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Detroit, MI, United States

Woodall D.W.,Wayne State University | Wang B.,Wayne State University | Inutan E.D.,Wayne State University | Narayan S.B.,Detroit Medical Center Detroit Hospital | Trimpin S.,Wayne State University
Analytical Chemistry | Year: 2015

Matrix assisted ionization vacuum (MAIV) rapidly generates gas-phase analyte ions from subliming solid-phase matrix:analyte crystals for analysis by mass spectrometry (MS). Ionization from the solid-phase allows the use of a variety of surfaces for introducing matrix:analyte samples to the vacuum of a mass spectrometer, including common laboratory materials, such as disposable pipet tips, filter paper, tooth picks, and nylon mesh. MAIV is shown here to be capable of analyses as fast as 3 s per sample with achievable sensitivities in the low femtomole range. MAIV-MS coupled with ion mobility spectrometry (IMS)-MS and tandem mass spectrometry (MS/MS) is shown to be especially powerful for analysis and characterization of a wide range of molecules ranging from small molecules such as drugs and metabolites (∼300 Da) to intact proteins (25.6 kDa). Automated sample introduction is demonstrated on two different commercial mass spectrometers using a programmable XYZ stage. A MAIV high-throughput nontargeted MSE approach is also demonstrated utilizing IMS for rapid characterization of small molecules and peptides from standard solutions, as well as drug spiked human urine. © 2015 American Chemical Society.

Chakrabarty S.,INC MS | Chakrabarty S.,Wayne State University | Deleeuw J.L.,Wayne State University | Woodall D.W.,Wayne State University | And 4 more authors.
Analytical Chemistry | Year: 2015

Matrix-assisted ionization (MAI) mass spectrometry (MS) is a simple and sensitive method for analysis of low- and high-mass compounds, requiring only that the analyte in a suitable matrix be exposed to the inlet aperture of an atmospheric pressure ionization mass spectrometer. Here, we evaluate the reproducibility of MAI and its potential for quantification using six drug standards. Factors influencing reproducibility include the matrix compound used, temperature, and the method of sample introduction. The relative standard deviation (RSD) using MAI for a mixture of morphine, codeine, oxymorphone, oxycodone, clozapine, and buspirone and their deuterated internal standards using the matrix 3-nitrobenzonitrile is less than 10% with either a Waters SYNAPT G2 or a Thermo LTQ Velos mass spectrometer. The RSD values obtained using MAI are comparable to those using ESI or MALDI on these instruments. The day-to-day reproducibility of MAI determined for five consecutive days with internal standards was better than 20% using manual sample introduction. The reproducibility improved to better than 5% using a mechanically assisted sample introduction method. Hydrocodone, present in a sample of undiluted infant urine, was quantified with MAI using the standard addition method. © 2015 American Chemical Society.

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