On the Quantification of Lignin Hydroxyl Groups With 31 P and 13 C NMR Spectroscopy (original) (raw)

Abstract

Factors affecting the accuracy of the analysis of lignin hydroxyl and carboxyl groups with 31 P NMR have been further elucidated. Two modifications of 31 P NMR analysis of lignin, namely the protocols using 1,3,2-dioxaphospholane (PR-I) and 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane (PR-II) as phosphorylation reagents with different internal standards, were studied. The previous 31 P NMR standard protocol with PR-II underestimated OH groups by about 30%, whereas the 31 P NMR standard protocol with PR-I tended to produce overestimated data. It has been shown that cholesterol is not an appropriate internal standard, resulting in underestimated values for OH groups due to incomplete baseline resolution. The best internal standard has been found to be endo-N-hydroxy-5-norbornene-2,3-dicarboximide. Strong care should be taken related to the stability of the internal standards to avoid inflated results due to IS degradation. Under modified optimized conditions, both methods show a good correlation with the 13 C NMR protocol in the quantification of hydroxyl groups as average, with the variability between the methods in the range of 5-15%. However, the 31 P NMR protocols report COOH content that is twice as low as that of 13 C NMR data. Finally, the best approach for the use of the 31 P and 13 C NMR methods in lignin analysis is discussed.

Figures (13)

*Recalculated per mmol/g from the reported data (in per C9-unit) using the C9-formulae deduced for this lignin.” **Produced by lab cook of aspen wood under Alcell conditions. TABLE 1. Comparison of the prior work on 3'P NMR analysis (mmol/g lignin) of Alcell lignin

*Recalculated per mmol/g from the reported data (in per C9-unit) using the C9-formulae deduced for this lignin.” **Produced by lab cook of aspen wood under Alcell conditions. TABLE 1. Comparison of the prior work on 3'P NMR analysis (mmol/g lignin) of Alcell lignin

FIGURE 1. 2'P NMR-II spectra of Alcell (A), Indulin (B), AMWL (C), and PMWL (D) lignins demonstrate strong overlap of phenolic OH in S-units and 5-condenced G-units. Corrected integration mode is also suggested.

FIGURE 1. 2'P NMR-II spectra of Alcell (A), Indulin (B), AMWL (C), and PMWL (D) lignins demonstrate strong overlap of phenolic OH in S-units and 5-condenced G-units. Corrected integration mode is also suggested.

FIGURE 2. 2'P NMR-I spectra of AMWL (A), PMWL (B), Alcell (C), and Indulin lignins (D) illustrate strong overlap of aliphatic primary OH and 5-substituted phenolic OH (S-units and 5-condenced G-units) groups’ signals. This implies that total aliphatic and total phenolic OH cannot be accurately quantified.

FIGURE 2. 2'P NMR-I spectra of AMWL (A), PMWL (B), Alcell (C), and Indulin lignins (D) illustrate strong overlap of aliphatic primary OH and 5-substituted phenolic OH (S-units and 5-condenced G-units) groups’ signals. This implies that total aliphatic and total phenolic OH cannot be accurately quantified.

FIGURE 3. °'P NMR-II spectrum of Alcell lignin with cholesterol as a typical internal standard (IS-1) shows that the resonance of the internal standard is not baseline resolved and inflated by the resonances of lignin signals.

FIGURE 3. °'P NMR-II spectrum of Alcell lignin with cholesterol as a typical internal standard (IS-1) shows that the resonance of the internal standard is not baseline resolved and inflated by the resonances of lignin signals.

FIGURE 4. The effect of internal standard on the amount of total OH groups as reported by the 7'P NMR-II (A) and 3'P NMR-I (B) methods. The ratio of all IS to lignin was about 0.3 yzmol/mg. 1S1 x 2 and IS1 x 4, corresponding to experiments with twice and four times’ higher ratio of IS to lignin (about 0.6 and 1.2 pmol/mg, correspondingly).

