高通量微孔板DAMBO-P~H荧光检测一氧化氮

一氧化氮(NO)是生物体内的一种重要生物信号传导分子,广泛参与生物体内多种生理及病理过程.为建立快速高效、准确检测生物体释放NO的分析方法,本文选用高灵敏度、高选择性的NO特异性荧光探针8-(3,4-diaminophenyl)-2,6-bis(2-carboxyethyl)-4,4-difluoro-1,3,5,7-tetramethyl-4- bora-3a,4a-diaza-s-indacene (DAMBO-P~H),激发波长和发射波长分别为520 nm和535 nm,以高通量微孔板(384孔)作为实验工具载体.该方法荧光强度与NO浓度在8.0×10~(-10)～8.0×10~(-7) mol·~(-1)范围内呈良好线性关系,R=0.9989,检出限为0.18 nmol·~(-1),回收率为98%～102%.该方法应用于多种生物样品中释放NO的分析检测,结果令人满意.     

A Bait-and-Switch Method for the Construction of Artificial Esterases for Substrate-Selective Hydrolysis

Outcomes of chemical reactions are generally dominated by the intrinsic reactivities of reaction partners, but enzymes frequently override such constraints to transform less reactive molecules in the presence of more reactive ones. Despite the attractiveness of such catalysis, it is difficult to build synthetic catalysts with these features. Micellar imprinting is a powerful method to create template-complementary binding sites inside protein-sized water-soluble nanoparticles. When a photocleavable functional monomer was used to bind two phosphonate/phosphate templates as transition-state analogues, active sites with predetermined size and shape were formed inside doubly cross-linked micelles through molecular imprinting. Postmodification replaced the binding group with a catalytic pyridyl group, forming highly selective artificial esterases. The catalysts displayed enzyme-like kinetics and turnover numbers that were in the hundreds. The selectivity of the catalysts, derived from the substrate-complementary imprinted active sites, enabled transformation of less reactive esters in the presence of more reactive ones.     

A New Bioautographic Screening Method for the Detection of Estrogenic Compounds

The yeast estrogen screen was introduced as biological detection method for high performance thin layer chromatography. Yeast cells were grown directly on HPTLC plates, where in the presence of estrogenic substances the production of the enzyme -galactosidase was induced. For the natural ligand 17 -estradiol, sensitivity could be improved by a factor of 20 using the fluorogenic substrate 4-methylumbelliferyl -D-galactopyranoside instead of the chromogenic substrate chlorophenol red--D-galactopyranoside. The fluorescence intensity of estrogenic zones was measured using a commercial TLC-Scanner. A nearly full dose-response curve was obtained for 17 -estradiol masses between 2.75 and 550 pg, or concentrations of 2.75 to 550 g L^–1.     

A New TLC Method for Quantification of Paraquat,Diquat, Difenzoquat,Mepiquat and Chloromequat in Water

JPC – Journal of Planar Chromatography – Modern TLC - We report improved separation of the highly toxic contact herbicides paraquat, diquat, difenzoquat, mepiquat, and chloromequat by...     

A Sensitive and Selective High‐Throughput Screening Fluorescence Assay for Lipases and Esterases

Long‐chain fatty acid esters of 7‐(3,4‐dihydroxybutyloxy)‐2H‐1‐benzopyran‐2‐one ( 6 ) such as octanoate 2a are shown to be exceptionally sensitive and selective fluorogenic substrates for lipases and esterases. Umbelliferone ( 8 ) is released upon hydrolysis of the ester function in 2a in the presence of bovine serum albumin and sodium periodate. These substrates are at least by one order of magnitude more sensitive to lipases than the commercial fluorogenic substrate 4‐methylumbelliferyl heptanoate. Furthermore, they are stable to a broad range of pH‐induced‐ and thermal‐hydrolysis conditions and do not react with non‐catalytic proteins such as bovine serum albumin (BSA).     

New Monofunctionalized Fluorescein Derivatives for the Efficient High‐Throughput Screening of Lipases and Esterases in Aqueous Media

Monoalkylation or acylation of fluorescein ( 1 ) with various acyloxymethyl or acyl halides afforded, respectively, a series of ether‐ ( 2 ) and ester‐functionalized ( 3 ) fluorogenic probes. The highly reactive and water‐soluble substrates release fluorescein ( 1 ) upon reaction with lipases and esterases within seconds or minutes, both under fully aqueous conditions or in the presence of DMSO (20%) as a co‐solvent. The most‐reactive substrates in the two series were the octanoic acid derivatives 2f (= 2‐{6‐[(octanoyloxy)methoxy]‐3‐oxo‐3H‐xanthen‐9‐yl}benzoic acid) and 3a (= 2‐[6‐(octanoyloxy)‐3‐oxo‐3H‐xanthen‐9‐yl]benzoic acid). Esterases were found to generally react faster under aqueous conditions, while lipases were more reactive in the presence of DMSO as a co‐solvent.     

