Do samples need to be desiccated prior to MS analysis?
No, LAESI is performed at atmospheric pressure and therefore the native sample can be analyzed directly.

Can I observe the low mass range during a LAESI-MS experiment?
Both the low mass range and high mass range can be observed simultaneously. In MALDI the high mass range is generally only observed because of contamination from the matrix ions/clusters.

What is the mass range LAESI is capable of analyzing?
Because LAESI-MS spectra resemble ESI-MS spectra, the mass range is identical and the spectra exhibit multiply charged ions like observed in ESI-MS. However, both the low mass range and high mass range can be observed simultaneously, where in MALDI the high mass range is generally only observed because of contamination from the matrix ions/clusters.

How are LAESI imaging experiments different from MALDI imaging experiments?
LAESI imaging experiments are performed at atmospheric pressure and do not need an external MALDI matrix to perform imaging experiments. Therefore, sample preparation is significantly decreased because the matrix application and sample drying steps can be omitted. Consequently, LAESI-MS imaging experiments do not suffer from issues related to heterogeneous matrix application.

What is the footprint of the DP-1000?
The DP-1000 is 18” deep x 24” wide x 48” tall.

Does the system contain the electrospray? How does that work?
Yes. The electrospray module uses standard stainless steel emitters for extended lifetime and durability, and our emitter module allows the option of using a sheath gas for increased desolvation and sensitivity. The syringe pump provides flow rates from 100 nL/min to 5 mL/min for optimum flexibility. The integrated high voltage power supply can output 0 to ± 5000 V, allowing both positive and negative ion modes of analysis.

What types of optics are used?
The DP-1000 also includes two integrated cameras: a wide angle camera used for capturing images of the entire sample area and a targeting camera used for a 5 mm near-field magnified view of the ablation spot. Using the wide-angle camera, a user can quickly obtain an image of the sample being analyzed and use this image to select the analysis location(s) or regions of interest. Once an analysis has begun, the targeting camera can be used to view the actual sample analysis in real-time. The targeting camera is focus-matched with the MIR laser to provide convenient focal alignment and robust ablation performance.

How do you focus the laser?
The laser is focused using traditional optics coated for MIR transparency and the final focusing lens is controlled with a stage to allow for different sample sizes. To determine the optimum focal point simply, adjust the focusing lens position until the optical image from the in-line camera is in focus, because the laser focal point has been matched to the camera focal point.

What type of software comes with the system?
The DP-1000 unit is controlled by our fully functional LAESI Desktop Software™ (LDS) platform. The LDS software enables everything from quick discovery experiments in the Interactive Mode to more sophisticated LAESI-MS method development and sample analysis in the Project Mode. In addition, our ProteaPlot™ post-processing software is used to analyze and interpret the LAESI-MS data after collection. This unique software can create publication-quality 2D and 3D images (ion maps) with up to four distinct m/z on a single plot while maintaining all of the functionality of traditional MS viewing software.

What is the temperature range of the sample nest?
The DP-1000 sample nest has a 4-quadrant Peltier thermoelectric cooler that is controllable from -10 to +60 °C. In the cooling mode, frozen tissue sections will maintain their integrity at -10°C, and well plate samples can be cooled to minimize evaporation at +4 °C. In the heating mode, kinetic studies can be performed at elevated temperatures up to +60 °C.

How large of a sample can I analyze?
The sample nest of the DP-1000 is capable of accommodating a 96, 384, or 1536 well plate with standard 127.76 x 85.48 mm dimensions. Aluminum tissue plates allow analyses of standard 1" x 3" or 3" x 4" slide mounted tissue sections.

What is included with the system?
This fully integrated source contains all components necessary to perform a LAESI-MS analysis, including a mid-infrared (MIR) laser, electrospray emitter, high voltage power supply, syringe pump, dual cameras for sample imaging, an integrated ultra-precision x,y,z stage, and a temperature-controlled sample nest. In addition, a complete software suite has been developed to support LAESI-MS data collection and analysis.

Which instruments does the LAESI adapt with?
Currently, the LAESI can be fitted with Thermo Scientific and Waters mass spectrometers.

How long does it take to analyze a sample?
Sample analysis time is dependent upon the sample and the objective of the experiment, typically a single location is analyzed in about a second. For simple identification of a liquid sample the analysis time can be a second or less. Similarly, a 96 well plate can be completely analyzed in about 8 minutes, spending one second at each well. For imaging experiments, the analysis time depends on sample size and the “mesh” of the analysis, or how close the consecutive analysis locations are to each other. For a 2D analysis, we have analyzed a 7 mm x 15 mm area with a 300 μm center-to-center mesh (1,086 total pixels) in about 75 minutes.

What sample preparation is required?
Sample preparation is generally minimal for a LAESI experiment but is dependent upon the sample and the objective of the experiment.

What are the specifications of the laser?
The LAESI DP-100 uses a 2.940 μm mid-IR (MIR) wavelength laser with 1.0 mJ maximum output energy. The laser is capable of a 0.1 to 10 Hz repetition rate, has a 5 ns pulse width, and a 200 μm spot size. The MIR laser outputs a wavelength that matches the absorption of the stretching mode of the O-H bond in water. Using this wavelength, water functions as the “matrix” for the sample, which facilitates the analysis of any water containing sample.

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