A simple and accurate bench top method is presented for the analysis of chemically bonded reversed-phase (C1, C8, C18) HPLC packing materials, based on HF digestion and analysis by capillary or packed column GC. Bonded silanes of six carbon atoms or more are analyzed by hexane extraction and GC, white the more volatile trimethylsilane "capping" silanes are analyzed by a headspace technique. Overall analysis time is 2-3 h digestion time and 10-20 min GC separation time. Overall precision of the method averaged 1.7-3.9%, depending upon the chemistry of the phase, while the accuracy compared against elemental analysis was 2.2-4.0%. The method was used to analyze a variety of commercial phases, showing widespread use of monofunctional silane chemistries and surprising bonding consistency among different manufacturers.