Analytical and Bioanalytical Chemistry (v.391, #3)

Bioanalysis and environmental analysis in Spain by Alfredo Sanz-Medel; Víctor Cerdà (721-723).
has been Professor in the Department of Physical and Analytical Chemistry of Oviedo University (Spain) since 1982. He is author or coauthor of around 500 scientific publications in international journals, as well as several patents and books. Dr. Sanz-Medel’s current main research interests include:1. New atomic detectors and ion sources for ultratrace analysis using plasmas;2. New molecular optical sensors, particularly those based on the use of quantum dots;3. Hybrid techniques that couple a separation unit to an atomic detector for ultratrace and trace metal speciation in order to help solve biological and environmental problems;4. Speciation for proteomics, which involves integrating MS “molecular” [MALDI- and electrospray-(MS)n] and “atomic” (ICP-MS) techniques and introducing the extensive use of ICP-MS to carry out “heteroatom-tagged proteomics” for both qualitative and quantitative purposes.Dr. Sanz-Medel has been Editor of Analytical and Bioanalytical Chemistry since January 2002. He received the 2007 Robert Kellner Award at the most recent Euroanalysis in Antwerp. has been Professor in the Department of Chemistry of the University of the Balearic Islands (Spain) since 1982. He is author or coauthor of about 350 scientific publications in international journals and 12 books. Dr. Cerdà’s current main research interests include:1. The development of new analytical instrumentation;2. The development of new automatic methods of analysis based on flow techniques;3. New analytical methods for environmental monitoring.Dr. Cerdà is a member of the Advisory Editorial Board of Microchimica Acta (Springer New York), and is founder and president of the Association of Environmental Sciences and Techniques.

Recent trends in the use of organized molecular systems combined with chromatographic techniques in environmental analysis by José Juan Santana Rodríguez; Zoraida Sosa Ferrera; Daura Vega Moreno; M. Esther Torres Padrón; Cristina Mahugo Santana (725-733).
The establishment of new analytical methods which improve quality and sensitivity in the determination of environmental pollutants in liquid and solid samples is demanded. The use of micellar systems have become an advantageous tool for the extraction of pollutant compounds, due to their easy handling, biodegradability, and the one-step procedure, and they are compatible with the hydroalcoholic mobile phases used in HPLC. The focus of this review is to present recently developed methods and the main trends in the use of micellar media combined with solid-phase microextraction and solid-phase extraction in the chromatographic analysis of organic compounds in different types of environmental matrix, including water, sediments, and biological samples. Selected samples illustrate the benefits of these systems in the whole of analytical process. The advantages of micellar media over conventional extractants are reduction of solvent usage, low cost, easy handling, and non-toxic procedure.
Keywords: Micellar medium; Extraction methods; Microwave; Solid-phase extraction; High-performance liquid chromatography

Micelle-mediated extractions using nonionic surfactant mixtures and HPLC-UV to determine endocrine-disrupting phenols in seawaters by Jessica López-Darias; Verónica Pino; Juan H. Ayala; Venerando González; Ana M. Afonso (735-744).
An environmentally friendly method to extract endocrine-disrupting phenols (EDPs) from seawaters was realized using nonionic surfactant mixtures and micelle-mediated extractions. The preconcentration step was achieved directly in the seawater matrix, and was followed by high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection without any clean-up steps to remove the surfactant mixture prior to injection. Various nonionic surfactant mixtures were used, and polyoxyethylene-10-laurylether (POLE) with polyoxyethylene-4-laurylether (Brij 30) was found to be the best to work with. Method optimization involved maximizing the preconcentration factor using the studied mixtures. The proposed method gave extraction recoveries ranging from 83.3 to 114.4% for an EDP spiking level of 46.7 μg L−1, and from 63.4 to 112.4% for a spiking level of 4.7 μg L−1 for EDPs studied in real seawater matrices, with relative standard deviations of <12.1%. The detection limits of the method varied from 0.18 μg L−1 for bisphenol A (BPA) to 1.17 μg L−1 for 4-cumylphenol (4-CP). The method was applied to seawaters from the Canary Islands with successful results.
Keywords: Micelle-mediated extractions; Cloud-point extraction; Nonionic surfactant mixtures; Seawater analysis; Endocrine-disrupting phenols

Development of an analytical method based on microwave-assisted extraction and solid phase extraction cleanup for the determination of organochlorine pesticides in animal feed by I. Iglesias-García; M. Barriada-Pereira; M. J. González-Castro; S. Muniategui-Lorenzo; P. López-Mahía; D. Prada-Rodríguez (745-752).
A method to determine 21 organochlorine pesticides in animal feed samples using microwave assisted extraction and solid phase extraction cleanup was optimised regarding its main parameters. After extraction with hexane–acetone (50:50), three different sorbents (alumina/ENVI™-Florisil®, ENVI™-Carb and ENVI™-Carb II/PSA) were assayed for the cleanup step. Analytes were eluted with hexane–ethyl acetate (80:20) and determined by gas chromatography and electron capture detection followed by gas chromatography–mass spectrometry. ENVI™-Carb and ENVI™-Carb II/PSA provided colourless eluates but fewer interferent compounds were found in ENVI™-Carb II/PSA chromatograms, so this system was selected to carry out the purification of the extracts. The analytical recoveries obtained with this method were close to 100% in most cases with relative standard deviations lower than 10%. These percentages were similar to those obtained with the Soxhlet extraction procedure, which shows the method suitable for the determination of organochlorine pesticides in animal feed material. The method was also validated with the analysis of a certified reference material (CRM-115 BCR®), and the results obtained were in good accordance with the certified values.
Keywords: Organochlorine pesticides; Animal feedstuffs; Microwave-assisted extraction; Soxhlet; Cleanup; Gas chromatography and electron capture detection

A sensitive and solvent-free method for the determination of ten polycyclic aromatic hydrocarbons, namely, naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene and chrysene, with up to four aromatic rings, in milk samples using headspace solid-phase microextraction and gas chromatography–mass spectrometry detection has been developed. A polydimethylsiloxane–divinylbenzene fiber was chosen and used at 75°C for 60 min. Detection limits ranging from 0.2 to 5 ng L−1 were attained at a signal-to-noise ratio of 3, depending on the compound and the milk sample under analysis. The proposed method was applied to ten different milk samples and the presence of six of the analytes studied in a skimmed milk with vegetal fiber sample was confirmed. The reliability of the procedure was verified by analyzing two different certified reference materials and by recovery studies. Figure Milk is safe, healthy food
Keywords: Headspace solid-phase microextraction; Gas chromatography–mass spectrometry; Polycyclic aromatic hydrocarbons; Milk

