Solving Analytical Problems. using the Frontier Multi-Functional Pyrolyzer

Transcription

1 Solving Analytical Problems using the Frontier Multi-Functional Pyrolyzer

2 Introduction to Frontier Laboratories In 1989, Frontier Laboratories introduced the first commercially available pyrolyzer based on a patented vertical micro-furnace. Since then, a number of innovative accessories have been developed which extend the capabilities of the system beyond simple pyrolysis. Today, the Frontier system can be configured to perform evolved gas analysis (EGA), multi-step thermal desorption and pyrolysis (TD/Py), reactive pyrolysis, and heart-cutting of individual EGA fractions all automatically! A complete system enables the analyst to fully characterize virtually any complex sample. The Frontier Multi-Functional Pyrolyzer is used to solve analytical problems problems that occur in production, problems caused by product failure, problems with instrument contamination, problems with challenging sample preparation regimes, or problems that arise when faced with superior competitive products. These are just few of the areas which a Frontier Multi-Functional Pyrolyzer will prove to be the most cost effective means of responding to the everyday challenges encountered in the modern analytical laboratory. This monograph presents several examples where the Frontier system is used to provide chemical characterization of a diverse set of sample matrices. In most instances, the sample is analyzed directly, which not only saves time but eliminates the inherent errors associated with conventional sample preparation techniques such as solvent extraction, derivatization, etc. If you desire more information about any of the solutions presented or should you find yourself with a difficult analytical problem similar to these presented, your best source of information is the Frontier web site: All information subject to change without notice

3 Analytical Problems and Frontier-Based Solutions A. Paper (Page 3 5) A-1. What causes small yellow spots on cigarette paper? A-2. What kinds of hazardous volatile organic compounds evolve from the wrapping materials used for the preservation of museum art? A-3. How can low levels of additives like wet-strength resins, Kymene 557 (Polyacrylamide-Epichlorohydrin polymer) be measured in paper? B. Environmental (Page 6 9) B-1. What is the best method to determine flame retardants (like Decabromodiphenyl ether: DeBDE) in plastic? B-2. How can the residual formaldehyde in automotive coatings and paints be determined? B-3. Is there an easy way to analyze hazardous compounds out-gassing from plastic films used to wrap food? B-4. Is it possible to analyze compounds out-gassing during the curing of polyimide? C. Hydrocarbon Processing (Page 10 11) C-1. Is there an easy way to differentiate coal from different sources? C-2. How can the discrimination of high molecular weight compounds that occurs during sample injection be reduced? D. Rubber (Page 12 13) D-1. What is the best method to quantiitate additives in rubber? D-2. Is there a simple method to analyze the chemical composition of blended rubber? E. Polymers (Page 14 17) E-1. What is an easiest way to identify and quantiitate additives in polyethylene (PE)? E-2. What is the proper analytical method to detect odors emanating from polypropylene (PP) materials? E-3. Is there a simple way to determine the terminal groups on polycarbonate (PC)? E-4. Is there a technique to obtain information about the sequence distributions of polyacetal? F. Inks and Paint (Page 18 19) F-1. Is it possible to identify the volatiles and polymers used in paint? F-2. Is there an easy way to analyze the differences in inks used in ball point pens? G. Operational Factors on Data Quality G-1. How does the pyrolysis temperature affect the pyrozates formed during pyrolysis? G-2. How do cold spots in the analytical system, such as a sample injection port and various interfaces, effect the results of the analysis? (Page 20 21) - 2 -

4 A-1 Problem:What causes small yellow spots on cigarette paper? Zone A Zone B Paper yellow spot on paper Analysis:Small discs (2mm id) of paper containing the yellow spots are punched out by Harris Micro Puncher (F-Lab) and placed in a sample cup. The sample is analyzed by EGA and (TD)- GC/MS ºC plain paper Result: Fig.1 shows the EGA thermograms of the yellow spots and a control paper. The EGA results are clearly different in zone A and B. Fig.2 shows the chromatogram obtained using TD-GC/MS analysis for zone A. It shows that a number of hydrocarbons are detected between 10 to 14 minutes along with the flavor and additives components in the cigarette paper. The compositions of these hydrocarbons are basically the same as those of lubricating oil. Therefore, it is clear that the yellow spots are caused by lubricating oils deposited during the paper processing. 100 Acetic acid 1,2-propanediol ºC Fig.1 EGA themograms for cigarette paper samples 3-methylpentanoic acid 2-methyl butanoic acid Triacetine Eugenol Eugenol acetate Causes of yellow spots (lubricating oil) Palmitic acid 10 min Fig.2 Chromatogram of the TD-GC/MS analysis of zone A (TD: ºC) - 3 -