Synthesis,Photoisomerization, Antioxidant Activity,and Lipid-Lowering Effect of Ferulic Acid and Feruloyl Amides

The Ugi four-component reaction employing naturally occurred ferulic acid (FA) is proposed as a convenient method to synthesize feruloyl tertiary amides. Applying this strategy, a peptoid-like derivative of ferulic acid (FEF77) containing 2 additional hydroxy-substituted aryl groups, has been synthesized. The influence of the configuration of the double bond of ferulic acid and feruloyl amide on the antioxidant activity has been investigated thanks to light-mediated isomerization studies. At the cellular level, both FA, trans and cis isomers of FEF77 were able to protect human endothelial cord vein (HECV) cells from the oxidative damage induced by exposure to hydrogen peroxide, as measured by cell viability and ROS production assays. Moreover, in steatotic FaO rat hepatoma cells, an in vitro model resembling non-alcoholic fatty liver disease (NAFLD), the molecules exhibited a lipid-lowering effect, which, along with the antioxidant properties, points to consider feruloyl amides for further investigations in a therapeutic perspective.     

Validated TLC-Image Analysis Method for Simultaneous Quantification of Curcuminoids in Curcuma longa

A simple and rapid thin layer chromatographic (TLC)-image analysis method was developed for simultaneous quantification of three curcuminoids; curcumin (CUR), desmethoxycurcumin (DES) and bisdesmethoxycurcumin (BIS), in Curcuma longa (turmeric). Chromatographic separation of the curcuminoids was achieved on silica gel 60 F254 TLC plates, using chloroform–hexane–methanol (1:1:0.1, v/v/v) as the mobile phase. Image analysis of the scanned TLC plate was performed by Photoshop 7.0 to quantify the amount of each curcuminoid. The method was validated and found to be accurate, reliable and convenient for the analysis of CUR, DES and BIS in turmeric.

     

A New HPLC Method for the Simultaneous Determination of Acetaminophen,Phenylephrine, Dextromethorphan and Chlorpheniramine in Pharmaceutical Formulations

Abstract

Acetaminophen, phenylephrine, dextromethorphan, and chlorpheniramine are frequently associated in pharmaceutical formulations against the common cold. A new high performance liquid chromatography (HPLC) method has been developed for the simultaneous determination of these active pharmaceutical ingredients in pharmaceutical formulations. The separation and quantitation were achieved on a 25 cm underivatized silica column using a mobile phase of methanol: water (containing 6.0 g of ammonium acetate and 10 ml of triethylamine per liter, pH adjusted to 5.0 with orthophosphoric acid), 95:5%(v/v). Detection was carried out using a variable wavelength UV-vis detector at 254 nm for acetaminophen, at 220 nm for phenylephrine, and at 227 nm for dextromethorphan and chlorpheniramine. The method showed linearity for the acetaminophen, phenylephrine, dextromethorphan, and chlorpheniramine in the 162.5–650, 2.5–10, 7.5–30, and 1–4 µg/ml ranges, respectively. The intraday and interday RSDs ranged from 0.92 to 1.52%, 1.00 to 1.76%, 1.21 to 1.74% and 1.26 to 1.80% for the acetaminophen, phenylephrine, dextromethorphan, and chlorpheniramine, respectively. Compounds were eluted in a run time of less than 12 min.     

A New and Sensitive HPLC-UV Method for Rapid and Simultaneous Quantification of Curcumin and D-Panthenol: Application to In Vitro Release Studies of Wound Dressings

Curcumin (CUR) and D-panthenol (DPA) have been widely investigated for wound-healing treatment. In order to analyse these two compounds from a dosage form, such as polymer-based wound dressings or creams, an analytical method that allows the quantification of both drugs simultaneously should be developed. Here, we report for the first time a validated high-performance liquid chromatographic (HPLC) method coupled with UV detection to quantify CUR and DPA based on the standards set by the International Council on Harmonization (ICH) guidelines. The separation of the analytes was performed using a C₁₈ column that utilised a mobile phase consisting of 0.001% v/v phosphoric acid and methanol using a gradient method with a run time of 15 min. The method is linear for drug concentrations within the range of 0.39–12.5 μg mL⁻¹ (R² = 0.9999) for CUR and 0.39–25 μg mL⁻¹ for DPA (R² = 1). The validated method was found to be precise and accurate. Moreover, the CUR and DPA solution was found to be stable under specific storage conditions. We, therefore, suggest that the HPLC-UV method developed in this study may be very useful in screening formulations for CUR and DPA within a preclinical setting through in vitro release studies.     

一种同时测定桂油中肉桂醛和苯甲醛双组分的新方法

建立了一种双波长分光光度法同时测定桂油中肉桂醛和苯甲醛的分析方法。苯甲醛的线性方程为A=0.1089x-0.0014,线性范围为1~12 mg/L,检出限为0.1047 mg/L;肉桂醛的线性方程为A=0.1442x-0.0006,线性范围为0.8~8 mg/L,检出限为0.0735 mg/L。     

Densitometric HPTLC Method for Simultaneous Quantification of Sennosides A and B and Gallic Acid in a Pharmaceutical Dosage Form

JPC – Journal of Planar Chromatography – Modern TLC - A densitometric HPTLC method has been established for simultaneous quantification of sennosides A and B and gallic acid in a...     

