Rut Fernández-Torres

Mineral content and botanical origin of Spanish honeys

Eleven elements (Zn, P, B, Mn, Mg, Cu, Ca, Ba, Sr, Na and K) were determined by inductively plasma coupled spectrometry in 40 honey samples from different places of Spain and four different botanical origins: Eucalyptus (Eucalyptus sp.), Heather (Erica sp.), Orange-blossom (Citrus sinensis) and Rosemary (Rosmarinus officinalis). K, Ca and P show the higher levels with average concentrations ranged between 434.1-1935mgkg(-1) for K; 42.59-341.0mgkg(-1) for Ca and 51.17-154.3mgkg(-1) for P. Levels of Cu (0.531-2.117mgkg(-1)), Ba (0.106-1.264mgkg(-1)) and Sr (0.257-1.462mgkg(-1)) are the lowest in all honey samples. Zn (1.332-7.825mgkg(-1)), Mn (0.133-9.471mgkg(-1)), Mg (13.26-74.38mgkg(-1)) and Na (11.69-218.5mgkg(-1)) concentrations were found strongly dependent on the kind of botanical origin. Results were submitted to pattern recognition procedures, unsupervised methods such as cluster and principal components analysis and supervised learning methods like linear discriminant analysis in order to evaluate the existence of data patterns and the possibility of differentiation of Spanish honeys from different botanical origins according to their mineral content. Cluster analysis shows four clusters corresponding to the four botanical origins of honey and PCA explained 71% of the variance with the first two PC variables. The best-grouped honeys were those from heather; eucalyptus honeys formed a more dispersed group and finally orange-blossom and rosemary honeys formed a less distinguishable group.

HPLC determination of ibuprofen, diclofenac and salicylic acid using hollow fiber-based liquid phase microextraction (HF-LPME).

This paper describes an extraction method using a polypropylene membrane supporting dihexyl ether (three-phase hollow fiber-based liquid phase microextraction (HF-LPME)) for the analysis of several pharmaceuticals (salicylic acid (SAC), ibuprofen (IBU) and diclofenac (DIC)) followed by a HPLC determination using a monolithic silica type HPLC column, that allows lower retention times than the usual packed columns with adequate resolution. Detection was realized by means of a coupled in series diode array (DAD) and fluorescence (FLD) detectors. HF-LPME is a relatively new technique employed in analytical chemistry for sample pretreatment which offers more selectivity and sensitivity than any traditional extraction technique. Detection limits by DAD are 12, 53 and 40 ng mL(-1) for salicylic acid, diclofenac and ibuprofen, respectively and by FLD 7 and 2 ng mL(-1) for salicylic acid, and ibuprofen. The method has been successfully applied to their direct determination in human urine and the results obtained demonstrated that could be also applied to the determination of the corresponding metabolites.

New developments in microextraction techniques in bioanalysis. A review

In recent years, the interest in new extraction methods with lower sample volume requirements, simpler equipment and handling, and lower reagent consumption, has led to the development of a series of microextraction methods based on extraction phases in the microliter order. Nowadays, many references can be found for several of these methods, which imply a wide range of applications referred to both the analyte and the sample nature. In this paper, recent developments in both well-established microextraction techniques (solid phase microextraction, hollow-fiber liquid phase microextraction, dispersive liquid-liquid microextraction, etc.) and recently appeared microextraction procedures (nanoextraction systems, microchip devices, etc.) for the clinical analysis of biological samples will be reviewed and discussed.

Analytical Applications of Hollow Fiber Liquid Phase Microextraction (HF-LPME): A Review

The increasing demand of faster, less expensive, easier, and more environmentally-friendly methods has favored the miniaturization of systems for sample preparation. These new procedures have led to lower reagent and materials consumption and waste production. One extraction technique recently introduced is based on the use of hollow fibers as support to liquid membranes which enables the extraction with solvents of a different nature from a donor external phase to an acceptor phase inside the lumen of the fiber. This is an up-to-date comprehensive review on the analytical applications of hollow fiber liquid phase microextraction (HF-LPME) that includes two and three-phase configurations, carried-mediated extraction and electromembrane extraction. A brief review on the basic extraction principles for these techniques, describing and discussing the different operation and configuration modes, has been carried out. Supplementary materials are available for this article. Go to the publishers online edition of Analytical Letters for the following free supplemental resources: Additional tables.