5 A-2 Paper Problem:What kinds of hazardous volatile organic compounds evolve from the wrapping materials used for the preservation of museum art? Paper A CO 2 TD:50 220ºC Analysis:Small discs (2mg i.d) of each wrapping paper are punched out using a Harris Micropuncher and placed in the sample cup. The sample is analyzed using a TD-GC/MS method. Result: TD-GC/MS chromatograms of the two samples are shown in Fig.1. No significant compounds, which might cause damage to the art material were found in paper A. On the other hand, about 10 ppm of total volatile compounds such as isocyanic acid and phthalates (DBP and DOP) evolved from sample B. These compounds may damage the art materials. THF min Isocyanic acid Paper B CO 2 THF Acetol DBP DOP min Fig.1 Chromatograms of volatile components from materials used to wrap museum-quality pieces of art

6 A-3 Paper Problem:How can low levels of additives like wetstrength resins like Kymene 557(Polyacrylamide-Epichlorohydrin polymer) be measured in paper? A. The pyrogram of Kymene 557 cyclopentanone Analysis:Small discs (2mm id) punched out of the paper with a Harris Micro Puncher (F-Lab) are placed in a sample cup prior to pyrolysis at min Result: The pyrogram of pure Kymene 557 is shown in Fig.1 A. Cyclopentanone, which is derived from the adipic acid moiety of Kymene 557, is detected as a characteristic pyrolyzate. The pyrogram of a paper towel sample with 0.4% of Kymene 557 is shown in Fig.1B. A small peak of cyclopentanone is observed suggesting that this paper sample contains Kymene 557 to some extent. B. The pyrogram of paper towel with 0.4% of Kymene (m/z) min Ref.:T.Yano, H.Ohtani, S.Tsuge;Tappi Journal, 74, (1991) 10 min Fig.1 Pyrograms of wet-strength resin (Kymene 557) and paper towel containing it (Pyrolysis temperature:600 ) - 5 -

7 B-1 Problem:What is the best method to determine flame retardants (like Decabromodiphenyl ether: DeBDE) in plastic? Analysis:A few hundred micrograms of the polystyrene (PS) sample containing DeBDE is placed in a sample cup is analyzed using EGA and (TD)- GC/MS. DeBDE Zone A (200~350ºC) Environmental ºC m/z:800 TIC Result: The thermogram of EGA of the PS sample is shown in Fig.1. DeBDE, which evolves as the sample is heated, is detected in zone A. Fig.2 shows the chromatogram of zone A obtained using TD-GC/MS. The content of DeBDE is estimated to be 7%; the precision of the analysis is on the order of 3.5%RSD which is excellent considering the instability of the DeBDE molecule. Ref.:Double-Shot Pyrolyzer Technical Note, PYA1-051, 052 m/z: ºC Fig.1 Thermogram of polystyrene containing DeBDE area ratio of DeBDE (x 10 6, m/z: 800) Average RSD (n=5) 3.5 % TD: ºC Styrene trimer NoBDE DeBDE min Fig.2 Reproducibility of chromatograms and quantitative analysis by TD-GC/MS for Zone A - 6 -

