World Congress on Biosensors 2014

World Congress on Biosensors 2014
Biosensors 2014

Tuesday 3 September 2013

Just Published: Journal of Analytical and Applied Pyrolysis

A new issue of this journal has just been published. To see abstracts of the papers it contains (with links through to the full papers) click here:
Journal of Analytical and Applied Pyrolysis
http://rss.sciencedirect.com/publication/science/5247

Selected papers from the latest issue:

The effect of redox conditions on sphagnum acid thermochemolysis product distributions in a northern peatland

02 September 2013, 22:12:23
Publication date: September 2013
Source:Journal of Analytical and Applied Pyrolysis, Volume 103
Author(s): Eleanor Y. Swain , Geoffrey D. Abbott
Thermally assisted hydrolysis and methylation (THM) in the presence of tetramethylammonium hydroxide (TMAH) of a range of layers in eight peat cores from the Ryggmossen peatland (central Sweden) was carried out. This yielded a complex mixture including components I (methylated 4-isopropenylphenol (IUPAC name: 1-methoxy-4-(prop-1-en-2-yl)benzene)), IIa/b (methylated cis/trans 3-(4′-hydroxyphen-1-yl)but-2-enoic acid (IUPAC names: (E/Z)-methyl 3-(4-methoxyphenyl)but-2-enoate)) and III (methylated 3-(4′-hydroxyphen-1-yl)but-3-enoic acid (IUPAC name: methyl 3-(4-methoxyphenyl)but-3-enoate)) which have been assigned as products from “bound” sphagnum acid. The proportion of the individual sphagnum acid products relative to total Sphagnum yield revealed the simultaneous degradation of all four components in the unsaturated layer (which is characterised by oxic conditions) concomitant with the decrease of the total Sphagnum yield. Following their degradation in the surficial oxic layer, the total amounts of the sphagnum acid thermochemolysis products stabilise in the deeper seasonally saturated peat. With a further increase in burial depth, in the permanently saturated anoxic peat, the distribution of thermochemolysis products becomes dominated by I. The increase of σ I % relative to σ (IIa/b and III) % indicates that the mode of binding of sphagnum acid into the peat changes as a function of burial depth and hence position relative to the water table. Therefore the relative amounts of the four sphagnum acid THM products show some promise as indicators of redox conditions in young surficial peats.

Highlights

► THM in the presence of TMAH liberated four Sphagnum phenols from surficial peat. ► Compare changes in distributions of four Sphagnum phenols as a function of peat depth. ► Changes in distributions of the Sphagnum phenols reflect redox conditions of the peat. ► Increased proportion of I relative to IIa/b and III reflects anoxia in surficial peats.

Using Py-GC/MS to detect and measure silicone defoamers in pulp fibres and mill deposits

02 September 2013, 22:12:23
Publication date: September 2013
Source:Journal of Analytical and Applied Pyrolysis, Volume 103
Author(s): Bruce Sithole , Chu Watanabe
Defoamers are often used to control or reduce foam problems in a variety of pulp and papermaking processes. It has been recognised that non-judicious use of defoamers can lead to undesirable deposition problems. Amide-based defoamers have been largely supplanted by waterbased or water-extended defoamers that are supposed to be non-depositing. However, mill experience and research has shown otherwise. Hence, there is a need for analytical procedures to determine silicone defoamer components in deposits. In this work, for the first time, Py-GC/MS has been used to analyse for silicone defoamers in pulp and paper matrices. This work demonstrates that the technique is ideal for analysis and characterisation of silicone defoamers on pulp fibres and in mill deposits. The technique is easier and much more rapid than using solvent extraction and solid phase extraction, previously developed for analysis of silicone oil defoamers in deposits. It is applicable to silicone defoamers irrespective of molecular weight and can be used to ascertain the source of a particular defoamer formulation. Application of the technique to a washed kraft pulp, previously treated with silicone defoamers, shows that silicone defoamer oil carryover on pulp fibres can be substantial, depending on the defoamer formulation used. In pitch deposits, the level of silicone oil can be over 25% (w/w). In addition, analysis of deposits from mills using the defoamers shows that silicone defoamers have the potential to cause pitch deposition contrary to claims that the defoamers do not cause such problems. Thus, the method can be used to assess the impact of defoamer carryover on pulp properties and the contribution of silicone defoamers to pitch deposition.