The air quality in the Aragón valley, in the central Pyrenees, has been assessed by evaluation of lichen biodiversity and mapped by elaboration of the Index of Air Purity (IAP) based on observations of the presence and abundance of eight kinds of lichen with different sensitivity to air pollution. The IAP values obtained have been compared with quantitative analytical measures of 16 PAHs in the lichen Evernia prunastri, because this species was associated with a wide range of traffic exposure and levels of urbanization. Analyses of PAHs were carried out by the DSASE method followed by an SPE clean-up step and GC–MS analysis. The concentration of total PAHs found in lichen samples from the Aragón valley ranged from 692 to 6420 ng g−1 and the PAHs profile showed predominance of compounds with three aromatic rings. The influence of the road traffic in the area has been shown because values over the median concentration of PAHs (>1092 ng g−1), percentage of combustion PAHs (>50%), and equivalent toxicity (>169) were found in lichens collected at places exposed to the influence of traffic. The combination of both methods suggests IAP as a general method for evaluating the air pollution referenced to PAHs because it can be correlated with the content of combustion PAHs and poor lichen biodiversity can be partly explained by the air pollution caused by specific PAHs. Figure Map of the air pollution level in the Aragón valley (Pyrenees) based on the Index of Air Purity (IAP) calculation (lichen biodiversity)
Keywords: Lichens; Polycyclic aromatic hydrocarbons (PAH); Biomonitoring; Analysis; Principal component analysis (PCA)

A bulk liquid membrane system has been developed and applied to the simultaneous separation and preconcentration of up to seven heavy metals (copper, zinc, lead, cadmium, aluminium, manganese, and nickel) in seawater. Copper was selected to optimize transport conditions and then, under these conditions, the simultaneous extraction of other heavy metals was studied. The system achieved preconcentration yields ranging between 44.11% (Cd) and 77.77% (Cu) after nine hours of operation, the effectiveness of metal transport being Cu > Zn > Pb > Mn > Ni > Al > Cd. The system was applied to the preconcentration of four real seawater samples before their quantification by inductively coupled plasma–mass spectrometry (ICP–MS). Compared with the analytical procedures commonly used for trace metal determination in oceanography, the results obtained demonstrated that the new system may be used as a very clean (sample contamination-free), simple, and one-step alternative for semiquantitative, and even quantitative, simultaneous determination of heavy metals in seawater.
Keywords: Liquid membranes; ICP–MS; Seawater; Heavy metals; Preconcentration

Study of the kinetics of the transport of Cu(II), Cd(II) and Ni(II) ions through a liquid membrane by María D. Granado-Castro; María D. Galindo-Riaño; F. C. Domínguez-Lledó; C. Díaz-López; M. García-Vargas (779-788).
The coupled transport of Cu(II), Cd(II) and Ni(II) ions through a bulk liquid membrane (BLM) containing pyridine-2-acetaldehyde benzoylhydrazone (2-APBH) as carrier dissolved in toluene has been studied. Once the optimal conditions of extraction of each metal were established, a comparative study of the transport kinetics for these metals was performed by means of a kinetic model involving two consecutive irreversible first-order reactions. The kinetic parameters (apparent rate constants of the metal extraction and re-extraction reactions (k 1, k 2), the maximum reduced concentration of the metal in the liquid membrane ( $$R^{{max }}_{o} $$ ), the time of the maximum value of R o ( t max) and the maximum entry and exit fluxes of the metal through the liquid membrane ( $$J^{{max }}_{f} $$ and $$J^{{max }}_{s} $$ ) of the extraction and stripping reactions were evaluated and results showed good agreement between experimental data and theoretical predictions. Complete transport through the membrane took place according to the following order: Cd(II)>Cu(II)>Ni(II), with similar kinetic parameters obtained for Cu(II) and Cd(III). The transport behaviour of Ni(II) was different to that of Cu(II) and Cd(III), probably due to the different stoichiometry of the nickel complex compared to those of the other metal ions and the different chemical conditions required for its formation. The influence of the sample salinity on the transport kinetics was studied. k 1 values decreased slightly when the feed solution salinity was increased for Cu(II) and Ni(II), but not for Cd(II). Values of k 2 were practically unaffected. The proposed BLM was applied to the preconcentration and separation of metal ions (prior to their determination) in water samples with different saline matrices (CRM, river water and seawater), and good agreement with the certified values was obtained.
Keywords: Bulk liquid membrane; Heavy metal; Transport kinetics; Aroylhydrazones; Natural water; Seawater

On-line monitoring of gas-phase bioreactors for biogas treatment: hydrogen sulfide and sulfide analysis by automated flow systems by Rosa Redondo; Vinicius Cunha Machado; Mireia Baeza; Javier Lafuente; David Gabriel (789-798).
Biogas is produced by biological processes under anaerobic conditions and may contain up to 20,000 ppmv hydrogen sulfide (H2S), a corrosive substance that attacks power engines and can affect the health of the industrial staff. H2S must be removed from the biogas, especially in co-generation facilities where the biogas is burnt for energy production. Nowadays, biofiltration is being studied and considered as an interesting alternative for removing H2S from the biogas besides classical chemical processes. The novelty of this work is the design and construction of an automated H2S on-line analyser to assess the composition of the liquid and gas phases of gas-phase bioreactors. The analyser is made of two parallel flow configurations which share the same detection device. The first configuration is a single-channel flow injection analyser (FIA) to detect S2− in the liquid phase. The second configuration is a continuous flow analyser (CFA) with a gaseous diffusion step (GD–CFA) for detecting H2S in the gas phase. The diffusion step enables separation of the H2S(g) from the sample and its conversion into a detectable chemical species (S2−). S2− detection was performed with an Ag2S ion-selective electrode (ISE) selective to $${ ext{S}}^{{ ext{2}} - } _{left( {{ ext{aq}}} ight)} $$ . The main response parameters of the FIA system are a linear range between 3 × 10−5 and 1 × 10−1 mol L−1 S2− (0.61–3,200 mg L−1), with a sensitivity of 27.9 mV decade−1 and a detection limit of 1.93 × 10−5 mol L−1 S2−. The GD–CFA configuration presents a linear range between 400 and 10,000 ppmv H2S(g) with a sensitivity of 26.1 mV decade−1 and a detection limit of 245 ppmv H2S. The proposed analyser was used by analysing real gas and liquid samples with optimal results at a full-scale biotrickling filter for biogas treatment at a municipal wastewater treatment plant. Figure The novelty of this work is the design and construction of an automated H2S on-line analyzer to assess the composition of the liquid and gas phases of gas-phase bioreactors. The analyser is made of two parallel flow configurations which share the same detection device. The first configuration is a single-channel flow injection analyser (FIA) to detect S2- in the liquid phase. The second configuration is a continuous flow analyser (CFA) with a gaseous diffusion step (GD-CFA) for detecting H2S in the gas phase.
Keywords: Monitoring; Biofilter; Hydrogen sulfide; FIA; GD–CFA; ISE

