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Jale Hacaloglu - One of the best experts on this subject based on the ideXlab platform.
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Characterization of polylactide/poly(ethylene glycol) blends via direct Pyrolysis Mass Spectrometry
Journal of Analytical and Applied Pyrolysis, 2016Co-Authors: Esra Ozdemir, Teoman Tinçer, Jale HacalogluAbstract:Abstract In this study, melt blended poly(lactic acid) and poly(ethylene glycol), (PLA)/PEG samples involving 10, 15 and 20 wt% PEG were prepared and characterized by direct Pyrolysis Mass Spectrometry technique in addition to classical techniques such differential scanning calorimetry, thermogravimetric analyses and mechanical tests. The incorporation of PEG resulted in consistent and significant decrease in the tensile strength and modulus, and reduction in endothermic melting peak of PLA due to the plasticizing effect of PEG with the virgin PLA matrix. Both TGA and DP-MS analyses pointed out that the thermal decomposition of the blend occurred mainly in two steps. In addition, the Pyrolysis Mass Spectrometry analyses indicated presence of chains generated by the interactions of ether linkages of PEG and COOH groups of PLA, present either as end groups or due to reactions with water, during the blending and/or Pyrolysis process. As a consequence, decrease in the thermal stability of PEG chains was detected. Analyses of the blends prepared by solution mixing for variable periods confirmed that these interactions took place mainly during the blending process. In addition, increase in the thermal stabilities of both components for the blends prepared by stirring for prolonged times was detected and associated with generation of a crosslinked structure.
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Direct Pyrolysis Mass Spectrometry to investigate the effects of dopants on characteristics of polypyrrole and its copolymers
Journal of Thermal Analysis and Calorimetry, 2012Co-Authors: Evren Aslan Gurel, Levent Toppare, Jale HacalogluAbstract:Polypyrrole and its copolymers with terepthalic acid bis-(2-thiophen-3-yl-ethyl)ester, (P(TATE-co-Py) were characterized by direct Pyrolysis Mass Spectrometry to investigate the effects of dopant on thermal stability and conductivity. Conductivities of the films were measured with four-probe technique, and the results were compared with the Pyrolysis data. In general, an increase in conductivity was detected as the stability of dopant increased. The extent of doping and the strength of interaction between the dopant and the polymer were decreased upon copolymerization with terepthalic acid bis-(2-thiophen-3-yl-ethyl)ester.
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The characterization of polyaniline and polypyrrole composites by Pyrolysis Mass Spectrometry
Journal of Applied Polymer Science, 2009Co-Authors: Jale Hacaloglu, Feride Tezal, Ziihal KücükyavuzAbstract:In this work, direct insertion probe Pyrolysis Mass Spectrometry technique was applied to investigate the thermal and structural characteristics of electrochemically prepared polyaniline (PANI), polypyrrole (PPy), and their composites/copolymers synthesized either by electrochemical polymerization of pyrrole on PANI-coated electrode (PANI/PPy) or by coating PANI on PPy (PPy/PANI) in H2SO4 solutions. It has been determined that the polymer first coated on the electrode degraded to a certain extent during the polymerization of the second. The extent of degradation was greater for PPy and increased with the increase in acid concentration. On the other hand, the detection of mixed dimers confirmed copolymer formation. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
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Characterization of polyaniline via Pyrolysis Mass Spectrometry
Journal of Applied Polymer Science, 2008Co-Authors: Jale Hacaloglu, Emir Argin, Ziihal KücükyavuzAbstract:In this work, direct insertion probe Pyrolysis Mass Spectrometry technique was applied to investigate the thermal and the structural characteristics of electrochemically prepared HCl and HNO3-doped polyaniline (PANI) films. It has been determined that the thermal degradation of both samples showed three main thermal degradation stages. The first stage around 50–60°C was associated with evolution of solvent and low-molecular-weight species adsorbed on the polymer, the second stage just above 150°C was attributed to evolution of dopant-based products, and the final degradation stage at moderate and elevated temperatures was associated with evolution of degradation products of the polymer. Chlorination and nitrolysis of aniline during the electrochemical polymerization were detected. Extent of substitution increased as the electrolysis period was increased. Furthermore, for the HNO3-doped PANI, the evolution of CO2 at elevated temperatures confirmed oxidation of the polymer film during electrolysis. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
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A Pyrolysis Mass Spectrometry study of polythiophene copolymers
Polymer Degradation and Stability, 2007Co-Authors: Evren Aslan, Jale Hacaloglu, Levent ToppareAbstract:The thermal behaviour of copolymers of thiophene with decanedioic acid bis-(2-thiophen-3-yl-ethyl)ester (DATE) and terephthalic acid bis-(2-thiophen-3-yl-ethyl)ester (TATE) prepared by potentiostatic polymerization was studied via Pyrolysis Mass Spectrometry. It was determined that the electrolytic films correspond to the related homopolymers. The increase in thermal stability of ester linkages, and evolution of characteristic degradation products of TATE and DATE together with thiophene based products above 400 °C confirmed copolymer formation.