Highlights

► We describe the first known application for detection and determination of silicone defoamers in pulp and paper matrices. ► Silicone defoamer formulations from different suppliers can be differentiated by Py-GC/MS. ► Contrary to claims, silicone defoamers adsorb significantly to pulp fibres and significant amounts remain after washing of the pulp. ► Some silicone defoamer formulations contain penta and tetra cyclic silicone components that may be a health hazard. ► Silicone defoamers can cause pitch deposition in pulp and paper making operations.

Lao lacquer culture and history—Analysis of Lao lacquer wares

02 September 2013, 22:12:23
Publication date: September 2013
Source:Journal of Analytical and Applied Pyrolysis, Volume 103
Author(s): Masako Miyazato , Rong Lu , Takayuki Honda , Tetsuo Miyakoshi
Four kinds of Lao lacquer wares were analyzed using a digital optical microscope, infrared, field emission scanning electron microscope with energy dispersive X-ray spectrometry, and pyrolysis gas chromatography–mass spectrometry. 3-Heptylphenol, 3-pentadecanylphenol, 3-(10-phenyldecyl)phenol, and 3-(12-phenyldodecyl)phenol, which belong to the characteristic pyrolysis products of thitsiol were detected in the mass chromatograms at m/z =108 of all the objects. In addition, some kind of natural resin was also detected. These results suggest that in the development of Lao lacquer history and culture, lacquer workers used the local lacquer resources to produce lacquer-ware, and learned to use natural resin in the restoration and protection of the lacquer-ware.

Highlights

► Four kinds of Lao lacquer wares were analyzed. ► 3-Heptylphenol and 3-pentadecanylphenol which belongs to the characteristic pyrolysis products of thitsiol were detected. ► The results shown that Lao people have used local lacquer as an adhesive or coating material. ► During the restoration of lacquer wares, Lao people were also able to use natural resin efficiently.

Physicochemical characterisation of torrefied biomass

02 September 2013, 22:12:23
Publication date: September 2013
Source:Journal of Analytical and Applied Pyrolysis, Volume 103
Author(s): Raimie H.H. Ibrahim , Leilani I. Darvell , Jenny M. Jones , Alan Williams
Torrefaction is a mild pyrolysis treatment under inert atmosphere that has been found to improve the physical and chemical properties of biomass as a fuel. In this study, several wood fuels: willow, eucalyptus, a mixture of hardwoods (oak and birch) and a mixture of softwoods (pine, larch and spruce) were torrefied at 270 and 290°C with two residence times (30 and 60min). Physicochemical properties of the torrefied materials, such as grindability, density, hydrophobicity and surface area were investigated. Furthermore, information was also obtained from microscopic and spectrometric studies, namely transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), to gain an insight into any changes in morphology and chemical composition due to the treatments. Temperature plays a major role during torrefaction and choosing an optimum condition is fundamental to attaining a satisfactory energy yield. Results show the lower temperature and shorter residence time was the best treatment to achieve good physical properties with a relatively high energy yield. When treated at these conditions, the softwood mixture had the highest energy (95%), followed by the hardwood mixture (80%), then willow (79%), and finally eucalyptus (75%). Increasing the severity of the torrefaction conditions greatly improved the physical characteristics of the torrefied biomass, in terms of grindability properties and hydrophobicity. While little difference in porosity and surface area were detected by the methods used, the XPS and FTIR studies showed that torrefaction results in a decrease in the ROH groups and an increase in CO groups within the fuels. This results in a decrease in the affinity of the fuels to absorb water, and therefore improves their hydrophobicity. For all the fuels, there was a critical temperature for torrefaction, above which abrupt changes in many properties occurred. These include hydrophobicity, energy yield, and grindability. The critical temperatures were fuel dependent and therefore the results indicate that careful optimisation is required for all fuel types to maximise the benefits of torrefaction whilst maintaining a good energy yield.

