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Nynas has started to apply the MALDI-TOF measurement to determine molecular weight and to develop a greater understanding of mineral oils' chemical composition
Many Nynas customers appreciate the use of Matrix-Assisted Laser Desorption/Ionization – Time-of-Flight Mass Spectroscopy. "We're getting an increasing number of requests where knowing an estimated Mw is not enough – the absolute Mw or chain length distribution is required," says Dr. Markus Hoffmann, Chemical Industries Technical Manager at Nynas. "This is a method that can provide this information quickly and accurately, and even though this is not a standard test method yet, Nynas is a pioneer in the field."
The measurement of molecular weight (Mw) and molecular weight distribution is used to analyse and improve Nynas products. Until now the industry standard has been ASTM D2502, which is based on a calculation and provides information on the relative Mw. In contrast, MALDI-TOF is a direct measurement that gives an absolute value for the average molecular weight. It detects the molecular weight distribution as well. The applicable Mw range is 100 – 500,000 Da (compared to 250-700 Da for ASTM D2502).
"The MALDI spectra make it possible for us to get a better understanding of the molecular structures present in mineral oils; we can determine the exact chain length and degree of branching. Mineral oils contain a variety of structures, and until now the identification of these molecules has not really been possible since the other analytical techniques don't provide the information required," says Hoffmann. "Besides, it is important to know the Mw since some regulations specify certain Mw requirements and we need to make sure our products are compliant. The Mw is also an important factor for determining the risk of migration."