Evidence of bad recycling practices:BFRs in children's toys and food-contact articles

Brominated flame retardants (BFRs) have been used intentionally in a wide range of plastics, but are now found in an even wider range of such materials (including children's toys and food contact articles) as a result of recycling practices that mix BFR-containing waste plastics with “virgin” materials.</p

Thermal desorption – progressive way of analytical chemistry on plastics and rubbers

Desorpcja termiczna jest to technika pobierania próbek, wykorzystująca ciepło w celu zwiększenia lotności analizowanych substancji w taki sposób, że mogą być usuwane ze stałej osnowy (tworzywa sztucznego, drewna, tekstyliów, wyciągów, piany, włosów, żelu, farby itp.). Umożliwia ona analizę prawie wszystkich rodzajów materiałów na poziomie śladowym, bez wstępnej obróbki próbek. W artykule opisano krótko analityczne podejście do badania wielu materiałów z tworzyw sztucznych / gumy za pomocą desorpcji termicznej z chromatografią gazową połączoną ze spektrometrią masową (TD-GC-MS). Opisano dostępne systemy: bezpośrednią desorpcję termiczną, przekierowaną desorpcję termiczną (zimna pułapka), komorę emisyjną TD-GC-MS, analizę gazów wydzielonych (EGA), a także ich potencjalną przydatność, szczególnie dla przemysłu motoryzacyj¬nego, jak wykrywanie dodatków w tworzywach sztucznych i gumie, lotnych związków organicznych(VOC / SVOC), analizę defektów, ciekłe nastrzyki / ekstrakty / płukanki.Thermal desorption is defined as a sampling technology that utilizes heat to increase the volatility of analytes such that they can be removed (separated) from the solid matrix (plastics, wood, textile, extracts, foam, hair, gel, paint, etc.). Thermal desorption allows analysis of almost all sorts of materials including insoluble materials and complex materials at trace levels without any pretreatment of samples. This paper describes briefly the analytical approach of analyzing a broad range of plastic/rubber materials with thermal desorption gas chromatography coupled with mass spectrometry (TD-GC-MS). In the paper were described available systems: direct thermal desorption, refocusing thermal desorption (cold trap), emission chamber-TD-GC-MS, Evolved-Gas-Analysis (EGA), as well as potential applications for automotive industry: additives from plastic material and rubber, volatile organic compounds (VOC/SVOC), defect analysis, liquid injections/extracts/washes

Identification of Drosophila Wing Imaginal Disc Proteins by Two-Dimensional Gel Analysis and Microsequencing

We have combined high-resolution two-dimensional (21)) gel electrophoresis with microsequencing techniques in order to identify proteins in the 2D gel database of wing imaginal discs of Drosophila melanogaster. First, a high-resolution 2D gel separation pattern of the [35S]methionine-labeled polypeptides from CME W2 cells, a stable cell line derived from wing imaginal discs, is presented and compared with the standard pattern of polypeptides of wing imaginal discs. These studies reveal significant qualitative and quantitative alterations in polypeptide expression between both samples. Second, we carried 2D PAGE to the preparative level using the CME W2 cell line mixed with radioactivelly labeled wing imaginal discs in order to identify some common polypeptides and subsequently characterized them by microsequencing techniques. Using these methods we obtained partial amino acid sequences of several Drosophila proteins of the 2D gel protein database. As an illustration we present 12 of them: 8 corresponding to proteins already known in Drosophila and the 4 showing homologies with proteins of other organisms.Peer reviewe

Discerning between natural and synthetic rubber by analytical pyrolysis (Py-GC/MS)

Rubber is an isoprene polymer (polyisoprene) that can be obtained from different sources (natural/vegetative or mineral/fossil). Analytical pyrolysis has been widely used mainly dealing with vulcanised tyre rubbers with forensic purposes [1 and references therein]. In this study, a detailed pyrolysis biomarker approach is used to discern the origin of unvulcanised rubber samples. Pyrolysis-gas chromatography¿mass spectrometry (Py-GC/MS) was performed using a double-shot pyrolyser (Frontier Laboratories, model 2020i) attached to a GC/MS system Agilent 6890N. Samples 1 mg in weight were introduced into a preheated micro-furnace at (400 °C) for 1 min and the evolved gases were injected into the GC/MS for analysis. The gas chromatograph was equipped with a 30 m HP-5ms-UI column. The oven temperature was held at 50 °C for 1 min and then increased to 100 °C at 30 °C min-1, from 100 °C to 300 °C at 10 °C min-1, and stabilized at 300 °C for 10 min using a heating rate of 20 °C min-1 in the scan modus. The carrier gas was helium at a controlled ¿ow of 1 mL min-1. Mass spectra were acquired at a 70 eV ionising energy in an MSD detector (Agilent 5973). Compound assignment was achieved via single-ion monitoring (SIM) for various homologous series, via low-resolution mass spectrometry, and via comparison with published and stored (NIST and Wiley libraries) data. In a previous study, optimum pyrolysis conditions for the analysis of rubber were established at 400 ºC for 1 minute more drastic pyrolysis conditions i.e. 600 ºC resulted in an excessive degradation of the polymer producing abundant low molecular weight degradation products i.e. xylenes/alkylnaphthalenes and a diminished abundance of the expected polymeric moieties. The analytical pyrolysis results performed at 400º C were in line with hose published elsewhere [1, 2]. In general consisted of a major peak of the monoterpene limonene [1-Methyl-4-(prop-1-en-2-yl)cyclohex-1-ene], isoprene [2-Methylbuta-1,3-diene] and oligomers up to the hexamer (Fig. 1). A remarkably similar chemical profile was found in all polyisoprene samples analysed (2 natural and 2 synthetic) that did not allow a straight forward differentiation between natural and synthetic rubbers. It was necessary to search for minor pyrolysis compounds, mainly known plant biomarkers, to discern between rubbers with distinct origin. These biomarkers included phytosterols (Fig. 2), waxes and tocopherols. Using analytical pyrolysis, we were able to detect molecular markers from plant origin only in natural rubber that were absent from the synthetic samples. The technique is a useful tool to evaluate the authenticity of the raw materials and therefore to detect possible frauds in relation with unvulcanised rubbers.Peer Reviewe