Florina Copaciu

Determination of some frequently used antibiotics in waste waters using solid phase extraction followed by high performance liquid chromatography with diode array and mass spectrometry detection

AbstractThis study is focused on the determination of some important antibiotics from different classes in waste water samples using solid phase extraction followed by high performance liquid chromatography with two detectors, diode array and mass spectrometer in positive ionisation mode. The investigated antibiotics include three penicillins (amoxicillin, ampicillin, penicillin G), two cephalosporins (ceftazidime, ceftriaxone), and two tetracyclines (tetracycline, doxycycline). The studied antibiotics were extracted from waste water samples using hydrophilic-lipophilic balanced cartridges. The extraction of antibiotics from water matrices was tested at several pH values. The best recoveries were obtained at pH 3 and 7 respectively. Depending on the nature of antibiotic, the limits of detection and quantification were obtained in the range of 0.07–0.92 µg mL−1 and 0.21–2.77 µg mL−1 respectively. Influent and effluent waste water samples were collected from a Waste Water Treatment Plant from Romania in order to detect the studied antibiotics. The antibiotics detected in the influent waste water samples were ceftriaxone (334 µg L−1), tetracycline (146 µg L−1) and doxycycline (110 µg L−1). In effluent waste water samples no target antibiotics were detected.

Identification of anthocyanins and anthocyanidins from berry fruits by chromatographic and spectroscopic techniques to establish the juice authenticity from market

The profiles of anthocyanins and anthocyanidins present in berry fruits can be used as fingerprints for the evaluation of authenticity of raw materials, juices, fruit extracts, and food products. The aim of our work was to establish the authenticity of fruit juices from the market according to the label inscription. With this end in view, we used spectroscopic and TLC techniques for the preliminary identification of main groups of anthocyanins and to obtain a fingerprint of each berry fruit used in the preparation of juice. For the same purpose, we achieved a RP-HPLC method for the determination in detail of the composition of natural pigments, such as anthocyanins from alcoholic extracts of colored fruits and anthocyanidins from their hydrolyzed products. The RP-HPLC chromatographic fingerprints gave us the possibility to identify seventeen anthocyanins (glycosylated anthocyanidins) and five major anthocyanidins (delphinidin, cyanidin, petunidin, pelargonidin, and malvidin) from the extracts of colored fruits. The TLC separation was achieved on cellulose pre-coated plates developed with concentrated hydrochloric acid-glacial acetic acid-water as mobile phase followed by densitometric measurements in visible. The HPLC separation was carried out on ODS-2 Hypersil column by gradient elution and detection at 520 nm. The mobile phase was a mixture of acetonitrile and phosphoric acid buffer in different ratios. Our methods have been successfully applied to find the fingerprint of anthocyanins and anthocyanidins of eight berry fruits which we used as reference materials at the analysis of fruit juices from market in order to establish their authenticity and conformity with the label inscription.

Solid Phase Extraction and High-Performance Thin-Layer Chromatography Quantification of Some Antibiotics from Surface Waters

Excessive use of antibiotics leads to their occurrence into the environment. In spite of their benefit properties and desired effects during the therapeutic applications, the same properties can be disadvantageous for the environment having negative influences over the plants and microorganisms and the potential risks for human health. Regarding the monitoring of antibiotics and their subsequent elimination from environment, it is necessary to develop analytical procedures for their determination. In the present study, the quantitative determination of seven antibiotics belonging to three different classes is reported: tetracyclines (tetracycline and doxycycline), cephalosporins (ceftazidime and ceftriaxone), and penicillins (amoxicillin, ampicillin, and penicillin G) from surface waters. The proposed procedure consists of the solid phase extraction (SPE) of studied antibiotics from river water samples, their separation by high-perfomance thin-layer chromatography (HPTLC), and quantification by UV densitometry. The antibiotics were extracted from water matrices using hydrophilic-lipophilic-balanced Oasis HLB cartridges. The cartridge efficiency of the SPE method was checked by recovery experiments and evaluated by HPTLC. The chromatographic separation was performed on pre-coated Alugram SIL G/UV254 plates with ethyl acetate-methanol-acetone-water 5:2.5: 2.5:1.5 (v/v) mobile phase. The bands were detected and quantified at 254 nm by densitometry. For method validation, studies of selectivity, linearity, limits of detection and quantification, and precision and accuracy were achieved. The proposed procedure was applied to the determination of studied antibiotics on surface water samples collected from Someoul Mic River (Romania).

