Many advances have been made in the past decade for the analysis of biomolecules such as DNA, proteins and carbohydrates. A sample plate may contain hundreds of different samples in a single run. Each sample crystal is then analyzed by moving the sample plate underneath a fixed, pulsed laser beam. A pulse of laser energy liberates and ionizes a small portion of the DNA sample. The matrix protects the DNA molecules from fragmentation and assists in the ionization process.
Small ions have a greater velocity than large ones and reach the detector first.
To improve signal processing, the results from multiple laser pulses are averaged, which lengthens the measurement time to a few seconds for each sample. High-speed electronics and computers are required to keep up with the data collection process, which occurs on a nanosecond time scale. DNA molecules are liberated from a solid-phase matrix environment with a laser pulse. For each run, hundreds of samples are prepared in parallel using a robotic workstation and spotted onto a sample plate that is introduced to the vacuum environment of the mass spectrometer. The sample plate moves under the fixed laser beam to allow sequential sample analysis.