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This feature article discusses the enabling role of analytical chemistry in important fields of research and development such as life science, material sciences and environmental sciences. It comments on the often limited visibility of analytical sciences in the public perception and suggests ways to overcome this shortcoming and to create bigger impact. [ABSTRACT FROM AUTHOR]

RATIONALE The capabilities of modified non-spherical Doehlert-type experimental designs to optimize the performance of a hybrid mass spectrometer were investigated in this paper for the first time. The optimization process was completed in three successive steps with groups of variables avoiding any univariable approach. Glutathione (GSH, reduced) was selected as a very interesting analyte since it is considered to be one of the most abundant tripeptides in human organism and its action against xenobiotics and oxidative radicals is well known. METHODS In particular, a tandem technique based on sequential ion management by an ion trap followed by a time-of-flight mass analyzer (ITTOFMS) was introduced commercially in recent years and investigated for glutathione determination. Glutathione was injected in a stream of a typical mobile phase used in liquid chromatography (LC) and analyzed after electrospray ionization (ESI) in tandem MS. RESULTS The three main steps of the LC/MS system, namely the LC mobile phase, the ESI interface and the MS analyzer, were independently optimized in terms of maximum sensitivity. In this context quadratic models were found and their prediction power was evaluated. A calibration study was performed at default and optimum conditions in order to quantitatively estimate the sensitivity enhancement of the employed technique for this analyte. Satisfactory precision (RSD 5.7%) and detectability (LOD 0.07 µmol L-1) were achieved. CONCLUSIONS The results highlighted the possibilities offered by the employment of multifactorial optimization towards the improvement of performance of tandem mass spectrometry techniques. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

• A method was developed for the characterization of (poly)phenols and flavonoids. • This technique was applied to asparagus. • The new method was optimized to comprehensively analyze polyphenols by LC-DAD-MS. • The optimum operating conditions of the method were examined. • The sample preparation step was also optimized. The main objective of the present work was to develop a method for the simultaneous and comprehensive analysis of (poly-)phenolic and flavonoid compounds with liquid chromatography with diode array and mass spectrometric detection and its application to green asparagus samples. To this end, a representative set of polyphenols was used to develop the method. A through method validation was carried out with these. The method was applied to asparagus samples known as a healthy vegetable being rich in bioactive compounds. Polyphenol contents of asparagus samples were determined by carrying out quantitative and qualitative analyses by LC-DAD-ESI/MS. In this context asparagus sample extracts were obtained using solvents of different polarity. The results were evaluated statistically and showed that rutin is the major phenolic compound in asparagus. This demonstrates the versatility of this rapid and sensitive method for the simultaneous analysis of (poly-)phenolic and flavonoid compounds which was successfully applied to asparagus samples. [ABSTRACT FROM AUTHOR]

Abstract: A novel LC–ESI–MS method for the simultaneous determination of four of the most significant estrogenic compounds naturally occurring in beer, 8-prenylnaringenin (8-PN), zearalenone (ZON), α-zearalenol (α-ZOL) and β-zearalenol (β-ZOL) which requires minimal sample preparation was developed using a chemometric approach. Experimental design was applied to assess the effects of the LC–ESI–MS parameters (mobile phase flow rate, drying gas flow, nebuliser pressure and capillary potential) on the obtained signal and to optimize the values in order to provide maximum sensitivity and detectability. The proposed method is simple, consisting only of degassing the beer and diluting with water (1:1, v/v) before injection. Comparison between the two internal standards used, zearalanone (ZAN) and 4,2′-dihydroxychalcone (4,2′-DHC), showed that ZAN performs better as internal standard not only for the mycotoxins but for 8-PN as well, giving lower % RSDs. Under inter-day conditions mean recoveries were 107% for ZON, 87.8% for α-ZOL, 72.8% for β-ZOL, and 77.5% for 8-PN. The corresponding % RSDs ranged between 5.0 and 8.0. The method limits of detection were 1.3, 1.4, 1.0 and 0.8ngmL−1 for ZON, α-ZOL, β-ZOL and 8-PN, respectively. The method was applied to 15 beer samples obtained from local supermarkets and the concentration of the phytoestrogen 8-PN in beer ranged between <0.8 and 38.6ngmL−1, while neither ZON nor its metabolites, α-ZOL and β-ZOL, were detected. [Copyright &y& Elsevier]

Abstract: A set of monolithic capillary columns for liquid chromatography, synthesized according to a recently developed protocol which uses methyltrimethoxysilane (MTMS) as a sole precursor, is characterised by various chromatographic tests to assess its physico-chemical properties. The new stationary phase material shows a hydrophobicity (assessed on the basis of methylene selectivity) comparable to commercial C8 columns. The MTMS-based columns exhibit a reduced affinity towards planar molecules such as PAHs, compared to C18 modified columns, which can be explained by a retention mechanism that is more governed by adsorption rather than partitioning. In comparison to commercial products an only moderate silanol activity was observed, even without any endcapping procedure applied. Selectivity between hydrophobic test compounds showed to be uniform between the columns investigated in this study, whereas retention factors differed up to 20% (batch-to-batch reproducibility) between columns produced under the same conditions. For most of the materials investigated in this study, size exclusion towards even only slightly larger molecules such as triphenylene was observed. It was demonstrated that inclusion of a micelle-forming detergent such as Brij in the synthetic protocol could partially overcome this problem. [Copyright &y& Elsevier]

