Direct Analysis of Single Rat Peritoneal Mast Cells with Laser Vaporization/Ionization Mass Spectrometry

Abstract

A linear time-of-flight mass spectrometer was used as a detector for flow cytometry. These two techniques were coupled by a laser vaporization/ionization interface. The estimated mass detection limit of the combined system was 20 amol of serotonin standard with one laser pulse. An aqueous buffer at physiological pH was used to ensure compatibility with cells. Rat peritoneal mast cells (RPMCs) were dispensed into the mass spectrometer in a single file confined within a 20-micron-i.d. capillary. By using the mass spectrometer as a detector, no precolumn staining or derivatization is required. Determination of serotonin and histamine in individual cells was demonstrated. With this method, hundreds of cells can be analyzed within a few minutes. The average amounts of histamine and serotonin per RPMC were found to be 0.75 +/- 0.33 and 0.11 +/- 0.06 fmol, respectively. No correlation was found between the amounts of the two amines in each cell.

Atypical mobilities of single native DNA molecules in microchip electrophoresis revealed by differential interference contrast microscopy

“…Once again the intensity of the 1.5 kb fragment was too weak to be reliably monitored to determine mobilites. Unlike traditional hydrophilic polymers used in CE for DNA analysis such as polyacrylamide [33], cellulose derivatives [34], PEG [35], poly(ethylene oxide) [36], or PVP [37], the nonionic polymeric surfactant C 16 E 6 forms micelles that consist of a hydrophobic core of alkyl chains surrounded by hydrophilic polyoxyethylene chains [38]. C 16 E 6 also behaves as a dynamic polymer and has been successfully implemented as a separation medium for DNA analysis [39,40].…”

Microfluidics for multiplexed MS analysis

“…The plume of the desorbed ions is mostly analyzed by a TOF mass spectrometer. Although there are reports on using liquid matrices for on-line coupling with the separations [62], MALDI is generally practiced in an off-line arrangement on fractions collected from the separation column on a MALDI target. Commercial systems for this technique are widely used especially in proteomics (www.lcpackings.com).…”

Capillary electrophoresis mass spectrometry and its application to the analysis of biological mixtures

“…There are two approaches to the mass spectrometric analysis of the chemical contents of a single intact cell: (1) direct analysis of the entire contents of the cell using laser desorption techniques (microspot matrix-assisted laser desorption/ionization-MALDI [75] or direct laser vaporization/ionization [76]), and (2) on-line separation, ionization, and detection of cell contents using CE/ESI-MS [77,78]. The first approach has a faster analysis time, since no on-line separation is performed, but additional sample clean-ups and the transfer of cells to a new buffer system [76], or off-line sampling and lysing [75] are necessary for successful MS analysis.…”

“…The first approach has a faster analysis time, since no on-line separation is performed, but additional sample clean-ups and the transfer of cells to a new buffer system [76], or off-line sampling and lysing [75] are necessary for successful MS analysis. For on-line separation, CZE, with its rapid and highly efficient separation of compounds in extremely small volume samples (<1 nl), has rapidly become the separation method of choice for single-cell analysis [77,78,79,80,81,82,83,84,85,86,87,88].…”