8 B-2 Problem:How can the residual formaldehyde in automotive coatings and paints be determined? Analysis:A few µl of a clear-coat resin solution is placed in a sample cup. The solvent is evaporated at 40ºC for 20 minutes. The sample is analyzed using EGA and (TD)- GC/MS. Result: The thermogram of EGA is shown in Fig.1 together with mass chromatograms of the characteristic ions for formaldehyde at m/z=29 and 30. Formaldehyde formed from paraformaldehyde is expected to be included in zone A. The TD-GC/MS chromatogram of zone A is shown in Fig.2. The reproducibility of the peak area measurements is 3.4%(RSD) for 5 repeated runs. Thus, the extremely precise determination of paraformaldehyde can easily be achieved Zone A (50~220ºC) methanol Environmental Zone B (components derived from polymer) ºC ºC Fig.1 Thermograms of clear coat sample TD:50 220ºC m/z: 29 m/z: 30 Ref.:Takeda, Watanabe, Tsuge, 55 th Japan Society for Analytical Chemistry, B3027 formaldehyde butanol m/z: min Fig.2 Masschromatogram of TD-GC/MS analysis for Zone A - 7 -

9 B-3 Problem:Is there an easy way to analyze hazardous compounds out-gassing from food films used to wrap food? Zone A (40~200ºC) Zone B (200~240ºC) Environmental Zone C (240~500ºC) Analysis:A piece of polyvinylide chloride film (ca, 0.25cm 2, 0.5mg) is placed in the sample cup and analyzed by EGA and heart cutting EGA- GC/MS ºC Result: The EGA thermogram of the film is presented in Fig. 1. Each zone is analyzed separately using a heart-cutting EGA-GC/MS technique. The results of the analyses are shown in Fig. 2. The data indicates that a number of additives and pyrolyzates of the polymer back bone are present in each EGA zone. Zone A (40~200ºC) Fig.1 Thermogram of food wrapping acetic acid butanol tributyl aconitate tributyl acetylcitrate (CITROFLEX A-4) Ref.:Double-Shot Pyrolyzer Technical Note, PYA1-023 Zone B (200~240ºC) HCl Zone C (240~500ºC) dichlorobenzene trichlorobenzene min Fig.2 Chromatograms for Zone A-C by heart cutting EGA-GC/MS method - 8 -

10 B-4 Problem:Is it possible to analyze compounds outgassing during the curing of polyimide? Analysis:Microgram quantities of the sample containing bisphenyl tetracarboxylic acid di-anhydride (BPDA) and sulfonyl bisbenzamine (3,3-DDS) are placed in a sample cup. EGA is performed during the thermal polymerization of the mixture. Result: Fig.1 shows that polyimide is synthesized when the mixture is heated using a two step process. Fig.2 presents the thermograms for various outgassing compounds formed during the preparation of polyimide. This result demonstrates that DMAA* and CO 2 are formed during the first heating process and SO 2 and aniline are generated during the second heating process. *DMAA: dimethyl acetamide O H3C N C CH3 H3C Ref.:Double-Shot Pyrolyzer Technical Note, PYA3-002 O O O The first heating process 150 (30min) (BPDA) Polyamic acid O O O Fig.1. The synthetic process of polyimide A. equivalent of first heating m/z=18 ( H2O ) + H2N SO2 (3,3-DDS) NH2 The second heating process (3 /min) Polyimide is formed m/z=44 ( CO2, DMAA) m/z=87 ( DMAA ) Environmental Out-gases are evolved B. equivalent of second heating m/z=64 ( SO2 ) m/z=93 ( aniline ) temperature( ) Fig.2. Thermogram with masscromatogram in the process of polyimide synthesis - 9 -

11 C-1 Hydrocarbon Processing Problem:Is there an easy way to differentiate coal from different sources? Analysis:A few hundred microgram of powdered coal is placed in a sample cup and analyzed by EGA. Result:The EGA results are presented in Fig.1. The thermal profiles differ depending on the types and localities. Generally, it is possible to differentiate similar samples by EGA. Thermal desorption-gc/ms enables the analyst to detail the differences in similar samples. Coal (KELLERMAN) Coal (KEYSTONE) Lignite ºC Fig.1 Comparison of thermograms for three coal samples

