A Review of Waters'' Bonded-Phase Shield Technology and Its Use in High Performance Liquid Chromatography (HPLC)
Shield bonded phases have been introduced to HPLC over the past 10 years. These phases represent a major departure from traditional reliance on 30-year-old silane and bonding technology. Application of second generation one-step synthesis methodologies afford a well-rounded column for any reversed-phase separation. In comparison to their purely alkyl counterparts, shield phases provide the end user with three significant benefits: -- 1) improved peak shape for basic analytes; -- 2) unique selectivity, and -- 3) stable retention in highly aqueous mobile phases. Significant progress has been made into understanding the mechanism of this novel class of RP materials. More insight is expected as these materials become increasingly utilized to solve difficult separation problems.