Highlights

► We study solid properties of torrefied willow, eucalyptus, softwood, hardwood. ► Changes in chemical groups upon torrefaction lead to hydrophobicity and grindability. ► Gradual changes in solid properties occur below a critical torrefaction temperature. ► Abrupt changes in solid properties occur above a critical torrefaction temperature. ► Optimisation maximises benefits of torrefaction whilst maintaining good energy yield.

Thermochemolysis using TMAAc and TMAH reagents as means to differentiate between free acids and esters

02 September 2013, 22:12:23
Publication date: September 2013
Source:Journal of Analytical and Applied Pyrolysis, Volume 103
Author(s): T. Ohra-aho , J. Ropponen , T. Tamminen
The reactivity of aromatic and aliphatic esters in on-line thermochemolysis in the presence of methylation reagents was studied using model compounds. Guaiacyl and 2-nonyl palmitates were synthesised, representing aromatic and aliphatic ester bonds, respectively. These model compounds were analysed by on-line thermochemolysis using tetramethylammonium acetate (TMAAc) and tetramethylammonium hydroxide (TMAH) in order to differentiate free acids from esterified acids. The released palmitic acid with TMAH for both model compounds was close to the theoretical palmitic acid content in the model compounds, even if part of the aliphatic ester had not reacted with TMAH. The free palmitic acid content by TMAAc was one third of the theoretical value for aromatic ester and only a few percentages for aliphatic ester. The result indicated that the less basic reagent is able to hydrolyse the aromatic ester linkage to some extent, whereas the aliphatic ester remains intact. Thus, differentiation of free acids by TMAAc from the esterified acids cannot be reliably performed from matrices containing aromatic esters. It was found that transesterification due to the use of methanol as a solvent with TMAAc is an insignificant reaction in on-line thermochemolysis.

Highlights

► The reactivity of aromatic and aliphatic esters in on-line thermochemolysis was studied. ► Guaiacyl palmitate and 2-nonyl palmitate represented the aromatic and aliphatic ester bonds, respectively. ► Total amount of acids can be determined by TMAH from samples containing aliphatic and aromatic ester. ► The aromatic ester bond is partly hydrolysed in the presence of less basic reagent TMAAc, whereas the aliphatic ester bond is stable against TMAAc.

Analytical pyrolysis as an instrument to study the chemical transformations of hydrothermally modified wood

02 September 2013, 22:12:23
Publication date: September 2013
Source:Journal of Analytical and Applied Pyrolysis, Volume 103
Author(s): Juris Grinins , Bruno Andersons , Vladimirs Biziks , Ingeborga Andersone , Galina Dobele
In the present study, changes in the chemical structure of the components of deciduous wood species, i.e., birch (Betula spp.), aspen (Populus tremula) and grey alder (Alnus incana) wood, after hydrothermal modification (HTM) were investigated by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and wet chemical analysis. The objective of this study was to elucidate the chemical changes in HTM deciduous wood dependent on the treatment parameters using chemical analysis and analytical pyrolysis and to evaluate the differences between the tree species. The results of both chemical and analytical pyrolysis studies demonstrate the effect of HTM on the chemical composition of deciduous wood. Wet chemical analyses showed that the hemicellulose content in wood decreased considerably (by 60–75%), whereas the cellulose and lignin contents increased by 6–20% and ∼50%, respectively. The thermal destruction of hemicelluloses during HTM was also indicated by the water condensates, which contained acids and sugars. As a result of the HTM, wood transitions from a solid state to an aggregate state, in which the chemical composition of the gases (gas mixture) depends on the chemical composition of the wood. Py-GC/MS can quantitatively and promptly detect changes in the chemical composition of wood after HTM. As a result of the high HTM of wood above 160°C, hemicelluloses are thermochemically destroyed and the primary products are acids (e.g., acetic acid and formic acid). Cellulose and lignin are more thermally stable than the hemicelluloses, as evidenced by the analytical pyrolysis results, which showed that the hemicellulose content in the wood decreased and the lignin content increased by revealing that the acid, ester and ether content in the gases decreased (by 24–33%) and the guaiacyl and syringyl derivative content increased (by 5–7%). Analytical pyrolysis is a promising method for understanding chemical transformations in HTM wood.