The main goal of this work was determination of residues of the antibiotics ofloxacin (OFLO), norfloxacin (NOR), ciprofloxacin (CIPRO), and enrofloxacin (ENRO) in wastewater samples. The samples, after acidification to pH 4.5 and addition of EDTA, were extracted on an anion-exchange cartridge in tandem with an Oasis HLB cartridge. The LC–FD method, developed in previous studies, was based on application of a monolithic C18 column. The limit of quantification (LOQ) of the method was 250 ng L−1 for OFLO, 25 ng L−1 for NOR and CIPRO, and 50 ng L−1 for ENRO. Mean recovery ranged between 75 and 121% for OFLO, NOR, CIPRO, and ENRO. A total of 14 wastewater samples were analyzed; these were collected from four hospitals and from influent and effluent from a wastewater-treatment plant in Coimbra, Portugal, during spring and autumn. CIPRO was present in all the samples, NOR was detected second most often, followed by OFLO. ENRO was found at concentrations under the LOQ in five hospital samples, and the highest level was found in influent from the WWTP.
Keywords: Fluoroquinolones; LC; Monolithic column; Pharmaceuticals; Hospital and municipal wastewater

Enhanced resonance light scattering properties of gold nanoparticles due to cooperative binding by A. Cruz Enriquez; I. A. Rivero Espejel; E. Andrés García; M. E. Díaz-García (807-815).
The interaction of 11-mercaptoundecanoic acid capped gold nanoparticles (MUA-GNPs) with europium ions and aminoacids has been studied by UV-Vis spectrophotometry, fluorescence, confocal fluorescence microscopy, resonance light scattering and TEM. Results demonstrated that hyper-Rayleigh scattering emission occurs upon the addition of lysine to the MUA-GNPs–Eu(III) system, thus providing an inherently sensitive method for lysine determination. The effects of geometrical factors of the gold nanoparticles (aspect ratio, particle size, cluster formation) and the surrounding medium (pH) on this behavior are discussed. The cooperative binding interactions of Eu3+ and lysine with gold nanoparticles permitted the discrimination of lysine from other amino acids. The probable mechanism for the spectral changes and the enhanced resonance light scattering observed is outlined. Figure Gold nanoparticle resonance light scattering plasmon enhancement through cooperative binding with europium and lysine
Keywords: Gold nanoparticles; Resonance light scattering; Lysine; Europium; Amino acids

In this paper, a time-based multicommutated flow system is proposed for appropriate selection and modulation of mobile phase composition in flow-injection (FI)/sequential-injection (SI) chromatography. The novel flow assembly involves the on-line coupling of a short monolithic reversed-phase chromatographic column with a multisyringe flow injection set-up furnished with a set of solenoid valves. The proposed hyphenated technique was applied to the simultaneous spectrophotometric determination of thiamine (B1), pyridoxine (B6) and cyanocobalamin (B12) which were taken as model analytes. The separation method capitalizes on a dual isocratic elution protocol involving the use of a single forward stroke of the multisyringe pump for initial delivery of 50 mmol L−1 ammonium acetate (pH 7.0) for 2.4 min followed by 50 mmol L−1 ammonium acetate–methanol (80:20, v/v) for 6.4 min at 0.5 mL min−1 and room temperature. Detection was performed at the maximum wavelength for each target vitamin—280 nm for B1, 325 nm for B6, and 360 nm for B12. A first-order, two-level full-factorial design was utilized to ascertain the significant variables influencing the chromatographic separation and the magnitude of the interaction effects. The experimental design method revealed that resolution of the target vitamins is highly dependent on the pH, percentage of organic modifier, and their second-order interaction. The multisyringe flow-injection-based monolithic column separation method, which should be viewed as an expeditious and cost-effective alternative to the high-performance liquid chromatography counterpart, was applied to the separation and determination of B1, B6, and B12 in different pharmaceutical dosage forms in less than 9 min. Statistical comparison of the results from the proposed procedure with those from the HPLC method endorsed by the US Pharmacopeia revealed there were no significant differences at the 95 % confidence level.
Keywords: Monolithic column; Multisyringe liquid chromatography; Pyridoxine; Thiamine; Cyanocobalamin; Pharmaceutical preparations

Second-order multivariate calibration methods in combination with a continuous flow system, which allows for the continuous on-line irradiation of the analytes, have been employed for the determination of folic acid and its main metabolite 5-methyltetrahydrofolic acid in serum samples. An experimental central composite design, together with response surface methodology, has been used to find the optimum instrumental variables to perform the photochemical reaction. The time evolution of the emission spectra of the generated photoproducts, in the range 330–540 nm, after irradiation at 275 nm for 20 min, provided the three-way data set employed. On the basis of the differences on the kinetic rates of the photoreaction of both analytes, direct determination of the compounds in human plasma has been accomplished. The second-order methods assayed were parallel factor analysis (PARAFAC), self-weighted alternating trilinear decomposition (SWATLD), and unfolded partial least-squares (U-PLS), multidimensional partial least-squares (N-PLS), and bilinear least-squares (BLLS), all three in combination with the residual bilinearization procedure (RBL). Figure Kinetic evolution of the emission spectra of aqueous solutions containing FA, 5-MTF and a mixture of both compounds, with the photoirradiation time
Keywords: Folic acid; 5-Methyltetrahydrofolic acid; Photochemically induced fluorescence; Three-way data; Human serum

