Significant Parameters in the Optimization of MALDI-TOF-MS for Synthetic Polymers

• Published in: Journal of the American Society for Mass Spectrometry 2006-02, Vol.17 (2), p.246-252
• Main Authors: Wetzel, Stephanie J., Guttman, Charles M., Flynn, Kathleen M., Filliben, James J.
• Format: Article
• Language: English
• Subjects: Applied sciences; CALIBRATION; Chemistry; CONCENTRATION RATIO; Delay; DESORPTION; Electric potential; Exact sciences and technology; EXTRACTION; INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; IONIZATION; Ions; LASER RADIATION; Lasers; MASS DISTRIBUTION; MASS SPECTRA; Mass spectrometry; MASS SPECTROSCOPY; Mathematical analysis; NOISE; Optimization; Organic chemistry; Organic polymers; Physicochemistry of polymers; POLYSTYRENE; Polystyrene resins; Properties and characterization; Reactivity and mechanisms; Retinoic acid; Structure, morphology and analysis; TIME DELAY; TIME-OF-FLIGHT METHOD
• ISSN: 1044-0305; 1879-1123
• DOI: 10.1016/j.jasms.2005.11.007

One of the most significant issues in any analytical practice is optimization. Optimization and calibration are key factors in quantitation. In matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), instrument optimization is a limitation restricting quantitation. An understanding of the parameters that are most influential and the effects of these parameters on the mass spectrum is required for optimization. This understanding is especially important when characterizing synthetic polymers by MALDI-TOF-MS, due to the breadth of the polymer molecular mass distribution (MMD). Two considerations are important in quantitation, additivity of signal and signal-to-noise (S/N). In this study, the effects of several instrument parameters were studied using an orthogonal experimental design to understand effects on the signal-to-noise (S/N) of a polystyrene distribution. The instrument parameters examined included detector voltage, laser energy, delay time, extraction voltage, and lens voltage. Other parameters considered were polymer concentration and matrix. The results showed detector voltage and delay time were the most influential of the instrument parameters for polystyrene using all trans-retinoic acid (RA) as the matrix. These parameters, as well as laser energy, were most influential for the polystyrene with dithranol as the matrix.