Influence of geographic origin, plant source and polyphenolic substances on antimicrobial properties of propolis against human and honey bee pathogens

Natural honey bee products, especially propolis are well known for their biological properties. However, less well known are the impact of propolis’ single phenolic substances and variation across different landscapes, geographic locations and botanical origins. Here, we determined the chemical composition of propolis samples collected in different geographic areas of Romania with a continental climate. Main groups of polyphenols, as well as individual phenolics (phenolic acids and flavonoids), were identified and quantified. The antimicrobial activity of propolis ethanolic extracts and some of the most important propolis phenolics (caffeic and ferulic acid, pinocembrin, chrysin and galangin) were evaluated against different bacterial species. Analyzing the interaction of bacterial growth inhibition and different chemical parameters, revealed that flavone/flavonol, flavanone/dihydroflavonol, chrysin and galangin are largely responsible for the propolis’ antimicrobial activity against Gram-positive bacteria. Gram-negative bacteria were mostly inhibited by galangin, caffeic acid and naringenin. Chemical composition and antimicrobial activity of the propolis samples might be explained by the botanical sources present in the specific foraging areas. The highest amounts of polyphenols and flavonoids were measured in regions where deciduous forests were dominant to coniferous, or where large areas of willow could be observed.

Determination of some textile dyes in wastewater by solid phase extraction followed by high-performance thin-layer chromatography

The objective of this paper is to report a procedure for the extraction and the determination of five textile dyes (Lanasyn Blue F-L 150, Lanasyn Dark Brown M-GLN, Lanasyn Red M-GA, Nylosan Dark Brown S-MBL, and Nylosan Red N-2RBL) which were not yet studied in literature by high-performance thin-layer chromatography. For SPE of these dyes, four types of Strata cartridges (WAX/NH2, SAX, C18-U and C18-E) were tested. The best results were obtained on Strata WAX/NH2. The dyes were separated on precoated Alugram RP-18W/UV254 plates with the n-butanol-ethyl acetate-5% ammonium hydroxide 4:4:1 (v/v) mobile phase. The densitometric scanning was performed at 550 nm. Linear regression analysis of the calibration data indicated a good linear relationship between the peak area and the dye concentration in the range of 20–60 ng per band. For the HPTLC method, the detection and the quantification limits of the studied dyes were calculated. The obtained detection limits (ng per band) were: 6.6 for Lanasyn Blue F-L 150, 5.90 for Lanasyn Dark Brown M-GLN, 3.38 for Lanasyn Red M-GA, 5.49 for Nylosan Dark Brown S-MBL, and 1.07 for Nylosan Red N-2RBL. The SPE-HPTLC procedure was applied to monitor these textile dyes in the effluent wastewater samples collected from a textile factory from Romania.

DETERMINATION OF TWO TEXTILE DYES IN WASTEWATER BY SOLID PHASE EXTRACTION AND LIQUID CHROMATOGRAPHY/ELECTROSPRAY IONIZATION TANDEM MASS SPECTROMETRY ANALYSIS

This study describes a procedure for the determination of two textile dyes (Nylosan Red N-2RBL-azo and Optilan Blue MF-GL-anthraquinone) from wastewater by solid phase extraction and liquid chromatography/electrospray ionization tandem mass spectrometry (SPE-LC/ESI-MS/MS) analysis. Four types of Strata SPE cartridges (C18-U, C18-E, WAX/NH2, and SAX) were tested; the best results being obtained on Strata WAX/NH2. The detection of dyes was carried out by mass spectrometry with an API 3200 QTRAP ESI-MS/MS system using a TurboV ionization source in ESI negative ion mode. The method of multiple reaction monitoring transitions was followed to quantify the precursor molecular ions and the related product ions. A mobile phase of methanol:water (70/30, v/v) at 0.65 mL min−1 flow rate was used for elution. The procedure was validated by: linearity, limits of detection and quantification, accuracy, and precision. The obtained detection/quantification limits were: 0.285/0.864 ng mL−1 for Nylosan Red N-2RBL and 0.433/1.310 ng mL−1 for Optilan Blue MF-GL. The presented procedure has been applied for monitoring the studied textile dyes in influent and effluent wastewater from a treatment plant from an area in Romania that has a textile factory.