Elke Anklam - One of the best experts on this subject based on the ideXlab platform.
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Contribution of Pyrolysis-Mass Spectrometry (Py-MS) to authenticity testing of honey
Journal of Analytical and Applied Pyrolysis, 2001Co-Authors: Branka Radovic, Royston Goodacre, Elke AnklamAbstract:Abstract Pyrolysis Mass Spectrometry (Py-MS) was used to investigate discrimination of honey samples from different floral (ten) and geographical (seven) origins. The data were analysed statistically (using Principal Component and Discriminant Factor Analysis) in order to check the possibility of the use of these profiles for characterising the botanical source of honey. Py-MS showed as a very useful tool for the rapid discrimination of honeys from different botanical origins. Separation of the geographical origin of honey was unsuccessful and this is likely to be due to the very large and varied botanical origins of honey located within a single geographical region.
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Characterisation of milk samples with various whey protein contents by Pyrolysis–Mass Spectrometry (Py–MS)
Food Chemistry, 1999Co-Authors: M.a.e Schmidt, Markus Lipp, Branka Radovic, G Harzer, Elke AnklamAbstract:Abstract Different milk samples and their 2, 5 and 10% mixtures with ‘artificial’ or natural whey protein were analysed by means of Pyrolysis–Mass Spectrometry (Py–MS). Py–MS followed by multivariate analysis of the resulting Mass spectra enabled the determination of the whey protein addition in milk samples. Obtained results showed that this determination seems not to be influenced by the fat content and freezing of the samples, as well as a dilution of the samples. ©
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Characterisation of vinegar by Pyrolysis-Mass Spectrometry
Food Control, 1998Co-Authors: Markus Lipp, Branka Radovic, Elke AnklamAbstract:Abstract A number of vinegars (wine, malt, apple, balsamic and ‘synthetic’) were analysed by means of Pyrolysis-Mass Spectrometry (Py-MS). For the data analysis with neural networks, the samples were divided into training set of 108 samples and a validation set of 52 samples. The prediction of the validation set with a trained network revealed a good discrimination of all kind of vinegars except the ‘synthetic’ ones.
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characterisation of italian vinegar by Pyrolysis Mass Spectrometry and a sensor device electronic nose
Food Chemistry, 1998Co-Authors: Elke Anklam, Markus Lipp, Branka Radovic, Emma Chiavaro, Gerardo PallaAbstract:Abstract Industrially made vinegar ‘Aceto Balsamico di Modena’ and traditionally produced vinegar ‘Aceto Balsamico Tradizionale di Modena e di Reggio Emilia’ were analysed by means of Pyrolysis–Mass Spectrometry (Py–MS) and a sensor technique (‘electronic nose’). Both methods allow a fast classification (typically about 5 min). While the ‘electronic nose’ is analysing the volatile compounds of the samples simultaneously with 32 sensors, Py–MS applies thermal decomposition of the samples, subsequently analysing the pyrolysate with a Mass spectrometer. Both techniques were demonstrated to be capable of discriminating between the two groups of vinegar. Although the number of samples available for this study did not seem to be sufficient for detailed analysis, both methods indicated possible discrimination of the samples within the group of ‘Aceto Balsamico Tradizionale di Modena’ regarding the age of the sample.
