned film is better.Conclusions The feature of the patterned TiO_2 films can be controlled by adding different amount of Organic template;and it has been proved that a certain kind of patterned structure can imeprove the wear resistance of the film.

Preparation and characteristics of patterned TiO_2 thin film on TC4 made by sol-gel method / 医用生物力学

Objective To improve the long-term biocompatibility and mechanical stability of Titanium alloy implants.Method Micro-nano patterned TiO_2 thin films have been prepared on TC4 substrates via a sol-gel dipcoating method with Ti(OC_4H_9)_4(TEOT)as precursor and polyethylene glycol(PEG)as organic template.The Influence of PEG concentration upon the morphology of the target films has been studied by using AFM.The wettability and tribological properties of the target films have been studied by means of optical contact angle measuring instrument and UMT-2.Results When increasing the PEG concentration to 3.5 g/100 mL,a parallel arranged groove structure can be obtained on the surface of the sample;compared with TiO_2 sol-gel film without adding organic template,the wear resistance of the patterned film is better.Conclusions The feature of the patterned TiO_2 films can be controlled by adding different amount of Organic template;and it has been proved that a certain kind of patterned structure can imeprove the wear resistance of the film.

Determination of Cholesterol in Human Serum Based on Flow-injection Chemiluminescence Method by Sol-gel Immobilized Enzyme / 分析化学

The cholesterol esterase and its oxidase were respectively immobilized onto sol-gel(tetraethyl orthosilicate)and then an enzymatic reaction column was prepared. Hydrolysis of cholesterol ester took place in the presence of cholesterol esterase to form cholesterol under catalysis of cholesterol oxidase, and Cholesterol was oxidized to produce hydrogen peroxide which reacted with luminal in the presence of simulated enzyme hemoglobin to result in the emission of light. Thereupon, a chemiluminescence system combined with flow injection technology by sol-gel immobilized enzyme was developed for the determination of cholesterol including free and total amount in human serum. The CL intensity was well linear with the concentration of cholesterol;liner range of total and free cholesterol was 1.01×10~(-6)～2.02×10~(-4) mol/L with a detection limit of 7.5×10~(-7) mol/L) and 5.0×10~(-8)～2.18×10~(-5) mol/L) with a detection limit of 5.0×10~(-9) mol/L respectively. Contrasted the method) with the biochemical analyzer (TBA-120FR), both the methods had no significant difference. This method has been successfully applied for the detection of cholesterol in clinic serum samples.

Preparation and Characterization of Butylaminopropyl Silica Monolithic Column for Capillary Electrochromatography / 分析化学

A novel silica monolithic stationary phase functionalized with butylaminopropyl ligands for capillary electrochromatography(CEC) has been presented. The monolithic capillary columns were prepared by a sol-gel) process and subsequent a chemical modification. The amino groups on the surface of the stationary phase are meant to generate a substantial anodic electroosmotic flow (EOF). The butyl and propyl groups provide) hydrophobic properties. To evaluate the column performance, effects of buffer pH and organic modifier content on the EOF and electrochromatographic retention behavior of alkylbenzenes, organic acids and anilines were investigated. The monolithic stationary phase exhibited reversed phase (RP) chromatographic behavior toward neutral solutes. The model organic acid anion solutes were separated by the mixed mode mechanism, which comprised RP interaction, weak anion-exchange, and electrophoresis. Basic compounds such as anilines) were well separated on the butylaminopropyl silica monolithic column without peak tailing.