Determination Of Several Compounds Research Articles

Development and validation of the method for simultaneous determination of benzydamine hydrochloride and methylparaben in benzydamine dosage form by GC

Introduction: Modern analytical chemistry is heading to the side of the “Green Chemistry” approach. The implementation of the current approach is in the development of fast analytical methods that combine the determination of several compounds with the utilization of methods that do not generate wastes of organic solvents. Aim: The aim of the current work was to develop a method for the simultaneous determination of benzydamine hydrochloride (API) and methyl parahydroxybenzoate (preservative) in the dosage form. Materials and Methods: The development and validation of the proposed methodology were carried out. Results and Discussion: The validation parameters were determined; it was shown that the technique is robust, specific to determinable analytes. Conclusion: The developed technique can be used in control laboratories for the simultaneous determination of benzydamine hydrochloride and methyl parahydroxybenzoate in the finished dosage form of benzydamine.

Applicability of Capillary Gas-Liquid Chromatography for Determination of Parabens in Pharmaceutical Analysis

The traditional gas-liquid chromatography (GLC) method using packed columns is still used in pharmaceutical analysis for determination of parabens, despite the fact that this technique has a number of serious drawbacks.The aim of the study was to develop a more effective capillary GLC method for determination of parabens in active pharmaceutical ingredients and finished pharmaceutical products.Materials and methods: the study was performed using Agilent 6890N and Agilent 7890B systems with flame-ionisation detectors. The systems were equipped with Agilent 7683B and Agilent G4513A autosamplers, respectively. The following columns were used in the study: ZB-1 15 m х 0.32 mm х 0.25 pm, DB-1 30 m х 0.32 mm х 3.0 pm, Cp-Sil 5-CB 30 m х 0.32 mm х 3.0 pm.Results: the authors developed a method for methylparaben and propylparaben determination using capillary column GLC. The chromatographic parameters (chromatographic system performance, reproducibility of peak areas, peak asymmetry) were determined for both capillary and packed column GLC. The authors outlined the prospects for simultaneous determination of several compounds using the proposed method: a four-component mixture containing methyl-, ethyl-, propyl-, and butylparaben was separated in 9 minutes. The authors used Loma Lux Psoriasis to perform partial validation of the test method. They determined the linearity range and the limit of quantitation for methylparaben and propylparaben, and verified accuracy and intermediate precision of the test method.Conclusions: the results of the study allowed for selection of optimal chromatographic conditions for rapid and high-precision determination of methylparaben and propylparaben in medicinal products. The developed method is recommended for control of the content of these compounds in medicinal products.

Characterization and classification of three common Bambusoideae species in Korea by an HPLC-based analytical platform coupled with multivariate statistical analysis

PhyllostacShys bambusoides, Phyllostachys nigra var. henonis, and Pseudosasa japonica are Bambusoideae species widely cultivated in Korea. They are used in herbal medicines due to their potent bioactivities. However, the various chemical compositions of the different Bambusoideae species have not been documented; on the market, all are typically being labeled as bamboo, without species discrimination. Therefore, the present study aimed to evaluate the differences between these three Bambusoideae species based on simultaneous quantitative determination of several compounds. An analysis platform, consisting of ultrasound-assisted liquid-liquid extraction combined with high-performance liquid chromatography equipped with a diode array detector (HPLC-DAD) and a triple quadrupole mass spectrometer in multiple reaction monitoring mode (HPLC-MRM/MS), was developed and validated to analyze the biochemical compounds in these three Bambusoideae species. Multivariate statistical analysis was applied to discriminate samples, data visualization, and identification of sample clustering. As a result, nine compounds were identified as marker compounds for species differentiation. This study demonstrated that the chemotaxonomic application of three common Bambusoideae species could be achieved using our analytical platform coupled with appropriate multivariate statistical analysis. These abilities will help prevent possible side effects and unexpected biological activity resulting from incorrect species identification.

Evaluation of polar organic chemical integrative and hollow fibre samplers for the determination of a wide variety of organic polar compounds in seawater