P. R. Sisson - One of the best experts on this subject based on the ideXlab platform.
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Pyrolysis Mass Spectrometry analysis of free-living and symbiotic cyanobacteria.
Antonie van Leeuwenhoek, 1999Co-Authors: N.j. West, P. R. Sisson, R. Freeman, D.g. Adams, P.m. HawkeyAbstract:The potential of Pyrolysis Mass Spectrometry to distinguish closely related cyanobacterial strains was assessed by using the technique to compare symbiotic cyanobacteria isolated from the hornwort Phaeoceros laevis and free-living cyanobacterial strains at the same field site. The same strains had previously been compared using polymerase chain reaction-based DNA fingerprinting techniques (West & Adams 1997, Appl. Environ. Microbiol. 63: 4479–4484). Many of the strains were grouped identically by the two techniques, although there were some differences, possibly resulting from the ability of these cyanobacteria to develop a range of specialised cell types having different chemical compositions to the vegetative cells. Although growth conditions were chosen to suppress cellular differentiation, this may not always have been completely successful. With careful control of growth conditions Pyrolysis Mass Spectrometry has considerable potential as an additional tool for the phenetic comparison of cyanobacterial strains. It has the advantage that analysis is directly derived from whole cells, and hence is simpler and cheaper than DNA-based methods, although it does require the growth of axenic strains. The technique may be particularly useful in the study of some of the more cryptic unicellular and non-heterocystous filamentous cyanobacterial groups, in which the lack of cellular differentiation should minimise any variability in the chemical composition of cells.
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Pyrolysis Mass Spectrometry as a Technique For Studying Inter- and Intraspecific Relationships in the Genus Fucus
Journal of the Marine Biological Association of the United Kingdom, 1998Co-Authors: F. G. Hardy, Graham W Scott, N F Lightfoot, P. R. Sisson, MulyadiAbstract:Pyrolysis Mass Spectrometry (PyMS) was used to investigate the relationships of members of the genus Fucus (F. spiralis, F. veskulosus, F. ceranoides and F. serratus), and between F. spiralis and F. spiralis forma nanus. Fucus spiralis and F. spiralis forma nanus were not separable by PyMS and are thus a single species. Fucus spiralis, F. veskulosus, F. ceranoides and F. serratus were separable and their status as species confirmed. The pattern of relatedness between these species suggests a re-evaluation of their evolutionary history in that F. spiralis, F. vesiculosus and F. serratus are more similar to one another than to F. ceranoides. Pyrolysis Mass Spectrometry was also used to investigate the position of plants identified as putative hybrids between F. spiralis and F. vesiculosus. These plants were found to be intermediate between the two species thus confirming morphological evidence.
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Differentiation between bacterial species and sub-species by Pyrolysis Mass Spectrometry of extracted DNA.
Zentralblatt fur Bakteriologie : international journal of medical microbiology, 1997Co-Authors: Kate Mathers, R. Freeman, P. R. Sisson, N F LightfootAbstract:Whole cell samples from cultures of Staphylococcus aureus, S. hominis, S. epidermidis and Streptococcus pyogenes were analysed by Pyrolysis Mass Spectrometry and the results were compared with Py-MS-derived analyses of samples of DNA extracted from the same organisms. Py-MS analysis differentiated the four organisms in both circumstances. These results challenge previous assumptions that Py-MS is restricted to detecting phenotypic differences, although the basis for the differentiation of the DNA extracts has yet to be determined.
