Darwin J. Asa

Bruker Daltonics Application Note

The author discusses the use of high-performance mass spectrometry for small molecule and protein applications.

For many years, and after several notable failures, many researchers were convinced that it was impossible to design a quadrupole time-of-flight (qTOF) mass spectrometer that was able to retain its ability to perform the high-resolution measurements necessary for definitive molecular formula determination of unknowns. Conventional wisdom indicated that there were many reasons (for example, temperature stability, ion diffusion, and ion loss on grids of reflectrons) that would make it impossible to improve resolution of these types of instruments. Figure 1 shows a schematic of an instrument designed for high-resolution measurements with fast chromatography (Maxis UHR-TOF mass spectrometer, Bruker Daltonics, Billerica, Massachusetts). The instrument includes an ion chiller, a series of ion refocusing operations, a single reflectron, and temperature control of the overall flight tube of the instrument.

A detection method based upon aerosol charging was examined for its applicability and performance with high performance liquid chromatography.

A new detection method based upon aerosol charging was examined for its applicability and performance with high performance liquid chromatography (HPLC). Our results demonstrate universal detection of nonvolatile analytes with response magnitude that is independent of analyte chemical properties, four orders of magnitude dynamic range, low nanogram, lower limits of detection, and < 2% relative standard deviation response variability. Broad applicability was demonstrated for a range of methods including those using gradient elution, reversed phase, hydrophilic interaction, and ion chromatography; normal and narrow bore column formats; and in combination with other detectors (for example, UV detectors, evaporative light-scattering detectors, and mass spectrometers).

A new detection method based upon aerosol charging was examined for its applicability and performance with high performance liquid chromatography (HPLC). Our results demonstrate universal detection of nonvolatile analytes with response magnitude that is independent of analyte chemical properties, four orders of magnitude dynamic range, low nanogram, lower limits of detection, and < 2% relative standard deviation response variability. Broad applicability was demonstrated for a range of methods including those using gradient elution, reversed phase, hydrophilic interaction, and ion chromatography; normal and narrow bore column formats; and in combination with other detectors (for example, UV detectors, evaporative light-scattering detectors, and mass spectrometers).