This review discusses the characterisation of natural organic dyestuffs of historical interest by liquid chromatography–mass spectrometry. The structures of the most important natural organic dyestuffs traditionally used are presented and discussed from the perspective of their analytical chemical determination. The practical aspects of the determination of this inhomogeneous range of compounds with different structures, such as anthraquinones, flavonoids, indigoids or tannins, are discussed with their implications for sample preparation, liquid chromatographic separation and mass spectrometric detection. The particular focus of this review is the discussion of the mass spectral fragmentation patterns of the different classes of natural organic dyestuffs, which in the ideal case allow the identification of the dyestuff actually used, and thereby provide a key to the better characterisation and understanding of historical objects dyed with natural organic dyestuffs. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The use of mass spectrometry based on atmospheric pressure ionisation techniques (atmospheric pressure chemical ionisation, APCI, and electrospray ionisation, ESI) for speciation analysis is reviewed with emphasis on the literature published in and after 1999. This report accounts for the increasing interest that atmospheric pressure ionisation techniques, and in particular ESI, have found in the past years for qualitative and quantitative speciation analysis. In contrast to element-selective detectors, organic mass spectrometric techniques provide information on the intact metal species which can be used for the identification of unknown species (particularly with MS–MS detection) or the confirmation of the actual presence of species in a given sample. Due to the complexity of real samples, it is inevitable in all but the simplest cases to couple atmospheric pressure MS detection to a separation technique. Separation in the liquid phase (capillary electrophoresis or liquid chromatography in reversed phase, ion chromatographic or size-exclusion mode) is particularly suitable since the available techniques cover a very wide range of analyte polarities and molecular mass. Moreover, derivatisation can normally be avoided in liquid-phase separation. Particularly in complex environmental or biological samples, separation in one dimension is not sufficient for obtaining adequate resolution for all relevant species. In this case, multi-dimensional separation, based on orthogonal separation techniques, has proven successful. ESI-MS is also often used in parallel with inductively coupled plasma MS detection. This review is structured in two parts. In the first, the fundamentals of atmospheric pressure ionisation techniques are briefly reviewed. The second part of the review discusses recent applications including redox species, use of ESI-MS for structural elucidation of metal complexes, characterisation and quantification of small organometallic species with relevance to environment, health and food. Particular attention is given to the characterisation of biomolecules and metalloproteins (metallothioneins and phytochelatins) and to the investigation of the interaction of metals and biomolecules. Particularly in the latter field, ESI-MS is the ideal technique due to the softness of the ionisation process which allows to assume that the detected gas-phase ions are a true representation of the ions or ion–biomolecule complexes prevalent in solution. It is particularly this field, important to biochemistry, physiology and medical chemistry, where we can expect significant developments also in the future. [Copyright &y& Elsevier]

Multiplex sampling, so far mainly used as a tool for S/N ratio improvement in spectroscopic applications and separation techniques, has been investigated here for its potential suitability for time-resolved monitoring where chromatograms of transient signals are recorded at intervals much shorter than the chromatographic runtime. Different designs of multiplex sample introduction were developed and utilized to analyze lithium-ion battery degradation products under normal or abuse conditions to achieve fast and efficient sample introduction. After comprehensive optimization, measurements were performed on two different GC systems, with either barrier discharge ionization detection (BID) or mass spectrometric detection (MS). Three different injector designs were examined, and modifications in the pertinent hardware components and operational conditions used. The shortest achievable sample introduction time was 50 ms with an interval of 6 s. Relative standard deviations were lower than 4% and 10% for the intra- and inter-day repeatability, respectively. The sample introduction system and column head pressure had to be carefully controlled, as this parameter most critically affects the amount of sample introduced and, thus, detector response. The newly developed sample introduction system was successfully used to monitor volatile degradation products of lithium-ion batteries and demonstrated concentration changes over the course of time of the degradation products (e.g., fluoroethane, acetaldehyde and ethane), as well as for solvents from the battery electrolyte like ethyl carbonate. [ABSTRACT FROM AUTHOR]

Graphene oxide is a compound with a form similar to graphene, composed of carbon atoms in a sp2 single-atom layer of a hybrid connection. Due to its significant surface area and its good mechanical and thermal stability, graphene oxide has a plethora of applications in various scientific fields including heterogenous catalysis, gas storage, environmental remediation, etc. In analytical chemistry, graphene oxide has been successfully employed for the extraction and preconcentration of organic compounds, metal ions, and proteins. Since graphene oxide sheets are negatively charged in aqueous solutions, the material and its derivatives are ideal sorbents to bind with metal ions. To date, various graphene oxide nanocomposites have been successfully synthesized and evaluated for the extraction and preconcentration of metal ions from biological, environmental, agricultural, and food samples. In this review article, we aim to discuss the application of graphene oxide and functionalized graphene oxide nanocomposites for the extraction of metal ions prior to their determination via an instrumental analytical technique. Applications of ionic liquids and deep eutectic solvents for the modification of graphene oxide and its functionalized derivatives are also discussed. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) is a chemical compound with a form similar to graphene that consists of one-atom-thick two-dimensional layers of sp2-bonded carbon. Graphene oxide exhibits high hydrophilicity and dispersibility. Thus, it is difficult to be separated from aqueous solutions. Therefore, functionalization with magnetic nanoparticles is performed in order to prepare a magnetic GO nanocomposite that combines the sufficient adsorption capacity of graphene oxide and the convenience of magnetic separation. Moreover, the magnetic material can be further functionalized with different groups to prevent aggregation and extends its potential application. Until today, a plethora of magnetic GO hybrid materials have been synthesized and successfully employed for the magnetic solid-phase extraction of organic compounds from environmental, agricultural, biological, and food samples. The developed GO nanocomposites exhibit satisfactory stability in aqueous solutions, as well as sufficient surface area. Thus, they are considered as an alternative to conventional sorbents by enriching the analytical toolbox for the analysis of trace organic compounds. [ABSTRACT FROM AUTHOR]

The article discusses the analysis and identification of dyes in historical Chinese textiles. Topics include details on the use of plant indigo for dye and its extraction from Persicaria tinctoria; details on the use of methods such as Fourier transform infrared spectroscopy, high-performance liquid chromatography (HPLC), and mass spectrometry to characterize dyestuffs; details on the research of dyestuffs from costumes of the East Zhou, Han, Tang, and Song dynasties in China; and mention of the colors of historical plant-based dyes such as blue, red, and yellow.