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Curie-point Pyrolysis Mass Spectrometry as a tool in clinical microbiology
Zentralblatt fur Bakteriologie : international journal of medical microbiology, 1997Co-Authors: Michael Goodfellow, R. Freeman, P. R. SissonAbstract:Pyrolysis Mass Spectrometry is a well established analytical tool that has received a considerable boost from the development of low cost, dedicated instruments and sophisticated statistical analyses on personal computers. Further analytical developments, especially in the area of neural networks, are pushing the technology to the forefront of methods for the discrimination and identification of microorganisms and their products. The speed and reproducibility of Pyrolysis Mass Spectrometry and its applicability to a wide range of microorganisms make it an attractive method for epidemiological studies. For inter-strain comparisons, the method is at least as discriminatory as conventional typing systems and usually gives discrimination similar to that of nucleic acid fingerprinting techniques. There has been some success in using neural networks to make identifications across Pyrolysis Mass spectrometric batches. Further development of methods used to handle data from multiple PyMS analyses can be expected to extend the value of Pyrolysis Mass Spectrometry in clinical microbiology.
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An outbreak of colonisation or infection by Corynebacterium jeikeium reanalysed by Pyrolysis-Mass Spectrometry
Journal of Analytical and Applied Pyrolysis, 1997Co-Authors: P. R. Sisson, R. Freeman, W. C. NobleAbstract:Abstract A Pyrolysis-Mass Spectrometry (Py-MS) analysis of isolates of Corynebacterium jeikeium broadly confirmed the course of an outbreak previously defined by analysis of plasmid structure. Plasmidless isolates could not be assessed by the initial plasmid profiling and had had to be disregarded. Py-MS analysis demonstrated that these were part of the outbreak. The clustering of isolates achieved by Py-MS accorded with the progression of two plasmids through a set of isolates of C. jeikelum which were otherwise closely related to each other. However, the loose structure of the Py-MS clusters may reflect genetic drift in C. jeikeium, which has been proposed in other studies.
Levent Toppare - One of the best experts on this subject based on the ideXlab platform.
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Direct Pyrolysis Mass Spectrometry to investigate the effects of dopants on characteristics of polypyrrole and its copolymers
Journal of Thermal Analysis and Calorimetry, 2012Co-Authors: Evren Aslan Gurel, Levent Toppare, Jale HacalogluAbstract:Polypyrrole and its copolymers with terepthalic acid bis-(2-thiophen-3-yl-ethyl)ester, (P(TATE-co-Py) were characterized by direct Pyrolysis Mass Spectrometry to investigate the effects of dopant on thermal stability and conductivity. Conductivities of the films were measured with four-probe technique, and the results were compared with the Pyrolysis data. In general, an increase in conductivity was detected as the stability of dopant increased. The extent of doping and the strength of interaction between the dopant and the polymer were decreased upon copolymerization with terepthalic acid bis-(2-thiophen-3-yl-ethyl)ester.
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A Pyrolysis Mass Spectrometry study of polythiophene copolymers
Polymer Degradation and Stability, 2007Co-Authors: Evren Aslan, Jale Hacaloglu, Levent ToppareAbstract:The thermal behaviour of copolymers of thiophene with decanedioic acid bis-(2-thiophen-3-yl-ethyl)ester (DATE) and terephthalic acid bis-(2-thiophen-3-yl-ethyl)ester (TATE) prepared by potentiostatic polymerization was studied via Pyrolysis Mass Spectrometry. It was determined that the electrolytic films correspond to the related homopolymers. The increase in thermal stability of ester linkages, and evolution of characteristic degradation products of TATE and DATE together with thiophene based products above 400 °C confirmed copolymer formation.