FIGURE 4. The effect of internal standard on the amount of total OH groups as reported by the 7'P NMR-II (A) and 3'P NMR-I (B) methods. The ratio of all IS to lignin was about 0.3 yzmol/mg. 1S1 x 2 and IS1 x 4, corresponding to experiments with twice and four times’ higher ratio of IS to lignin (about 0.6 and 1.2 pmol/mg, correspondingly).

FIGURE 5. Relative stability of different internal standards phosphorylated with PR-II (A) and PR-I (B). These data, along with Figure 4, indicate that IS-2 is the best for 'P NMR analysis, while the stability of IS-3 is low.

FIGURE 5. Relative stability of different internal standards phosphorylated with PR-II (A) and PR-I (B). These data, along with Figure 4, indicate that IS-2 is the best for 'P NMR analysis, while the stability of IS-3 is low.

FIGURE 6. Correlation between the standard and the modified 31P NMR protocols using PR-I and PR-II in the quantification of total OH groups. There is a significant difference between the data obtained under the conditions of the standard 7'P NMR-II and 31P NMR-I protocols, but the correlation between the modified methods is good.

FIGURE 6. Correlation between the standard and the modified 31P NMR protocols using PR-I and PR-II in the quantification of total OH groups. There is a significant difference between the data obtained under the conditions of the standard 7'P NMR-II and 31P NMR-I protocols, but the correlation between the modified methods is good.

TABLE 2. Comparison of the 7P NMR-I and 3'P NMR-II analytical protocols (the data are in mmol/g lignin)

TABLE 2. Comparison of the 7P NMR-I and 3'P NMR-II analytical protocols (the data are in mmol/g lignin)

FIGURE 7. Correlation between the modified 31P NMR protocols using PR-I and PR-II in the quantification of different OH groups and COOH groups. In most cases, the correlation is not good due to primary AlipOH and 5-substituted PhOH signals overlapping in 3'P NMR-I spectra.

FIGURE 7. Correlation between the modified 31P NMR protocols using PR-I and PR-II in the quantification of different OH groups and COOH groups. In most cases, the correlation is not good due to primary AlipOH and 5-substituted PhOH signals overlapping in 3'P NMR-I spectra.

FIGURE 8. Quantification of hydroxyl groups in '3C NMR spectra of Alcell (A) and Indulin (B) acetylated lignins. where X is the amount of the specific moiety; Ix lis, and Ioutotal are the resonance values of the specific moiety, the internal standard, and total OH groups, correspondingly; mig and mis are the masses of the lignin and the internal standard.

FIGURE 8. Quantification of hydroxyl groups in '3C NMR spectra of Alcell (A) and Indulin (B) acetylated lignins. where X is the amount of the specific moiety; Ix lis, and Ioutotal are the resonance values of the specific moiety, the internal standard, and total OH groups, correspondingly; mig and mis are the masses of the lignin and the internal standard.

TABLE 3. Comparison of the 7'P NMR-II and '3C NMR-IS analytical protocols (the data are in mmol/g lignin

TABLE 3. Comparison of the 7'P NMR-II and '3C NMR-IS analytical protocols (the data are in mmol/g lignin

FIGURE 9. Correlation between the data obtained by the mod- ified 3'P NMR-II and the '23C NMR-IS protocols. The correlation between the average values is fairly good, but significant deviation for AliphOH and PhOH groups should be taken into account.

FIGURE 9. Correlation between the data obtained by the mod- ified 3'P NMR-II and the '23C NMR-IS protocols. The correlation between the average values is fairly good, but significant deviation for AliphOH and PhOH groups should be taken into account.

TABLE 4. Pros and cons of the 3'P and '3C NMR methods in lignin analysis *For CryoProbe™ experiment.

TABLE 4. Pros and cons of the 3'P and '3C NMR methods in lignin analysis *For CryoProbe™ experiment.

Loading...

Loading Preview

Sorry, preview is currently unavailable. You can download the paper by clicking the button above.

