Liquid-liquid extractions have traditionally been performed manually, including the time-consuming steps of partitioning by relative solubility and the use of hazardous organic solvents. Analytical chemists have been looking for a way to automate these processes to increase throughput and reduce exposure to solvents, without compromising data quality.
A GERSTEL team found that the same X-Y-Z coordinate autosamplerused for sample introduction in GC/MS or LC/MS/MS can also perform liquid-liquid sample preparation procedures, using a single instrument and accompanying software. The team’s results were presented last summer at the American Society for Mass Spectrometry (ASMS) Conference on Mass Spectrometry and Allied Topics, in St. Louis, Missouri.
The researchers tested the ability of the dual head version of the MPS autosampler, equipped with the GERSTEL mVORX, mVAP, centrifuge and Universal Filtration Options (depending on the requirements of the extraction protocols). They then tested recovery and precision data from several samples: drugs including ketamine, d4-ketamine, buprenorphine, d3-buprenorphine, norbuprenorphine, and d3-norprenorphine, spiked in either horse serum or bovine plasma, and Vitamin B samples contained in a vitamin-fortified breakfast shake, infant formula, and a fortified sports recovery drink. These samples were compared to the appropriate standards.
The researchers found that the recovery of ketamine following liquid-liquid extraction was 88.7 percent. Precision data derived from four individual horse serum replicates was found to have a low coefficient of variation of 0.467 percent. Vitamin B recovery data also was comparable to data derived from manual methods. These data indicated that manual liquid-liquid extraction methods could easily be incorporated into automated sample preparation sequences, using the MPS autosampler and MAESTRO analytical software.
You can learn more about GERSTEL’s research on automated sample prep for liquid-liquid extractions by reviewing the poster, “Automating Liquid-Liquid Extractions using an X-Y-Z Coordinate Autosampler for LC/MS/MS Analysis,” here. After reading the poster, we would be happy to talk with you about how you may incorporate this new method into your liquid-liquid sample preparation and analysis.