Effect of delay time and grid voltage changes on the average molecular mass of polydisperse polymers and polymeric blends determined by delayed extraction matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.
The dependence of the calculated average molecular mass of a polyethylene glycol with a large polydispersity on the instrumental parameters adopted in the acquisition of mass spectra using delayed extraction matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (DE MALDI-TOFMS) was investigated. It has been shown that a combined effect of delay times and potential gradients can act on the ion cloud in the source chamber affecting both mass resolution and average molecular mass value of the analyzed polymeric sample. Also examined was a blend of two different polymers (a PEG and a PMMA commercial sample having a similar average molecular mass), which presents an additional problem concerning the discrimination among the different polymer species as a function of the experimental conditions. In this work, the best instrumental conditions to obtain both good resolution and a correct average molecular mass for the examined polydisperse sample are reported.
Mineo
Placido
P
Istituto di Chimica e Tecnologia dei Polimeri, CNR Catania, Viale A. Doria 6, 95125 Catania, Italy. gmineo@dipchi.unict.it
Vitalini
Daniele
D
Scamporrino
Emilio
E
Bazzano
Sebastiano
S
Alicata
Rossana
R
D016477:Artifacts; D045424:Complex Mixtures / Q000032:analysis* / Q000737:chemistry / Q000528:radiation effects*; D004574:Electromagnetic Fields; D008970:Molecular Weight; D011108:Polymers / Q000032:analysis* / Q000737:chemistry / Q000528:radiation effects*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013997:Time Factors
D045424:Complex Mixtures; D011108:Polymers