An amperometric immunosensor for the quantification of Staphylococcus aureus based on the coimmobilization of rabbit immunoglobulin G (RbIgG) and tyrosinase on a mercaptopropionic acid self-assembled monolayer modified gold electrode is reported. A competitive mode in which protein-A-bearing S. aureus cells and antiRbIgG labeled with alkaline phosphatase (AP) compete for the binding sites of immobilized RbIgG was used. Monitoring of the affinity reaction was carried out by the amperometric detection at –0.15 V of phenol generated in the enzyme reaction with AP, at the tyrosinase-modified electrode through the electrochemical reduction of the o-quinone formed. Optimization of the working variables, such as the immunosensor composition and incubation times, the applied potential, the working pH and the concentration of phenyl phosphate used as the AP substrate, was carried out. Under the optimized conditions, both the repeatability of the measurements and the reproducibility of the responses obtained with different immunosensors yielded relative standard deviation values for the steady-state current lower than 10%. The immunosensor showed a dynamic range from 4.4×105 to 1.8×107 S. aureus cells mL−1, with a detection limit of 1.7×105 cells mL−1. The limit of detection was remarkably improved by subjecting S. aureus cells to wall lysis by heat treatment. The value obtained was 2.3×103 cells mL−1, which is adequate for the monitoring of S. aureus contamination levels in some foodstuffs. As an application, milk samples spiked with bacteria at the 4.8×103 cells mL−1 level were analyzed. Figure The immunosensor configuration. AP alkaline phosphatase, RbIgG rabbit immunoglobulin G, MPA mercaptopropionic acid
Keywords: Electrochemical immunosensor; Staphylococcus aureus ; Self-assembled monolayer modified electrodes

Identification and migration of degradation compounds from irradiation of multilayer polyamide 6 films for meat foodstuffs and cheese by J. S. Félix; M. Monteiro; J. E. Manzoli; M. Padula; D. Pezo; J. Romero; C. Nerín (847-857).
The aim of this work was to identify the degradation compounds produced during irradiation of multilayer polyamide 6 (PA-6) films and to study their migration into water and 95% ethanol food simulant. After irradiation of multilayer PA-6 films at 3, 7 and 12 kGy, degradation compounds were extracted using solid-phase microextraction, for which the time and temperature of extraction and stirring were optimized, and identified by gas chromatography–mass spectrometry. Caprolactam, 2-cyclopentylcyclopentanone and aldehydes, among other compounds, were identified in the headspace of the films. Polydimethylsiloxane was considered the best fiber for extraction. The optimum conditions of time, temperature and stirring to extract the compounds were 20 min, 80 °C and 225 rpm. For validation purposes, the compounds were quantified in water and 95% ethanol and the results showed high sensitivity, good precision and accuracy. Migration of compounds from irradiated and non-irradiated multilayer PA-6 films into water and 95% ethanol food simulants was carried out at 40 °C for 10 days. The method was efficient for the quantification of decaldehyde, 2-cyclopentylcyclopentanone and caprolactam that migrated from multilayer PA-6 films into food simulants.
Keywords: Degradation compounds; γ radiation; Polyamide 6; Migration; Solid-phase microextraction; Gas chromatography–mass spectrometry

An analytical method based on ion-interaction chromatography with UV detection for simultaneous in-vitro estimation of the percutaneous absorption of the most used water-soluble UV filters in sunscreen cosmetics is proposed. These UV filters were phenylbenzimidazole sulfonic acid, disodium phenyl dibenzimidazole tetrasulfonate, benzophenone-4, and terephthalylidene dicamphor sulfonic acid. The methodology is based on applying the sunscreen containing the target UV filters to human epidermis in a diffusion cell. Analytes are determined in the receptor solution. To ensure skin integrity, screening of the cells was carried out by analytical determination of a marker. Analytical variables such as percentage ethanol, concentration of ion-pairing agent, pH of the mobile phase, and temperature were studied in order to achieve high resolution of the chromatographic peaks in the lowest possible time of analysis. The conditions selected consisted of a mobile phase composed of 35:65 (v/v) ethanol–ammonium acetate buffer solution (pH 4, containing 50 mmol L−1 tetra-n-butylammonium bromide). The chromatographic determination was carried out with the analytical column at 50 °C. UV detection was carried out at the maximum absorption wavelength for each analyte. The limit of detection (3s y/x /b) ranged from 16 to 65 ng mL−1, depending on the analyte.
Keywords: UV filter; Sunscreen; In vitro; Percutaneous absorption; Ion-interaction chromatography

A new method based on matrix solid-phase dispersion (MSPD) extraction was studied for the extraction of amitrole (3-amino-1,2,4-triazole), and its metabolite urazole (3,5-dihydroxy-1,2,4-triazole), in apple samples. The influence of experimental conditions on the yield of the extraction process and on the efficiency of the cleanup step was evaluated. Determination was carried out by capillary electrophoresis (CE) with electrochemical detection, demonstrating the compatibility between MSPD and CE techniques. The method has been successfully applied to different apple varieties. Recoveries in samples spiked at 1.6 and 1.7 μg g−1 for amitrole and urazole were 88 and 82%, respectively. The limits of detection were 0.4 μg g−1 for both compounds using electrochemical detection.
Keywords: Matrix solid-phase dispersion; Capillary electrophoresis; Electrochemical detection; Amitrole; Urazole

Thomas Lummerstorfer wins ABC Best Paper Award by Christina E. Dyllick (873-874).

is a professor of analytical chemistry at the University of Idaho. He has taught courses in introductory analytical chemistry at Ohio University, the University of California, Riverside, and the University of Idaho, between 1972 and 2007. He is best known for his work in analytical applications of vibrational spectroscopy, having written three, and edited nine, books on this subject. Dr. Griffiths has authored over 300 refereed papers and book chapters and has received several national and international awards for his work. He currently serves on the international advisory board of Analytical and Bioanalytical Chemistry.