12 C-2 Problem:How can the discrimination of high molecular weight compounds that occurs during sample injection be reduced? Analysis:A mixture of hydrocarbons containing equimolar quantities of C18 and C44 is used as a test sample. Two different methods of injecting the sample are compared. Hydrocarbon Processing A. Inject the sample directly to GC injection port C18 C44 Result: Two gas chromatograms of the mixture via (A) a conventional split injection at 320 and (B) through a pyrolyzer (Frontier Lab) at 450, are shown in Fig.1. The area ratio (C44/C18) is used as a measure of discrimination. The area ratios and %RSD are shown in Figure 1. The decrease in the discrimination and vastly improved precision (Fig.1B) can be attributed to the homogenous mixing and higher thermal capacity of the pyrolyzer min C44/C18 = 0.64 RSD = 17.0% (n=5) B. Inject the sample through pyrolyzer min C44/C18 = 0.94 RSD = 4.6% (n=5) Fig.1 Comparison of chromatograms by two kinds of injection methods

13 D-1 Rubber Problem:What is the best method to quantiitate additives in rubber? Zone A (50~300ºC) Analysis:A piece of an acrylonitrile-butadiene rubber sample (NBR) weighing about 1 mg is placed in a sample cup. The sample was analyzed using EGA and thermal desorption-gc/ms. Result: The EGA thermogram of the NBR sample, containing various types of additives, is shown in Fig.1. This suggests that the volatile components are desorbed in zone A. Fig.2 shows the TD-GC/MS chromatogram of zone A fraction. The reproducibility of the relative peak intensities for two types of antioxidants is less than 2 %RSD ºC TD:50 300ºC Fig.1 EGA thermogram of NBR NOCRAC 810-NA NOCRAC 6C Internal standard material Ref.:Double-Shot Pyrolyzer Technical Note, PYA min Fig.2 Chromatogram for Zone A by TD-GC/MS analysis NOCRAC810-NA NOCRAC 6C : N-Phenyl-N -isopropyl-p-phenylenediamine : N-Phenyl-N -(1,3-dimethylbutyl)-p-phenylenediamine

14 Relative peak area for butadiene(%) D-2 Rubber Problem:Is there a simple method to analyze the chemical composition of a blended rubber sample? isoprene styrene Analysis:About 200 µg of a rubber mixture, composed of polybutadiene(pb)- polyisoprene (PI)- polystyrene (PS), is placed in a sample cup and pyrolyzed at 550ºC. Result: Fig.1 shows the pyrogram for the blended rubber sample. The monomers of each component, which are butadiene, isoprene and styrene, are the main pyrolyzates. The calibration curves between relative peak intensities for the specific peaks and the ratio of PB to total weight of the sample shows a fairly good linear relationship with a correlation coefficient greater than The calibration curve for the PB composition in the blended sample is shown in Fig.2. Using this calibration curve, a fairly accurate determination of the component is possible within 3% of accuracy. Ref.:Double-Shot Pyrolyzer Technical Note, PYA1-047 butadiene min Fig.1 Pyrogram of a blended rubber Ratio of PB in the blend(wt. %) Fig.2 Calibration curve for PB in the blend

15 E-1 Problem:What is the easiest way to identify and quantiitate additives in polyethylene (PE)? Zone A (100~200ºC) Polymers Analysis:Microgram quantities of a HDPE are placed directly in the sample cup prior to EGA and TD- GC/MS analysis. Result: The EGA thermogram and characteristic ion chromatograms of a PE sample containing approximately 400 ppm of BHT* and various types of additives are presented in Fig.1. It shows that the BHT fraction evolves from the sample in zone A. The chromatogram of the TD-GC/MS analysis of zone A is shown in Fig.2. The reproducibility of the BHT peak measurements area exhibits RSD of 2.4% (n=5). TIC m/z: 205 m/z: ºC Fig.1 EGA thermogram of HDPE OH 205 BHT * (BHT : 2,6-Di-tert-butyl hydroxy toluene) m/z min Fig.2 Chromatogram for Zone A by TD-GC/MS analysis

16 iso-butanol ethyl tert-butyl ether tert-pentanol 4-methylheptene C 9 E-2 Problem:What is the proper analytical method to detect odors emanating from polypropylene (PP) materials? A. Good product TD:100ºC (5 min) Polymers Analysis:About 7 mg of the PP sample is placed in the sampling cup and analyzed by TD- GC/MS. fraction a C 9 C 12 C 15 C 18 Result: The TD-GC/MS chromatograms of good and defective PP are presented in Fig.1. The defective sample contains a number of volatiles which are not present in the good sample. Therefore, it can be postulated that these additional volatiles may be responsible for the odors in the defective PP sample. B. Defective product C 21 Ref.:Double-Shot Pyrolyzer Technical Note, PYA1-006 n-c 9 fraction b min Fig.1 Chromatograms of good and defective PP sample by TD-GC/MS analysis

