There are five anesthetics that we can currently test for in our laboratory: Bupivacaine, Lidocaine, Mepivacaine, Prilocaine
and Ropivacaine. These local anesthetics act to block the conduction of impulses in the peripheral nervous system, and therefore,
are widely used for local and regional treatments. The structural differences within these five anesthetics allows for easy
detection by gas chromatograph.
The method we employ is modeled after the one developed by Björk1. Using Waters Millennium32® chromatography software, a calibration curve is derived by using the concentration and peak areas obtained from each standard
injection. The concentration values (ng/ml) of each patient sample are then determined mathematically by the software. This
one-extraction assay to determine the free-fraction of drug with the use of a capillary column and nitrogen phosphorous detector
has shown to be reproducible. If several anesthetics are administered simultaneously, this method can detect each drug by
their retention times. We have recently performed Ropivacaine levels for the Anesthesia Department at Yale University and
Ropivacaine levels for Duke University’s Anesthesia Department. The limit of detection in our lab for Ropivacaine is 25ng/ml.