8th Dresdner Sensor Symposium: Christmas market, mulled wine and sensors by Stefanie Jaeger; Goran Markovic (883-884).

Hyphenated mass spectrometry in the analysis of the central carbon metabolism by Birgit Timischl; Katja Dettmer; Peter J. Oefner (895-898).

In situ molecular imaging of proteins in tissues using mass spectrometry by William M. Hardesty; Richard M. Caprioli (899-903).

Biomolecular structural separations by ion mobility–mass spectrometry by Larissa S. Fenn; John A. McLean (905-909).

Modern chemical analysis in archaeometry by Marek Trojanowicz (915-918).

Nanoparticle: is it promising in capillary electrophoresis? by Zhengxiang Zhang; Bo Yan; Yiping Liao; Huwei Liu (925-927).

New approach in gas-phase microwave-assisted extraction by Jacqueline M. R. Bélanger; J. R. Jocelyn Paré; Fulvia N. Sánchez; Kyoichi Komori; Jean-François Rochas (929-932).

Microfluidics offers an ideal platform to integrate cell-based assays with electric measurements. The technological advances in microfluidics, microelectronics, electrochemistry, and electrophysiology have greatly inspired the development of microfluidic/electric devices that work with a low number of cells or single cells. The applications of these microfluidic systems range from the detecting of cell culture density to the probing of cellular functions at the single-cell level. In this review, we introduce the recent advances in the electric analysis of cells on a microfluidic platform, specifically related to the quantification and monitoring of cells in static solution, on-chip patch-clamp measurement, and examination of flowing cells. We also point out future directions and challenges in this field. Figure Different microfluidic devices applied to electrical analysis of cells
Keywords: Microfluidics; Electric analysis; Patch-clamp; Flow cytometry; Single-cell analysis

Gold nanoparticles for the development of clinical diagnosis methods by Pedro Baptista; Eulália Pereira; Peter Eaton; Gonçalo Doria; Adelaide Miranda; Inês Gomes; Pedro Quaresma; Ricardo Franco (943-950).
The impact of advances in nanotechnology is particularly relevant in biodiagnostics, where nanoparticle-based assays have been developed for specific detection of bioanalytes of clinical interest. Gold nanoparticles show easily tuned physical properties, including unique optical properties, robustness, and high surface areas, making them ideal candidates for developing biomarker platforms. Modulation of these physicochemical properties can be easily achieved by adequate synthetic strategies and give gold nanoparticles advantages over conventional detection methods currently used in clinical diagnostics. The surface of gold nanoparticles can be tailored by ligand functionalization to selectively bind biomarkers. Thiol-linking of DNA and chemical functionalization of gold nanoparticles for specific protein/antibody binding are the most common approaches. Simple and inexpensive methods based on these bio-nanoprobes were initially applied for detection of specific DNA sequences and are presently being expanded to clinical diagnosis. Figure Colorimetric DNA/RNA detection using salt induced aggregation of AuNP-DNA nanoprobes
Keywords: Nanoparticles; Gold nanoparticles; Nanotechnology; Nucleic acids (DNA/RNA); Bioanalytical methods; Biological samples

The Ti–TPyP reagent, i.e. an acidic aqueous solution of the oxo[5,10,15,20-tetra(4-pyridyl)porphyrinato] titanium(IV) complex, TiO(tpyp), was developed as a highly sensitive and selective spectrophotometric reagent for determination of traces of hydrogen peroxide. Using this reagent, determination of hydrogen peroxide was performed by flow-injection analysis with a detection limit of 0.5 pmol per test. The method was actually applied to determination of several constituents of foods, human blood, and urine mediated by appropriate oxidase enzymes. The reaction specificity of the TiO(tpyp) complex for hydrogen peroxide was clarified from the viewpoint of the reaction mechanisms and molecular orbitals based on ab initio calculations. The results provided a well-grounded argument for determination of hydrogen peroxide using the Ti–TPyP reagent experimentally. This review deals with characterization of the high sensitivity and reaction specificity of the Ti–TPyP reagent for determination of hydrogen peroxide, to prove its reliability in analytical applications.
Keywords: Determination of H2O2 ; Ti–TPyP reagent; Flow-injection analysis; Ab initio calculation

Trends and recent applications of matrix solid-phase dispersion by M. García-López; P. Canosa; I. Rodríguez (963-974).
Matrix solid-phase dispersion (MSPD) is a sample-preparation technique with increasing acceptance in trace analysis of organic compounds using chromatographic and electro-driven separation techniques. It has been applied to the extraction and fractionation of a large number of substances from solid, semi-solid, and liquid matrices. Low sample and solvents consumption, straightforward application, and reduced cost, and its ability to simultaneously perform extraction and clean-up in a single step, are some of its major advantages. This review attempts to provide an updated, concise and critical overview on the latest trends and applications of MSPD, placing emphasis on comparison of its performance with that of other techniques, besides focusing on practical features to take into account depending on the nature of the sample and the properties of the analytes. Achievements, advantages, and limitations are discussed. The paper also highlights future challenges to be faced.
Keywords: Review; Sample treatment; Matrix solid-phase dispersion; Accuracy evaluation; Environmental analysis

Relationship between wine scores and visible–near-infrared spectra of Australian red wines by D. Cozzolino; G. Cowey; K. A. Lattey; P. Godden; W. U. Cynkar; R. G. Dambergs; L. Janik; M. Gishen (975-981).
Sensory analysis of wine involves the measurement, interpretation and understanding of human responses to the properties perceived by the senses such as sight, smell and taste. The sensory evaluation of wine is often carried out by wine judges, winemakers and technical staff, and allows characterization of the quality of the wine. However, this method is lengthy, expensive, and its results depend on panel training and the specific vocabulary used by the panel. A robust, rapid, unbiased and inexpensive method to assist in quality assessment purposes will therefore be beneficial for the modern wine industry. This study aims to investigate the relationship between sensory analysis, visible (VIS) and near-infrared (NIR) spectroscopy to assess sensory properties of commercial Australian wine varieties. For the purposes of this study 118 red wine samples (Cabernet Sauvignon, Shiraz, Pinot Noir, Tempranillo, Nebbiolo and blends) graded by a panel of experienced tasters and scored according to the Australian wine show system were scanned in transmission in the VIS and NIR range (400–2,500nm). Partial least squares regression models were developed between the overall score given by the judges and the combined VIS–NIR spectra, using full cross validation (leave-one-out method). The results showed that NIR spectroscopy was able to predict wine quality scores in red wine samples (R = 0.61 and standard error of prediction of 0.81). The practical implication of this study is that instrumental methods such as VIS–NIR spectroscopy can be used to complement sensory analysis and can facilitate the task at early stages of product development, making high-throughput screening of novel products feasible or maintaining the consistency of the product.
Keywords: Near-infrared spectroscopy; Visible spectroscopy; Red wine; Partial least squares; Wine quality