The calibration of two passive samplers for the determination of 20 emerging organic compounds in seawater is described in this work: i) a new version of polar organic chemical integrative sampler (POCIS) containing 100 mg of mixed-mode anion exchanger (Strata X-AW) and 100 mg of polymeric HLB (Plexa) sorbent materials and using a highly porous Nylon membrane (30-μm pore size) and ii) polyethersulfone (PES) hollow fibre. Among the studied contaminants, herbicides, hormones, life style products (stimulants and artificial sweeteners), industrial chemicals (corrosion inhibitor and fluorinated compounds), personal care products and several pharmaceuticals were included. In the case of POCIS, both the sorbents and the Nylon membranes were extracted and analysed independently. The calibration set up consisted on a continuous-flow tank that was fed with a continuous flow of seawater (2 L/h) and a stock mixture of contaminants (20 mL/h), assuring a nominal concentration of ~ 600 ng/L (each analyte) in the tank. The uptake was linear in POCIS sorbent and Nylon membranes but exponential for PES hollow fibres. Furthermore, the highest sampling rates (Rs) values were obtained in POCIS sorbent (between 2.7 for acetaminophen and 491 mL/day for perfluoro-n-octanoic acid, PFOA) followed by Nylon membranes (between 3.6 for OBT and 50 mL/day for telmisartan) and the lowest were those from PES fibres (between 1.7 for bezafibrate and 157 mL/day for butylparaben). Additionally, five deuterated compounds ([2H5]-atrazine, [2H3]-amitriptyline, [2H7]-irbesartan, [2H3]-ketoprofen and [2H9]-progesterone) were studied as candidates for performance reference compounds (PRCs) in both POCIS and PES, and though [2H5]-atrazine, [2H9]-progesterone and [2H3]-amitriptyline showed acceptable results in the case of POCIS, only [2H5]-atrazine provided a good validation. In the case of PES fibres, the PRC corrections did not provide acceptable results due to a low dissipation of the PRCs. Finally, POCIS were deployed in two sites of the low part of the estuary of Bilbao (northern Spain) from where water samples were also taken and analysed. As a result, in addition to the overall good agreement between the passive and active samplings, passive samplers allowed the determination of several compounds that were below the detection limits in the active sampling.

Ontogenia de los esporangios, formación y citoquímica de esporas en licopodios (Lycopodiaceae) colombianos

Studies on reproductive aspects of Lycopodiaceae are not very abundant in the scientific literature, and constitute essential information to support taxonomic and systematic relationships among the group. Here we present a detailed study of the ontogeny of sporangia and sporogenesis, and the chemical determination of several compounds generated during spore formation. The analyses were performed in 14 taxa of six genera of the family, Diphasiastrum, Diphasium, Huperzia (a genus which is treated here including Phlegmariurus), Lycopodiella, Lycopodium and Palhinhaea. Specimens were collected in three departments from the Colombian Andes between 1 454-3 677m altitude. Ontogeny was studied in small, 1cm long pieces of strobili and axis, which were fixed in glutaraldehyde or FAA, dehydrated in alcohol, embedded in LR White, sectioned in 0.2-0.5 microm and stained with toluidine blue (TBO), a metachromatic dye that allows to detect both sporopollenin and lignin or its precursors, during these processes. For other studies, paraplast plus-embedded sections (3-5 microm) were stained with safranin-fast green and alcian blue-hematoxylin. Chemical tests were also conducted in sections of fresh sporangia at different stages of maturity using alcian blue (mucopolysaccharides), Lugol solution (starch), Sudan III (lipids), phloroglucinol (lignin) and orcein (chromosomes). Sections were observed with photonic microscope equipped with differential interference contrast (DIC) and fluorescence microscopy (for spore and sporangium walls unstained). Strobili and sporangia were dehydrated with 2.2 dimethoxypropane, critical point dried and coated with gold for scanning electron microscopy (SEM). Our results indicated that the ontogeny of sporangia and sporogenesis were very similar to the previously observed in Huperzia brevifolia. Cutinisation occurs in early stages of development of sporangium cell walls, but in their final stages walls become lignified. As for the sporoderm development, the exospore is the first layer formed, composed by sporopollenin. The endospore deposits as a thin inner layer composed of cellulose, pectin and carboxylated polysaccharides. The perispore, if present, deposits at last. Mucopolysaccharides were found on the sporocyte coat and its abundance in sporangial cavity persists up to the immature tetrads stage, and then disappears. The lipids were abundant in the sporocytes, tetrads and spores, representing the main source of energy of the latter. In contrast, starch is not detected in the spores, but is abundant in premeiotic sporocytes and immature tetrads, developmental stages of high cellular metabolic activity. Intrinsic fluorescence corroborates the presence of lignin and cutin in the sporangium wall, while the sporopollenin is restricted to the exospore. The transfusion cells and the perispore are not always present. However, the processes of ontogeny and sporogenesis are extremely similar throughout the taxa studied, suggesting that they represent conservative family traits, nonspecific or generic.

Assessment of MEKC suitability for residue drug monitoring on pharmaceutical manufacturing equipment

The suitability of micellar electrokinetic chromatography for the simultaneous trace determination of several compounds (sulfamethoxazole, trimethoprim, sulfanilic acid, sulfanilamide, 3,4,5-trimethoxybenzoic acid and nonoxynol-9) was assessed. The mixture was separated within 14 min at an applied voltage of 22 kV by using 30 mM phosphate electrolyte, containing 10 mM SDS, adjusted to pH 7.8. Under optimized separation conditions acceptable levels of linearity, precision and accuracy were obtained for all compounds. The method could be used as part of a cleaning validation study when assaying trace levels of co-trimoxazole drug, some of its decomposition products and detergent in the swab samples collected from pharmaceutical manufacturing equipment, after cleaning.