17 C E-3 Polymers Problem:Is there a simple way to determine the terminal groups ob polycarbonate (PC)? Analysis:Microgram quantities of the PC sample are placed in the sample cup along with 3 µl of a 25 wt% of methanol solution of tetramethyl ammonium hydroxide (TMAH). The sample is then analyzed using a reactive pyrolysis GC (FID) method. CH 3 O CH 3 CH 3 C O C O C CH 3 CH 3 O n CH 3 Result: Fig.1 shows the pyrogram of the reactive pyrolysis of the PC sample synthesized by solvent method. Basic TMAH selectively cleaves the ester bond, and the resulting products undergo immediate etherification. The pyrogram clearly shows that the methyl ether of bisphenol A is the main component The presence of bisphenol A and the methyl ether of t- butylphenol demonstrates that the PC has terminal groups of t-butylphenol. Additionally, it is possible to estimate the average molecular weight from the relative peak intensity of the product derived from the terminal groups against that from the main chain. Ref.:Double-Shot Pyrolyzer Technical Note, PYA2-001 CH 3 CH 3 O CH min Fig.1 Reactive pyrogram of PC with TMAH reagent (Pyrolyzed at 400ºC) CH 3 CH 3 O C CH 3 OCH

18 E-4 Polymers Problem:Is there a technique to obtain information about the sequence distributions of polyacetal (PA)? Analysis:Multi-component copolymers of PA, containing 1-9 mol% of oxyethylene units [ (-OCH2CH2- )(E) ] against the main chain oxymethylene units [ (-OCH 2 -)(F) ], are analyzed. The PA sample combined with solid cobalt sulfate (CoSO 7H 2 O) catalyst is frozen and pulverized. About 100 µg of the powder sample is placed in the sample cup prior to reactive pyrolysis GC/MS at F 2 EF 3 F3 4 EF2 5 E2F 6 F4 7 EF3 9 E3F 10 E4F 11 (E2F)2 12 E5F 13 E6F 14 E7F 15 (E2F)3 Result: The pyrogram from the reactive pyrolysis GC/MS for the PA sample is shown in Fig.1. A series of cyclic ethers consisting of E and F units is observed. This reflects the sequence structures of E units in the original polymer chain. From the relative peak intensity of these cyclic ethers, it is possible to estimate the E unit content in the polymer sample as well as the sequence distributions min Fig. 1 Pyrogram of copolyacetal by reactive pylolysis Ref.:Double-Shot Pyrolyzer Technical Note, PYA

19 F-1 Inks and Paint Problem:Is it possible to identify the volatiles and polymers used in paint? Analysis:Microgram quantities of the paint sample is placed in the sample cup and analyzed by the double-shot method, which is a combination of thermal disorption (TD) and flash pyrolysis GC/MS. x pyrrolidone (solvent) TD: ºC Result: The TD-GC/MS chromatogram of the paint sample for the TD fraction (100 to 250 ) is shown in Fig.1. Information about volatile components, such as the residual solvents present, is obtained. Information about the polymer components in the sample is obtained by flash pyrolysis at 570 using the residual sample in the cup after the preceding TD min Fig.1 Chromatogram for a paint sample by TD-GC/MS analysis x PY: 570ºC min Fig.2 Pyrogram for the residue after preceding TD

20 F-2 Problem:Is there an easy way to analyze the compositional differences in the inks used in ball point pens? Ink A phenoxyethanol Inks and Paint Analysis:About 200 µg of each ink is placed in the sample cup prior to flash pyrolysis at 550. Ink B Result: The pyrograms and their enlarged figure for two black ball point inks from different companies are presented. The main component in both ink sample is phenoxyethanol; however, the minor peaks (red dots) differ. It is a simple matter to differentiate the two inks min Ink A Different peaks from each other Enlarged Ink B min Fig.1 Comparison of pyrograms for two kinds of ball point inks

