SAMPLE PREPARATION WITH AN AUTOMATED ROBOTIC WORKSTATION FOR ORGANIC-ACID ANALYSIS BY GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

We attempted to automate sample preparation for analysis of organic ac ids by gas chromatography-mass spectrometry using a computer-controlle d, automated robotic workstation that is integrated and connected to t he gas chromatography-mass spectrometry (HP-5890/5971) system. Of the two methods developed, one employed solvent extraction, while the othe r utilized a silica. solid-phase extraction cartridge. Both automated methods were compared to a manual, solvent extraction procedure used r outinely in our laboratory. Normal, spiked urine, and urine from patie nts with a variety of metabolic abnormalities were analyzed. The robot ic workstation did not meet all our requirements for a rapid, reliable , laboratory device. Recoveries with the automated procedures were les s than with the manual method, and some organic acids important in the diagnosis of inborn errors of metabolism were not detected. Additiona lly, the robotic device had mechanical and design problems that made i t slower and less reliable than the manual procedure.