| We developed a simple, highly-automated method that requires minimal hands-on processing. Using liquid handling automation, patient serum samples were diluted with internal standard then extracted using supported liquid extraction in 96-well format. After evaporation and reconstitution, samples were injected onto the LC-MS/MS and subjected to 4.5 minutes of isocratic separation and negative mode electrospray ionization. Daily calibrations between 0.1 and 40.0 umol/L were reliably linear and reproducible. Intra- and inter-assay CVs were 1-9%. The limit of quantitation was 0.1 umol/L. Hands-on sample preparation time was reduced from seven to less than three hours as compared to a similar manual method. |
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