21 G-1 Operational Factors on Data Quality Problem:How pyrolysis temperature affects the result of analysis? Analysis:Microgram quantities of a copolymer of styrene butadiene rubber is placed in a sampling cup and analyzed by EGA and flash pyrolysis. Result:The EGA thermogram of the SBR sample is shown in Fig.1. It clearly shows that at 550 the thermal degradation of the sample is complete. Fig.2 shows the pyrograms of the SBR at 550ºC and 800ºC. [ CH 2 CH = CH CH 2 ] m [ CH 2 CH (C 6 H 5 ) ] n Optimum pyrolysis temperature range ºC Pyrolyzed at 550ºC Fig.1 The thermogram of SBR styrene hybrid SBB trimer The optimum temperature for flash pyrolysis is generally about 50~100ºC greater than the finishing temperature of the EGA thermogram (see Fig.1). Pyrolysis at even higher temperatures may result in non-characteristic lower molecular fragments and reducing relatively bigger characteristic products, such as dimers and trimers, reflecting the polymer structures. butadiene (BD) BD dimer toluene Pyrolyzed at 800ºC α-methylstyrene hybrid SB dimer palmitic acid stearic acid min Fig.2 Effects of pyrolysis temperature to pyrograms

22 G-2 Operational Factors on Data Quality Problems:How the cold spots in the analytical system, such as a sample injection port and various interfaces, affect the result of the analysis? Analysis:Microgram quantities of a sample, containing equal amount of linear hydrocarbons (C18~44), which differs drastically in boiling temperature, is placed in the sample cup and analyzed using (TD)-GC. Result: As shown in Fig.1, the possible cold spots around the septum of the GC injection port are eliminated by positioning a heat-sink adapter between the septum cap and the interface heating block. The effectiveness of the heat sink is shown in Fig.2 which compares pyrograms of the sample with and without the heat-sink. It should be noticed that the relative peak intensities of the hydrocarbons v. C 18 decrease above C 36 without using the heat-sink, while the discrimination is much improved by using the heat-sink. Ref.:Double-Shot Pyrolyzer Technical Note, PYT-026 Pyrolyzer furnace Interface heating block Heat-sink adapter Septum of GC injection port A. with heat-sink adapter C18 C24 B. without heat-sink adapter C min C44 Area ratio in regards to C Pyrolyzer furnace temp.: 450ºC Interface temp. : 320ºC GC injection port temp. : 320ºC Fig.1 The structure of Py-GC terminal area with heatsink adapter A. with heat-sink B. without heat-sink Carbon number Fig.2 Comparison of chromatograms and the area ratio of peaks against C 18 for a mixture sample by TD-GC analysis

23 Various kinds of application using Frontier Multi-Functional Pyrolyzer Polymer chemistry : analysis of component, molecular structure, heat-stability and thermal decomposition structure Quality control of factories : quality inspections of various types of polymer molecule materials in automobile and air craft industries Biochemistry, microbiology : identification of chemical structures of protein and polysaccharide, pathology differentiation of bacteria, identification of cancer cell Forensic science : identification of plastic, rubber, fabric, paint, adhesive agent, hair, paper Association with energy : basic study of coal liquefaction, effective utilization of biomass, recycle of polymer molecule Environmental science : combustion process of municipal waste, mechanism of derivation of dioxin Earth sphere hydrosphere : analysis of soils or deposits in hydrosphere, analysis of material recycling in organic geology the natural world, oil exploration Food science : analysis of cancer-causing substance in cigarette smoke and smoked foods smoke pollution Cosmic science : search for extraterrestrial life Others

24 Versatile: Analyze virtually any solid or viscous liquid Flexible: Multiple operating modes Reproducible: Guaranteed Simple operation: A single computer screen for each operating mode Simple sample prep: Insert sample cup Simple maintenance: Only two gas seals - only three consumable parts Frontier Laboratories Multi-functional Pyrolyzer (PY-2020iD) Frontier Laboratories Ltd , Saikon, Koriyama, Fukushima, , Japan TEL: FAX: MK704011E