Analysis Of Commercial Products Research Articles

Development of an electrochemical sensor based on carbon black for the detection of cannabidiol in vegetable extracts.

A glassy carbon electrode chemically modified with a carbon black coating is proposed here for the rapid and portable determination of cannabidiol (CBD) in a commercial Cannabis seed oil and in fibre-type Cannabis sativa L. leaves. The mechanism of CBD oxidation was studied in relation to simpler phenyl derivatives bearing the same electroactive group, namely resorcinol and 2-methylresorcinol. These molecules also allowed us to determine the best conditions for the electrochemical detection of CBD, as to the pH value and to the best solvent mixture to use. Carbon black was chosen among nanostructured carbon-based materials owing to its outstanding features as an electrode modifier for analyte detection. The performance of the modified electrode was determined by flow injection analyses of standard solutions of CBD, obtaining a linear correlation between the oxidation current and the analyte concentration; the sensor response is characterised by suitable repeatability and reproducibility. The analysis of commercial products by the standard addition method allowed us to ascertain the accuracy of the sensor for the detection of CBD in real samples.

Voltammetric Determination of Anethole on La2O3/CPE and BDDE.

In this work, DPV determination of anethole was presented using various carbon, two-diameter (1.5 and 3 mm) electrodes, that is, BDD, GC, CP, and CP doped by La2O3 and CeO2 nanoparticles. La2O3/CPE to our best knowledge was proposed first time. Cyclic voltammograms confirmed totally irreversible electrode electrooxidation process, controlled by diffusion, in which two electrons take part. The most satisfactory sensitivity 0.885 ± 0.016 µA/mg L−1 in 0.1 mol L−1 acetate buffer was obtained for La2O3/CPE with the correlation coefficient r of 0.9993, while for BDDE it was 0.135 ± 0.003 µA/mg L−1 with r of 0.9990. The lowest detection limit of 0.004 mg L−1 was reached on La2O3/CPE (3 mm), what may be compared with the most sensitive conjugate methods, but in the proposed approach, no sample preparation and analyte separation was needed. Anethole was successfully determined in specially prepared ethanol extracts of herbal mixtures of various compositions, which imitated real products. The proposed procedure was verified in analysis of commercial products, that is, anise essential oil, which contains a large concentration of anethole, and in alcohol drinks like Metaxa, Ouzo, and Rakija, in which the considered analyte occurs on trace levels. Structure and properties of the considered nanopowders and graphite pastes were investigated by EDX, SEM, and EIS.

Comparison of High-Performance Liquid Chromatographic and Thin-Layer Chromatographic Methods for Determination of Aloin in Herbal Products Containing Aloe vera

Aloe vera is a medicinal plant used worldwide to treat a variety of conditions and, as such, has important commercial value. Aloin is a principal component of aloe vera leaves and is used for quality control of products containing it. A semiquantitative thin-layer chromatographic (TLC) method for determining the concentration of aloin in aloe-based products was validated. The results were similar to those of a validated high-performance liquid chromatographic method; therefore, TLC, which is a simple, sensitive, specific, rapid, and cheap method, may be ideal for use in any laboratory for routine analysis of commercial products containing aloe vera.

Silicate release from glass for pharmaceutical preparations

Glass is made of polymeric silica and other minor components, which are necessary for turning the silica into a material more easily moldable and resistant to temperature changes. Glass containers for pharmaceutical usage are classified according to their resistance to a chemical attack, a test carried out in the presence of water and heat. The test is designed to show the released alkalinity, a variable dependent on the amount of sodium oxide, one of the minor components added to the glass mass. In this work, the release of silica from glass by action of constituents from pharmaceutical formulations was investigated. The study included products used in large volumes and usually stored in glass containers. Solutions of amino acids, electrolytes, glucose, oligoelements and others such as heparin and sodium bicarbonate were individually stored in glass containers and heated at 121 °C for 30 min, as in the water attack test. The test was also carried out only with water, where the pH varied from 2 to 12. The released silicate was measured either by photometry or atomic absorption spectrometry, depending on the nature of the sample. The results showed that silicate is released during the heating cycle even if the contact is with pure water only. The pH exerts a considerable influence on the release, being that the higher the pH, the higher the silica dissolved. An elevated pH, however, is not the only factor responsible for silica dissolution. While in the solutions of NaCl, KCl, Mg Cl 2 and ZnSO 4 and in most of the amino acids, the concentration of silicate was as high as in pure water (0.1–1.0 mg Si/L). In the solutions of sodium acetate, bicarbonate and gluconate, its concentration was much higher, over 30 mg Si/L. These results were confirmed by the analysis of commercial products, where in solutions of amino acids the level of silicate ranged from 0.14 to 0.19 mg Si/L. On the other hand, calcium gluconate, sodium bicarbonate and potassium phosphate presented silicate levels from 1 to 4 mg/L. Although silica is not considered a toxic substance for humans, it is necessary to be aware of its presence in solutions for parenteral nutrition due to the direct introduction into the bloodstream and the large volume usually administrated, even to pre-term infants.

