title: Measurement of serum salicylate levels by solid-phase extraction and desorption/ionization on silicon mass spectrometry.
abstract: The applicability of the matrix-free laser desorption/ionization on silicon mass spectrometry (DIOS-MS) to measuring serum drug levels was examined by analyzing serum salicylic acid. The optimized and simple solid-phase extraction (SPE) allowed good recovery, 88.9 +/- 5.8%, for 1.4 mM (200 mg/L) of salicylic acid in serum. The negative ion MS allowed measurements of deprotonated molecules without interference from other signals. Using a deuterium-labeled internal standard, good linearity was obtained in the 0.14 to 4.2 mM (20-600 mg/L) range, which was sufficient for monitoring the therapeutic anti-inflammatory dose. SPE followed by DIOS-MS is anticipated to be a method of measuring drug levels in blood and may allow high throughput analysis.
authors.affiliation: Japan Science and Technology Agency, Innovation Plaza Osaka, Izumi, Osaka 594-1144, Japan.
authors.forename: Shoji
authors.initials: S
authors.lastname: Okuno
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Wada
mesh_terms: D006801:Humans; D020156:Salicylic Acid / Q000097:blood*; D012680:Sensitivity and Specificity; D012825:Silicon / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D020156:Salicylic Acid; D012825:Silicon