Resins spectrometry

Latexes of synthetic resins are identified by ir spectrometry. Selective extraction with organic solvents is used to obtain purified fractions of the polymers for spectrometric identification. Polymeric films can be identified by the multiple internal reflectance ir technique, if the film is smooth enough to permit intimate contact with the reflectance plate. TAPPI and ASTM procedures have not been written for these instmmental methods, because the interpretation of spectra is not amenable to standardization. 

Mandal and Hay28 used MALDI-TOF mass spectrometry to determine the absolute molecular masses and endgroups of 4-phenylphenol novolac resins prepared in xylene or chlorobenzene. Peaks with a mass difference of 44 (the molecular weight of a xylene endgroup) suggested that reactions conducted in xylene included some incorporation of xylene onto the chain ends when a strong acid such as sulfuric acid was used to catalyze the reaction. By contrast, no xylene was reacted into the chain when a milder acid catalyst such as oxalic acid was used. No chlorobenzene was incorporated regardless of the catalyst used. 

Dichlorodibenzo- -dioxin. 2-Bromo-4-chlorophenol (31 grams, 0.15 mole) and solid potassium hydroxide (8.4 grams, 0.13 mole) were dissolved in methanol and evaporated to dryness under reduced pressure. The residue was mixed with 50 ml of bEEE, 0.5 ml of ethylene diacetate, and 200 mg of copper catalyst. The turbid mixture was stirred and heated at 200°C for 15 hours. Cooling produced a thick slurry which was transferred into the 500-ml reservoir of a liquid chromatographic column (1.5 X 25 cm) packed with acetate ion exchange resin (Bio-Rad, AG1-X2, 200-400 mesh). The product was eluted from the column with 3 liters of chloroform. After evaporation, the residue was heated at 170°C/2 mm for 14 hours in a 300-cc Nestor-Faust sublimer. The identity of the sublimed product (14 grams, 74% yield) was confirmed by mass spectrometry and x-ray diffraction. Product purity was estimated at 99- -% by GLC (electron capture detector). 

Residues of isoxaflutole, RPA 202248 and RPA 203328 are extracted from surface water or groundwater on to an RP-102 resin solid-phase extraction (SPE) cartridge, then eluted with an acetonitrile-methanol solvent mixture. Residues are determined by liquid chromatography/tandem mass spectrometry (LC/MS/MS) on a Cg column. Quantitation of results is based on a comparison of the ratio of analyte response to isotopically labeled internal standard response versus analyte response to internal standard response for calibration standards. 

Bone Sample wet ashed, spiked with 243Am, and purified by anion exchange resin column, solvent extraction, and electrodeposition a -Spectrometry No data 98% Mclnroy et al. 1985... 

Another means of moving beyond pure protein preparations to high-throughput characterization of proteomes is to enrich for phosphopeptides from complex mixtures by metal affinity chromatography (Andersson and Porath, 1986). Using this method, protein mixtures are proteolyzed to create peptides and phosphorylated peptides are enriched by metal affinity chromatography and subsequently identified by mass spectrometry. This method is limited, however, because in many cases phosphopeptides absorb poorly or nonphosphorylated peptides absorb nonspecifically to the metal affinity resins (Ahn and Resing, 2001). 

Wright, M. and B. Wheals (1987), Pyrolysis-mass spectrometry of natural gums, resins and waxes and its use for detecting such materials in ancient Egyptian cases, /. Appl. Pyrol. 11,195-211. 

M.P. Colombini, F. Modugno, E. Ribechini, Chemical study of triterpenoid resinous materials in archaeological findings by means of direct exposure electron ionisation mass spectrometry and gas chromatography/mass spectrometry, Rapid Communications in Mass Spectrometry, 20, 1787 1800 (2006). 

G.A. van der Doelen, K.J. van den Berg, J.J. Boon, N. Shibayama, E.R. de la Rie, W.J.L. Genuit, Analysis of fresh triterpenoid resins and aged triterpenoid varnishes by high performance liquid chromatography atmospheric pressure chemical ionisation (tandem) mass spectrometry, Journal of Chromatography A, 809, 21 37 (1998). 

E. Ribechini, F. Modugno, M.P. Colombini, Direct exposure (chemical ionization) mass spectrometry for a rapid characterization of raw and archaeological diterpenoid resinous substances, Microchimica Acta, 162, 405 413 (2008). 

In the following sections, the instrumental features of direct mass spectrometry based techniques (DI-MS, DE-MS and DTMS) are presented, followed by a discussion of some mass spectra of standard compounds and reference materials. Finally, a series of case studies related to the presence of resinous materials in archaeological findings and works of art are reported and discussed. 

Direct mass spectrometry based techniques such as DI-MS, DE-MS and DTMS are unique in their ability to yield complete chemical structure assignments and to identify a great variety of resinous amorphous materials. 

D. Scalarone, J. van der Horst, J. J. Boon and O. Chiantore, Direct temperature mass spectrometric detection of volatile terpenoids and natural terpenoid polymers in fresh and artificially aged resins, Journal of Mass Spectrometry, 38, 607 617 (2003). 

Besides the well-established chromatographic/mass spectrometric or spectroscopic methods there is always a need for complementary methods for the study of organic materials from art objects. The application of laser desorption/ionisation mass spectrometry (LDI-MS) methods to such materials has been reported only sporadically [12, 45 48] however, it is apparently increasing in importance. After GALDI-MS had been applied to triterpenoid resins, as described in Section 5.2, this relatively simple method was evaluated for a wider range of binders and other organic substances used for the production or conservation of artwork. Reference substances as well as original samples from works of art were analysed. 

D. Scalarone, M.C. Duursma, J.J. Boon, and O. Chiantore, MALDI TOF Mass Spectrometry on Cellulosic surfaces of Fresh and Photo aged Di and Triterpenoid Varnish Resins, J. Mass Spectrom., 40, 1527 1535 (2005). 

In addition to GC/MS, high performance liquid chromatography (HPLC/MS) has been used to analyse natural resins in ancient samples, particularly for paint varnishes containing mastic and dammar resins [34]. A partial limitation of chromatographic techniques is that they do not permit the analysis of the polymeric fraction or insoluble fraction that may be present in the native resins or formed in the course of ageing. Techniques based on the direct introduction of the sample in the mass spectrometer such as direct temperature resolved mass spectrometry (DTMS), direct exposure mass spectrometry (DE-MS) and direct inlet mass spectrometry (DI-MS), and on analytical pyrolysis (Py-GC/MS), have been employed as complementary techniques to obtain preliminary information on the... 

Other MS based analytical approaches have occasionally been applied to ancient resin samples, in particular for paint varnishes. Such techniques include FABS (fast atom bombardment mass spectrometry) [35], MALDI (matrix assisted laser desorption-ionization mass spectrometry) and GALDI (graphite assisted laser desorption-ionization mass spectrometry) [36 38]. 

F. Modugno, E. Ribechini, M. P. Colombini, Aromatic resin characterisation by gas chromato graphy mass spectrometry raw and archaeological materials, J. Chromatogr., A, 1134, 298 304(2006). 

P. Dietemann, S. Zumbuhl, R. Knochenmuss, R. Zenobi, Aging of triterpenoid resin varnishes on paintings studied by graphite assisted laser desorption/ionization mass spectrometry, Adv. Mass Spectrom., 15, 909 910 (2001). 

G. Chiavari, D. Fabbri, R. Mazzeo, P. Bocchini and G.C. Galletti, Pyrolysis gas chromatogra phy mass spectrometry of natural resin used for artistic objects, Chromatographia, 41,273 281... 

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