The response behavior and performance characteristics of the recently introduced barrier discharge ionization detector (BID) for gas chromatography (GC-BID) were investigated by analyzing different classes of organic compounds such as alcohols, alkanes, cycloaliphatic compounds, polycyclic aromatic hydrocarbons (PAHs), and others. The results obtained by GC-BID were compared with those of gas chromatography with flame ionization detection (GC-FID), aiming to demonstrate the particular merits of the new BID detector over the well-established FID. The response of the BID not only was found to be strongly dependent on the detector settings, but also shows a high dependence on the analyte class and the individual analyte. The sensitivity of the BID detector compared to the FID was higher by a factor of ca. 4 on average when considering all compounds analyzed. The relative standard deviation (RSD) was better than 5% for the majority of the cases. The BID detector showed better precision (lower RSD) in comparison with the FID for the investigated compounds. Linear calibrations were obtained for the analytes over more than four orders of magnitude with coefficients of determination typically higher than 0.999 and the limits of detection varied from 0.04 to 1.48 ng/s for the GC-BID. [ABSTRACT FROM AUTHOR]

The existence of interfacial carbides is a well-known phenomenon in Al/diamond composites, although quantitative analyses are not described so far. The control of the formation of interfacial carbides while processing Al(Si)/diamond composites is of vital interest as a degradation of thermophysical properties appears upon excessive formation. Analytical quantification was performed by GC-MS measurements of gaseous species released upon dissolving the matrix and interfacial reaction products in aqueous NaOH solutions and the CH4/N2 ratio of the evolving reaction gases can be used for quantification. Although the formation of interfacial carbides is significantly suppressed by adding Si to Al, also a decline in composite thermal conductivity is observed in particular with increasing contact time between the liquid metal and the diamond particles during gas pressure infiltration. Furthermore, surface termination of diamond particles positively affects composite thermal conductivity as oxygenated diamond surfaces will result in an increase in composite thermal conductivity compared to hydrogenated ones. In order to understand the mechanisms responsible for all impacts on the thermal conductivity and thermal conductance behaviour, the metal/diamond interface was electrochemical etched and characterized by SEM. Selected specimens were also cut by an ultrashort pulsed laser system to characterize interfacial layers at the virgin cross section in the reactive system Al/diamond. [ABSTRACT FROM AUTHOR]

Polymeric composite materials are gaining importance due to their universal applicability and easy adaptability for their intended use. For the comprehensive characterization of these materials, the concurrent determination of the organic and the elemental constituents is necessary, which cannot be provided by classical analysis methods. In this work, we present a novel approach for advanced polymer analysis. The proposed approach is based on firing a focused laser beam onto a solid sample placed in an ablation cell. The generated gaseous and particular ablation products are measured online parallelly by EI-MS and ICP-OES. This bimodal approach allows direct characterization of the main organic and inorganic constituents of solid polymer samples. The LA-EI-MS data showed excellent agreement with the literature EI-MS data allowing not only the identification of pure polymers but also of copolymers, as demonstrated with acrylonitrile butadiene styrene (ABS) as the sample. The concurrent collection of ICP-OES elemental data is vital for classification, provenance determination, or authentication studies. The applicability of the proposed procedure has been demonstrated by analysis of various polymer samples from everyday use. [Display omitted] • New ablation cell design allows direct coupling of laser ablation with EI-MS and ICP-OES. • EI-MS data allows identification of polymers even in mixture. • ICP-OES data is vital for detection of additives and impurities. • Method enables classification and differentiation of polymeric composite material. [ABSTRACT FROM AUTHOR]

Provides information on the 5th Euroconference on Environmental Analytical Chemistry which took place in Ireland. Topics discussed at the conference; Format of the meeting; Persons who contributed to the success of the event.

In this work, a solid-phase microextraction (SPME) Arrow method combined with comprehensive two-dimensional gas chromatography–mass spectrometry (GC × GC–MS) was developed for the elucidation of the volatile composition of honey samples. The sample preparation protocol was optimized to ensure high extraction efficiency of the volatile organic compounds (VOCs) which are directly associated with the organoleptic properties of honey and its acceptance by the consumers. Following its optimization, SPME Arrow was compared to conventional SPME in terms of sensitivity, precision, and number of extracted VOCs. The utilization of SPME Arrow fibers enabled the determination of 203, 147, and 149 compounds in honeydew honey, flower honey, and pine honey, respectively, while a significantly lower number of compounds (124, 94, and 111 for honeydew honey, flower honey, and pine honey, respectively) was determined using conventional SPME. At the same time, the utilization of SPME Arrow resulted in enhanced sensitivity and precision. All things considered, SPME Arrow and GC × GC–MS can be considered as highly suitable for the elucidation of the volatile composition of complex food samples resulting in high sensitivity and separation efficiency. [ABSTRACT FROM AUTHOR]

The unique properties of per- and polyfluoroalkyl substances (PFAS) have led to their extensive use in consumer products, including ski wax. Based on the risks associated with PFAS, and to align with PFAS regulations, the international ski federation (FIS) implemented a ban on products containing "C 8 fluorocarbons/perfluorooctanoate (PFOA)" at all FIS events from the 2021/2022 season, leading manufactures to shift their formulations towards short-chain PFAS chemistries. To date, most studies characterising PFAS in ski waxes have measured a suite of individual substances using targeted analytical approaches. However, the fraction of total fluorine (TF) in the wax accounted for by these substances remains unclear. In this study, we sought to address this question by applying a multi-platform, fluorine mass balance approach to a total of 10 commercially available ski wax products. Analysis of TF by combustion ion chromatography (CIC) revealed concentrations of 1040–51700 μg F g−1 for the different fluorinated waxes. In comparison, extractable organic fluorine (EOF) determined in methanol extracts by CIC (and later confirmed by inductively-coupled plasma-mass spectrometry and 19F- nuclear magnetic resonance spectroscopy) ranged from 92 to 3160 μg g−1, accounting for only 3–8.8 % of total fluorine (TF). Further characterisation of extracts by cyclic ion mobility-mass spectrometry (IMS) revealed 15 individual PFAS with perfluoroalkyl carboxylic acid concentrations up to 33 μg F g−1, and 3 products exceeding the regulatory limit for PFOA (0.025 μg g−1) by a factor of up to 100. The sum of all PFAS accounted for only 0.01–1.0 % of EOF, implying a high percentage of unidentified PFAS, thus, pyrolysis gas chromatography-mass spectrometry was used to provide evidence of the nature of the non-extractable fluorine present in the ski wax products. [Display omitted] • PFAS profile among the ski wax products varies between manufacturers. • Analysis of EOF and TF by CIC aid to estimate the total PFAS burden. • Complementary techniques such as ICP-MS or 19F NMR have shown potential for the determination of F. • Pyrolysis GC-MS was used to study the nature of the non-extractable fluorine present in the ski wax products. • The developed multi-platform approach provides a more holistic perspective on the PFAS and F content in ski wax products. [ABSTRACT FROM AUTHOR]

