Development of a combined standard additions/internal standards method to quantify residual PEG in ethoxylated surfactants by MALDI TOFMS.

Measuring the residual polyethylene glycol (PEG) in polyethylene oxide (PEO)-based surfactants is important to fully understanding the performance of these materials. Traditional methods of quantitating PEG in PEO-based surfactants can be time-consuming and struggle with low amounts or overlapping molecular mass distributions. This paper describes a matrix-assisted laser desorption/ionization (MALDI) mass spectrometry method developed to quantitate residual PEG in a series of ethoxylated surfactants.

Determining the time needed for the vortex method for preparing solvent-free MALDI samples of low molecular mass polymers.

Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry is an important technique to characterize many different materials, including synthetic polymers. MALDI mass spectral data is used to determine the polymer average molecular weights, repeat units, and end groups. The development of the vortex method of solvent-free sample preparation showed that remarkably short mixing times could prepare samples that yielded high quality MALDI mass spectra.

Imaging the morphology of solvent-free prepared MALDI samples.

Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry is an important technique to characterize many different materials, including synthetic polymers. MALDI mass spectral data can be used to determine the polymer average molecular weights, repeat units, and end groups. The development of solvent-free sample preparation methods has enabled MALDI to analyze insoluble materials and, interestingly, can provide higher-quality mass spectral data.

A study of gas-phase cationization in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

A specially constructed split sample probe was used to unequivocally demonstrate that gas-phase cationization occurs within the desorption plume during a matrix-assisted laser desorption/ionization experiment. Two separate samples were prepared for analysis: on side A, a mixture of poly(ethylene glycol) (PEG) 1500 analyte and 2,5-dihydroxybenzoic acid (DHB) matrix, and on side B a mixture of DHB matrix and lithium hydroxide (LiOH), the cationization reagent. Analysis of the data showed that when the ionization laser was focused on the split (so that both sides were illuminated), Li(+)-cationized PEG peaks were observed.

The fragmentation of ethoxylated surfactants by AP-MALDI-QIT.

Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry has become an important technique to characterize the chemical structure of industrial polymer materials. MALDI methods have been developed to address a broad variety of different polymer materials containing different chemistries. One of the key aspects of the typical MALDI experiment is the generation of intact ions.

Extending the solvent-free MALDI sample preparation method.

Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry is an important technique to characterize many different materials, including synthetic polymers. MALDI mass spectral data can be used to determine the polymer average molecular weights, repeat units, and end groups. One of the key issues in traditional MALDI sample preparation is making good solutions of the analyte and the matrix.

Investigations of electrospray sample deposition for polymer MALDI mass spectrometry.

In the interest of a more thorough understanding of the relationship between sample deposition technique and the quality of data obtained using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry, details of the electrospray (ES) process of sample deposition are investigated using a number of techniques. Sample morphology was observed with scanning electron microscopy (SEM) and atomic force microscopy (AFM), while matrix-enhanced secondary ion mass spectrometry (MESIMS) monitored surface coverage. Electrospray deposition reduces the analyte segregation that can occur during traditional dried droplet deposition for MALDI.

Living alternating copolymerization of N-alkylaziridines and carbon monoxide as a route for synthesis of poly-beta-peptoids.

The title copolymerization catalyzed by BnCOCo(CO)4 affords poly-beta-alanoids in excellent yields and selectivity. The poly-beta-alanoids have narrow molecular weight distributions, controllable molecular weights, and definite end groups.