References (47)

  1. Adler, E. Lignin chemistry: Past, present and future. Wood Sci. Technol. 1977, 11, 169-218.
  2. Sakakibara, A. Chemistry of lignin. In Wood and Cellulose Chemistry; Hon, D.N.-S., Shiraishi, N., Eds.; Marcel Dekker, Inc.; New York, 1991, 113-175.
  3. Chen, C.-L. Lignin: Occurrence in wood tissues, isolation, reactions and structure. In Wood Structure and Composition; Lewis, M., Goldstein, I.S., Eds.; Marcel Dekker Inc.: New York, 1991, 183-261.
  4. Glasser, W. Classification of lignin ac- cording to chemical and molecular structure. In Lignin: Historical, Biological, and Mate- rial Perspectives; Glasser, W., Northey, R., Schultz, T., Eds.; ACS: Washington, DC, 2000, 216-238.
  5. Evtuguin, D.V.; Pascoal Neto, C.; Silva, A.M.S.; Dominges, P.M.; Amado, F.M.L.; Robert, D.; Faix, O. Comprehensive study on the chemical structure of dioxane lignin from Downloaded by [50.206.169.150] at 06:42 23 April 2015 plantation Eucalyptus globulus lignin. J. Agric. Food Chem. 2001, 49, 4252-4261.
  6. Capanema, E.A.; Balakshin, M. Yu.; Kadla, J.F. A comprehensive approach for quantitative lignin characterization by NMR spectroscopy. J. Agric. Food Chem. 2004, 52, 1850-1860.
  7. Balakshin, M. Yu.; Capanema, E.A.; Chang, H.-M. Recent advances in isolation and analysis of lignins and lignin-carbohydrate com- plexes. In Characterization of Lignocellulosics;
  8. Hu, T., Ed.; Blackwell: Oxford, UK, 2008, 148-166.
  9. Zhang, L.; Gellerstedt G. Quantitative 2D HSQC NMR determination of polymer struc- tures by selecting suitable internal standard ref- erence. Magn. Res. Chem. 2007, 45, 37-45.
  10. Milne, T.; Chum, H.; Agblevor, F.; John- son, D.K. Standardized analytical methods. Biomass & Bioenergy 1992, 2(1-6), 341-366.
  11. Faix, O.; Argyropoulos, D.S.; Robert, D.; Neirinck, V. Determination of hydroxyl groups in lignins: Evaluation of 1 H-, 13
  12. C-, 31 P-, FTIR and wet chemistry methods. Holzforschung 1994, 48, 387-394.
  13. Berlin, A.; Balakshin M. Industrial lignins: Analysis, properties and applications. In Bioen- ergy Research: Advances and Applications;
  14. Gupta, V.K., Kubicek, C.P., Saddler, J., Xu, F., Tuohy, M., Eds.; Elsevier: Amsterdam, 2014, 315-336.
  15. Archipov, Y.; Argyropoulos, D.S.; Bolker, H.I.; Heitner, C. 31 P NMR spectroscopy in wood chemistry. I. Model compounds. Jour- nal of Wood Chemistry and Technology 1991, 11(2), 137-157.
  16. Argyropoulos, D.S. Quantitative phosphorus-31 NMR analysis of six solu- ble lignins. Journal of Wood Chemistry and Technology 1994, 14, 65-82.
  17. Kostukevich, N.G.; Filippov, V.A.; Arkhipov, Yu. M. Determination of the hy- droxyl containing functional groups of the oxygen-acetic lignins by 31 P NMR spec- troscopy. Proceedings of the 7th International Symposium on Wood and Pulping Chemistry, Beijing, China, May 25-28, 1993, 503-507.
  18. Granata, A.; Argyropoulos, D.S. 2-Chloro- 4,4,5,5-tetramethyl-1,3,2-dioxaphospholane, a reagent for the accurate determination of the uncondensed and condensed phenolic moieties in lignins. Journal of Agricultural and Food Chemistry 1995, 43(6), 1538-1544.