Hollow fiber-based liquid phase microextraction (HF-LPME) for a highly sensitive HPLC determination of sulfonamides and their main metabolites

In this paper, three phase-hollow fiber-based liquid phase microextraction (HF-LPME) combined with a HPLC procedure using diode array (DAD) and fluorescence detection (FLD) has been developed for the determination of four widely used sulfonamides: sulfadiazine, sulfamerazine, sulfamethazine, sulfamethoxazole and their main metabolites, the corresponding N(4)-acetyl derivatives: N(4)-acetyl-sulfadiazine, N(4)-acetyl-sulfamerazine, N(4)-acetyl-sulfamethazine, N(4)-acetyl-sulfamethoxazole. A Q3/2 Accurel KM polypropylene hollow fiber supporting 1-octanol was used between a 2 M Na(2)SO(4) aqueous solution (pH 4) as a donor phase and aqueous solution (pH 12) as an acceptor phase. The procedure allows very low detection and quantitation limits of 0.3-33 ng L(-1) and 0.9-100 ng L(-1), respectively. The proposed method was applied to the determination of the analytes in environmental water samples (surface, tap and wastewater).

Hollow fiber-based liquid phase microextraction (HF-LPME) as a new approach for the HPLC determination of fluoroquinolones in biological and environmental matrices

In this paper, a three phase hollow fiber-based liquid phase microextraction (HF-LPME) combined with a HPLC procedure using diode array (DAD) and fluorescence detection (FLD) has been developed for the determination of eight widely used fluoroquinolones: marbofloxacin (MRB), norfloxacin (NRF), ciprofloxacin (CPR), danofloxacin (DNF), enrofloxacin (ENR), gatifloxacin (GTF), grepafloxacin (GRP) and flumequine (FLM). A Q3/2 Accurel PP polypropylene hollow fiber supporting 1-octanol was used between a 2 M Na2SO4 aqueous solution (pH 7) as donor phase and aqueous solution (pH 12) as acceptor phase. The microextraction parameters were optimised from an experimental central composite design. The procedure allows very low detection and quantitation limits of 0.3-16 ng L(-1) and 1-50 ng L(-1), respectively. The proposed method was applied to the determination of the analytes in bovine urine and in environmental water samples (surface, tap and wastewater).

Simultaneous determination of 11 antibiotics and their main metabolites from four different groups by reversed-phase high-performance liquid chromatography-diode array-fluorescence (HPLC-DAD-FLD) in human urine samples.

A new, accurate and sensitive reversed-phase high-performance liquid chromatography (RP-HPLC) as analytical method for the quantitative determination of 11 antibiotics (drugs) and the main metabolites of five of them present in human urine has been worked out, optimized and validated. The analytes belong to four different groups of antibiotics (sulfonamides, tetracyclines, penicillins and anphenicols). The analyzed compounds were sulfadiazine (SDI) and its N(4)-acetylsulfadiazine (NDI) metabolite, sulfamethazine (SMZ) and its N(4)-acetylsulfamethazine (NMZ), sulfamerazine (SMR) and its N(4)-acetylsulfamerazine (NMR), sulfamethoxazole (SMX), trimetroprim (TMP), amoxicillin (AMX) and its main metabolite amoxicilloic acid (AMA), ampicillin (AMP) and its main metabolite ampicilloic acid (APA), chloramphenicol (CLF), thiamphenicol (TIF), oxytetracycline (OXT) and chlortetracycline (CLT). For HPLC analysis, diode array (DAD) and fluorescence (FLD) detectors were used. The separation of the analyzed compounds was conducted by means of a Phenomenex Gemini C(18) (150mm x 4.6mm I.D., particle size 5microm) analytical column with LiChroCART LiChrospher C(18) (4mm x 4mm, particle size 5microm) guard column. Analyzed drugs were determined within 34min using formic acid 0.1% in water and acetonitrile in gradient elution mode as mobile phase. A linear response was observed for all compounds in the range of concentration studied. Two procedures were optimized for sample preparation: a direct treatment with methanol and acetonitrile and a solid phase extraction procedure using Bond Elut Plexa columns. The method was applied to the determination of the analytes in human urine from volunteers under treatment with different pharmaceutical formulations. This method can be successfully applied to routine determination of all these drugs in human urine samples.

