Self-assembly of a monolayer (SAM) stationary phase bonding is a novel concept developed by Separation Methods Technologies (SMT, Newark, Del.) for giving high surface coverage of silica bonding. Generally, high coverage improves stability and often reduces tailing. SMT claims coverage of 99.99% of the silanols compared to about 50% for conventional bonding, before end-capping. SAM bonding is especially useful in prep since the columns are so robust and peaks shapes are ideal.