Investigation of the hybrid molecular probe for intracellular studies by Karen Martinez; Colin D. Medley; Chaoyong James Yang; Weihong Tan (983-991).
Monitoring gene expression in vivo is essential to the advancement of biological studies, medical diagnostics, and drug discovery. Adding to major efforts in developing molecular probes for mRNA monitoring, we have recently developed an alternative tool, the hybrid molecular probe (HMP). To optimize the probe, a series of experiments were performed to study the properties of HMP hybridization kinetics and stability. The results demonstrated the potential of the HMP as a prospective tool for use in both hybridization studies and in vitro and in vivo analyses. The HMP has shown no tendency to produce false positive signals, which is a major concern for living cell studies. Moreover, HMP has shown the ability to detect the mRNA expression of different genes inside single cells from both basal and stimulated genes. As an effective alternative to conventional molecular probes, the proven sensitivity, simplicity, and stability of HMPs show promise for their use in monitoring mRNA expression in living cells. Figure Hybrid molecular probe (HMP). HMPs consist of two single strands of DNA (green) and a polyethylene glycol (PEG, purple) linker that is used to tether these two sequences together. When a target (orange strand) containing the complementary sequences to both probes at adjacent positions is added, each strand binds to its corresponding target sequence, thus bringing the two fluorophores into close proximity, which allows energy transfer to occur
Keywords: DNA detection; Fluorescence probes; Molecular beacons; Fluorescence resonance energy transfer (FRET); mRNA monitoring

The investigation of microbial extracellular polymeric substances (EPS) is helpful for the implementation of analytical methods which are suitable for biofilm analysis in order to understand the architecture and function of biofilms. A procedure for the qualitative and quantitative determination of various monosaccharides, oligosaccharides and uronic acids as important components of the carbohydrate fraction of microbial EPS by high-performance liquid chromatography (HPLC) and refractive index (RI)/UV detection is presented. Porous graphitic carbon and lead-form cation-exchanger have been examined as stationary phases. Therefore, two complementary HPLC methods are presented. To simulate the conditions of hydrolysis, the influences of various salts, acids and alkalis as matrix components have been investigated. Furthermore, the dependencies on the pH value and temperature of the mobile phase have been thoroughly studied. The results showed that the lead-form cation-exchanger is suitable for the separation of the neutral monosaccharides. However, for direct analysis after acidic hydrolysis with H2SO4, HCl or trifluoroacetic acid, an additional purification step, e.g., precipitation or lyophilization, is necessary when the cation-exchanger is used. With the exception of hydrolysis with HCl, the porous graphitic carbon stationary phase can be used without any further purification step and is appropriate for the separation of uronic acids and their γ-lactones. Additionally, the separation of a single monosaccharide and its derivatives is possible. Analytical parameters including the sensitivities, repeatabilities, limits of detection and limits of quantification of both HPLC methods using the RI detector are presented. The optimized method has been applied for the characterization of alginates and is also suitable for other extracellular polysaccharides in biofilms.
Keywords: HPLC; Uronic acids; Monosaccharides; Porous graphitic carbon; Lead-form cation exchanger; Alginates

Reference measurement procedure for Δ9-tetrahydrocannabinol in serum by S. Lott; A. Henrion; F. Malz; A. Kessler; B. Güttler; R. Aderjan (1003-1010).
An isotope dilution gas chromatography/mass spectrometry (ID-GC/MS) reference measurement procedure for Δ9-tetrahydrocannabinol (THC) in serum was developed and validated. The method complies with the concept of a ratio primary reference measurement procedure. The uncertainty was determined for two concentrations of THC in serum (1 ng/mL and 2.4 ng/mL). The calculation procedure is based on the Guide to the Expression of Uncertainty in Measurement (GUM). The relative expanded uncertainty was found to be less than 2% for both concentration levels, corresponding to a 95% confidence interval. For the reference method, it was shown that the measurement of THC within the concentration range covered by the current threshold values is very accurate. The method has the potential to provide traceability for the methods used in practical forensics.
Keywords: THC; Uncertainty of measurement; GUM; Threshold value; Reference material; Primary method; Quantitative NMR

Multi-residue analysis of traces of pesticides and antibiotics in honey by HPLC-MS-MS by Delphine Debayle; Guy Dessalces; Marie Florence Grenier-Loustalot (1011-1020).
The aim of this work was to develop an analytical method for simultaneous assay of residues of two families of antibiotics, and three pesticides, in honey. The assays involved a mixture of five tetracyclines, four sulfamides, and the pesticides coumaphos, carbendazim, and amitraz (two metabolites). All the compounds were extracted from honey and pre-concentrated by optimised solid-phase extraction (SPE). Analysis was by high-performance liquid chromatography-mass spectrometry-mass spectrometry (HPLC-MS-MS) using a triple-quadrupole spectrometer in multiple reaction monitoring (MRM) mode in order to identify and quantify the compounds present (Sheth et al J Agric Food Chem 38:1125–1130, 1990). During development of the analytical method a strong matrix effect was found that depended on the floral origin of the honey. This led to the development of a standard additions method to quantify the contaminants sought.
Keywords: Honey; Antibiotics; Pesticides; Multi-residues; HPLC-MS-MS; Solid-phase extraction