The interphases on the electrodes that form from electrolyte decomposition play a crucial role in the battery performance. However, with a thickness of only a few nanometres the formed passivation layers present a challenge to explore. In this work, we implemented a new approach by combining operando GC/MS gas analysis supported by surface sensitive XPS to investigate the electrolyte decomposition during SEI formation and deepen the understanding of the decomposition reactions of vinylene carbonate (VC) and fluoroethylene carbonate (FEC). Electrolyte degradation results in the formation of 29 different gas species. Adding additives resulted in (i) reduced gas formation and (ii) a clear shift from hydrocarbons to carbon oxides. Carbon dioxide was found to be indicative of the formation of poly-VC which was supported by findings from post-mortem XPS. An increased amount of fluorine was found in the interphases of cells using FEC as electrolyte additive. Acetaldehyde was identified as gaseous component to differentiate the decomposition of VC and FEC. For the decomposition of the base electrolyte components ethylene carbonate (EC) and diethyl carbonate (DEC), methane, ethane, ethene and butane were found to be indicative, and a scavenging effect of VC for alkoxides was confirmed by monitoring ethanol. • Solid electrolyte interphase and cathode electrolyte interphase investigation. • Comparison of SEI forming additives VC and FEC. • Analysis of complex gas mixture from electrolyte decomposition. • Decomposition pathways investigated by operando GC/MS and XPS. [ABSTRACT FROM AUTHOR]

Omics is used as an analytical tool to investigate wine authenticity issues. Aging authentication ensures that the wine has undergone the necessary maturation and developed its desired organoleptic characteristics. Considering that aged wines constitute valuable commodities, the development of advanced omics techniques that guarantee aging authenticity and prevent fraud is essential. Α solid phase microextraction Arrow method combined with comprehensive two-dimensional gas chromatography-mass spectrometry was developed to identify volatiles in red wines and investigate how aging affects their volatile fingerprint. The method was optimized by examining the critical parameters that affect the solid phase microextraction Arrow extraction (stirring rate, extraction time) process. Under optimized conditions, extraction took place within 45 min under stirring at 1000 rpm. In all, 24 monovarietal red wine samples belonging to the Xinomavro variety from Naoussa (Imathia regional unit of Macedonia, Greece) produced during four different vintage years (1998, 2005, 2008 and 2015) were analyzed. Overall, 237 volatile compounds were tentatively identified and were treated with chemometric tools. Four major groups, one for each vintage year were revealed using the Hierarchical Clustering Analysis. The first two Principal Components of Principal Component Analysis explained 86.1% of the total variance, showing appropriate grouping of the wine samples produced in the same crop year. A two-way orthogonal partial least square – discriminant analysis model was developed and successfully classified all the samples to the proper class according to the vintage age, establishing 17 volatile markers as the most important features responsible for the classification, with an explained total variance of 88.5%. The developed prediction model was validated and the analyzed samples were classified with 100% accuracy according to the vintage age, based on their volatile fingerprint. The developed methodology in combination with chemometric techniques allows to trace back and confirm the vintage year, and is proposed as a novel authenticity tool which opens completely new and hitherto unexplored possibilities for wine authenticity testing and confirmation. [Display omitted] • Optimized SPME-Arrow method combined with GC × GC-MS for wine aging testing. • Tentative identification of 237 volatile compounds. • Establishment of 17 volatile markers responsible for the classification. • Sample classification with 100% accuracy according to the vintage age. [ABSTRACT FROM AUTHOR]

This study introduces the first mid-infrared (IR)–based method for determining the fatty acid composition of human milk. A representative milk lipid fraction was obtained by applying a rapid and solvent-free two-step centrifugation method. Attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy was applied to record absorbance spectra of pure milk fat. The obtained spectra were compared to whole human milk transmission spectra, revealing the significantly higher degree of fatty acid–related spectral features in ATR FT-IR spectra. Partial least squares (PLS)–based multivariate regression equations were established by relating ATR FT-IR spectra to fatty acid reference concentrations, obtained with gas chromatography–mass spectrometry (GC-MS). Good predictions were achieved for the most important fatty acid sum parameters: saturated fatty acids (SAT, R2CV = 0.94), monounsaturated fatty acids (MONO, R2CV = 0.85), polyunsaturated fatty acids (PUFA, R2CV = 0.87), unsaturated fatty acids (UNSAT, R2CV = 0.91), short-chain fatty acids (SCFA, R2CV = 0.79), medium-chain fatty acids (MCFA, R2CV = 0.97), and long-chain fatty acids (LCFA, R2CV = 0.88). The PLS selectivity ratio (SR) was calculated in order to optimize and verify each individual calibration model. All mid-IR regions with high SR could be assigned to absorbances from fatty acids, indicating high validity of the obtained models. Graphical Abstract [ABSTRACT FROM AUTHOR]

• Optimization of a HS-SPME-GC-MS methodology to investigate walnut oils' volatile profile. • Discrimination between organic and conventional walnut oils. • Development of a sPLS-DA model with high prediction accuracy. • Establishment of characteristic volatile markers. It is challenging to establish a correlation between the agronomical practices and the volatile profile of high-value agricultural products. In this study, the volatile metabolome of walnut oils from conventional and organic farming type was explored by HS-SPME-GC-MS. The SPME protocol was optimized after evaluating the effects of extraction time, extraction temperature, and sample mass. The optimum parameters involved the extraction of 0.500 g walnut oil at 40 °C within 60 min. Twenty Greek walnut oils produced with conventional and organic farming were analyzed and 41 volatile compounds were identified. The determined compounds were semi-quantified, and further processed with chemometrics. Agglomerative hierarchical clustering (AHC) and principal component analysis (PCA) were used. A robust classification model was developed using sparse partial least squares–discriminant analysis (sPLS-DA) for the discrimination of walnut oils into conventional and organic, establishing volatile markers that could be used to guarantee the type of farming. [ABSTRACT FROM AUTHOR]