Highlights

► Hydrothermal modification – modification in a saturated steam environment at superatmospheric pressure. ► The relative amount of hemicelluloses in the modified wood decreases, but that of cellulose and lignin increases. ► Hemicelluloses–the most thermally unstable component of the cell wall. ► Water condensate – a mixture of the products of thermal destruction of hemicelluloses. ► In lignin pyrolysis products, the content of compounds with a short aliphatic chain increases.

Identification and classification of glucose-based polysaccharides by applying Py-GC/MS and SIMCA

02 September 2013, 22:12:23
Publication date: September 2013
Source:Journal of Analytical and Applied Pyrolysis, Volume 103
Author(s): Valentina Becerra , Jürgen Odermatt , Martin Nopens
This paper describes a simplified method for the identification of glucose-based polymers (polysaccharides). The method developed consists of classifying the results from analytical pyrolysis gas chromatography mass spectrometry (Py-GC/MS) by applying soft independent modelling of class analogy (SIMCA). Since the amount of inorganic compounds in the sample influences the pyrolysis results, the classification model is applied to the pyrolysis results obtained from samples in their original form and after pre-treatment. The pre-treatment aims at removing the inorganic compounds from the polysaccharides and consists of washing out the samples with acid solutions. Depending on the acid used, pyrolysis results may differ. Therefore, the pre-treatment impact on the pyrolysis results is evaluated as well. After optimisation of the sample pre-treatment, it is possible to discriminate between various subgroups of starches (native, cationic, oxidised starches and dextrin). This indicates that appropriate sample pre-treatment in combination with chemometric data evaluation results in a clear classification of very similar samples showing very similar pyrograms. The methodology developed facilitates the analysis and identification of deposits originating from polysaccharides found in paper production processes.

Highlights

► Glucose-based polysaccharides are classified based on their pyrolysis results. ► Classification is done by means of implementing soft independent modelling of class analogy (SIMCA) based on pyrolysis results. ► The classification ability of the pyrolysis results of original polysaccharides and after their treatment is examined. ► Pyrolysis product distribution varies depending on the treatment (acid solution). ► After treatment, the accurate classification by SIMCA is facilitated.

Pyrolysis of wood, cellulose, lignin–brominated epoxy oligomer flame retardant mixtures

02 September 2013, 22:12:23
Publication date: September 2013
Source:Journal of Analytical and Applied Pyrolysis, Volume 103
Author(s): Zsuzsanna Czégény , Emma Jakab , Marianne Blazsó
The thermal decomposition of brominated epoxy oligomer (BrEpoxy)–natural polymer mixtures were examined by Py-GC/MS and TG/MS techniques in order to clarify the reactions between the components of the mixtures. The natural polymer components were: pine and beech wood, pine and beech milled wood lignin and two types of cellulose (Avicel and Whatman cellulose). It was found that the decomposition of both celluloses shifts to the temperature range of BrEpoxy decomposition. Significantly decreased formation of hydroxyacetaldehyde, hydroxypropanone and levoglucosan and increased yield of levoglucosenone was observed from cellulose–BrEpoxy mixtures. Drastically increased evolution of bromomethane was found from lignin or wood–BrEpoxy mixtures, indicating a radical scavenging reaction of lignin leading to the formation of bromomethane and phenoxy radicals.

