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Public health is threatened worldwide by counterfeit medicines. Their quality, safety and efficacy cannot be guaranteed since no quality control is performed during and/or after the manufacturing process. Characterization of these products is a very important topic. During this study a High Performance Liquid Chromatography–Photodiode Array (HPLC-PDA) and a High Performance Liquid Chromatography –...
Modified matrix volatilization (MV) method has been described to characterize high purity germanium material of 7N (99.99999%) purity. Transport of both, the chlorine gas generated in-situ in this method and the argon gas (carrier) is fine controlled by means of a mass flow controller. This enabled both uniform reaction of chlorine gas with the germanium matrix and smooth removal of germanium matrix...
Paints, a complex matrix, have a variable composition that is dependent on the application. In this work, a new wet digestion procedure for the determination of Al, As, Ba, Cd, Cr, Cu, Mn, Ni, Pb, Sn, Sr, Ti and Zn in paint samples using inductively coupled plasma optical emission spectrometry (ICP OES) has been developed. An experimental design approach was employed to determine the optimal conditions...
Proteomic analysis using capillary zone electrophoresis (CZE) typically is performed with linear polyacrylamide (LPA) coated capillaries. These capillaries both minimize the adsorption of peptides and proteins to the inner wall of the capillary and decrease electroosmosis, which increases the separation capacity. LPA coating protocols were first reported by Hjerten in 1985. Conventional LPA production...
Organic solvents are widely used in microbial fermentations to reduce gas stripping effects and capture hydrophobic or toxic compounds. Reliable quantification of biochemical products in these overlays is highly challenging and practically difficult. Here, we present a significant improvement of identification and quantification methods for farnesene produced by Saccharomyces cerevisiae in two-liquid-phase...
Electrochemical genosensors have undergone an enormous development in the last decades, but only very few have achieved a quantification of target content in highly processed food samples. The detection of allergens, and particularly gluten, is challenging because legislation establishes a threshold of 20ppm for labeling as gluten-free but most genosensors expresses the results in DNA concentration...
Bactericidal water filters were developed. For this purpose, nitrocellulose membrane filters were impregnated with different biosynthesized silver nanoparticles. Silver nanoparticles (AgNPs) from Aspergillus niger (AgNPs-Asp), Cryptococcus laurentii (AgNPs-Cry) and Rhodotorula glutinis (AgNPs-Rho) were used for impregnating nitrocellulose filters. The bactericidal properties of these nanoparticles...
The biosensing for rapid detection of bacteria based on surface-enhanced Raman scattering (SERS) has been widely explored for recent years. It is still a challenge to achieve a high sensitive, reproducible label free detection method for bacteria. In this work, a label-free SERS detection method of Escherichia coli based on incubation with silver colloid was reported. Optimized incubation conditions...
Environmental pollutants, such as the polycyclic aromatic hydrocarbons (PAHs), become widely distributed in the environment after emission from a range of sources, and they have potential biological effects, including toxicity and carcinogenity. In this work, we have demonstrated the analytical potential of a covalently linked l-cysteine-capped CdSeTe/ZnSe/ZnS core/shell/shell quantum dot (QD)–graphene...
A low-pressure liquid chromatography system for the on-line quantification of caffeine loaded into lipid nanoparticles that permeates pig skin was developed. The apparatus includes a Franz diffusion cell with computer-controlled sampling that allows collection of acceptor solution with automatic compensation for sample withdrawing, and a C-18 reversed-phase monolithic column integrated in a typical...
2-(2′-Hydroxyphenyl)benzimidazole derivatives (X-HBIs), modified by various substituents X (X=H, CH3, OH, OCH3, NO2, NHCOCH3, NH2, N(CH3)2), were synthesized and their fluorescent behaviors and equilibriums in aqueous solution were studied. Strong fluorescence attributed to the tautomer emission was observed in aqueous solution at pH 7.4. The fluorescence intensities of the X-HBIs were enhanced selectively...
Flow injection amperometric (FI-Amp) sensor was developed for sensitive and selective determination of hydroquinone. A simple screen printed carbon electrode (SPCE) was modified with various nanomaterials for improvement of sensitivity on the determination of quinone. As a result, the appropriate sensitivity is obtained from the SPCE modified with carbon nanotube (CNT) which indicated that CNT contributed...
In this study, we found that iodophenol blue can enhance the weak chemiluminescence (CL) of luminol–H2O2 system. With the aid of CL spectral, electron spin resonance (ESR) spectral measurements and studies on the effects of various free radical scavengers on the iodophenol blue-enhanced luminol–H2O2 system, we speculated that iodophenol blue may react with H2O2 and oxygen to produce oxidizing radical...
In this work, we propose for the first time a simple and novel approach based on SERS and As (III) -aptamer for detection of As (III) with excellent selectivity and sensitivity. To maintain the wonderful SERS substrate, Au@Ag shell–core nanoparticle has been successfully synthesized by seeds growth method. As-prepared Au@Ag not only has well-dispersed but also obtains high SERS efficiency. The novel...
To determine whether the effect observed in a study is related to the nanoparticle only or to their synergic effect with the “free” metal ions, the real concentration of silver (104±8 and 100±2mgL−1) after AgNP synthesis is obtained through ICP-MS and ICP OES in the solution after the AgNP synthesis and in different fractions after centrifugation (at 8100g for 40min). From the resuspension of the...
An array of chemiresistors based on conducting polymers was assembled for the differentiation of coconut oil products. The chemiresistor sensors were fabricated through the potentiostatic electrodeposition of polyaniline (PANi), polypyrrole (PPy) and poly(3-methylthiophene) (P-3MTp) on the gap separating two planar gold electrodes set on a Teflon substrate. The change in electrical resistance of the...
The solubilities of several cobalt(III) chelates (CoL3) with in supercritical carbon dioxide (SC-CO2) were investigated in the presence of fluorine- and trifluoromethyl-substituted phenols (PhOH) using UV–vis spectrophotometry. Solubility enhancement of CoL3 complexes in SC-CO2 was accomplished by adding PhOH. The association constants for tris(pentane-2,4-dionato)cobalt(III) (Co(acac)3) with various...
Screen-printed electrodes (SPEs) have gone through significant improvements over the past few decades with respect to both their format and their printing materials. Thus, SPEs have been successfully applied for the in situ detection of a plethora of analytes in a wide range of sample matrixes due to their advantageous material properties, such as disposability, simplicity, and rapid responses. In...
The main limitation in the standard application of head space analysis employing solid phase microextraction (HS-SPME) for the evaluation of plants as sources of essential oils (EOs) are different quantitative relations of EO components from those obtained by direct analysis of EO which was got in the steam distillation (SD) process from the same plant (EO/SD). The results presented in the paper for...
A novel colorimetric and fluorescent iminocoumarin-based turn-off chemosensor for acetate ion was designed and synthesized. The chemosensor could fast detect acetate ion in a 1:1 ratio within 150ms, which could not be affected by various coexisting anions, even F−. Futher studies showed that the detect limit was as low as 2.05×10−7M, and the binding constant was determined to be 1.02×108M−1. Due to...
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