Cloud point extraction is an environmentally benign and simple separation/concentration procedure that can be regarded as an alternative to classical liquid-liquid extraction. In the current work, it was studied the compatibility of cloud point extraction followed by back-extraction in low volume of organic solvent with gas chromatography-mass spectrometry (GC-MS and GC-MS/MS). Triton X-100 was preferred than Triton X-114 as a surfactant to produce the clouding phenomenon and hexane or isooctane was found to be appropriate organic solvents which can be used at the back-extraction step. It was observed that ca. 0.09 % w/w Triton X-100 was co-extracted in the organic phase (hexane or isooctane) so further study was carried out to find out its effect on the GC-MS (GC-MS/MS) measurement when liquid samples are injected without any pre-cleaning to remove the surfactant. The chromatographic separation and the mass detection were not deteriorated by the concomitant Triton X-100 for analysis of several Organochlorine and Organophosphorus pesticides (alpha-HCH, beta-HCH, gamma-HCH, Pentachlorobenzene, Hexachlorobenzene, Chlorpyrifos, Chlorpyrifos-methyl, Aldrin, Endrin, Dieldrin, alpha-Endosulfan, Heptachlor, Heptachlor- endo -epoxide-A, o,p-DDD, p,p-DDD, o,p-DDE, p,p-DDE, o,p-DDT and p,p-DDT). The stability of the GC system when introducing surfactant was assessed as acceptable (typically the peak area RSD% for 20 consecutive injections were below 5 %). Under the developed vaporization conditions using PTV or PSS injectors it can be deduced that Triton X-100 is deposited on the inner surface of the liner. This effect is beneficial since the resulting surfactant layer makes a surface which facilitates the pesticides transfer to the GC column. As a consequence, for some analytes, a substantial enhancement (up to 2.3 times) in the sensitivity was observed when the matrix-matched medium (0.09 % w/w Triton X-100 in organic solvent) is used compared to calibration in solely hexane or isooctane. Meanwhile, the measurement precision in the presence of Triton X-100 remains unchanged. The GC-MS/MS analysis was alternatively accomplished by the use of glass or metal liner and it was found that the glass one should be preferable. Finally, it can be concluded that cloud point extraction with Triton X-100 can be combined with GC-MS or GC-MS/MS analysis by applying liquid injection of the target analytes transferred in organic solvents such as hexane or isooctane. We have established a positive effect of Triton X-100 on the instrumental performance which is on opposite to the generally accepted concern of the negative influence of the surfactants on the gas chromatographic analysis. [Display omitted] • Hexane or Isooctane containing 0.09 % Triton X-100 can be injected without cleanup. • The injected amount of Triton X-100 improves the analytical figures of merit. • Matrix-matched calibration can be applied by spiked solvent with Triton X-100. • The use of glass liner is preferable to obtain the best performance characteristics. [ABSTRACT FROM AUTHOR]

Abstract: The present work aims at the optimisation of the synthesis of methyl-silsesquioxane monolithic capillary columns using a sol–gel based protocol. The influence of reaction conditions such as temperature, reaction mixture composition and catalyst concentration has been examined. The morphology of the products was studied by scanning electron microscopy and nitrogen adsorption. Monolithic capillary columns were obtained with a skeleton-like structure with open pores. Pore diameters vary from 0.8 to 15μm, diameters of the xerogel network vary from 0.4 to 12μm, respectively. Specific surface areas up to 334m2/g have been observed, however, many materials did not possess areas above few m2/g which represents the limit of detection of the nitrogen porosimetry measurements. Excellent adhesion to the capillary wall was observed in all cases, and drying was possible at ambient conditions without the formation of cracks. [Copyright &y& Elsevier]

A procedure for the determination of fatty acids (FA) and glycerol in oils has been developed. The method includes a derivatization step of the FAs into their methyl esters or a transesterification of the triacylglycerols with trimethylsulfonium hydroxide (TMSH), respectively. The analysis is carried out by gas chromatography with parallel flame ionization and mass spectrometric detection. The parameters involved in the transesterification reaction were optimized. Only the stoechiometric ratio of TMSH:total FA amount showed a significant influence on the reaction yield. Relative standard deviations for 10 replicates were below 3% for all FAs studied and their linearity range was 0.5–50 mmol/L, when using heptadecanoic acid as an internal standard. The final procedure was rapid and required little sample handling. It was then tested on fresh oil samples and presented satisfying results, in agreement with previous works. [Copyright &y& Elsevier]

The reason for the compound-dependent over-estimation of the recoveries of several volatile organic sulfur compounds when using a Silcosteel cylinder for sample storage as reported earlier was examined. From the different possible sources of errors that were taken into consideration, the silicone tubing, which was used to fill a standard Tedlar sample bag for calibration, was identified as the cause of the artefact. The comparison of different tubing materials showed that PTFE is the best choice since it causes only minor losses (<10%) of propyl- and butylmercaptans. [Copyright &y& Elsevier]

In this work, a solid-phase microextraction (SPME) method combined with two-dimensional gas chromatography coupled to mass spectrometry (GC × GC-MS) was optimized and used to assess the authenticity of pomegranate juice to prevent fraudulent practices. A divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber was used for the extraction of the volatiles. The critical parameters that affect the extraction process, such as the sample volume, and the extraction time were studied. The optimized protocol involved the addition of 15 mL of juice in 50 mL vial and saturation with 30% w/v NaCl.The extraction was carried out within 45 min under 1000 rpm stirring and was applied in the analysis of real juice samples to assess authenticity and detect low levels of pomegranate juice adulteration with grape and apple juice down to 1%. Commercially available pomegranate juice samples were acquired (n 1 = 6) and adulterated with 1% of apple juice (n 2 = 6), 1% of grape juice (n 3 = 6), and a mixture of 1% apple juice and 1% grape juice (n 4 = 6). Authentic pomegranate juice samples and adulterated mixtures were analyzed by SPME-GC × GC-MS. The analysis resulted in the identification of 123 volatile compounds that were further processed with chemometric tools. Principal component analysis (PCA) was employed to visualize the clustering of the samples, and a two-way orthogonal partial least squares discriminant analysis (O2PLS-DA) chemometric model was developed and successfully classified the samples to authentic pomegranate juice or adulterated with an explained total variance of 87.4%. The O2PLS-DA prediction model revealed characteristic volatile markers that could be used to detect pomegranate juice fraud. [Display omitted] • Optimized SPME method combined with GC × GC-MS to address food fraud. • 2D-GC volatilomics for the exploration of the fingerprint of juices. • Chemometrics successfully discriminated between pure pomegranate juices and adulterated. • Identification of characteristic volatile markers. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) are crystalline porous materials composed of metal ions or clusters coordinated with organic linkers. Due to their extraordinary properties such as high porosity with homogeneous and tunable in size pores/cages, as well as high thermal and chemical stability, MOFs have gained attention in diverse analytical applications. MOFs have been coupled with a wide variety of extraction techniques including solid-phase extraction (SPE), dispersive solid-phase extraction (d-SPE), and magnetic solid-phase extraction (MSPE) for the extraction and preconcentration of metal ions from complex matrices. The low concentration levels of metal ions in real samples including food samples, environmental samples, and biological samples, as well as the increased number of potentially interfering ions, make the determination of trace levels of metal ions still challenging. A wide variety of MOF materials have been employed for the extraction of metals from sample matrices prior to their determination with spectrometric techniques. [ABSTRACT FROM AUTHOR]

