Multi-detection Size Exclusion Chromatography: A Novel Method for Band Broadening Correction

L.A. CLEMENTI, M.M. YOSSEN, J.R. VEGA

Mar del Plata

Congreso; XVI Simposio Latinoamericano de Polímeros (SLAP 2018) y XIV Congreso Iberoamericano de Polímeros (CIP 2018); 2018

Sizeexclusion chromatography (SEC) is the most popular technique for estimatingmolar mass distributions (MMD) of polymers. The band broadening (BB) effectproduces a whole distribution of molar masses in the detector cell; as aconsequence, the MMD results artificially broadened and the samplepolydispersity is overestimated. The BB effect is strong for narrow samples orfor samples that exhibit multiple narrow peaks.1 BB-correction involves theestimation of the BB function (BBF) through complex computational algorithms.These aspects turn the BB correction unpractical for most SEC users. This workpresents a simple method for BB correction in a chromatograph fitted with adifferential refractometer (DR) and a light scattering (LS) detector. Themethod consists in solving an optimization problem (not presented here forspace reasons), which requires the knowledge of: (i) both measuredchromatograms; (ii) the interdetector volume; and (iii) the molar masscalibration. Such method is tested in laboratory on the basis of narrowchromatographic standards of polystyrene (PS) and poly(methyl-methacrylate)(PMMA).