Development of Fast Gradient Separations for Different Polymethacrylates

Abstract

Liquid chromatography of polymers is traditionally a slow technique with analysis times of typically 30 min per sample. To adapt liquid chromatographic techniques to combinatorial materials research the sample throughput must be significantly increased. Preferably, the analysis time per sample is to be reduced to a few minutes. Short analysis times can be achieved using high resolution stationary phases, high flow rates, and fast gradients. The present work demonstrates that gradient HPLC of polymethacrylates can be accomplished in less than 2 min. The fast separation of poly(methyl methacrylate), poly(i-propyl methacrylate), poly(n-butyl methacrylate), poly(tbutyl methacrylate), and poly(n-decyl methacrylate) is conducted on a short monolithic stationary phase using a flow rate of up to 7 mL/min. The optimization of the gradient is conducted by running a number of linear gradients and by simulating an optimum step gradient. Further modification of the simulated gradient results in the desired short analysis times.

Separation of bimodal high density polyethylene using multidimensional high temperature liquid chromatography

“…at decreasing the time needed for a single HT 2D-LC experiment (methods I-III in Table 2). Yet, less time is available for an individual SEC analysis, which may lead to overlap of two fractions [93][94][95][96]. The theoretical plate number (N) (column efficiency) and the resolution (R) of this column were determined to be 4500 (N 4500 ) and 0.35, respectively (Eqs.…”

Separation of water‐soluble polymers using capillary‐channeled polymer fiber stationary phases

“…Methodologies used to characterize polymers and polymer systems lag far behind what is required as synthetic and natural polymer technologies continue to move ahead. Currently, many LC methodologies are being employed to analyze the molar mass, chemical composition, and functionality distributions of various polymer types, but the needs presented by polymer research are outpacing the capabilities presented by commercial technology and hence it is imperative that separation techniques be advanced to meet the advances in polymer research [2,3]. Thus, the impetus for the present volume.…”