[Display omitted] • Design of second generation TiO 2 based FPSE membranes. • Analysis of clarified and unclarified apple juice samples. • Development of an FPSE-GC–MS method for OPPs determination. • Higher extraction efficiency for OPPs compared to their silica analogues. In this work, different sol–gel sorbent-coated second-generation fabric phase sorptive extraction (FPSE) membranes were synthesized using titania-based sol–gel precursors. The proposed membranes were tested for their efficiency to extract eleven selected organophosphorus pesticides (OPPs) from apple juice samples. Among the examined materials, sol–gel C 18 coated titania-based FPSE membranes showed the highest extraction efficiency. These membranes were used for the optimization and validation of an FPSE method prior to analysis by gas chromatography-mass spectrometry. The detection limits for OPPs ranged between 0.03 and 0.08 ng mL−1. Moreover, the relative standard deviation was < 8.2% and 8.4% for intra-day and inter-day studies, respectively. The relative recoveries were 91–110% (intra-day study) and 90–106% (inter-day study) for all the target analytes, demonstrating good overall method accuracy. Moreover, the novel membranes were reusable at least 5 times. The titania-based membranes were compared to the conventional silica-based membranes and their utilization resulted in higher extraction recoveries. [ABSTRACT FROM AUTHOR]

[Display omitted] • Extraction of organochlorine pesticides employing sol–gel PEG 300 capsules. • The CPME–GC–MS method was simple, economic, accurate and precise. • Capsule preparation meets most of the criteria of ComplexGAPI index. • Successful application for the monitoring of OCPs in environmental water. In this study, a capsule phase microextraction (CPME) protocol followed by gas chromatography-mass spectrometry is proposed for the accurate and sensitive monitoring of organochlorine pesticides (OCPs) in environmental water samples. Different monolithic sol–gel encapsulated sorbents were compared and monolithic sol–gel poly(ethylene glycol)-based sorbent incorporated into porous microextraction capsules resulted in the highest extraction efficiency. Following the selection of the microextraction device, the CPME conditions were optimized, while linearity, limits detection (LODs), limits of quantification (LOQs), accuracy, and precision were the figures-of-merit measured. Under optimum conditions the LODs for the OCPs ranged between 0.01 ng mL−1 and 0.03 ng mL−1. The relative standard deviations were better than 5.3 % and 9.2 % for intra-day and inter-day study, respectively. The relative recoveries ranged between 90.5 and 105.2 % (intra-day) and 93.0–105.0 % (inter-day), demonstrating good method trueness. Finally, the proposed protocol was implemented for the monitoring of OCPs in tap, river, pond, and lake water. The developed method presents better analytical features than existing methods. [ABSTRACT FROM AUTHOR]

[Display omitted] • Extraction of benzoyl urea pesticides using sol–gel PCAP-PDMS-PCAP capsules. • Successful application for the monitoring of pesticides in commercial apple juices. • CPME provides efficient sample clean-up and high analyte preconcentration. • The CPME-HPLC-DAD method showed good accuracy, precision, and sensitivity. • The CPME capsules are easy to fabricate, cost-effective and reusable. Fruit juices may contain harmful residues of pesticides that are associated with ecological and health risks. Thus, it is critical to develop sensitive and accurate methods for the monitoring of pesticides in these food products. In the present study, a simple and sensitive capsule phase microextraction (CPME) protocol combined with high-performance liquid chromatography-diode array detection (HPLC-DAD) was developed for the monitoring of benzoyl urea pesticides (chlorfluazuron, diflubenzuron, hexaflumuron, lufenuron, and triflumuron) in apple juices. Among the different examined sorptive phases, monolithic sol–gel poly(caprolactone)-poly(dimethylsiloxane)-poly(caprolactone) capsules were found to exhibit the highest extraction efficiency. The adsorption and desorption steps of the CPME method were optimized and the proposed method was validated. Under optimum conditions, the limits of detection for all analytes were in the range 0.15–0.30 ng mL−1. Moreover, the proposed protocol exhibited good linearity, accuracy, and precision. The relative recoveries of the method ranged between 90% and 108%, and the relative standard deviations were <8% and 9% for intra-day and inter-day precision, respectively. The ComplexGAPI index was used to evaluate the green potential of the proposed method. Finally, the proposed method was employed in the analysis of a wide variety of commercially available apple juice samples. [ABSTRACT FROM AUTHOR]

• Headspace analysis of different whiskeys by conventional SPME and SPME Arrow. • Determination of whiskey volatiles by newly developed comprehensive GC × GC/MS method. • SPME Arrow outperforms conventional SPME by identifying a larger number of compounds. • Comprehensive characterization of whiskey headspace by cryomodulation GC × GC/MS. We present a novel sample preparation method for the extraction and preconcentration of volatile organic compounds from whiskey samples prior to their determination by comprehensive two-dimensional gas chromatography (GC × GC) coupled to mass spectrometry (MS). Sample preparation of the volatile compounds, important for the organoleptic characteristics of different whiskeys and their acceptance and liking by the consumers, is based on the use of the solid-phase microextraction (SPME) Arrow. After optimization, the proposed method was compared with conventional SPME regarding the analysis of different types of whiskey (i.e., Irish whiskey, single malt Scotch whiskey and blended Scotch whiskey) and was shown to exhibit an up to a factor of six higher sensitivity and better repeatability by a factor of up to five, depending on the compound class. A total of 167 volatile organic compounds, including terpenes, alcohols, esters, carboxylic acids, ketones, were tentatively-identified using the SPME Arrow technique, while a significantly lower number of compounds (126) were determined by means of conventional SPME. SPME Arrow combined with GC × GC-MS was demonstrated to be a powerful analytical tool for the exploration of the volatile profile of complex samples, allowing to identify differences in important flavour compounds for the three different types of whiskey investigated. [ABSTRACT FROM AUTHOR]

