Analysis methodDirect analysis of microstructures of alkyl phenol resin using atmospheric pressure chemical ionization-mass spectrometry

Alkyl phenol resin was directly analyzed using atmospheric pressure chemical ionization-mass spectrometry (APCI-MS). Analysis was performed in both positive and negative ion modes, and product ions were only observed in the negative ion mode. By interpreting the m/z values of [M - H]− ions, the degree of polymerization, the types of linkages and the types of terminals could be determined. The monomer, dimer, trimer, tetramer and pentamer species were observed. The methylene and dimethylene ether linkages were distinguished. For the terminal types, the methylol, o-methylene quinone, hydrogen, and aldehyde were distinguished. Influence of the types of solvents and eluents on the ionization efficiencies were investigated using acetone, chloroform and tetrahydrofuran. Recommendable solvent and eluent system for the analysis of resin using APCI-MS was acetone.