Objective

Due its ability to generate high quality, label-free data for positive compound identification and quantification, LC-MS has become an essential tool for metabolomic studies. However, as the field of metabolomics has experienced tremendous growth, so to has the need for analyzing larger numbers of samples. Unfortunately, LC-MS throughput has not significantly increased beyond about 1 sample per minute. Other techniques such as automated solid-phase extraction have shown promise but still only offer analysis rates of slightly better than 6 samples per minute. For over a decade, acoustic energy has been used to reliably transfer liquid in small, precise increments from one microtiter plate (the source) to another plate (the destination). Because there is no direct contact with the sample, the possibility of carryover during transfer is non-existent. It is also very fast. Our collaboration with AstraZeneca Pharmaceuticals and Waters Corporation has led to the study of a technology which combines acoustic delivery of liquid with high resolution mass spectrometry. This acoustic mist ionization - mass spectrometry (AMI-MS) combination has produced label-free MS data at a rate of up to 3 samples per second. In our presentation, we will describe the fundamentals behind acoustic mist ionization-mass spectrometry, construction of a prototype system and data we have collected with biochemical assay development and prosecution.