Chromatographic analysis of lypophilic compounds in eggs from organically fed hens

SUMMARY Egg yolks represent a common foodstuff in the human diet and are an important source of nutrients including lipids and carotenoids. The aim of this study was to compare the carotenoid, fatty acid and vitamin E contents of the yolk of eggs from nine hen breeds (Barred Plymouth Rock, Speckled Italian, Black Italian, Red Italian, Rhode Island, Silver Laced Wyandotte, Gold Araucana, Partridge Brahma and Yellow Cochin) raised in barns in an enclosed house. Gas chromatography‐mass spectrometry (GC‐MS) was used for the fatty acid analyses, and reversed phase‐high performance liquid chromatography‐photodiode array detection (RP‐HPLC‐PDA) for carotenoids and vitamin E quantification. The major carotenoids identified were lutein and zeaxanthin, which together represented more than 93% of the total carotenoids, followed by &bgr;‐cryptoxanthin and &bgr;‐carotene. The results indicated that the total carotenoid content of the eggs ranged from 16.84‐87.31 &mgr;g/g egg yolk (average value 49 &mgr;g/g egg yolk). The most representative fatty acids found were palmitic acid, stearic acid, oleic acid and linoleic acid. Significant differences in the proportions of &agr;‐linolenic acid were observed among the samples. The &agr;‐tocopherol content was directly correlated with the total carotenoid content. The results show that the chemical composition of egg yolk varies greatly among hen breeds.

Analysis of Dyes and Inks

Abstract Instrumental thin-layer chromatography (TLC) offers automation, reproducibility, and accurate quantification for a wide variety of applications. This chapter is focused on an overview of the instrumental TLC applied to the dye and ink analysis. Even though TLC is a destructive chromatographic technique, it is widely used to separate and identify compounds from different matrices due to its capability to generate qualitative information unavailable through the nondestructive spectroscopic techniques. Instrumental TLC occupies a very important place in the advances obtained in the separation, identification, and quantification of dyes from various matrices such as food, textiles, cosmetics, inks, and so on. The performances of different instrumental TLC methods are highlighted by the use of dyes as test compounds. Instrumental TLC is generally accepted as a scientific methodology used to compare and characterize dyes from different ink formulations having the highest discrimination power for the individual techniques.

Dielectroosmotic effects in electric current pulse

The solvent movement under the influence of different forces (hydrostatic, centrifugal, gravitational, electrical, etc.) is essential in most of the industrial and laboratory processes. In our previous works, we used an electrohydrodynamic device to simulate the movements of some chromatographic solvents that are utilized in dielectrochromatography. In those experiments, we used sinusoidal current as high voltage alternating current. The most significant results were obtained for the movement of non-polar solvents in comparison with the polar ones. The aim of this paper is to study the behavior of non-polar and polar solvents in the pulsating electric field. A special attention was paid to some physical properties of polar solvents under electric current pulse.

Influence of barium titanate over V-LDEC separation under AC external nonuniform electric field

In our previous papers, we defined layer (planar) dielectrochromatography and we presented its fundamentals (theoretical aspects) such as the displacement of dielectric liquids under nonuniform external alternating electric fields (dielectroosmotic flow [DEOF] effect), the displacement of solute particles or polarized granules (dielectrophoresis [DEP] effect) in electric fields generated by armatures, the theoretical evaluation of the electric intensity generated in the stratified dielectrics, etc. Ready-to-use plates of alumina, silica gel, and cellulose were used for experiments. The obtained results have encouraged us to create our own TLC plates based on alumina enriched with compounds of high dielectric constants like barium sulfate, barium titanate, and titanium dioxide. In this paper, we present the preparation of seven plates containing increasing amounts (1, 2, 3, 4, 6, 8, 10) g of barium titanate in 35 g alumina, the methodology used in their characterization, as well as the obtained results and the perspectives of using this ingredient.