Monodisperse lignin fractions as standards in size-exclusion analysis: comparison with polystyrene standards.
The difficulty of preparing monodisperse lignin fractions on a large scale is a limiting factor in many applications. The present paper addresses this problem by examining the properties and size-exclusion behavior of lignin isolated by the acetosolv pulping process from post-extraction crushed sugarcane bagasse. The isolated lignin was subjected to a solvent pretreatment, followed by preparative gel permeation chromatography fractionation. The fractions were analyzed by high-performance size-exclusion chromatography (HPSEC) and these samples showed a great decrease in polydispersity, compared to the original acetosolv lignin. Several fractions of very low polydispersity, close to unity, were employed as calibration curve standards in HPSEC analysis. This original analytical approach allowed calibration with these lignin fractions to be compared with the polystyrene standards that are universally employed for lignin molecular mass determination. This led to a noteworthy result, namely that the lignin fractions and polystyrene standards showed very similar behavior over a large range of molecular masses in a typical HPSEC analysis of acetosolv lignin.
Botaro
Vagner Roberto
VR
Universidade Federal de São Carlos-Campus de Sorocaba, Rod. João Leme dos Santos, km 110, CEP 18052-780, CP 3031-Sorocaba, SP, Brazil. vagner@ufscar.br
Curvelo
Antonio Aprígio da Silva
AA
D002138:Calibration; D002850:Chromatography, Gel / Q000379:methods / Q000592:standards*; D002851:Chromatography, High Pressure Liquid / Q000379:methods* / Q000592:standards*; D008031:Lignin / Q000737:chemistry*; D008970:Molecular Weight; D011137:Polystyrenes / Q000737:chemistry*; D012015:Reference Standards
D011137:Polystyrenes; D008031:Lignin