Improving the signal-to-noise ratio in gel permeation chromatography by Hadamard encoding

Increasing sensitivity without further preconcentration steps is a major challenge in separation sciences. In this study a macro control approach that allows the implementation of Hadamard encoding on standard HPLC instrumentation was applied to the analysis of polysiloxane and polystyrene polymers by gel permeation chromatography. Here, the use of pseudo-random modulation sequences with 1023 elements (512 sample injections) improved the signal-to-noise ratio (S/N) by up to an order of magnitude. Comparison with conventional single injection confirmed the linearity and accuracy of the deconvolution process for the whole mass range of the column.