title: Interactions between naphthenic acids; dependence on molecular structure revealed through statistical analysis of ultra-high-resolution electrospray mass spectra.
abstract: Negative-ion electrospray mass spectra of samples of naphthenic acids contain peaks due to monomeric species [M-H](-) and dimeric species [2M-H](-). Working with a model system, intensities of the dimers were related to the intensities of monomers through linear inverse modelling. The statistical approaches investigated and the details of their applications to naphthenic acids are described here. The statistical analysis gives estimates of the relative probabilities of association of all pairs of monomers, where the monomers are defined by their accurate masses. The trends observed in these calculated probabilities of association exhibit breakpoints in the vicinity of monomers with 16 carbon atoms. These findings are discussed in terms of hydrophobic effects influencing the probability of association of naphthenic acids.
authors.affiliation: Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
authors.forename: Penelope A
authors.initials: PA
authors.lastname: Bilton
authors.affiliation: Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom.
authors.forename: Raffaello
authors.initials: R
authors.lastname: da Campo
authors.affiliation: Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand, Department of Physics and Department of Chemistry, The University of Auckland, Auckland, New Zealand. r.nikzad@auckland.ac.nz.
authors.forename: Ramin
authors.initials: R
authors.lastname: Nikzad
authors.affiliation: Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
authors.forename: Martin
authors.initials: M
authors.lastname: Hazelton
authors.affiliation: Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand, Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom, Department of Physics and Department of Chemistry, The University of Auckland, Auckland, New Zealand.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Derrick