Highlights

► The decomposing brominated flame retardant initiates the decomposition of cellulose. ► The presence of BrEpoxy alters the decomposion products of cellulose. ► The presence of lignin protects the cellulose from the effect of BrEpoxy. ► Bromomethane evolves from decomposing lignin containing material–BrEpoxy mixtures.

Determination of polycyclic aromatic hydrocarbons in biochar and biochar amended soil

02 September 2013, 22:12:23
Publication date: September 2013
Source:Journal of Analytical and Applied Pyrolysis, Volume 103
Author(s): Daniele Fabbri , Alessandro G. Rombolà , Cristian Torri , Kurt A. Spokas
A method for the determination of the 16 USEPA polycyclic aromatic hydrocarbons (PAHs) in biochar and biochar amended soil was developed. Samples were Soxhlet extracted with an acetone/cyclohexane (1:1) solvent mixture, and PAHs were analyzed by GC–MS after silica gel clean-up. In a comparative study based on reflux extraction, the Soxhlet solvent system acetone/cyclohexane exhibited a higher extraction efficiency of low molecular weight PAHs (e.g. naphthalene) than toluene or dichloromethane. Utilizing a reference biochar, this Soxhlet method possessed a 67–88% recovery of spiked deuterated PAHs (acenaphthene, phenenthrene, and chrysene), analytical precision (as assessed by relative standard deviations) between 5 and 18%, and a limit of detection in the 0.01–0.4ngg−1 range. The method was successfully validated through the analysis of a certified soil material, and was capable to quantify total PAHs following biochar addition at 1% (w/w). The concentration of the 16 USEPA-PAHs along with the 15 EU-PAHs (priority hazardous substances in food) was determined in a suite of currently available biochars for agricultural field applications, which were derived from a variety of parent materials and pyrolysis conditions. The total PAH levels ranged between 1.2–19μgg−1 and 0.2–5μgg−1 interval for USEPA and EU PAHs, respectively. Specifically, benzo[a]pyrene ranged between 0.01 and 0.67μgg−1 across these various biochars. Considering an application of 20–60tbiocharha−1, the degree of PAH contamination will be dependent on both the presence of background PAHs in soil and the sorbed concentrations of PAHs on the biochar. Our data, along with PAH levels determined in other studies, suggest that biochars produced by slow pyrolysis from woody biomass possess the lowest level of sorbed PAHs (<10μgg−1).

Highlights

► New method for the determination of PAHs in biochar. ► Based on Soxhlet extraction with acetone/cyclohexane. ► Appropriate for the analysis of biochar amended soils.

Analysis of Japanese Jōmon lacquer-ware by pyrolysis-gas chromatography/mass spectrometry

02 September 2013, 22:12:23
Publication date: September 2013
Source:Journal of Analytical and Applied Pyrolysis, Volume 103
Author(s): Rong Lu , Takayuki Honda , Yoshimi Kamiya , Kunio Yoshida , Tetsuo Miyakoshi
Japanese Jōmon period lacquer-ware objects were analyzed using a digital optical microscope and pyrolysis gas chromatography–mass spectrometry. Comparison with standard lacquer films showed that all the objects were coated with sap tapped from Rhus vernicifera lacquer trees. Red iron oxide was used as a red pigment. Natural resin found in the lacquer pieces suggested that during the development of Japanese Jōmon lacquer-ware, lacquer workers used local lacquer resources to produce lacquer, and learned to use natural resin in the restoration and protection of the lacquer-ware objects. In addition, the production and technology of Jōmon lacquer-ware are also discussed.

