AUTOMATED SAMPLE PREPARATION FOR CHOLESTEROL DETERMINATION IN FOODS

An automated sample preparation system has been developed for the dete rmination of cholesterol in a wide range of matrices. Isolation of cho lesterol is performed with a robotic arm coupled with a series of modu lar stations. Samples are introduced into the system which adds the ap propriate reagents, carries out the saponification, pH adjustment, sol id-phase extraction and drying steps. This system was evaluated using 15 different food matrices. The average recovery for NIST standards ex ceeded 97%. A solution of n-hexane-2-propanol was substituted for the traditional methanol-chloroform extraction. Manual pH adjustment was r eplaced with a buffer. Manual and automated methods were compared and no difference was observed at the 95% confidence level.