Molecular weight analysis by Mass Spectrometry: ESI by MS-QTOF, MS-ION TRAP, Orbitrap-MS, FT-ICR-MS , TSQ-MS or MALDI-TOF

Service description

ESI and APCI techniques are very soft ionization techniques that hardly produce fragmentation in the molecule of interest. The (M+H)+ and (M-H)- ions are observed depending on whether the work is in positive or negative mode. In addition, the appearance of ions (M+Na)+, (M+K)+, (M+NH4)+ in positive mode and (M+Cl)¿, (M+Br)¿, (M+CH3COO) is frequent. ¿, (M+HCOO)¿, (M+CF3COO)¿ in negative mode, depending on the eluents that we use. Electrospray (ESI): labile molecules or of high polarity, which in solution (with or without additives) give rise to ions. Molecules with charge in their internal structure are very suitable to be analyzed by this technique. In the event that the molecule does not have a charge in its structure, the addition of a volatile acid or base is normally used in order to generate them. It is not possible to analyze insoluble samples. Atmospheric pressure chemical ionization (APCI): compounds of lower polarity and a certain thermal stability. The analysis request will specify the technique to be used (ESI, APCI) and its polarity mode (positive or negative), and various modalities may be indicated if deemed necessary. If the choice is left to the technician, it will be mandatory to clearly indicate the molecular structure assumed for the sample. If not specified otherwise, spectra will be recorded at different fragmentation voltages, chosen by the technician. If the bibliography recommends the use of a technique, modality or conditions for compounds similar to the sample, it is very convenient to indicate these data in the Analysis Request. Mass range: Molecular weight between 10 and 2000 u for monocharged ions and higher masses for multiply charged ones. With this technique, multiply charged ions (z > 1) can be generated, which allows the study of molecules with a molecular mass above the limit of the analyzer, as long as the multicharge process occurs. Solvents: Volatile solvents are the most suitable Preferred: methanol, acetonitrile, and water Avoid solvents with high boiling points, such as DMSO, which are problematic in mass spectrometry. Please consult before using other solvents and additives Available equipment: -UHPLC-MS Liquid chromatograph coupled to the mass spectrometer with a quadrupole mass analyzer. FEATURES: Mass range: 10-2000 u. Ionization sources: ESI APCI