[Display omitted] • MI-FPSE can be utilized as a stand-alone sample preparation device in food analysis. • Sol-gel PTHF is the most appropriate sorbent for the extraction of triazine herbicides. • The MI-FPSE media are reusable for at least 5 times. Magnet integrated fabric phase sorptive extraction (MI-FPSE) is a novel sample preparation technique that utilizes a magnet integrated stand-alone sample preparation device consisting of two FPSE membranes sandwiched together with a cylindrical magnetic bar inside. This technique has been successfully employed for the analysis of biofluids; however, its applicability in food analysis is still unexplored. In this study, MI-FPSE using a sol–gel poly(tetrahydrofuran) coated FPSE cellulose membrane was utilized for the first time for the extraction of six triazine herbicides from herbal infusions. Determination of the target analytes after their extraction from the real samples was conducted using high performance liquid chromatography. The factors that may potentially influence the extraction performance were optimized and the proposed method was validated in terms of accuracy, precision, linearity, limits of detection (LODs) and limits of quantification (LOQs). The enhancement factors for the target analytes were 34.1–49.5. Moreover, the LODs (signal/noise = 3.3) for the target analytes were 0.30 ng mL−1 and the LOQs (signal/noise = 10) were 1.00 ng mL−1. The intra-day repeatability and inter-day precision expressed as relative standard deviation were found to be better than 6.5% and better than 8.5%, respectively. Finally, the herein developed protocol was successfully applied for the analysis of herbal infusion samples. [ABSTRACT FROM AUTHOR]

Elucidation and quantitative determination of some of commonly used penicillins (ampicillin, penicillin G and carbenicillin) in the presence of their main degradation product (penicilloic acid) were developed. Forced acidic and basic degradation processes were applied at different time intervals. The formed degradation products were elucidated and quantified using surface enhanced Raman spectroscopy (SERS). Silver nanoparticles (AgNPs) prepared by reduction of silver nitrate using hydroxylamine-HCl in alkaline medium were used as SERS substrate. The results obtained in SERS were confirmed by the application of LC/MS method. The concentration range was 100–600 ng/ml in case of the studied penicillins and 100–700 ng/ml in case of penicilloic acid. An excellent correlation coefficient was found in case of ampicillin ( r =0.9993) and in the case of penicilloic acid ( r =0.9997). Validation procedures were carried out including precision, robustness and accuracy by comparing F - and t -values of both the proposed and reported methods. [ABSTRACT FROM AUTHOR]

• Expansion of the applicability of MI-FPSE in environmental analysis • Sol-gel Carbowax 20M MI-FPSE media were used for the extraction of benzoyl urea insecticides • High enrichment factors and good method sensitivity were obtained. • MI-FPSE media can be regenerated and reused Benzoyl urea insecticides are a class of pesticides used in agriculture for the inhibition of chitin synthesis in pests. These compounds are persistent in environmental samples, and thus their monitoring is necessary to avoid detrimental effects to human health and the environment. Magnet integrated fabric phase sorptive extraction (MI-FPSE) is a recently introduced sample preparation technique that combines sample stirring and analyte extraction into one stand-alone device. However, the applicability and the potential benefits of this technique in environmental analysis remain unexplored. In the present study, MI-FPSE was employed for the first time for the extraction and preconcentration of benzoyl urea insecticides (i.e., diflubenzuron, triflumuron, hexaflumuron, lufenuron and chlorfluazuron) from environmental water samples prior to their determination by high performance liquid chromatography-diode array detection (HPLC-DAD). The main factors affecting the performance of the proposed methodology were thoroughly investigated and optimized and the MI-FPSE-HPLC-DAD method was validated. The proposed method enabled the handling of relatively high sample quantity resulting in high preconcentration factors (501 and 731) and good sensitivity. Under optimum conditions, the limits of detection and the limits of quantification for the benzoyl urea insecticides were 0.06 ng mL−1 and 0.20 ng mL−1, respectively. Moreover, the relative standard deviations were less than 6.1% for intra-day study and less than 8.2% for inter-day study showing good method precision. After its validation, the herein developed method was successfully employed for the analysis of tap, mineral, river, and lake water samples. In addition, the ComplexGAPI index was used to present the green potential of developed method from the step of MI-FPSE device preparation to final determination. All things considered, MI-FPSE could potentially serve as an efficient tool for the monitoring of pollutants in environmental analysis. [ABSTRACT FROM AUTHOR]

Abstract: The synthesis of several sulfates of trichothecene mycotoxins is presented. Deoxynivalenol (DON) and its acetylated derivatives were synthesized from 3-acetyldeoxynivalenol (3ADON) and used as substrate for sulfation in order to reach a series of five different DON-based sulfates as well as T2-toxin-3-sulfate. These substances are suspected to be formed during phase-II metabolism in plants and humans. The sulfation was performed using a sulfuryl imidazolium salt, which was synthesized prior to use. All protected intermediates and final products were characterized via NMR and will serve as reference materials for further investigations in the fields of toxicology and bioanalytics of mycotoxins. [Copyright &y& Elsevier]

• Preparation of a novel sol–gel zwitterionic multi-mode extraction FPSE medium. • Development of a FPSE-HPLC-DAD method for the determination of triazines in juice samples. • The zwitterionic sorbent helped cleaning all the acidic interferences from fruit juices. • Analysis of commercial and freshly prepared fruit juices. Triazine herbicides are a class of common pesticides which are widely used to control the weeds in many agricultural crops. Although many studies have described methodologies for the determination of triazine herbicides in aqueous samples, the attention given to agricultural crops and their products is far more limited. In this study, a novel sol–gel zwitterionic multi-mode fabric phase sorptive extraction (FPSE) platform was developed for the matrix clean-up, extraction and preconcentration of five triazine herbicides from fruit juice samples prior to their determination by high performance liquid chromatography-diode array detection (HPLC-DAD). The novel zwitterionic multi-mode sorbent was characterized and its performance for fruit juice analysis was evaluated. Compared to other sol–gel sorbents, the novel zwitterionic sorbent helped cleaning all the acidic interferences from fruit juices. The herein reported FPSE protocol was optimized and validated. Under optimum conditions, the FPSE method showed good accuracy, precision and sensitivity. The limits of detection and limits of quantification for all analytes were 0.15 ng mL−1 and 0.50 ng mL−1, respectively. The enhancement factors of this method ranged between 36.7 and 51.8. The relative standard deviation for intra-day precision was below 5.6% and for inter-day precision was below 8.8%. Finally, the proposed FPSE-HPLC-DAD method was successfully employed for the analysis of various fruit juice samples. [ABSTRACT FROM AUTHOR]