A rapid method for determining diethylene glycol (DEG) in toothpaste based on the use of ultra-performance liquid chromatography (UPLC) coupled to time-of-flight mass spectrometry (TOF-MS) has been developed. The method has been validated in toothpaste samples spiked at different levels, 0.005, 0.1 and 5%, obtaining satisfactory recoveries (74–98%) and relative standard deviations (<4%). Quantification was carried out by using matrix-matched standards calibration. The developed method was applied to several types of toothpaste, making identification and quantification of DEG and other polyethylene glycols (PEG) feasible with very little sample manipulation, as only extraction with water is required. The excellent sensitivity of TOF-MS analysis performed in full-scan acquisition mode allowed the determination of DEG at concentration levels as low as 0.005% in samples and its reliable identification via the mass accuracy measurements provided by this instrument (<5 ppm).
Keywords: UPLC; TOF-MS; Toxic diethylene glycol; Toothpaste

An efficient extraction of sulfadiazine residues from soils is difficult, as sulfadiazine is known to form quickly sequestering residues. The objective of this study was to optimize an exhaustive extraction for aged residues of sulfadiazine and its two major metabolites, N-acetylsulfadiazine and 4-hydroxysulfadiazine, from soil. For this purpose two representative used agricultural soils (Luvisol, Cambisol) were blended with manure derived from [14C]sulfadiazine-treated pigs and incubated at 10 °C in the laboratory. After different extraction tests with various solvent mixtures (two- to four-component mixtures with water, methanol, acetonitrile, acetone, and/or ethyl acetate), different pH values (pH 4 and 9), and extraction temperatures (up to 200 °C), soil extracts were measured by liquid scintillation counting and liquid chromatography coupled to tandem mass spectrometry. With respect to sulfadiazine yields, stability of soil extracts, and the amount of coextracted matrix, a microwave extraction of soil (15 min, 150 °C) using acetonitrile/water 1:4 (v/v) is the method of choice for the exhaustive extraction of aged sulfadiazine residues from soils.
Keywords: Microwave extraction; Sulfadiazine; Metabolites; Soil; Manure; Aging

Renaissance patinas in Úbeda (Spain): mineralogic, petrographic and spectroscopic study by M. J. Campos-Suñol; A. Domínguez-Vidal; M. J. Ayora-Cañada; M. J. De la Torre-López (1039-1048).
Different analytical techniques were used for microstructural and compositional analysis of the ochre-coloured patinas that appear on the calcarenite substrate of monuments in the historical settings of Úbeda and Baeza (Spain). Optical microscopy, scanning electron microscopy–energy dispersive x-ray spectrometry (SEM-EDX), x-ray diffraction, Raman spectroscopy and attenuated total reflection–Fourier transform infrared spectroscopy (ATR-FTIR) were employed and a critical comparison of their experimental requirements, strengths and weaknesses is presented. The study focussed on two churches in Úbeda where patinas were widespread in ornamental elements. These films contained calcite as the principal component, and traces of dolomite and feldspars. Clear identification of calcium oxalate, mainly in the form of whewellite, was achieved by infrared and Raman spectroscopic studies. Results from texture, distribution and composition of the patinas in ornamental elements suggest that ancient treatments were applied for protection of Renaissance façades and consolidation of weathered older façades. The patinas were seldom found on supporting elements. Their different composition, apatite was found together with oxalates, and location may suggest a biogenic origin here. Gypsum crusts were sometimes found over the patinas.
Keywords: Raman; Infrared; Patina; Oxalate; Microscopy; XRD; Monument

The electrochemical behavior of paracetamol in 0.1 M acetate buffer solution (pH 4.6) was investigated at a traditional carbon paste electrode (TCPE) and a carbon ionic liquid electrode (CILE) fabricated by replacing nonconductive organic binders with a conductive hydrophobic room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF6). The results showed that the CILE exhibited better reversibility for the electrochemical redox of paracetamol. The oxidation potential of paracetamol at the CILE is +0.462 V, which is approximately 232 mV lower than that at the TCPE; the oxidation peak current response is nine times higher than that at the TCPE. The differential pulse voltammetric determination of paracetamol at the CILE was established based on this behavior. After optimizing several important parameters controlling the performance of paracetamol at the CILE, the oxidation peak current versus paracetamol concentration at the CILE showed linearity in the range from 1.0 μM to 2.0 mM (R 2  = 0.9992) with a detection limit of 0.3 μM (S/N = 3). The method has been applied to the determination of paracetamol in tablets and urine samples and the average recovery of paracetamol was 98.5% and 99.3%, respectively. The proposed CILE showed good sensitivity and reproducible response without influence of interferents commonly existing in pharmaceutical and urine samples. Figure CV curves of paracetamol illustrate the enhanced electrochemical behavior of paracetamol at the CILE (b), which forms the basis for the differential pulse voltammetric determination of paracetamol
Keywords: Voltammetry; Ionic liquid; Carbon ionic liquid electrode; Paracetamol

A sensitive high-performance liquid chromatography (HPLC)–fluorescence method for determination of morphine (Mor) in rat brain and blood microdialysates was developed using 4-(4,5-diphenyl-1H-imidazol-2-yl)benzoyl chloride (DIB-Cl) as a label. Mor was labeled with DIB-Cl under mild reaction conditions (at room temperature for 10 min). The separation of DIB-Mor was carried out on an octadecylsilica (ODS) column with CH3CN/0.1 M acetate buffer (pH 5.4) within 14 min. The detection limits of Mor in brain and blood microdialysates at a signal-to-noise ratio of 3 were 0.4 and 0.6 ng mL−1, respectively. The proposed method was successfully applied to the preliminarily study of potential pharmacokinetic interaction between Mor and diclofenac.
Keywords: Morphine; Microdialysate; 4-(4,5-Diphenyl-1H-imidazol-2-yl)benzoyl chloride (DIB-Cl); Diclofenac; Pharmacokinetic interaction

