MALDI-TOF Mass Spectrometry

Matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS) is a simple, time-efficient but powerful tool to analyze proteins with a molecular weight from 1,000 to 1,000,000 Da. MALDI is a soft ionization technique that utilizes a matrix to absorb laser energy to create ions from analytes. Initially, the matrix co-crystalizes with the analyte on the surface of the target plate as a solid phase. When the laser light is directed on the target plate, the matrix absorbs the laser energy and transfer the energy to analytes. Both of them then desorb from the target plate and form a gaseous phase. The desorption is followed by a proton transfer between the matrix and analyte, resulting in the ionization of analyte molecules. Analyte molecules can be the proton donor or acceptor. In contrast with the hard ionization methods, electron ionization, chemical ionization, or fast atom bombardment, MALDI minimizes analyte fragmentation, which is easier and more convenient in the analysis of biomacromolecules such as proteins and DNA. Compared with another soft ionization method, electrospray ionization, it produces much more ions with a single charge.

TOF mass spectrometer is the most widely used detector for MALDI because of its large detection range of mass. It is based on the fact that ions with the same energy but different masses travel with different velocities. Advantages of TOF mass detectors include their simplicity, ruggedness, high scan speed, a virtually unlimited mass range, and resolution higher than Q or IT mass detectors. In TOF mass spectrometry, the charged ions are accelerated by a known electric field and then fly through a high vacuum tube. The flying time lengths of all ions are recorded for mass-to-charge (m/z) ratio determination and further analysis.

Fig 1. Mechanism of MALDI-TOF MS (Beale, D. J., et al., 2016)

MALDI-TOF MS Service

Creative BioMart Nanocage is a leading company in MALDI-TOF MS. We are devoted to providing high-quality MALDI-TOF MS service. Our MALDI-TOF devices use the reflection model TOF detector for a high resolution. We accept different types of samples and offer sample pretreatments to save our client's time. Consultations on sample preparation, sample shipment, and potential applications of MALDI-TOF MS in protein nanocage research are free of charge. Discounts are available in multiple sample analyses.

• Accepted samples: purified protein nanocages, non-purified protein nanocages, protein in solutions, freeze-dried protein samples, cells expressing protein nanocages.
• Sample pretreatments (optional): protein desalting, protein concentration, protein purification, enzyme digestion.
• Matrices: α-cyano-4-hydroxycinnamic acid (CHCA), 2,5-dihydroxybenzoic acid (DHB), sinapinic acid (SA).
• Applications: determination of protein nanocage subunit molecular weight, molecular weight distribution, identification of protein post-translational modification.

Fig 2. Workflow of MALDI-TOF MS Service

If you are interested in our MALDI-TOF MS service, please do not hesitate to contact us through online inquiry. Our service includes 4 steps as shown above. After we know your research aim and requests, we would guide you through the sample preparation and sample shipment. After the conduction of MALDI-TOF MS, a detailed report with methods, results, and discussion will be sent to you through email.

References

• Kafka, A. P., et al. (2011). "The application of MALDI TOF MS in biopharmaceutical research." International journal of pharmaceutics, 417(1-2), 70-82.
• Kaklamanos, G.,et al. (2016). "Mass spectrometry: principles and instrumentation." Elsevier, 661-668.
• Beale, D. J., et al. (2016). "Omics-based approaches and their use in the assessment of microbial-influenced corrosion of metals." Corrosion Reviews, 34(1-2), 1-15.