LiChrospher® ADS – For direct on-line sample preparation of untreated bio fluids
HPLC analysis of low molecular compounds in biological samples can lead to an irreversible increase in back pressure, to loss of capacity, to a drop in selectivity, and, in the long run, to serious damage of HPLC columns. LiChrospher® ADS is especially designed to take care of this problem.
This on-line sample preparation method enables the direct extraction and enrichment of hydrophobic, low molecular analytes from untreated samples. Such samples can be haemolysed blood, plasma, serum, milk, salivary fluid, fermentation broth, supernatants of cell cultures and tissue as well as food homogenates.
LiChrospher® ADS allows fully automated sample preparation prior to the analytes being separated in the column. This allows untreated bio-fluids to be directly injected with no negative effects on either the column or the results achieved.
The enrichment is based on two chromatographic processes: reversed phase and size exclusion chromatography. This is due to LiChrospher® ADS sorbents, which are spherical silica gel particles (25µm) with DIOL modification on the exterior surface and alkyl modifications on the surface of the interior pores. Depending on the hydrophobicity of the analyte, three types of precolumns are available: C-4, C-8 and C-18.
Three types of ADS pre-columns are available with different hydrophobicity and retention and extraction properties for non-polar sample compounds: