title: Surface-assisted laser desorption/ionization mass spectrometry with a rotating ball interface.
abstract: A rotating ball interface for surface-assisted laser desorption/ionization (SALDI) mass spectrometry was designed and tested. One side of the ball was exposed to atmospheric pressure and the other to the vacuum in a time-of-flight mass spectrometer. Analytes (arginine, atenolol, reserpine, tofisopam, and chloropyramine) were applied using electrospray to a silicon substrate on the atmospheric side, the ball was rotated 180°, and the analyte was desorbed on the vacuum side using a pulsed, 200 Hz, 355 nm laser. In order to increase the desorption area, the laser focus was scanned over the substrate in a raster pattern repeated once every second. The design allows for rapid sample throughout with a sample turn-around time as short as 5 s. Newly produced porous silicon substrates initially yielded very low ion signals, and they required several hundred laser shots to attain maximum sensitivity. In contrast, amorphous silicon did not require such 'activation'. Quantitative analysis showed a sample-to-sample reproducibility of about 10%. The sensitivities with model analytes were in the 1000 to 10,000 ions/fmole range and detection limits in the low fg range.
authors.affiliation: Prokhorov General Physics Institute of Russian Academy of Sciences, Vavilov str. 38, 119991 Moscow, Russia.
authors.forename: Sergey
authors.initials: S
authors.lastname: Alimpiev
authors.forename: Alexander
authors.initials: A
authors.lastname: Grechnikov
authors.forename: Jan
authors.initials: J
authors.lastname: Sunner
authors.forename: Vladimir
authors.initials: V
authors.lastname: Karavanskii
authors.forename: Yaroslav
authors.initials: Y
authors.lastname: Simanovsky
authors.forename: Sergey
authors.initials: S
authors.lastname: Nikiforov
mesh_terms: D004364:Pharmaceutical Preparations / Q000032:analysis; D016062:Porosity; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012825:Silicon / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000295:instrumentation* / Q000379:methods
chemical_list: D004364:Pharmaceutical Preparations; D012825:Silicon