A simplex-optimized chromatographic separation of fourteen cosmetic preservatives: analysis of commercial products.

An ion-interaction high-performance liquid chromatography (HPLC)-diode-array detection method is developed and optimized for the separation of typical antimicrobial agents used in cosmetics and hygiene products. The most used preservatives contain different molecular structures, different functionalities, and are characterized by different chemical properties. Organic acids, alkyl esters of benzoic acids, alkyl p-hydroxy benzoic acids (parabens), phenol derivatives, and carbanilides represent the most used preservatives, and are often present in multicomponent mixtures. In order to develop a multicomponent method to be used in quality control analysis, the ion-interaction reagent reversed-phase HPLC technique seems to be particularly suitable, because it allows for the simultaneous separation of acidic, basic, and neutral species. The experimental conditions of the method are developed by OVAT (one variable at a time) treatment and further optimized by a multivariate approach based on a Simplex algorithm that works on a desirability function targeted to maximize the resolution in a multicomponent mixture. The new method proposed that is able to simultaneously separate fourteen preservatives is applied in the analysis of commercial products.

High Performance Liquid Chromatographic Analysis of Sulfonamides in Livestock Products Using Matrix Solid-Phase Dispersion (MSPD) Method with Silica Gel

The MSPD method with silica gel (Silica Gel-MSPD) was developed for the extraction of sulfonamides in livestock products. Residual sulfonamides such as sulfameradine (SMR), sulfadimidine (SDD), sulfamonomethoxine (SMM), sulfadimethoxine (SDM) and sulfaquinoxarine (SQO) were extracted from chicken muscle tissue, yolk and pork muscle tissue. A sample (0.5g) was mixed with 0.7g of silica gel and 1.5ml of acetonitrile, and the mixture was dried, washed with hexane and eluted with methanol or tetrahydrofuran (THF). An aliquot of the methanol or THE solution was subjected to HPLC for the determination of each sulfonamide. The recoveries of sulfonamides added to the chicken, yolk and pork were 78.1 to 93.1%, 74.6 to 86.2% and 69.6 to 87.1%, respectively. The limits of detection for the proposed method were 0.01ppm for SMR and SDD, 0.02ppm for SMM and 0.04ppm for SDM and SQO.In order to confirm the utility of the proposed method, analyses of commercial products were performed, and the result was compared with that obtained by MSPD with ODS. Consequently, 0.94ppm of SMM and 0.99ppm of SDM were detected in two samples of pork muscle by the proposed method, whereas the values detected by using ODS were 0.81 and 0.56ppm, respectively.

Determination of Nicarbazin in Chicken Muscle and Egg by High Performance Liquid Chromatography

High performance liquid chromatography (HPLC) with an ultraviolet absorption detector was examined for the determination of nicarbazin in chicken muscle and egg.After extraction with acetonitrile from homogenized sample, the extract was evaporated to dryness. The residue was dissolved in methanol and injected onto an HPLC column packed with LiChrosorb RP-18 (reverse phase) and eluted with a mixture of acetonitrile-water (7:3), with detection at 340nm.A linear calibration plot was obtained in the range of 10ng to 200ng for nicarbazin. The recoveries of nicarbazin added to chicken muscle and egg were 93.6% and 95.3%, respectively, on average. The detection limit of nicarbazin in this analytical procedure was 0.02ppm in chicken muscle and egg.In the analysis of commercial products, nicarbazin was detected in 8% of chicken muscle samples in the range of 0.05 to 0.52ppm, but it was not detected in eggs.

Determination of Neostigmine Bromide by Ion-Pairing Column Chromatography

Abstract A rapid and sensitive method for the assay of neostigmine bromide (NBr) in tablets and ophthalmic solutions has been developed. NBr is isolated from its pharmaceutical excipients by the ion-pairing partition column chromatographic principles of Levine and Doyle followed by ultraviolet determination of its alkaline hydrolysis product. Standard recoveries of NBr from simulated tablet mixtures and ophthalmic solutions averaged 99.8%. The standard deviation of repeated analyses of commercial products was less than±1%. The results of the proposed method for commercial products are in good agreement with the USP XVIII procedure. The procedure is applicable to individual tablet assay.