Improving the Selectivity of Semiconductor Gas Sensors Using the Pulse Adsorption Mode

A procedure is proposed for improving the selectivity of semiconductor gas sensors by the pulsed supply of the test gas mixture, with the use of transient spectroscopy for the separation and assessment of component contributions to the response of an electrical conductivity detector. The experimental verification of the procedure showed that the selective determination of several compounds and their mixtures can be performed using the same SnO2 detector. The simulation of the detector response as the sum of simplest relaxations revealed three types of surface sites on SnO2 films, with energy levels of 0.97, 1.38, and 1.50 eV. This means that the number of gas components that can be selectively determined with a single detector is limited to three.

Screening of aflatoxins in feed samples using a flow system coupled to capillary electrophoresis

A method is proposed which presents a new approach to the joint use of capillary electrophoresis (CE) commercial equipment and a flow system. This flow system allows the total determination of several compounds by using a fluorimetric screening system. The individual determination for each analyte is performed by the CE proposed method. The screening procedure uses simple equipment and operations and provides a yes/no binary response that occasionally requires confirmation. A fast, simple, and reliable method has been developed in order to determine the most frequent mycotoxins in feed samples using micellar electrokinetic capillary chromatography (MECC). An extraction step followed by a purification step was carried out on the samples in order to remove interference substances before analysis. A C 18 column was chosen to concentrate the mycotoxins, and the analytes were eluted from C 18 using methanol. The MECC method allows the separation of six mycotoxins within 50 min with a reproducibility as RSD between 7.45 and 13.06%, and a limit of detection (LOD) between 0.02 and 0.06 mg l −1 for all the mycotoxins. These LODs were clearly below legal limits (0.05 mg l −1).

Urinalysis of minor metabolites of ethylbenzene and m-xylene.

Gas chromatographic methods have been developed for the urinalysis of metabolic products of ethylbenzene. "Minor" metabolites were emphasized in this process. The methods were worked out so that simultaneous determination of several compounds could be achieved with one method. On the whole, four assays are described, which together allow 12 different compounds to be measured. Since one of the methods presented can be applied to determine "minor" metabolites of xylene as well, methodological data for these are also reported. The methods described have successfully been used in metabolic studies of ethylbenzene in rat and man.

L-Malate and sucrose as criteria for internal quality of golden delicious apples, size 70?80 mm

Sensory analysis and chemical determination of several compounds demonstrated that a batch of Golden Delicious apples, size 70–75/80 mm with al-malate content equal or higher than 0.55% and of sucrose equal or higher than 2% was acceptable on the basis of internal quality. The model is predictive.

Clinical biochemistry of tears

The composition of tear fluid as it exists in the conjunctival fornix and in the precorneal tear film is of a complicated nature. The precorneal tear film is a physically inhomogenous system, produced by the lacrimal glands, the accessory lacrimal glands and the goblet cells of the conjunctiva and the Meibomian glands of the lid margin. The method of collection is crucial for the quantity and concentration of a great number of different compounds that have been demonstrated in tears. A survey is given of the literature concerning tears as they are composed of proteins, enzymes, lipids, metabolites, electrolytes and drugs, the latter secreted during therapy. Clinical applications of the determination of several compounds for diagnosis or for monitoring drug therapy are summarized.

Gas-liquid chromatography of carbohydrate derivatives: the separation and quantitative determination of synthetic and naturally occurring glycosyl derivatives of amino acids

A gas-liquid chromatographic separation of the trimethylsilyl derivatives of several synthetic and naturally occurring glycosyl derivatives of amino acids is described. This technique may be used for the qualitative and quantitative determination of several compounds of biological interest including 3- O-β- D-xylopyranosyl- L-serine, 3- O-β- L-arabinopyranosyl- L-serine, 5- O-β- D-galactopyranosyloxy-D, L-lysine, and 2-acetamido- N-( L-aspart-4-oyl)-2-deoxy-β- D-glucopyranosylamine. In addition, the mobilities of these glycosyl derivatives of amino acids in paper chromatographic and paper electrophoretic systems are reported.

Volatiles from strawberries : II. Combined mass spectrometry and gas chromatography on complex mixtures

The technique of combined mass spectrometry and gas chromatography has been applied to the analysis of a complex oil of strawberry volatiles. Capillary gas chromatography indicated over 150 components. Most of the major components have been identified. These include alcohols, esters, acetals, aldehydes, furfural, methyl furfural, aromatic aldehydes, ketones, and esters, a few terpenes, and a few aromatic hydrocarbons. The strength of this technique is shown by the determination of several compounds in one sharp chromatographic peak. On the other hand certain prominent species could not bbe identified by the low resolution (resolution about 200) mass spectral data obtained.