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Investigation of Copolymers of Thiophene‐Functionalized Polystyrene with Pyrrole by Pyrolysis Mass Spectrometry
Journal of Macromolecular Science Part A, 2006Co-Authors: Ozge Papila, Levent Toppare, Jale HacalogluAbstract:The thermal and structural characterization of electrochemically synthesized thiophene‐functionalized polystyrene and pyrrole (PS/PPy) and their copolymers were investigated by direct Pyrolysis Mass Spectrometry. The Pyrolysis data confirmed the growth of polypyrrole onto the pendant thiophene moiety of polystyrene. It is determined that the electrolytic film has different properties from the mechanical mixture and the related homopolymers.
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Characterization of Conducting Copolymer of Pyrrole via Pyrolysis Mass Spectrometry
Journal of Macromolecular Science Part A, 2005Co-Authors: Anil Levent, Jale Hacaloglu, Levent ToppareAbstract:In this work, structural and thermal characterization of BF4 − doped copolymer of pyrrole (PPy) with 2‐methylbutyl‐2‐(3‐thienyl)acetate prepared by electrochemical polymerization were performed via a Pyrolysis Mass Spectrometry technique. The Pyrolysis Mass Spectrometry data of the copolymer PPy/PMBTA, and the homopolymers; polypyrrole, PPy, and poly(2‐methylbutyl‐2‐(3‐thienyl)acetate), PMBTA were analyzed and compared. It has been determined that when the electrochemical polymerization of pyrrole was achieved on a PMBTA coated anode through the thiophene moieties of PMBTA, thermal stability of PMBTA chains increased slightly and the decomposition of both units followed quite similar pathways indicating an increase in the thermal stability of PMBTA chains unlike what was observed for PTSA doped PPy/PMBTA copolymer.
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Characterization of the polymer of a dipyrrolyl monomer by Pyrolysis Mass Spectrometry
Polymer International, 2004Co-Authors: Merve Ertas, Jale Hacaloglu, Levent ToppareAbstract:In this work, characterization of a homopolymer of succinic acid bis(4-pyrrol-1-ylphenyl) ester prepared by galvonastatic polymerization was carried out by direct Pyrolysis Mass Spectrometry. Although decomposition of the monomer yielding mainly butadionic acid and pyrrole occurred under the galvonastatic polymerization conditions, growth of the polymer through the pyrrole moieties was also achieved, yielding a ladder-type polymer film. The polypyrrole chains contained both quinoid and aromatic units as in the case of polypyrrole, yet the extent of network structure was significantly diminished. A three-step mechanism is proposed for the thermal decomposition process. The first step involves the cleavage of C4H4NC6H4O end groups. In the second step, decomposition of phenyl ester units and polypyrrole chains having quinoid structure takes place. The final stage of thermal degradation was attributed to decomposition of polypyrrole chains having aromatic structure. Copyright © 2004 Society of Chemical Industry
R. Freeman - One of the best experts on this subject based on the ideXlab platform.
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Pyrolysis Mass Spectrometry analysis of free-living and symbiotic cyanobacteria.
Antonie van Leeuwenhoek, 1999Co-Authors: N.j. West, P. R. Sisson, R. Freeman, D.g. Adams, P.m. HawkeyAbstract:The potential of Pyrolysis Mass Spectrometry to distinguish closely related cyanobacterial strains was assessed by using the technique to compare symbiotic cyanobacteria isolated from the hornwort Phaeoceros laevis and free-living cyanobacterial strains at the same field site. The same strains had previously been compared using polymerase chain reaction-based DNA fingerprinting techniques (West & Adams 1997, Appl. Environ. Microbiol. 63: 4479–4484). Many of the strains were grouped identically by the two techniques, although there were some differences, possibly resulting from the ability of these cyanobacteria to develop a range of specialised cell types having different chemical compositions to the vegetative cells. Although growth conditions were chosen to suppress cellular differentiation, this may not always have been completely successful. With careful control of growth conditions Pyrolysis Mass Spectrometry has considerable potential as an additional tool for the phenetic comparison of cyanobacterial strains. It has the advantage that analysis is directly derived from whole cells, and hence is simpler and cheaper than DNA-based methods, although it does require the growth of axenic strains. The technique may be particularly useful in the study of some of the more cryptic unicellular and non-heterocystous filamentous cyanobacterial groups, in which the lack of cellular differentiation should minimise any variability in the chemical composition of cells.