Enzymatic-microwave assisted extraction and high-performance liquid chromatography–mass spectrometry for the determination of selected veterinary antibiotics in fish and mussel samples

A new method based on enzymatic-microwave assisted extraction prior to high performance liquid chromatography (HPLC) has been developed for the determination of 11 antibiotics (drugs) and the main metabolites of five of them in fish tissue and mussel samples. The analysed compounds were sulfadiazine (SDI), N(4)-acetylsulfadiazine (NDI), sulfamethazine (SMZ), N(4)-acetylsulfamethazine (NMZ), sulfamerazine (SMR), N(4)-acetylsulfamerazine (NMR), sulfamethoxazole (SMX), trimetroprim (TMP), amoxicillin (AMX), amoxicilloic acid (AMA), ampicillin (AMP), ampicilloic acid (APA), chloramphenicol (CLF), thiamphenicol (TIF), oxytetracycline (OXT) and chlortetracycline (CLT). The main factors affecting the extraction efficiency were optimized in tissue of hake (Merluccius merluccius), anchovy (Engraulis encrasicolus), mussel (Mytilus sp.) and wedge sole (Solea solea). The microwave extraction was carried out using an extraction time of 5 min with 5 mL of water at 50W and posterior clean up with dichloromethane. High-performance liquid chromatography (HPLC)-mass spectrometry was used for the determination of the antibiotics. The separation of the analysed compounds was conducted by means of a Phenomenex® Gemini C(18) (150 mm × 4.6mm I.D., particle size 5 μm) analytical column with LiChroCART® LiChrospher® C(18) (4 mm × 4 mm, particle size 5 μm) guard-column. Analysed drugs were determined using formic acid 0.1% in water and acetonitrile in gradient elution mode as mobile phase. Under the optimal conditions, the average recoveries of all the analysed drugs were in the range 70-100%. The proposed method was applied to samples obtained from Mediterranean sea and also evaluated by a laboratory assay consisting in the determination of the targeted analytes in samples of Cyprinus carpio that had been previously administered the antibiotics.

A novel application of three phase hollow fiber based liquid phase microextraction (HF-LPME) for the HPLC determination of two endocrine disrupting compounds (EDCs), n-octylphenol and n-nonylphenol, in environmental waters.

This work proposes for the first time the use of a three phase hollow fiber liquid phase microextraction (HF-LPME) procedure for the extraction, and the later HPLC determination using fluorescence detection, of two much known endocrine disrupting compounds (EDCs): n-octylphenol (OP) and n-nonylphenol (NP). The extraction was carried out through a dihexyl ether liquid membrane supported on an Accurel® Q3/2 polypropylene hollow fiber. Optimum pH for donor and acceptor phases and extraction time were established. Enrichment (preconcentration) factors of 50 were obtained that allows detection limits of 0.54 and 0.52 ng mL(-1) for OP and NP, respectively. The method was successfully applied to the determination of these EDCs in environmental water samples, including urban wastewaters.

New developments in the extraction and determination of parabens in cosmetics and environmental samples. A review.

Parabens are a family of synthetic esters of p-hydroxibenzoic acid widely used as preservatives in cosmetics and health-care products, among other daily-use commodities. Recently, their potential endocrine disrupting effects have raised concerns about their safety and their potential effects as emerging pollutants, leading to the regulation of the presence of parabens in commercial products by national and trans-national organizations. Also, this has led to an interest in developing sensible and reliable methods for their determination in environmental samples, cosmetics and health-care products. This paper is a comprehensive up-to-date review of the literature concerning the determination of parabens in environmental samples and cosmetic and health-care products. A brief revision of the literature concerning the traditional determination of parabens (1980-2003) is included, followed by an in-depth revision of the recent developments in both measurement and extraction methods for parabens in the last years (2003-2013). Finally, possible future perspectives in this field are proposed.