An advanced quantification method was developed with solid-phase extraction (SPE) and mass spectrometry (MS) determination for nafamostat, an unstable and highly polar drug, in human plasma. For unstable drugs with an ester group, the main analytical challenge is how to avoid the ester hydrolysis, and strong acid or alkaline conditions should be excluded during sample preparation. Considering that, we developed a relatively mild method with SPE for sample preparation without strong acid and alkaline treatment, which was optimized with different pHs and salt concentrations in phosphate-buffered saline treatment. The results indicated that pH 5 gave the most efficient extraction and 0.1 M salt concentration enhanced the extraction the most, with a minor effect on MS monitoring. The extraction method effectively avoided drug hydrolysis and achieved good drug enrichment over 82.2%. The linear range of quantification was 1.25–160 ng mL−1. The stability of the drug in sample treatment was fully validated according to the sample processing procedure, including the stability in fresh blood, mobile phase, plasma and acidic methanol, and the results indicated that the drug remained stable during the whole sample preparation. Compared with a previous isotope-labeling method, more accurate and specific quantification of plasma concentration was achieved with liquid chromatography–electrospray ionization MS determination. With use of our method, nafamostat mesilate pharmacokinetics in 30 Chinese healthy volunteers was investigated with three doses via intravenous-drip infusion. The pharmacokinetic parameters were also estimated and compared with those of Japanese volunteers (slightly lower plasma concentration and longer terminal elimination half-life for Chinese volunteers). The difference in the pharmacokinetics may be ascribed to the quantification method, because previous isotope labeling may have overestimated the parent drug.
Keywords: Nafamostat mesilate; Unstable drug; Highly polar drug; Solid-phase extraction; Clinical pharmacokinetics

Highly sensitive flow-injection chemiluminescence (CL) combined with molecularly imprinted solid-phase extraction (MISPE) has been used for determination of 2,4-dichlorophenol (2,4-DCP) in water samples. The molecularly imprinted polymer (MIP) for 2,4-DCP was prepared by non-covalent molecular imprinting methods, using 4-vinylpyridine (4-VP) and ethylene glycol dimethacrylate (EGDMA) as the monomer and cross-linker, respectively. 2,4-DCP could be selectively adsorbed by the MIP and the adsorbed 2,4-DCP was determined by its enhancing effect on the weak chemiluminescence reaction between potassium permanganate and luminol. The enhanced CL intensity was linear in the range from 1 × 10−7 to 2 × 10−5g mL−1. The LOD (S/N = 3) was 1.8 × 10−8g mL−1, and the relative standard deviation (RSD) was 3.0% (n = 11) for 1.4 × 10−6g mL−1. The proposed method had been successfully applied to the determination of 2,4-DCP in river water. Figure Effect of 4-VP content on the ultraviolet spectrum of 2,4-DCP in chloroform
Keywords: Molecularly imprinted polymer; 2, 4-Dichlorophenol; Flow chemiluminescence; Molecularly imprinted solid-phase extraction

Molecular iodine selective membrane for iodate determination in salt samples: chemical amplification and preconcentration by P. R. Bhagat; A. K. Pandey; R. Acharya; V. Natarajan; N. S. Rajurkar; A. V. R. Reddy (1081-1089).
A molecular iodine selective membrane has been used for preconcentration of I2 generated in situ by iodometric reaction of $${ ext{IO}}_{ ext{3}}^ - $$ with excess I in acidic medium (pH 1–2). This iodometric reaction amplifies the iodine content six times resulting in enhancement of analytical response ranging from three times for molecular methods to six times for elemental methods. The chemical conditions of this iodometric reaction were optimized for quantitative generation and subsequent sorption of I2 in the membrane samples (96 ± 3%). The homogeneous transparent membrane was prepared by immobilizing I2-complexing polyvinylpyrrolidone (PVP) in the plasticized cellulose triacetate matrix. Four different analytical methods were examined for quantitative determination of $${ ext{IO}}_{ ext{3}}^ - $$ in iodized salt samples by preconcentrating it as I2 in the membrane matrix. These methods were: (1) spectrophotometry of the PVP-I2 complex formed in the membrane matrix, (2) a radiotracer method using I tagged with 131I radiotracer, (3) instrumental neutron activation analysis (INAA), and (4) energy-dispersive X-ray fluorescence (EDXRF) analysis. The $${ ext{IO}}_{ ext{3}}^ - $$ contents thus determined in the iodized salt samples by the membrane-based radiotracer method were compared with the total iodine determined in salt samples by epithermal instrumental neutron activation analysis (EINAA). The membrane-based method for iodate determination in salt samples has advantages over conventional analytical methods, for example preconcentration and chemical amplification, and is free from interference from anions. Figure A molecular iodine selective membrane was used for the quantitative preconcentration of I2 generated in situ by iodometric reaction of $${ ext{IO}}_{ ext{3}}^ - $$ with excess I− in acidic medium, which amplifies iodine content six times
Keywords: Iodometric reaction; Iodate; Membrane; Preconcentration; Chemical amplification; Iodized salt

Single-drop microextraction (SDME) followed by gas chromatography–mass spectrometry detection was used for the determination of some carbamate pesticides in water samples. The studied pesticides were thiofanox, carbofuran, pirimicarb, methiocarb, carbaryl, propoxur, desmedipham and phenmedipham. Two alternative sample introduction methods have been examined and compared; SDME followed by cool on-column injection (without derivatization) and SDME followed by in-microvial derivatization and splitless injection. Acetic anhydride was used as derivatization reagent. Parameters that affect the derivatization reaction yield and the extraction efficiency of the SDME method were studied and optimized. The analytical performances and possible applications of both approaches were investigated. Relative standard deviations for the studied compounds ranged from 3.2 to 8.3%. The detection limits obtained by the derivatization method were found to be in the range 3–35 ng/L. Using cool on-column injection (without derivatization), the detection limits were between 30 and 80 ng/L.
Keywords: Single-drop microextraction; Derivatization; Environmental analysis; Carbamates

A new method for the highly sensitive and selective determination of boron at nanograms per cubic decimeter levels has been developed based on the derivatization reaction of boron using salicylaldehyde and 1-amino-8-naphtol-3,6-disulfonate with reversed-phase partition high-performance liquid chromatography. A detection limit as low as 2.0 nmol/dm3 (22 ng/dm3) was achieved without any preconcentration. No significant interference was observed in the determination of 16 μmol/dm3 of boron with the addition of nine metal ions (AlIII, CuII, CoII, FeII, FeIII, NiII, MnII, VV, ZnII) at concentrations 100 times greater than that of boron without any masking procedure. The proposed method was successfully applied to the determination of boron in river water, tap water, doubly distilled water, and highly purified water. Figure Scheme of formation of boron-azomethine-H complex with salicylaldehyde and 1-amino-8-naphthol-3, 6-disulfonate
Keywords: Boron; Nanograms per cubic decimeter; Salicylaldehyde; 1-Amino-8-naphthol-3; 6-disulfonate; High-performance liquid chromatography