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Curie-point Pyrolysis Mass Spectrometry as a tool in clinical microbiology
Zentralblatt fur Bakteriologie : international journal of medical microbiology, 1997Co-Authors: Michael Goodfellow, R. Freeman, P. R. SissonAbstract:Pyrolysis Mass Spectrometry is a well established analytical tool that has received a considerable boost from the development of low cost, dedicated instruments and sophisticated statistical analyses on personal computers. Further analytical developments, especially in the area of neural networks, are pushing the technology to the forefront of methods for the discrimination and identification of microorganisms and their products. The speed and reproducibility of Pyrolysis Mass Spectrometry and its applicability to a wide range of microorganisms make it an attractive method for epidemiological studies. For inter-strain comparisons, the method is at least as discriminatory as conventional typing systems and usually gives discrimination similar to that of nucleic acid fingerprinting techniques. There has been some success in using neural networks to make identifications across Pyrolysis Mass spectrometric batches. Further development of methods used to handle data from multiple PyMS analyses can be expected to extend the value of Pyrolysis Mass Spectrometry in clinical microbiology.
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Differentiation between bacterial species and sub-species by Pyrolysis Mass Spectrometry of extracted DNA.
Zentralblatt fur Bakteriologie : international journal of medical microbiology, 1997Co-Authors: Kate Mathers, R. Freeman, P. R. Sisson, N F LightfootAbstract:Whole cell samples from cultures of Staphylococcus aureus, S. hominis, S. epidermidis and Streptococcus pyogenes were analysed by Pyrolysis Mass Spectrometry and the results were compared with Py-MS-derived analyses of samples of DNA extracted from the same organisms. Py-MS analysis differentiated the four organisms in both circumstances. These results challenge previous assumptions that Py-MS is restricted to detecting phenotypic differences, although the basis for the differentiation of the DNA extracts has yet to be determined.
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An outbreak of colonisation or infection by Corynebacterium jeikeium reanalysed by Pyrolysis-Mass Spectrometry
Journal of Analytical and Applied Pyrolysis, 1997Co-Authors: P. R. Sisson, R. Freeman, W. C. NobleAbstract:Abstract A Pyrolysis-Mass Spectrometry (Py-MS) analysis of isolates of Corynebacterium jeikeium broadly confirmed the course of an outbreak previously defined by analysis of plasmid structure. Plasmidless isolates could not be assessed by the initial plasmid profiling and had had to be disregarded. Py-MS analysis demonstrated that these were part of the outbreak. The clustering of isolates achieved by Py-MS accorded with the progression of two plasmids through a set of isolates of C. jeikelum which were otherwise closely related to each other. However, the loose structure of the Py-MS clusters may reflect genetic drift in C. jeikeium, which has been proposed in other studies.
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Differentiation of Mycobacterium senegalense from related non-chromogenic mycobacteria using Pyrolysis Mass Spectrometry
Zentralblatt fur Bakteriologie : international journal of medical microbiology, 1997Co-Authors: J G Magee, Michael Goodfellow, P. R. Sisson, R. Freeman, N F LightfootAbstract:Twenty-six representative strains of Mycobacterium chelonae, Mycobacterium fortuitum, Mycobacterium peregrinum and Mycobacterium senegalense were compared by Curie point Pyrolysis Mass Spectrometry. The M. chelonae and M. senegalense strains formed distinct groups. A third, relatively diffuse group, contained the M. fortuitum and M. peregrinum strains. These results, together with those from corresponding analyses, suggest that Pyrolysis Mass Spectrometry provides a rapid and reliable way of distinguishing between members of closely related mycobacterial species which are difficult to differentiate using conventional taxonomic procedures.