New MSPQC Method for Rapid Identification and Quantification of Pseudomonas aeruginosa

Abstract

A new method for the rapid identification and quantification of Pseudomonas aeruginosa using multichannel series piezoelectric quartz crystal (MSPQC) was proposed. The identification of P. aeruginosa was based on the development of acetamide broth, which can selective culture P. aeruginosa and performed perfectly in MSPQC. The quantitative detection of P. aeruginosa was based on the fact that the frequency detection time (FDT) detected by MSPQC in developed medium had a linear relationship with the logarithm of its initial concentration in the range of 10–10⁸ colony ? forming units (cfu) ml^–1 (R=?0.984). The detection limit was 10 cfu ml^–1.     

A New Method for Quantification of Melamine in Milk by Absorption Diode-Array Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC -     

A New Chemometric Strategy in Electrochemical Method Optimization for the Quantification of Cefdinir in Tablets,Effervescent Tablets and Suspension Samples

A new voltammetric method, based on the use of single‐use pencil graphite electrode, was developed for the quantitative determination of cefdinir by square wave voltammetry. Chemometric optimization strategy was used to select the suitable values for three experimental parameters (pH of the supporting electrolyte, frequency and square wave amplitude) by applying a 3³ full factorial design model. The optimal voltammetric conditions were found to be pH 5.0 for supporting electrolyte (Britton‐Robinson buffer), 43 mV for square wave amplitude and 108 Hz for frequency. Square wave voltammograms of calibration, validation and unknown samples were recorded between 0.0–1400 mV under the optimized voltammetric conditions. Linear regression equation was computed in the linear working range of 0.5–20 μg/mL by using the relationship between the concentration and peak current at 600 mV. The optimized voltammetric method was validated by assessing the analysis results of validation samples. Then the proposed method was applied for the quantitative determination of cefdinir in three different pharmaceutical preparations, namely film‐coated tablets, effervescent tablets and powder for oral suspension. It was concluded that the proposed voltammetric method was suitable for the quantitative analysis of commercial pharmaceutical preparations containing cefdinir.     

Simultaneous Quantification of Flavonoids and Biflavonoids in Ginkgo biloba Using RP-HPTLC Densitometry Method

JPC – Journal of Planar Chromatography – Modern TLC - A reversed-phase high-performance thin-layer chromatography (RP-HPTLC) method was developed for the determination of flavonoids...     

Method for Screening and Quantification of Seven Phenothiazines in Whole Blood Samples by Non-Aqueous Capillary Electrophoresis

Seven phenothiazine derivatives (PHE) group were studied using non-aqueous capillary electrophoresis (NACE). The screening and quantification method for these drugs in blood was presented. Then the optimal medium for dissolution of the examined blood extracts was tested for. The precision of identification and quantification parameters comprised the ranges from 0.29 to 1.38 and from 1.21 to 9.15 % RSD, correspondingly. The detection limits were 0.08 for promazine and 0.15 g mL^–1 for the rest of drugs tested. The correlation coefficient of the method linearity was studied over the concentration range of 0.25–4.00 g mL^–1 and was higher than 0.996. Finally the proposed method was applied to two forensic blood samples and concentrations of the examined phenothiazines determined by HPLC and NACE methods were found to be comparable.     

A New Method for Olive Oil Screening Using Multivariate Analysis of Proton NMR Spectra

A new NMR-based method for the discrimination of olive oils of any grade from seed oils and mixtures thereof was developed with the aim of allowing the verification of olive oil authenticity. Ten seed oils and seven monovarietal and blended extra virgin olive oils were utilized to develop a principal component analysis (PCA) based analysis of ¹H NMR spectra to rapidly and accurately determine the authenticity of olive oils. Another twenty-eight olive oils were utilized to test the principal component analysis (PCA) based analysis. Detection of seed oil adulteration levels as low as 5% v/v has been shown using simple one-dimensional proton spectra obtained using a 400 MHz NMR spectrometer equipped with a room temperature inverse probe. The combination of simple sample preparation, rapid sample analysis, novel processing parameters, and easily interpreted results, makes this method an easily accessible tool for olive oil fraud detection by substitution or dilution compared to other methods already published.     

由含稳定化合物的二元相图计算化合物的活度

本文提出了一种含稳定化合物相图中化合物的活度计算的新方法,即根据已有的从相图提取活度的公式,结合质量作用定律,由纯组元的活度计算得到化合物的活度.用此方法计算了Al-Ca及In-Sb两个二元系中稳定化合物的活度,计算结果与文献值吻合较好.     

Development and Validation of a Stability-Indicating High-Performance Thin-Layer Chromatographic Method for the Simultaneous Quantification of Sparfloxacin and Flurbiprofen in Nanoparticulate Formulation

JPC – Journal of Planar Chromatography – Modern TLC - A simple, sensitive, precise, rapid, and reliable high-performance thin-layer chromatographic (HPTLC) method for the simultaneous...