The analysis of the mass spectrum of proteins is the most common application in MALDI-TOF mass spectrometry. However, this is limted to a few kDa owing to the decrease in detection sensitivity of standard ionizing detectors.
The following figure shows a comparison the mass spectrum of an equimolar protein mix
(1 pmol = 10-12 mol for every protein type) as measured by a standard ionizing detector and a MALDI-TOF mass spectrometer equipped with a CryoDetector:
The amount of substance is given by the SI unit "mol", where 1 mol of substance corresponds to the Avogadro's Constant N = 6.022 × 10²³ number of molecules.
Ferritin is a critical protein that stores iron and releases it when the body needs it. Understanding ferritin is vital for diagnosing iron disorders and managing whole-body health. It is the most accurate clinical indicator of the body's total iron reserves. The World Health Organization (WHO) standardizes ferritin testing to globally diagnose iron deficiency, track public health interventions, and prevent severe anemia.
Ferritin is, however, also a major acute-phase reactant, which means that blood levels can be high during active infections, autoimmune flares, or chronic diseases—even if the actual iron stores are normal. It is therefore of clinical interest to be able to measure also the iron content of ferritin. The mass of ferritin is very high: with no iron core the mass is equal to 504 kDa and fully loaded with iron the mass is equal to 853 kDa.
The following figure shows the result of CryoMass for a sample with empty ferritin and fully loaded ferritin. The plots show the intensity of the energy versus mass (time-of-flight) plots:
Because of the high detection efficiency of CryoDetectors for all masses, Metromol's CryoMass instrument will IMPROVE the clinical quality of the ferritin measurements in patients and healthy individuals.
The detection sensitivity od CryoMass being mass independent, allows principally also the detection of a single intact virus in a MALDI-TOF mass spectrometer. Under the condition that the virus survives the MALDI launch process and has a low charge.
The following figure shows that this can indeed be done with CryoMass:
In addition, because the CryoDetector response is sensitive only to the kinetic energy of the molecule (and not to the mass), both the low mass fragments of the capsid of the virus and the intact virus can be measured in the SAME experiment.