Evaluation of biodegradation behavior of poly(butylene succinate-co-butylene adipate) with lowered crystallinity by thermally assisted hydrolysis and methylation-gas chromatography

02 September 2013, 22:12:23
Publication date: September 2013
Source:Journal of Analytical and Applied Pyrolysis, Volume 103
Author(s): Siti Baidurah , Seiya Takada , Kazuki Shimizu , Yasuyuki Ishida , Tsuneo Yamane , Hajime Ohtani
In our previous paper, thermally assisted hydrolysis and methylation-gas chromatography (THM-GC) measurements of poly(butylene succinate-co-butylene adipate) (PBSA) in the presence of tetramethylammonium hydroxide had revealed that the butylene adipate (BA) content in the PBSA films gradually decreased with soil burial degradation time. In order to clarify the cause of this change in copolymer composition, biodegradation behavior of PBSA with lowered crystallinity was evaluated by THM-GC. PBSA film samples with lower degree of crystallinity, prepared by heating and cooling quickly the original commercially available films, were subjected to a soil burial biodegradation test at 30°C for up to 4 weeks. The copolymer compositions between BA and butylene succinate (BS) units in various stages of the degraded film samples were estimated on the basis of chromatograms obtained by THM-GC with less than 5% of the relative standard deviations. As a result, the change in copolymer composition for the heated PBSA films during soil burial was relatively small compared to the original films, suggesting that biodegradation for the heated films proceeded with the comparable rate for both BA and BS-rich moieties due to lowered crystallinity. Based on these results, the reason for the change in copolymer composition observed for the original PBSA films was clarified as follows: (1) the BA-rich moieties in the copolymer chains could show relatively lower crystallinity than the BS-rich moieties and (2) the BA-rich moieties were preferentially biodegraded during soil burial test, leading to the decrease in the BA content as the biodegradation proceeded.

Fractionation of technical lignins as a tool for improvement of their antioxidant properties

02 September 2013, 22:12:23
Publication date: September 2013
Source:Journal of Analytical and Applied Pyrolysis, Volume 103
Author(s): Alexander Arshanitsa , Jevgenija Ponomarenko , Tatiana Dizhbite , Anna Andersone , Richard J.A. Gosselink , Jacinta van der Putten , Maris Lauberts , Galina Telysheva
The modern biorefinery concept is aimed at the elaboration of sustainable processes with the most profitable utilization of all biomass products obtained at the technological cycle. Lignin separated as by-product in the lignocellulosic chemical processing is recognized as an important component of polymer systems. The presence of sterically hindered phenolic hydroxyl groups in the lignin macromolecule opens the possibility of its application as antioxidant for composites, e.g. polyurethanes (PU), which are considered as one of the most versatile polymeric materials. In the present work, the object of investigations was lignin obtained as a product, so-called BIOLIGNIN™, of wheat straw organosolv processing for pulp and fuel ethanol production (CIMV pilot plant, France). However, heterogeneity of the lignin obtained negatively influences its applicability that can be overcome by fractionation. Three soluble fractions were isolated from CIMV lignin by a sequential extraction with dichloromethane (A fraction), methanol (B fraction) and mixture of both the solvents (C fraction) and characterized in terms of their composition, functionality and structure using analytical pyrolysis (Py-GC/MS), 31P NMR and Size Exclusion Chromatography (SEC) methods. Antioxidant properties of BIOLIGNIN™ fractions were assessed in the tests with free radicals ABTS + and DPPH . Application of Py-GC/MS for characterization of the fractions opened an opportunity to found some novel “structure–activity” correlations needed for understanding and tuning of antioxidant properties of lignins. The antioxidant activity of the fractions under investigation was tested by their influence on thermo-oxidative destruction of prepared model PU films. The data of TGA method (oxidative conditions) clearly testified the antioxidant effect of all three fractions with the most prominent activity for C fraction. The shifting of the exothermal maxima connected with oxidizing of volatile products of PU destruction to the higher temperature region by 20–30K and 30–40K was registered.

Highlights

► We found a prospective tool for obtaining of homogeneous lignin products with high antioxidant activity. ► We showed benefits of antioxidant activity of fractionated lignin for its application in PU production. ► We found “structure–activity” correlations for understanding and tuning of antioxidant properties of lignins.

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