Manuel Callejón-Mochón

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.

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.

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.

Application of three phase hollow fiber based liquid phase microextraction (HF-LPME) for the simultaneous HPLC determination of phenol substituting compounds (alkyl-, chloro- and nitrophenols)

This work proposes for the first time the use of a three phase hollow fiber liquid phase microextraction (HF-LPME) procedure for the simultaneous extraction, and the later HPLC determination, of some phenol substituting compounds (alkyl-, chloro- and nitrophenols) that are considered as highly toxic compounds and/or endocrine disrupting ones. The substances studied include four chlorophenols (CPs): 2,4-dichlorophenol (2,4-DCP), 2,5-dichlorophenol (2,5-DCP), 2,6-dichlorophenol (2,6-DCP) and pentachlorophenol (PCP), three nitrophenols (NPs): 2,4-dinitrophenol (2,4-DNP), 2,5-dinitrophenol (2,5-DNP) and 2,6-dinitriphenol (2,6-DNP) and two alkylphenols (APs): tert butylphenol (TBP) and sec butylphenol (SBP). 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. The enrichment (preconcentration) factors obtained were between 30 and 700 that allows detection limits between 140 and 290 pg mL(-1). The method was successfully applied to the determination of the compounds in environmental water samples, including urban wastewaters.

A novel approach for electromembrane extraction based on the use of silver nanometallic-decorated hollow fibers

A novel approach based on the use of nanometallic-decorated hollow fibers to assist electromembrane extraction is proposed. Microporous polypropylene hollow fibers, on which nanometallic silver was deposited, have been used for the first time as liquid membrane support in electromembrane extraction (EME). Different methods for the generation/deposition of silver nanoparticles (AgNPs) were studied. The best results were obtained with chemical reduction of silver nitrate using NaBH4 in aqueous solution followed by direct deposition on the hollow fibers. The extraction performance of the new supports was compared with a previously developed EME procedure used for the extraction of selected non-steroidal anti-inflammatory drugs (NSAIDs), resulting in an increase in the extraction ratio by a factor of 1.2-2 with a 30% reduction in the extraction time. The new nanometallic-decorated supports open new possibilities for EME due to the singular properties of nanometallic particles, including chemical fiber functionalization.

Trace-metal distribution of cigarette ashes as marker of tobacco brands

The trace-metal distribution of cigarette ashes offers a potential interest from the point of view of forensics and criminology dealing with the determination and classification of tobacco brands. There is a vast bibliography related to the determination of different metals in tobacco leaves. Nevertheless, none of them are directly linked to this matter. Therefore, in this work we present a methodology to assess the viability of discriminating between different tobacco brands by analysing the ashes after smoking. This methodology encompasses the data analysis by atomic techniques (inductively coupled plasma) and further data analysis by principal component analysis and partial least squares-discriminant analysis. The metal distribution (Zn, B, Mn, Fe, Mg, Cu, Ti, Al, Sr, Ca, Ba, Na, Li, and K) of cigarette ashes of different tobacco brands was determined in 149 samples obtained from local stores, representing the most common brands of cigarettes readily available to consumers in Spain. Further analysis of the data with PCA denoted significant differences between different brands of tobacco in their metallic content. In that sense, blond tobaccos were found to contain different patterns in metallic content than black tobaccos. Intrinsic differences were found between different brands, being possible to study the relationship between each brand and its metallic concentration and compare this relationship with other brands. Moreover the possibility of developing classification models to be able to discriminate between different brands was also introduced.

Determination of imipenem and rifampicin in mouse plasma by high performance liquid chromatography–diode array detection

A high performance liquid chromatographic (HPLC) method for the determination of imipenem and rifampicin was developed and validated. The method involves plasma deproteinisation with methanol, gradient elution on a RP-18 column and diode array detection. Separation was carried out in 8 min using a mobile phase composed of methanol and 0.2M borate buffer (pH 7.2). Imipenem and rifampicin were detected at 300 nm and 255 nm, respectively. A linear response was observed at plasma levels ranged between 0.3 and 30 microgmL(-1) for imipenem and 1.5 and 20 microgmL(-1) for rifampicin. The detection limits were 0.07 microgmL(-1) and 0.47 microgmL(-1) for imipenem and rifampicin, respectively. The method was applied to the determination of both compounds in mouse plasma samples.

New nanostructured support for carrier-mediated electromembrane extraction of high polar compounds

A new support has been proposed to be used for carrier-mediated electromembrane extraction purposes. The new support (Tiss®-OH) is a 100µm thickness sheet nanofiber membrane manufactured by electrospinning and composed by acrylic nanofibers. It has been used in an electromembrane extraction (EME) combined with a HPLC procedure using diode array detection. The proposed method has been used for the extraction of four high polarity acidic compounds: nicotinic acid, amoxicillin, hippuric acid and salicylic acid. Analytes were extracted from an aqueous sample solution (pH 4) (donor phase) using a Tiss®-OH sheet that supports a 5% (w/v) Aliquat®336 in 1-octanol liquid membrane. Aqueous solution (pH 6) was used as acceptor phase. The electrical field was generated from a d.c. electrical current of 100V through two spiral shaped platinum wires placed into donor and acceptor phases. Analytes were extracted in 10min with recoveries in the 60-85% range. The proposed EME procedure has been successfully applied to the determination of the target analytes in human urine samples.

Easy, fast and environmental friendly method for the simultaneous extraction of the 16 EPA PAHs using magnetic molecular imprinted polymers (mag-MIPs)

An easy and environmental friendly method, based on the use of magnetic molecular imprinted polymers (mag-MIPs) is proposed for the simultaneous extraction of the 16 U.S. EPA polycyclic aromatic hydrocarbons (PAHs) priority pollutants. The mag-MIPs based extraction protocol is simple, more sensitive and low organic solvent consuming compared to official methods and also adequate for those PAHs more retained in the particulate matter. The new proposed extraction method followed by HPLC determination has been validated and applied to different types of water samples: tap water, river water, lake water and mineral water.

Hollow-fiber liquid-phase microextraction for the direct determination of flumequine in urban wastewaters by flow-injection analysis with terbium-sensitized chemiluminescence

A flow-injection analysis chemiluminescence method based on the enhancement effect of the flumequine-Tb(III) complex on the weak native emission of the Ce(IV)-Na2SO3 system has been developed for the determination of flumequine. The method includes a cleanup and preconcentration stage (750-fold) of the sample by hollow-fiber liquid-phase microextraction using an Accurel(®) Q 3/2 polypropylene hollow fiber impregnated with 1-octanol as the supported liquid membrane. The obtained 50 μL acceptor phase was injected in a 1 mM Tb(III) + 4 mM Ce(IV) in 5% v/v H2 SO4 stream and mixed with a 2 mM Na2 SO3 stream before its introduction into the flow cell. The chemiluminescence signal was linear in the 0.3-15 ng/mL range, with detection and quantitation limits of 0.1 and 0.3 ng/mL, respectively. The method allows the selective extraction and determination of flumequine in wastewater samples, using simpler and lower-cost instrumentation and with shorter extraction and analysis times than traditional high-performance liquid chromatography analysis.