The determination of triazine herbicides in water samples is of utmost importance, due to their persistence and excessive use. However, since the concentration of triazine pesticides in real samples is low, an extraction/preconcentration step is typically required. Capsule phase microextraction (CPME) is a recently introduced sample preparation technique in which highly efficient sol-gel sorbents are encapsulated in a tubular polymer membrane. This particular design integrates the filtration and stirring mechanism into one extraction device, enabling the application of CPME for in situ sampling. In this study, CPME coupled to high performance liquid chromatography-diode array detection (HPLC-DAD) was employed for the first time for the determination of six triazine herbicides (i.e., simazine, cyanazine, atrazine, prometryn, terbuthylazine and propazine) in water samples. Microextraction capsules containing a moderately hydrophobic sol‐gel Carbowax 20 M sorbent provided the highest extraction efficiency towards the examined pesticides. The main parameters affecting the adsorption and desorption steps of the CPME procedure were investigated and optimized. Under the selected conditions, limits of detection (signal/noise = 3.3) were 0.15 ng mL−1 for the target analytes. Moreover, the relative standard deviation for the within-day and between-days repeatability were less than 7.2% and 9.9%, respectively. The method was successfully applied to the analysis of mineral water, tap water, rainwater and lake water samples. The reported protocol could overcome the need for sample filtration prior to the sample preparation of the water samples, resulting in simplification of the overall sample handling, improved data quality with minimal loss of analytes and reduced sample preparation cost. [Display omitted] • Design of a moderately hydrophobic sol-gel CW 20 M sorbent. • In situ preparation of microextraction capsules. • Capsule phase microextraction of triazine pesticides. • Analysis of real water samples. [ABSTRACT FROM AUTHOR]

Abstract: The Cretan School of iconography is the last great flowering of the traditional Byzantine painting manner, which is however influenced by different schools and western art. Despite their historical significance, icons of the Cretan School have been rarely studied through modern chemical techniques and therefore very few information is available on the materials used by the Cretan painters. In the present investigation, the organic materials contained in several icons of the Cretan School of Iconography from the collection of the Benaki Museum, Athens, Greece, are analyzed and identified by High Performance Liquid Chromatography coupled to a Diode Array Detector (HPLC–DAD) and Gas Chromatography with Mass Spectrometry (GC–MS). The HPLC–DAD results provide support to a recently published report which showed that kermes used in “Cretan” icons of 15th century and early 16th century was replaced by cochineal which was used in icons dated after early 16th century. This trend is known for western art and it is now proved for Cretan icons, showing thus the influence of the Cretan painters by other European painting schools. Other dyes detected in the historical samples, extracted from Cretan icons are madder (possibly Rubia tinctorum L., according to HPLC profiles) and indigoid dyes. Oils, such as linseed and walnut oil, are identified in samples extracted from the seven icons tested by GC–MS. Egg yolk is identified in the extract of only one icon and animal glue, originated most likely from the gesso ground, is found in six samples. Other organic materials detected by GC–MS were wax, as well as synthetic resins, applied during conservation treatments. [ABSTRACT FROM AUTHOR]

Abstract: The main objective of the project “Screening methods for Water data InFormaTion in support of the implementation of the EU Water Framework Directive” (SWIFT-WFD) was to support the successful implementation of the WFD, which strongly depends on the quality and the comparability of monitoring data from river basin to river basin. In order to evaluate the performance of the laboratories using both classical and screening/emerging methods involved in the analysis of priority substances listed in the WFD, project activities included organization of three Proficiency Testing (PT) schemes at the European level for the determination of trace elements, major components, polyaromatic hydrocarbons and pesticides in water matrices, using the quality-control materials prepared within the project activities. The results of the three PT schemes were evaluated to provide a basis of information about the performance and thus the capacities of European analytical laboratories to comply with the requirements set out in the WFD. [Copyright &y& Elsevier]

The use of solid-phase microextraction (SPME) with gas chromatography coupled to microwave-induced plasma atomic-emission detection (GC-MIP-AED) is described for selenite [Se(IV)] speciation. Aqueous standards were derivatised with sodium tetraethyl- or tetrapropylborate and extracted by SPME. Headspace extraction of the ethyl and propyl derivatives was studied. Relevant experimental conditions were optimised, including conditions for derivatisation and extraction and those of gas chromatographic analysis. The limits of detection achieved for headspace sampling of derivatised Se(IV) were in the low ng mL-1 range for both ethylation and propylation. When the method was applied to analysis of selenite in selenised yeast reference material results were in good agreement with the indicated values. [ABSTRACT FROM AUTHOR]

The determination of organic trace gases in the ambient environment at the lower ppb level is demonstrated based on a novel technique combining sorption tube sampling on Molsieve and Carbosieve S-III, thermal desorption, and detection of the trace analyte by hollow waveguide Fourier transform infrared (HWG-FT-IR) spectroscopy. While ethene concentrations of ∼5 ppm can be directly observed using HWG-FT-IR, enrichment factors of up to 5000 were achieved by sorption tube sampling and thermal desorption. Detection limits of ∼1 ppb are reported. Efficient enrichment by the sampling tube is achieved due to the favorable internal volume (∼0.4 cm[SUP3] at a length of 470 mm) of the hollow waveguide serving as a miniaturized gas cell. This new method was validated for ethene by thermodesorption-cryofocusing-GC-FID as the reference method. Analytical performance has been compared for standard gas mixtures and for ethene measurements in urban air. Finally, ethene data from a sampling campaign at two alpine sites in Tyrol/Ausiria are presented. [ABSTRACT FROM AUTHOR]

Investigates phenyl-modified reversed-phase liquid chromatography coupled to atmospheric pressure chemical ionization mass spectrometry. Reference substances; Applications.