  19. Guerra, A.; Filpponen, I.; Lucia, L.A.; Ar- gyropoulos, D.S. Comparative evaluation of three lignin isolation protocols for various wood species. J. Agric. Food Chem. 2006, 54, 9696-9705.
  20. Zawadzki, M.; Ragauskas, A. New stan- dards for 31 P-NMR analysis of lignin hydroxy groupds. Holzforschung 2001, 55, 283-285.
  21. Gosselink, R.; van Dam, J.E.G; de Jong, E.; Scott, E.L.; Sanders, J.P.M; Li, J.; Gellerstedt, G. Fractionation, analysis, and PCA modeling of properties of four technical lignins for predic- tion of their application potential in binders. Holzforschung 2010, 64(2), 193-200.
  22. Wörmeyer, K.; Ingram, B.; Saake, B.; Brunner, G.; Smirnova, I. Comparison of dif- ferent pretreatment methods for lignocellulisic materials. Part II: Influence of pretreatment on the properties of rye straw lignin. Bioresource Technology 2011, 102, 4157-4164.
  23. Vanderlaan, M.; Thring, R. Polyurethanes from Alcell lignin fractions obtained by sequen- tial solvent extraction. Biomass & Bioenergy 1997, 14, 525-531.
  24. Cateto, C.A.; Barreiro, M.F.; Rodrigues, A.E.; Brochier-Salon, M.C.; Thielemans, W.; Belgacem, M.N. Lignins as macromonomers for polyurethane synthesis: A comparative study on hydroxyl group determination. J. Applied Poly- mer Science 2008, 109(5), 3008-3017.
  25. Saad, R.; Radovic-Hrapovic, Z.; Ahvazi, B.; Thiboutot, S.; Ampleman, G.; Hawari, J. Sorption of 2,4-dinitroanisole (DNAN) on lignin. Journal of Environmental Science 2012, 24(5), 808-813.
  26. Liu, Y.; Carriero, S.; Pye, K.; Argyropoulos, D.S. A comparison of the structural changes oc- curing in lignin during Alcell and Kraft pulping of hardwood and softwood. In Lignin: Historical, Biological, and Material Perspectives; Glasser, W., Northey, R., Schultz, T., Eds.; ACS: Wash- ington, DC, 2000, 447-464.
  27. Pu, Y.; Cao, S.; Ragauskas, A.J. Applica- tion of quantitative 31 P NMR in biomass lignin and biofuel precursors characterization. Energy & Environmental Science 2011, 4, 3154-3166.
  28. Chen, C.-L.; Robert, D. Characterization of lignin by 1 H and 13 C NMR spectroscopy. In Methods in Enzymology, Vol. 161B; Wood, W.A., Kellogg, S.T., Eds.; Academic Press Inc.: New York, 1988, 137-174.
  29. Capanema, E.A.; Balakshin, M. Yu.; Chang, H.-M.; Jameel, H. Isolation and char- acterization of residual lignins from hardwood pulps: Method improvements. Proc. 13th In- tern. Symp. Wood Fibre Pulping Chemistry, Vol.
  30. Auckland, New Zealand, May 16-19, 2005, 57-64.
  31. Balakshin, M. Yu.; Berlin, A.; Dellicolli, H.T.; Grunert, C.A.N.J.; Maximanko Gutman, V.; Ortiz, D.; Pye, E.K. Derivatives of native lignin. U.S. Patent 8431635 B2.
  32. Xia, P.; Akim, L.; Argyropoulos, D.S. Quantitative 13 C NMR of lignins with inter- nal standards. J. Agric. Food Chem. 2001, 49, 3573-3578.
  33. Capanema, E.A.; Balakshin, M. Yu.; Kadla, J.F.; Chang, H.-M. On isolation of milled wood lignin from eucalyptus wood. O Papel 2007, N5, 74-79.
  34. Björkman, A. Studies on finely divided wood. Part I. Extraction of lignin with neu- tral solvents. Svensk Papperstidn. 1956, 59, 477-485.
  35. Balakshin, M.; Capanema, E.A.; Chen, C.- L.; Gratz, H. Elucidation of the structures of residual and dissolved pine kraft lignins using an HMQC NMR technique. Journal of Agricul- tural and Food Chemistry 2003, 51(21), 6116- 6127.
  36. Capanema, E.A.; Balakshin, M. Yu.; Chen, C.-L. An improved procedure for isolation of residual lignins from hardwood Kraft pulps. Holzforschung 2004, 58, 464-472.
  37. Berlin, A.; Balakshin, M.; Gilkes, N.; Kadla, J.; Maximenko, V.; Kubo, S.; Saddler, J. Inhibition of cellulase, xylanase and beta- glucosidase activities by softwood lignin prepa- rations. Journal of Biotechnology 2006, 125(2), 198-209.
  38. Argyropoulos D.S. Heteronuclear NMR spectroscopy of lignins. In Lignin and Lignin: Ad- vances in Chemistry; Heitner, C., Dimmel, D.R., Schmidt, J.A., Eds.; CRC Press: Boca Raton, FL, 2010, 245-265.
  39. Akim, L.G.; Argyropoulos, D.S.; Jouanin, L.; Leplé, J.-C.; Pilate, G.; Pollet, B.; Lapierre, C. Quantitative 31 P NMR spectroscopy of lignins from transgenic poplars. Holzforschung 2001, 55, 386-390.
  40. Capanema, E.A.; Balakshin, M. Yu.; Kadla, J.F. Quantitative characterization of a hard- wood milled wood lignin by NMR spec- troscopy. J. Agric. Food Chem. 2005, 53, 9639-9649.
  41. Balakshin, M. Yu.; Capanema, E.A.; Gold- farb, B.; Frampton, J.; Kadla, J.F. NMR studies on Fraser fir Abies fraseri (Pursh) Poir. lignins. Holzforschung 2005, 59, 488- 496.
  42. Oliveira, L.; Evtuguin, D.V.; Cordeiro, N.; Silvestre, A.J.D.; Silva, A.M.S. Chemical com- position and lignin structural features of banana plant leaf sheath and rachis. In Characterization of Lignocellulosics; Hu, T., Ed.; Blackwell: Ox- ford, UK, 2008, 171-188.
  43. Capanema, E.A.; Balakshin, M. Yu.; Chen, C.-L.; Colson, K.L.; Gracz, H.S. Use of cryo- genic NMR probes in 13 C and 1 H-13 C 2D NMR techniques for structural analysis of lignin preparation. Proc. 12th Intern. Symp. Wood Pulping Chem., Madison, Wisconsin, USA, June 9-12, 2003, 179-182.
  44. Balakshin, M. Yu.; Capanema, E.A.; Gracz, H.; Chang, H.-M.; Jameel, H. Quan- tification of lignin-carbohydrate linkages with high-resolution NMR spectroscopy. Planta 2011, 233, 1097-1110.
  45. Capanema, E.A.; Balakshin, M. Yu.; Chang, H.-M.; Jameel, H. Quantitative analysis of technical lignins by a combination of 1 H-13 C HMQC and 13 C NMR methods. Proceedings of International Conference on Pulping, Papermak- ing and Biotechnology, Nanjing, China, Nov. 4- 6, 2008, 647-651.
  46. Li, S.; Lundquist, K. A new method for the analysis of phenolic groups in lignin by 1 H NMR spectrometry. Nordic Pulp and Paper Research Journal 1994, 9(3), 191-195.
  47. Kubo, S.; Kadla, J.F. Poly(ethylene ox- ide)/organosolv lignin blends: Relationship be- tween thermal properties, chemical structure, and blend behavior. Macromolecules 2004, 37, 6904-6911.